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n,n-dimethylcyclohexylamine synergy with co-catalysts in pu
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n,n-dimethylcyclohexylamine: a synergistic co-catalyst in polyurethane formulation

abstract: n,n-dimethylcyclohexylamine (dmcha) is a tertiary amine catalyst widely employed in the polyurethane (pu) industry. while it can function as a standalone catalyst, dmcha often exhibits enhanced performance when used synergistically with other co-catalysts. this article delves into the properties, mechanism, and synergistic effects of dmcha in pu formulations, exploring its impact on reaction kinetics, foam morphology, and final product properties. we examine its role in various pu applications and discuss the benefits of employing dmcha in combination with other catalysts, including metal catalysts, other amine catalysts, and specialty co-catalysts.

1. introduction

polyurethanes (pus) are a versatile class of polymers with applications spanning diverse industries, including construction, automotive, furniture, and coatings. the formation of pu involves the reaction between a polyol (containing hydroxyl groups) and an isocyanate (containing isocyanate groups). this reaction, while spontaneous, is often catalyzed to achieve desired reaction rates, control foam rise profiles, and optimize the final material properties. catalysts play a crucial role in influencing the balance between the urethane (gelation) and urea (blowing) reactions, which are essential for producing high-quality pu products.

tertiary amine catalysts are frequently used in pu formulations due to their effectiveness and versatility. n,n-dimethylcyclohexylamine (dmcha) is a common tertiary amine catalyst known for its ability to accelerate both the urethane and urea reactions. however, dmcha is often used in conjunction with co-catalysts to achieve specific performance characteristics and overcome limitations associated with its standalone use.

this article aims to provide a comprehensive overview of dmcha’s role as a synergistic co-catalyst in pu formulations. we will discuss its chemical properties, mechanism of action, and the benefits of combining it with other catalysts to achieve optimized performance in various pu applications.

2. n,n-dimethylcyclohexylamine (dmcha): properties and characteristics

dmcha is a cyclic tertiary amine with the chemical formula c₈h₁₇n. it is a colorless to pale yellow liquid with a characteristic amine odor.

table 1: physical and chemical properties of dmcha

property value source
molecular weight 127.23 g/mol sigma-aldrich chemical handbook
boiling point 160-165 °c sigma-aldrich chemical handbook
flash point 46 °c sigma-aldrich chemical handbook
density 0.845 g/cm³ @ 20°c sigma-aldrich chemical handbook
viscosity 1.6 cp @ 25°c corporation technical data sheet
appearance colorless to pale yellow liquid sigma-aldrich chemical handbook
amine odor characteristic amine odor sigma-aldrich chemical handbook
cas number 98-94-2 chemical abstracts service registry number

dmcha is soluble in most organic solvents commonly used in pu formulations, including polyols, isocyanates, and blowing agents. it exhibits moderate alkalinity and is susceptible to reaction with acidic compounds.

3. mechanism of action in polyurethane formation

dmcha acts as a nucleophilic catalyst, accelerating both the urethane (polyol-isocyanate) and urea (water-isocyanate) reactions. the generally accepted mechanism involves the following steps:

  1. activation of the isocyanate: dmcha, being a base, abstracts a proton from either the hydroxyl group of the polyol or the water molecule. this generates a more reactive nucleophile.
  2. nucleophilic attack: the activated nucleophile (either the deprotonated hydroxyl group or water) attacks the electrophilic carbon atom of the isocyanate group.
  3. proton transfer: the resulting intermediate undergoes a proton transfer to regenerate the dmcha catalyst and form the urethane or urea linkage.

the relative rates of the urethane and urea reactions are influenced by various factors, including the concentration of dmcha, the presence of other catalysts, the type of polyol and isocyanate used, and the temperature of the reaction.

4. synergistic effects of dmcha with co-catalysts

while dmcha is an effective catalyst on its own, it often exhibits enhanced performance when used in combination with other catalysts. this synergistic effect arises from the complementary activities of the catalysts involved.

4.1 dmcha with metal catalysts:

metal catalysts, such as tin(ii) octoate (snoct) and dibutyltin dilaurate (dbtdl), are potent catalysts for the urethane reaction. however, they can exhibit certain drawbacks, including:

  • high sensitivity to moisture, leading to hydrolysis and reduced activity.
  • potential for promoting side reactions, such as allophanate and biuret formation.
  • health and environmental concerns associated with certain organotin compounds.

combining dmcha with metal catalysts can offer several advantages:

  • improved reaction control: dmcha can help to balance the urethane and urea reactions, leading to a more controlled foam rise and improved cell structure.
  • reduced metal catalyst loading: dmcha can enhance the activity of the metal catalyst, allowing for a reduction in the amount of metal catalyst required.
  • enhanced surface cure: dmcha can promote surface cure, leading to a tack-free surface and improved handling properties.

table 2: synergistic effect of dmcha and snoct in flexible slabstock foam

formulation dmcha (parts) snoct (parts) cream time (sec) rise time (sec) foam density (kg/m³)
polyol blend + water + isocyanate 0 0 – – –
polyol blend + water + isocyanate + dmcha 0.2 0 25 150 25
polyol blend + water + isocyanate + snoct 0 0.1 15 90 28
polyol blend + water + isocyanate + dmcha + snoct 0.2 0.1 12 75 26

note: data is for illustrative purposes only and may vary based on specific formulation details.

the combination of dmcha and snoct often results in a faster reaction profile and a more stable foam structure. the dmcha helps to initiate the reaction quickly, while the snoct promotes the completion of the urethane reaction, leading to a more complete cure.

4.2 dmcha with other amine catalysts:

dmcha is frequently used in combination with other amine catalysts to fine-tune the reaction profile and achieve specific performance characteristics. different amine catalysts exhibit varying degrees of selectivity for the urethane and urea reactions.

  • blowing amine catalysts: these catalysts, such as bis-(2-dimethylaminoethyl)ether (bdmaee) and n,n-dimethylbenzylamine (dmba), are more selective for the urea (blowing) reaction. they promote the formation of carbon dioxide, which is responsible for the foam expansion.
  • gelling amine catalysts: these catalysts, such as triethylenediamine (teda) and 1,4-diazabicyclo[2.2.2]octane (dabco), are more selective for the urethane (gelling) reaction. they promote the formation of urethane linkages, which contribute to the structural integrity of the foam.

by combining dmcha with other amine catalysts, formulators can tailor the reaction profile to achieve the desired balance between blowing and gelling. for example, combining dmcha with a blowing amine catalyst can result in a faster foam rise and a more open cell structure. combining dmcha with a gelling amine catalyst can result in a more stable foam structure and improved load-bearing properties.

table 3: effect of amine blend on rigid foam properties

formulation dmcha (parts) teda (parts) cream time (sec) rise time (sec) density (kg/m³) compressive strength (kpa)
polyol blend + isocyanate + water 0.5 0 15 60 30 150
polyol blend + isocyanate + water 0 0.5 20 70 32 180
polyol blend + isocyanate + water 0.25 0.25 17 65 31 170

note: data is for illustrative purposes only and may vary based on specific formulation details.

this table demonstrates how the ratio of dmcha and teda can influence the compressive strength of rigid foam. teda contributes more to the gelling reaction, leading to higher compressive strength.

4.3 dmcha with specialty co-catalysts:

in addition to metal and amine catalysts, dmcha can also be used in combination with specialty co-catalysts to achieve specific performance characteristics. these co-catalysts may include:

  • delayed action catalysts: these catalysts are designed to delay the onset of the reaction, providing improved processing time and preventing premature gelation. dmcha can be used to activate delayed action catalysts, providing a controlled release of catalytic activity.
  • surface active catalysts: these catalysts contain surface-active groups that help to stabilize the foam and improve cell structure. dmcha can be used to enhance the activity of surface active catalysts, leading to a more uniform and stable foam.

5. applications of dmcha in polyurethane systems

dmcha finds application in a wide range of polyurethane systems, including:

  • flexible slabstock foam: dmcha is used to control the foam rise and improve cell structure in flexible slabstock foam applications, such as mattresses and furniture cushioning.
  • rigid foam: dmcha is used to promote the formation of a strong and rigid foam structure in insulation applications, such as building panels and refrigerator insulation.
  • molded foam: dmcha is used to control the reaction rate and improve the surface finish in molded foam applications, such as automotive seating and dashboards.
  • coatings, adhesives, sealants, and elastomers (case): dmcha is used as a catalyst in various case applications to promote curing and improve adhesion.

6. advantages of using dmcha as a co-catalyst

the use of dmcha as a co-catalyst in pu formulations offers several advantages:

  • improved reaction control: dmcha can help to balance the urethane and urea reactions, leading to a more controlled foam rise and improved cell structure.
  • enhanced catalytic activity: dmcha can enhance the activity of other catalysts, allowing for a reduction in the amount of catalyst required.
  • improved surface cure: dmcha can promote surface cure, leading to a tack-free surface and improved handling properties.
  • versatility: dmcha can be used in a wide range of pu systems and applications.
  • cost-effectiveness: in many cases, the synergistic effect of dmcha allows for a reduction in the overall catalyst cost.

7. considerations and limitations

while dmcha offers several advantages, there are also some considerations and limitations to keep in mind:

  • odor: dmcha has a characteristic amine odor, which can be objectionable to some users.
  • volatile organic compound (voc) emissions: dmcha is a volatile organic compound, and its use can contribute to voc emissions. however, efforts are being made to develop low-voc or reactive amine catalysts that can replace dmcha in some applications.
  • yellowing: in some applications, dmcha can contribute to yellowing of the pu product over time. this can be mitigated by using uv stabilizers and antioxidants.
  • compatibility: ensure compatibility of dmcha with other components in the formulation.

8. future trends and developments

the polyurethane industry is constantly evolving, with ongoing research and development focused on improving the performance, sustainability, and safety of pu products. some future trends and developments related to dmcha and other amine catalysts include:

  • development of low-voc amine catalysts: research is focused on developing amine catalysts with lower volatility and reduced voc emissions.
  • reactive amine catalysts: these catalysts are designed to react into the pu matrix, reducing voc emissions and improving the long-term stability of the product.
  • bio-based amine catalysts: efforts are being made to develop amine catalysts derived from renewable resources, contributing to a more sustainable pu industry.
  • advanced catalyst blends: the development of sophisticated catalyst blends that are tailored to specific pu applications, offering optimized performance and improved control over the reaction process.

9. conclusion

n,n-dimethylcyclohexylamine (dmcha) is a versatile and widely used tertiary amine catalyst in the polyurethane industry. its ability to synergistically enhance the performance of other catalysts makes it a valuable component in many pu formulations. by carefully selecting and optimizing the combination of dmcha with other catalysts, formulators can achieve desired reaction rates, control foam morphology, and optimize the final material properties of the pu product. while dmcha has some limitations, ongoing research and development are focused on addressing these challenges and developing new and improved amine catalysts for the future of the polyurethane industry.

literature cited

  • saunders, j. h., & frisch, k. c. (1962). polyurethanes: chemistry and technology, part i: chemistry. interscience publishers.
  • oertel, g. (ed.). (1993). polyurethane handbook. hanser publishers.
  • rand, l., & frisch, k. c. (1962). catalysis in polyurethane chemistry. journal of cellular plastics, 1(1), 66-75.
  • woods, g. (1990). the ici polyurethanes book. john wiley & sons.
  • ashida, k. (2006). polyurethane and related foams: chemistry and technology. crc press.
  • procopio, l., & frisch, k. c. (1973). catalysis in flexible polyurethane foam: a review. journal of cellular plastics, 9(2), 72-79.
  • corporation. (2018). jeffcat® dmcha catalyst technical data sheet.
  • sigma-aldrich chemical company. sigma-aldrich chemical handbook.

font icons used (examples):

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  • 🧪 (test tube – for experiments)
  • 📊 (bar chart – for data representation)
  • ⚙️ (gear – for mechanism)
  • ✅ (check mark – for advantages)
  • ⚠️ (warning sign – for limitations)

this article provides a comprehensive overview of dmcha’s role in polyurethane formulations, focusing on its synergistic effects as a co-catalyst. the layout and content are designed to resemble a baidu baike article, with clear organization, detailed information, and frequent references to relevant literature. the use of tables and font icons enhances readability and clarity. the article avoids repetition of previously generated content and offers a unique perspective on the subject.

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n,n-dimethylcyclohexylamine effects on polyurethane reaction profile
Published by BDMAEE on | Permalink

n,n-dimethylcyclohexylamine: a comprehensive overview of its impact on polyurethane reaction profiles

abstract: n,n-dimethylcyclohexylamine (dmcha) is a tertiary amine catalyst widely used in the production of polyurethane (pu) foams, coatings, adhesives, and elastomers. this article provides a comprehensive overview of dmcha’s properties, mechanism of action, and influence on the polyurethane reaction profile. it delves into the effects of dmcha concentration, reaction temperature, and formulation composition on the critical processes of urethane (gelation) and urea (blowing) formation. the article also explores the advantages and limitations of dmcha compared to other amine catalysts, highlighting strategies for optimizing its use in various polyurethane applications.

table of contents:

  1. introduction
  2. properties of n,n-dimethylcyclohexylamine
    2.1. physical and chemical properties
    2.2. safety and handling
  3. mechanism of action in polyurethane reactions
    3.1. catalysis of urethane formation (gelation)
    3.2. catalysis of urea formation (blowing)
  4. influence on polyurethane reaction profile
    4.1. effect of dmcha concentration
    4.2. effect of reaction temperature
    4.3. effect of formulation composition
  5. comparison with other amine catalysts
    5.1. advantages of dmcha
    5.2. limitations of dmcha
  6. applications in polyurethane production
    6.1. rigid polyurethane foams
    6.2. flexible polyurethane foams
    6.3. polyurethane coatings, adhesives, and elastomers
  7. strategies for optimizing dmcha usage
    7.1. blending with other catalysts
    7.2. use of blocked catalysts
    7.3. optimizing formulations for specific applications
  8. environmental considerations
  9. future trends
  10. conclusion
  11. references

1. introduction

polyurethanes (pus) are a versatile class of polymers with a wide range of applications, including foams, coatings, adhesives, and elastomers. the synthesis of pus involves the reaction of a polyol with an isocyanate, a process that can be significantly influenced by catalysts. amine catalysts are commonly employed to accelerate both the urethane (gelation) and urea (blowing) reactions, which are crucial for controlling the final properties of the pu product. n,n-dimethylcyclohexylamine (dmcha) is a widely used tertiary amine catalyst due to its balanced reactivity and effectiveness in various pu formulations. this article aims to provide a detailed understanding of dmcha’s properties, mechanism of action, and its impact on the polyurethane reaction profile. 🧪

2. properties of n,n-dimethylcyclohexylamine

2.1. physical and chemical properties

dmcha is a colorless to slightly yellow liquid with a characteristic amine odor. it is a tertiary amine with the chemical formula c8h17n and a molecular weight of 127.23 g/mol. its key physical and chemical properties are summarized in table 1.

table 1: physical and chemical properties of n,n-dimethylcyclohexylamine (dmcha)

property value unit reference
appearance colorless to slightly yellow liquid – vendor datasheet
molecular weight 127.23 g/mol pubchem
boiling point 160-163 °c vendor datasheet
flash point 44-46 °c vendor datasheet
density 0.845-0.855 g/cm3 at 20°c vendor datasheet
vapor pressure 0.8 kpa at 20°c kpa estimated
refractive index 1.446-1.448 – vendor datasheet
solubility in water slightly soluble – sigma-aldrich datasheet
solubility in organic solvents soluble in most organic solvents – –
pka 10.2 – scifinder

2.2. safety and handling

dmcha is a flammable liquid and a skin and eye irritant. it should be handled with appropriate personal protective equipment (ppe), including gloves, safety glasses, and a respirator if ventilation is inadequate. prolonged or repeated exposure can cause skin sensitization. refer to the material safety data sheet (msds) for comprehensive safety information before handling. proper storage in a cool, dry, and well-ventilated area away from incompatible materials is essential. ⚠️

3. mechanism of action in polyurethane reactions

dmcha acts as a catalyst by accelerating both the urethane (gelation) and urea (blowing) reactions in polyurethane synthesis.

3.1. catalysis of urethane formation (gelation)

the urethane reaction involves the nucleophilic attack of a polyol hydroxyl group (-oh) on the electrophilic carbon of the isocyanate group (-nco). dmcha facilitates this reaction through a general base catalysis mechanism. the amine nitrogen of dmcha abstracts a proton from the hydroxyl group of the polyol, making it a stronger nucleophile. this activated polyol then reacts more readily with the isocyanate, forming the urethane linkage. the proposed mechanism is shown below:

  1. dmcha + r-oh ⇌ dmcha-h+ + r-o– (activation of polyol)
  2. r-o– + r’-nco → r-o-c(o)-nh-r’ (urethane formation)
  3. dmcha-h+ + r-o-c(o)-nh-r’ → dmcha + r-o-c(o)-nh-r’ + h+ (catalyst regeneration)

3.2. catalysis of urea formation (blowing)

the urea reaction, also known as the blowing reaction, involves the reaction of isocyanate with water to form carbamic acid, which subsequently decomposes to form carbon dioxide (co2). the co2 acts as a blowing agent, creating the cellular structure in polyurethane foams. dmcha also catalyzes the urea reaction through a similar general base mechanism.

  1. dmcha + h2o ⇌ dmcha-h+ + oh– (activation of water)
  2. oh– + r-nco → r-nh-c(o)o– (carbamic acid formation)
  3. r-nh-c(o)o– + h+ → r-nh-c(o)oh (carbamic acid protonation)
  4. r-nh-c(o)oh → r-nh2 + co2 (carbamic acid decomposition)
  5. r-nh2 + r’-nco → r-nh-c(o)-nh-r’ (urea formation)

the formed carbon dioxide expands the polyurethane matrix, creating the foam structure. dmcha, therefore, plays a crucial role in both the chain extension (gelation) and blowing processes.

4. influence on polyurethane reaction profile

the reaction profile of polyurethane synthesis is significantly influenced by several factors, including the concentration of dmcha, the reaction temperature, and the formulation composition.

4.1. effect of dmcha concentration

increasing the concentration of dmcha generally accelerates both the gelation and blowing reactions. this leads to a shorter cream time (the time it takes for the mixture to begin to foam), a faster rise time (the time it takes for the foam to reach its maximum height), and a shorter tack-free time (the time it takes for the surface of the foam to become non-sticky). however, excessive dmcha concentration can lead to several problems:

  • rapid reaction: the reaction may proceed too quickly, resulting in uncontrolled foaming, poor foam structure, and potential defects such as cell collapse.
  • premature gelation: the mixture may gel before it has completely filled the mold or before the blowing reaction has sufficiently expanded the foam, leading to a dense and non-uniform product.
  • increased odor: high concentrations of dmcha can result in a strong amine odor in the final product, which may be undesirable.
  • reduced shelf life: highly catalyzed systems may exhibit reduced shelf life due to ongoing reactions, especially with moisture present.

table 2: effect of dmcha concentration on polyurethane foam properties (illustrative)

dmcha concentration (phr) cream time (s) rise time (s) tack-free time (s) foam density (kg/m3) cell size (mm)
0.2 30 120 240 30 1.0
0.5 20 90 180 32 0.8
1.0 10 60 120 35 0.6
1.5 5 45 90 40 0.4

note: phr = parts per hundred parts polyol. these values are for illustrative purposes only and will vary depending on the specific formulation and reaction conditions.

4.2. effect of reaction temperature

the rate of polyurethane reactions, including those catalyzed by dmcha, is highly temperature-dependent. higher reaction temperatures generally lead to faster reaction rates, shorter cream times, and faster rise times. this is due to the increased kinetic energy of the reactants and the increased frequency of collisions. however, similar to high catalyst concentration, excessively high temperatures can also lead to uncontrolled reactions and undesirable product properties.

  • increased volatility: higher temperatures can increase the volatility of the blowing agent (e.g., water or a physical blowing agent), leading to rapid expansion and potential cell rupture.
  • side reactions: elevated temperatures can promote undesirable side reactions, such as allophanate and biuret formation, which can affect the crosslink density and mechanical properties of the pu.
  • thermal degradation: extremely high temperatures can cause thermal degradation of the pu polymer, leading to discoloration, embrittlement, and loss of properties.

table 3: effect of reaction temperature on polyurethane foam properties (illustrative)

reaction temperature (°c) cream time (s) rise time (s) tack-free time (s) foam density (kg/m3)
25 40 150 270 30
35 25 100 200 32
45 15 75 150 35
55 10 50 100 38

note: these values are for illustrative purposes only and will vary depending on the specific formulation and reaction conditions.

4.3. effect of formulation composition

the formulation composition, including the type and amount of polyol, isocyanate, blowing agent, and other additives, also significantly affects the influence of dmcha on the reaction profile.

  • polyol type: polyols with higher hydroxyl numbers (more reactive) will react faster with the isocyanate, leading to a shorter gel time. the type of polyol (e.g., polyether polyol, polyester polyol) also influences the reaction rate and the final properties of the pu.
  • isocyanate index: the isocyanate index (the ratio of isocyanate groups to hydroxyl groups) affects the crosslink density and the mechanical properties of the pu. an excess of isocyanate can lead to the formation of allophanate and biuret linkages, increasing the crosslink density.
  • blowing agent type and amount: the type and amount of blowing agent (water or a physical blowing agent) determine the cell size and density of the pu foam. dmcha catalyzes the reaction of isocyanate with water, so the amount of water used will influence the blowing reaction rate.
  • additives: additives such as surfactants, cell stabilizers, and flame retardants can also affect the reaction profile and the final properties of the pu. surfactants help to stabilize the foam cells and prevent cell collapse.

5. comparison with other amine catalysts

dmcha is just one of many amine catalysts used in polyurethane production. other common amine catalysts include triethylenediamine (teda), dimethylaminoethanol (dmea), and bis(dimethylaminoethyl)ether (bdmaee).

5.1. advantages of dmcha

  • balanced reactivity: dmcha offers a good balance between gelation and blowing catalysis, making it suitable for a wide range of pu applications.
  • good solubility: dmcha is soluble in most polyols and isocyanates, ensuring good dispersion and uniform catalysis throughout the reaction mixture.
  • cost-effectiveness: dmcha is generally more cost-effective than some other amine catalysts.
  • relatively low odor: compared to some other amine catalysts, dmcha has a relatively low odor, which is advantageous in applications where odor is a concern.

5.2. limitations of dmcha

  • potential for amine odor: while relatively low, dmcha can still contribute to amine odor in the final product, especially at high concentrations.
  • yellowing: dmcha can contribute to yellowing of the pu product over time, especially when exposed to uv light.
  • volatility: dmcha is volatile and can be released during the reaction process, contributing to voc emissions.
  • hydrolytic instability: dmcha-catalyzed polyurethanes can exhibit hydrolytic instability, especially in humid environments.

table 4: comparison of dmcha with other amine catalysts

catalyst gelation activity blowing activity odor level yellowing potential voc emissions hydrolytic stability cost
dmcha moderate moderate low moderate moderate moderate low
teda high low high high high low moderate
dmea low high moderate low moderate moderate low
bdmaee low high moderate low moderate moderate moderate

note: this table provides a general comparison and the actual performance may vary depending on the specific formulation and reaction conditions.

6. applications in polyurethane production

dmcha is used in a wide variety of polyurethane applications, including rigid foams, flexible foams, coatings, adhesives, and elastomers.

6.1. rigid polyurethane foams

in rigid pu foams, dmcha helps to control the reaction rate and ensure proper cell formation, resulting in foams with good insulation properties and structural integrity. dmcha is often used in combination with other catalysts to achieve the desired balance of gelation and blowing.

6.2. flexible polyurethane foams

in flexible pu foams, dmcha contributes to the softness and resilience of the foam. it is particularly useful in formulations where a slower reaction rate is desired to allow for better cell opening and ventilation.

6.3. polyurethane coatings, adhesives, and elastomers

in coatings, adhesives, and elastomers, dmcha helps to control the curing rate and achieve the desired mechanical properties, such as hardness, flexibility, and adhesion. dmcha is often used in combination with metal catalysts in these applications.

7. strategies for optimizing dmcha usage

optimizing the use of dmcha in polyurethane formulations involves carefully considering the desired properties of the final product and adjusting the formulation and reaction conditions accordingly.

7.1. blending with other catalysts

blending dmcha with other amine catalysts or metal catalysts can provide a synergistic effect, allowing for better control over the reaction profile and the final properties of the pu. for example, combining dmcha with a strong gelation catalyst like teda can accelerate the overall reaction rate while maintaining a good balance between gelation and blowing.

7.2. use of blocked catalysts

blocked catalysts are catalysts that are chemically modified to be inactive at room temperature. upon heating or exposure to a specific trigger, the blocking group is removed, and the catalyst becomes active. using blocked dmcha can provide better control over the reaction start time and prevent premature gelation.

7.3. optimizing formulations for specific applications

the optimal dmcha concentration and reaction conditions will vary depending on the specific application and the desired properties of the final product. careful experimentation and optimization are essential to achieve the best results.

8. environmental considerations

the use of dmcha, like other volatile organic compounds (vocs), raises environmental concerns due to its potential contribution to air pollution and ozone depletion. efforts are being made to develop alternative catalysts with lower voc emissions and reduced environmental impact. the use of blocked catalysts and optimized formulations can also help to minimize dmcha emissions.

9. future trends

future trends in the use of dmcha in polyurethane production include:

  • development of lower-voc catalysts: research is ongoing to develop amine catalysts with lower volatility and reduced environmental impact.
  • use of bio-based catalysts: there is increasing interest in using bio-based amines as catalysts in polyurethane production.
  • advanced catalyst delivery systems: new methods for delivering catalysts, such as microencapsulation, are being explored to improve control over the reaction profile and reduce emissions.
  • increased focus on sustainability: the polyurethane industry is increasingly focused on developing sustainable products and processes, including the use of environmentally friendly catalysts and blowing agents.

10. conclusion

n,n-dimethylcyclohexylamine (dmcha) is a versatile and widely used tertiary amine catalyst in polyurethane production. its balanced reactivity, good solubility, and cost-effectiveness make it a valuable tool for controlling the reaction profile and achieving the desired properties in a wide range of pu applications. however, careful consideration must be given to the concentration of dmcha, the reaction temperature, and the formulation composition to optimize its use and minimize potential drawbacks such as amine odor and voc emissions. ongoing research and development efforts are focused on developing alternative catalysts with improved environmental performance and enhanced control over the polyurethane reaction. 🚀

11. references

  1. rand, l.; thir, b. f.; reegen, s. l. journal of applied polymer science 1965, 9(5), 1787-1796.
  2. saunders, j. h.; frisch, k. c. polyurethanes: chemistry and technology. interscience publishers, 1962.
  3. oertel, g. polyurethane handbook. hanser publishers, 1994.
  4. ashida, k. polyurethane and related foams: chemistry and technology. crc press, 2006.
  5. vendor datasheets (e.g., , , air products).
  6. sigma-aldrich material safety data sheet (msds) for n,n-dimethylcyclohexylamine.
  7. pubchem compound summary for cid 7961.
  8. scifinder database.
  9. domínguez, r.; fernández-berridi, m. j.; irusta, l.; iruin, j. j. polymer 1998, 39(2), 261-266.
  10. chattopadhyay, d. k.; raju, k. v. s. n. progress in polymer science 2007, 32(3), 352-418.

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n,n-dimethylcyclohexylamine applications in epoxy resin curing
Published by BDMAEE on | Permalink

n,n-dimethylcyclohexylamine: a comprehensive review of its application as an epoxy resin curing agent

contents

  1. introduction
    • 1.1. overview of epoxy resins
    • 1.2. the role of curing agents in epoxy resin systems
    • 1.3. introduction to n,n-dimethylcyclohexylamine (dmcha)
  2. product parameters and chemical properties
    • 2.1. physical properties
    • 2.2. chemical structure and reactivity
    • 2.3. specification table
  3. mechanism of action in epoxy resin curing
    • 3.1. amine curing mechanism
    • 3.2. catalytic effect of dmcha
    • 3.3. influence of dmcha concentration
  4. advantages and disadvantages of using dmcha
    • 4.1. advantages
      • 4.1.1. accelerated curing speed
      • 4.1.2. low viscosity
      • 4.1.3. improved physical properties
    • 4.2. disadvantages
      • 4.2.1. toxicity and handling precautions
      • 4.2.2. potential for blooming
      • 4.2.3. sensitivity to humidity
  5. applications in epoxy resin systems
    • 5.1. coatings
    • 5.2. adhesives
    • 5.3. composites
    • 5.4. casting and potting compounds
  6. formulation considerations and optimization
    • 6.1. stoichiometry
    • 6.2. blending with other curing agents
    • 6.3. impact of temperature on curing
    • 6.4. use of accelerators and modifiers
  7. safety, handling, and storage
    • 7.1. safety precautions
    • 7.2. handling procedures
    • 7.3. storage conditions
  8. comparison with other amine curing agents
    • 8.1. aliphatic amines
    • 8.2. aromatic amines
    • 8.3. cycloaliphatic amines
    • 8.4. polyamidoamines
  9. recent advances and future trends
    • 9.1. modified dmcha derivatives
    • 9.2. encapsulation techniques
    • 9.3. bio-based dmcha alternatives
  10. conclusion
  11. references

1. introduction

1.1. overview of epoxy resins

epoxy resins are a class of thermosetting polymers characterized by the presence of epoxide groups (oxirane rings). these resins are widely used in various industrial applications due to their excellent adhesive properties, chemical resistance, mechanical strength, and electrical insulation. epoxy resins typically consist of a resin component and a curing agent (also known as a hardener). the resin component is usually a diglycidyl ether of bisphenol a (dgeba) or a similar glycidyl ether oligomer. the curing agent initiates a chemical reaction that crosslinks the epoxy resin molecules, transforming the liquid resin into a solid, three-dimensional network.

1.2. the role of curing agents in epoxy resin systems

the curing agent plays a critical role in determining the final properties of the cured epoxy resin. the choice of curing agent significantly influences the curing speed, glass transition temperature (tg), mechanical properties (e.g., tensile strength, flexural modulus), chemical resistance, and thermal stability of the cured epoxy. different types of curing agents are available, each offering a unique set of properties and suitability for specific applications. common types include amines, anhydrides, phenols, and thiols. the selection of the appropriate curing agent is crucial to achieving the desired performance characteristics for the intended application.

1.3. introduction to n,n-dimethylcyclohexylamine (dmcha)

n,n-dimethylcyclohexylamine (dmcha) is a tertiary amine commonly employed as a curing agent or accelerator in epoxy resin systems. it is a colorless to slightly yellow liquid with a characteristic amine odor. dmcha acts primarily as a catalyst, accelerating the reaction between the epoxy resin and other curing agents, particularly anhydrides. it can also function as a co-curing agent in certain formulations. its use can lead to faster cure times, improved physical properties, and lower viscosity of the epoxy mixture, making it a valuable component in various applications.

2. product parameters and chemical properties

2.1. physical properties

dmcha exhibits the following typical physical properties:

  • appearance: colorless to slightly yellow liquid
  • molecular weight: 127.23 g/mol
  • boiling point: 160-162 °c
  • melting point: -70 °c
  • density: 0.845 g/cm³ at 20 °c
  • refractive index: 1.449 at 20 °c
  • flash point: 43 °c (closed cup)
  • vapor pressure: 1.3 hpa at 20 °c
  • viscosity: low viscosity (dependent on temperature)
  • solubility: soluble in organic solvents, slightly soluble in water

2.2. chemical structure and reactivity

dmcha is a tertiary amine with the following chemical structure:

      ch3
       |
   c6h11-n-ch3

the tertiary amine group in dmcha is responsible for its catalytic activity in epoxy resin curing. the lone pair of electrons on the nitrogen atom can initiate the ring-opening polymerization of the epoxide groups or accelerate the reaction between the epoxy resin and other curing agents. dmcha is relatively stable under normal storage conditions but can react with strong acids and oxidizing agents.

2.3. specification table

the following table summarizes the typical specifications for commercially available dmcha:

property specification test method
purity (gc) ≥ 99.0 % gc
water content (kf) ≤ 0.2 % karl fischer titration
color (apha) ≤ 20 astm d1209
specific gravity (20/20°c) 0.840 – 0.850 astm d1298
refractive index (20°c) 1.447 – 1.451 astm d1218
appearance clear, colorless liquid visual

3. mechanism of action in epoxy resin curing

3.1. amine curing mechanism

amine curing of epoxy resins involves the reaction of the amine group with the epoxide ring. this reaction results in ring-opening of the epoxide and the formation of a new carbon-nitrogen bond. the hydrogen atoms attached to the nitrogen atom of the amine are responsible for the curing reaction. primary and secondary amines can react directly with the epoxy resin. tertiary amines, like dmcha, typically act as catalysts, accelerating the reaction of other curing agents, especially anhydrides, with the epoxy resin.

3.2. catalytic effect of dmcha

dmcha’s catalytic activity stems from its ability to initiate the polymerization of epoxy resins via an anionic mechanism. it can also accelerate the reaction of anhydrides with epoxy resins through a nucleophilic addition mechanism. specifically, dmcha can react with an anhydride to form a reactive intermediate, which then reacts with the epoxy resin, leading to ring-opening and crosslinking.

the proposed mechanism involves the following steps:

  1. complex formation: dmcha forms a complex with the anhydride curing agent.
  2. epoxide ring opening: the complex attacks the epoxide ring, leading to its opening and the formation of an alkoxide anion.
  3. proton transfer: the alkoxide anion abstracts a proton from another molecule, regenerating the catalyst (dmcha) and propagating the polymerization.
  4. crosslinking: the process continues, leading to the formation of a three-dimensional crosslinked network.

3.3. influence of dmcha concentration

the concentration of dmcha significantly affects the curing rate and the properties of the cured epoxy resin. increasing the concentration of dmcha generally leads to a faster curing rate. however, excessive amounts of dmcha can negatively impact the final properties of the cured resin, potentially leading to lower glass transition temperature, reduced mechanical strength, and increased brittleness. therefore, optimizing the dmcha concentration is crucial for achieving the desired balance between curing speed and performance characteristics. typically, dmcha is used in concentrations ranging from 0.1 to 5 phr (parts per hundred resin).

4. advantages and disadvantages of using dmcha

4.1. advantages

4.1.1. accelerated curing speed

one of the primary advantages of using dmcha is its ability to accelerate the curing speed of epoxy resins, particularly when used in conjunction with anhydride curing agents. this faster curing speed can lead to increased productivity and reduced manufacturing cycle times.

4.1.2. low viscosity

dmcha has a relatively low viscosity, which can help to reduce the overall viscosity of the epoxy resin mixture. this lower viscosity can improve the processability of the resin, making it easier to apply and allowing for better penetration into substrates.

4.1.3. improved physical properties

in some formulations, the use of dmcha can improve the physical properties of the cured epoxy resin, such as its impact resistance, flexural strength, and adhesion. this is often achieved by optimizing the crosslinking density and network structure of the polymer.

4.2. disadvantages

4.2.1. toxicity and handling precautions

dmcha is a corrosive and potentially toxic chemical. it can cause skin and eye irritation, and inhalation of its vapors can be harmful. proper handling procedures and personal protective equipment (ppe) are essential when working with dmcha. refer to the material safety data sheet (msds) for detailed safety information.

4.2.2. potential for blooming

blooming, also known as amine blush, is a phenomenon where amine curing agents migrate to the surface of the cured epoxy resin, forming a white, hazy film. this can be particularly problematic in humid environments. dmcha, being a relatively volatile amine, has the potential to cause blooming. careful formulation and curing conditions are necessary to minimize this effect.

4.2.3. sensitivity to humidity

the curing process of epoxy resins with amine curing agents can be sensitive to humidity. moisture can react with the amine, consuming the curing agent and leading to incomplete curing or altered properties. dmcha is no exception, and controlling humidity during mixing and curing is important for achieving consistent results.

5. applications in epoxy resin systems

dmcha is used in a variety of applications involving epoxy resins, including:

5.1. coatings

dmcha is used in epoxy coatings to accelerate the curing process and improve the overall performance of the coating. it can enhance properties such as chemical resistance, abrasion resistance, and adhesion to various substrates. applications include protective coatings for metal, concrete, and wood.

5.2. adhesives

in epoxy adhesives, dmcha can improve the bonding strength and reduce the curing time. it is used in structural adhesives, automotive adhesives, and electronics adhesives.

5.3. composites

dmcha is employed in epoxy composites to facilitate the curing of the resin matrix. this can lead to improved mechanical properties and reduced processing time. applications include aerospace components, automotive parts, and sporting goods.

5.4. casting and potting compounds

dmcha is used in epoxy casting and potting compounds to accelerate the curing process and provide good electrical insulation properties. applications include encapsulating electronic components, manufacturing electrical insulators, and producing molds and tooling.

table: applications of dmcha in epoxy resin systems

application benefits of dmcha use examples
coatings accelerated cure, improved chemical resistance, enhanced adhesion protective coatings for pipelines, automotive primers, marine coatings
adhesives faster bonding, increased bond strength, improved temperature resistance structural adhesives for aircraft, automotive assembly, electronics bonding
composites reduced processing time, improved mechanical properties wind turbine blades, aircraft wings, automotive body panels
casting & potting accelerated cure, good electrical insulation encapsulation of electronic components, potting of transformers

6. formulation considerations and optimization

6.1. stoichiometry

the stoichiometry of the epoxy resin and curing agent is crucial for achieving optimal curing and desired properties. while dmcha is primarily a catalyst, its concentration still needs to be carefully considered in relation to the other curing agents present in the formulation. too little dmcha may result in slow curing, while too much may lead to undesirable side reactions or reduced performance.

6.2. blending with other curing agents

dmcha is often used in combination with other curing agents, such as anhydrides, to achieve a specific balance of properties. the type and concentration of the other curing agent will influence the overall curing process and the final properties of the cured epoxy resin. careful consideration should be given to the compatibility and reactivity of the different curing agents.

6.3. impact of temperature on curing

the curing temperature significantly affects the curing rate and the properties of the cured epoxy resin. higher temperatures generally lead to faster curing rates, but can also result in increased shrinkage and thermal stress. dmcha’s activity is temperature-dependent, and its effectiveness as a catalyst increases with temperature.

6.4. use of accelerators and modifiers

other accelerators and modifiers can be added to the epoxy resin formulation to further enhance the curing process or improve the final properties of the cured resin. examples include:

  • accelerators: other tertiary amines, metal catalysts
  • modifiers: toughening agents, fillers, plasticizers

table: effect of formulation parameters on curing and properties

parameter effect on curing rate effect on tg effect on mechanical strength effect on viscosity
dmcha concentration increases may decrease may decrease slight decrease
curing temperature increases may increase generally increases decreases
anhydride concentration increases (with dmcha) increases generally increases increases

7. safety, handling, and storage

7.1. safety precautions

  • wear appropriate personal protective equipment (ppe), including gloves, safety glasses, and a respirator if necessary.
  • avoid contact with skin and eyes.
  • work in a well-ventilated area.
  • read and understand the material safety data sheet (msds) before handling dmcha.

7.2. handling procedures

  • dispense dmcha carefully to avoid spills.
  • clean up any spills immediately with appropriate absorbent materials.
  • avoid mixing dmcha with incompatible materials.
  • use appropriate containers and equipment for handling dmcha.

7.3. storage conditions

  • store dmcha in a tightly closed container in a cool, dry, and well-ventilated area.
  • keep away from heat, sparks, and open flames.
  • protect from direct sunlight.
  • store away from incompatible materials, such as strong acids and oxidizing agents.

8. comparison with other amine curing agents

dmcha is just one of many amine curing agents available for epoxy resins. each type of amine curing agent offers different advantages and disadvantages, making them suitable for different applications.

8.1. aliphatic amines

aliphatic amines (e.g., diethylenetriamine (deta), triethylenetetramine (teta)) are typically fast-curing and provide good mechanical properties. however, they can be more toxic and have a higher vapor pressure than other amine types.

8.2. aromatic amines

aromatic amines (e.g., diaminodiphenylmethane (ddm), diaminodiphenylsulfone (dds)) offer excellent thermal stability and chemical resistance but typically require high curing temperatures.

8.3. cycloaliphatic amines

cycloaliphatic amines (e.g., isophoronediamine (ipda)) provide a good balance of properties, including good chemical resistance, mechanical strength, and color stability. they offer better handling characteristics than aliphatic amines.

8.4. polyamidoamines

polyamidoamines are derived from fatty acids and polyamines. they offer good flexibility, adhesion, and resistance to humidity, making them suitable for coatings and adhesives.

table: comparison of amine curing agents

curing agent type curing speed toxicity thermal stability chemical resistance applications
aliphatic amines fast high low fair general-purpose adhesives, fast-curing coatings
aromatic amines slow moderate high excellent high-performance composites, structural adhesives
cycloaliphatic amines moderate moderate moderate good coatings, adhesives, composites
polyamidoamines slow low fair good coatings, adhesives
dmcha accelerates moderate moderate moderate coatings, adhesives, composites

9. recent advances and future trends

9.1. modified dmcha derivatives

researchers are exploring modified dmcha derivatives to improve its performance and address some of its drawbacks. for example, attaching bulky groups to the nitrogen atom can reduce its volatility and potential for blooming.

9.2. encapsulation techniques

encapsulation of dmcha in microcapsules or nanoparticles can provide controlled release and improve the shelf life of epoxy resin formulations. this can also reduce the potential for toxicity and improve handling safety.

9.3. bio-based dmcha alternatives

with increasing emphasis on sustainability, there is growing interest in developing bio-based alternatives to dmcha. researchers are investigating the use of amines derived from renewable resources as potential curing agents or catalysts for epoxy resins.

10. conclusion

n,n-dimethylcyclohexylamine (dmcha) is a valuable tertiary amine curing agent and accelerator widely used in epoxy resin systems. its ability to accelerate curing, reduce viscosity, and potentially improve physical properties makes it suitable for a variety of applications, including coatings, adhesives, composites, and casting compounds. however, its toxicity, potential for blooming, and sensitivity to humidity must be carefully considered. proper handling procedures, formulation optimization, and storage conditions are essential for achieving the desired performance and ensuring safety. ongoing research efforts are focused on developing modified dmcha derivatives, encapsulation techniques, and bio-based alternatives to further improve its performance and address its limitations.

11. references

  • smith, j. g. "advanced polymer chemistry." academic press, 2002.
  • goodman, s. h. "handbook of thermoset resins." william andrew publishing, 2015.
  • ellis, b. "chemistry and technology of epoxy resins." blackie academic & professional, 1993.
  • may, c. a. "epoxy resins: chemistry and technology." marcel dekker, 1988.
  • pascault, j. p., sautereau, h., verdu, j., & williams, r. j. j. (2002). "thermosetting polymers." marcel dekker.
  • riew, c. k., & kinloch, a. j. (eds.). (1989). "toughened plastics i: science and engineering." american chemical society.
  • oswald, t., and weber, t., "epoxy resins", wiley-vch, weinheim, 2017.
  • european chemicals agency (echa). registration dossier for n,n-dimethylcyclohexylamine. available on echa website.
  • various material safety data sheets (msds) for n,n-dimethylcyclohexylamine from different manufacturers.

sales contact：sales@newtopchem.com

n,n-dimethylcyclohexylamine storage and stability guidelines
Published by BDMAEE on | Permalink

n,n-dimethylcyclohexylamine: storage, stability, and handling guidelines

introduction

n,n-dimethylcyclohexylamine (dmcha), represented by the chemical formula c8h17n, is a tertiary amine widely used in various industrial applications, primarily as a catalyst in polyurethane foam production. its reactivity and inherent chemical properties necessitate careful handling, storage, and adherence to specific stability guidelines to ensure product quality, safety, and efficacy. this article aims to provide comprehensive information on dmcha, covering its properties, potential hazards, storage recommendations, stability considerations, and relevant safety protocols. the information presented is intended for professionals involved in the handling, storage, and use of dmcha.

1. chemical and physical properties

understanding the fundamental properties of dmcha is crucial for proper handling and storage.

property value unit reference
chemical name n,n-dimethylcyclohexylamine –
cas registry number 98-94-2 –
molecular formula c8h17n –
molecular weight 127.23 g/mol
appearance colorless to pale yellow liquid –
odor amine-like –
boiling point 160-162 °c [1, 2]
melting point -60 °c [1, 2]
flash point 43-46 °c (closed cup) [1, 2]
density 0.845-0.855 g/cm³ @ 20°c [1, 2]
refractive index 1.447-1.451 – [1, 2]
vapor pressure 1.3 hpa @ 20°c – [3]
solubility in water slightly soluble – [3]
solubility in organic solvents soluble in most organic solvents (e.g., alcohols, ethers) – [3]
pka 10.4 – [4]

2. potential hazards and safety precautions

dmcha, like other tertiary amines, presents certain hazards that require careful consideration and appropriate safety measures.

  • flammability: dmcha is a flammable liquid and vapor. the low flash point necessitates keeping it away from ignition sources.
  • corrosivity: dmcha is corrosive to skin and eyes. direct contact can cause severe burns.
  • inhalation hazard: inhalation of dmcha vapors can cause irritation of the respiratory tract, coughing, and difficulty breathing.
  • environmental hazard: dmcha can be harmful to aquatic life. measures should be taken to prevent release into the environment.

safety precautions:

  • personal protective equipment (ppe): always wear appropriate ppe when handling dmcha, including:
    • chemical-resistant gloves (e.g., nitrile, neoprene) 🧤
    • safety goggles or face shield 🥽
    • chemical-resistant apron or suit 🦺
    • respiratory protection (if ventilation is inadequate) 😷
  • ventilation: work with dmcha in a well-ventilated area or under a fume hood.
  • handling: avoid contact with skin, eyes, and clothing. wash thoroughly after handling.
  • fire safety: keep dmcha away from heat, sparks, open flames, and other ignition sources. use explosion-proof equipment.
  • emergency procedures:
    • eye contact: immediately flush eyes with plenty of water for at least 15 minutes and seek medical attention.
    • skin contact: immediately wash affected area with soap and water. remove contaminated clothing and shoes. seek medical attention if irritation persists.
    • inhalation: move to fresh air. if breathing is difficult, administer oxygen. seek medical attention.
    • ingestion: do not induce vomiting. rinse mouth with water and seek medical attention immediately.
  • spill control: contain spills with absorbent materials (e.g., sand, vermiculite). dispose of contaminated materials properly according to local regulations.
  • first aid: ensure readily available first aid kits and trained personnel are present in the work area.

3. storage recommendations

proper storage of dmcha is essential to maintain its quality, prevent degradation, and minimize potential hazards.

  • container type: store dmcha in tightly closed, properly labeled containers made of compatible materials such as:
    • stainless steel
    • glass
    • high-density polyethylene (hdpe)
    • avoid containers made of copper, aluminum, or other reactive metals.
  • storage conditions:
    • temperature: store dmcha in a cool, dry, well-ventilated area, away from direct sunlight and heat sources. the recommended storage temperature is between 15°c and 25°c.
    • humidity: keep the storage area dry to prevent moisture absorption.
    • light: protect dmcha from direct sunlight and ultraviolet (uv) radiation, as these can accelerate degradation.
    • incompatible materials: store dmcha away from strong oxidizing agents, acids, and other incompatible materials.
    • ventilation: ensure adequate ventilation in the storage area to prevent the accumulation of vapors.
  • container labeling: clearly label all containers with the following information:
    • chemical name: n,n-dimethylcyclohexylamine
    • cas registry number: 98-94-2
    • hazard warnings
    • storage instructions
    • date of receipt or manufacture
  • storage location:
    • store dmcha in a designated storage area specifically for flammable and corrosive materials.
    • the storage area should be equipped with appropriate fire suppression systems.
    • restrict access to authorized personnel only.
  • inventory management: implement a proper inventory management system to track the quantity and age of dmcha in storage. use a "first-in, first-out" (fifo) approach to minimize the risk of product degradation.

4. stability considerations

the stability of dmcha can be affected by various factors, including temperature, light, air exposure, and the presence of impurities.

  • thermal stability: dmcha is relatively stable at room temperature. however, prolonged exposure to elevated temperatures can lead to degradation and the formation of undesirable byproducts.
  • photostability: exposure to light, especially uv radiation, can cause dmcha to degrade. storing dmcha in opaque containers or in a dark environment is recommended.
  • oxidative stability: dmcha can react with oxygen in the air, leading to the formation of n-oxides and other oxidation products. this process can be accelerated by the presence of catalysts such as metal ions. proper storage in tightly closed containers under an inert atmosphere (e.g., nitrogen or argon) can minimize oxidation.
  • hydrolytic stability: dmcha is relatively stable in the presence of water under normal conditions. however, prolonged exposure to acidic or alkaline conditions can promote hydrolysis.
  • effect of impurities: the presence of impurities, such as metal ions or other reactive compounds, can catalyze the degradation of dmcha. using high-purity dmcha and storing it in clean containers can minimize this risk.

stability testing:

regular stability testing is recommended to monitor the quality of dmcha during storage. common stability tests include:

  • appearance: visual inspection for color changes, turbidity, or the formation of precipitates.
  • assay: determination of the dmcha content using titration, gas chromatography (gc), or other suitable analytical methods.
  • acidity: measurement of the acidity of the dmcha sample using titration or ph measurement.
  • water content: determination of the water content using karl fischer titration.
  • peroxide content: measurement of the peroxide content using iodometric titration or other suitable methods.
  • gas chromatography (gc): gc analysis can identify and quantify any degradation products that may have formed.
test parameter acceptable range test method frequency
appearance colorless to pale yellow, clear liquid visual inspection every 3-6 months
assay (gc) ≥ 99.0% gas chromatography every 3-6 months
acidity (as hcl) ≤ 0.1% titration every 3-6 months
water content (kf) ≤ 0.2% karl fischer titration every 3-6 months
peroxide content ≤ 10 ppm iodometric titration every 3-6 months

5. handling and disposal

  • handling:
    • minimize exposure to air and moisture during handling.
    • use appropriate dispensing equipment to avoid spills and leaks.
    • avoid generating aerosols or vapors.
    • ensure adequate ventilation in the handling area.
  • waste disposal:
    • dispose of dmcha and contaminated materials in accordance with local, state, and federal regulations.
    • do not pour dmcha n the drain.
    • incineration is a common method for disposing of dmcha.
    • consult with a licensed waste disposal company for proper disposal procedures.

6. applications and considerations

dmcha finds its primary application as a catalyst in the production of polyurethane foams. its use is carefully managed to optimize the reaction kinetics and the final properties of the foam.

  • polyurethane foam production: dmcha catalyzes the reaction between polyols and isocyanates, which are the main components of polyurethane foam. the concentration of dmcha used affects the rate of the reaction and the properties of the resulting foam, such as density, hardness, and cell structure.
  • other applications: dmcha is also used as a building block in the synthesis of other organic compounds and as a corrosion inhibitor.
  • regulatory considerations: dmcha is subject to various regulations regarding its manufacture, handling, and use. it’s crucial to comply with all applicable regulations to ensure safety and environmental protection.

7. conclusion

n,n-dimethylcyclohexylamine is a valuable chemical compound with diverse industrial applications. however, its flammability, corrosivity, and potential environmental hazards necessitate careful handling, storage, and disposal practices. by adhering to the guidelines outlined in this article, professionals can ensure the safe and effective use of dmcha while minimizing risks to human health and the environment. regular monitoring of product quality through stability testing is crucial for maintaining its efficacy and preventing potential issues arising from degradation. always consult the safety data sheet (sds) for the most up-to-date information and safety recommendations.

8. future directions

research and development efforts are continuously focused on improving the stability and handling characteristics of dmcha. this includes exploring new additives and stabilizers to enhance its resistance to oxidation, light, and heat, as well as developing more environmentally friendly alternatives. furthermore, advancements in analytical techniques allow for more precise monitoring of dmcha quality and degradation products.

references:

[1] sigma-aldrich. safety data sheet for n,n-dimethylcyclohexylamine.

[2] alfa aesar. safety data sheet for n,n-dimethylcyclohexylamine.

[3] pubchem. n,n-dimethylcyclohexylamine. national center for biotechnology information.

[4] perrin, d. d. dissociation constants of organic bases in aqueous solution. butterworths: london, 1965.

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n,n-dimethylcyclohexylamine gelling catalyst performance data
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n,n-dimethylcyclohexylamine: a comprehensive review of its performance as a gelling catalyst

introduction

n,n-dimethylcyclohexylamine (dmcha), a tertiary amine, is a widely utilized catalyst in the production of polyurethane (pu) foams, elastomers, and coatings. its primary function is to accelerate the reaction between isocyanates and polyols, facilitating the gelling process and influencing the final properties of the resulting polyurethane material. this article provides a comprehensive overview of dmcha’s properties, reaction mechanisms, performance parameters, influencing factors, and applications as a gelling catalyst. the information is structured in a manner similar to a baidu baike entry, emphasizing rigorous language, standardized terminology, and clear organization.

1. chemical identity and properties

  • chemical name: n,n-dimethylcyclohexylamine
  • synonyms: dimethylcyclohexylamine; 1-(dimethylamino)cyclohexane; cyclohexane, (dimethylamino)-
  • cas registry number: 98-94-2
  • molecular formula: c8h17n
  • molecular weight: 127.23 g/mol
  • structural formula: (insert structural formula here – this is represented conceptually as this response cannot directly insert images) – a cyclohexane ring with a dimethylamino (-n(ch3)2) group attached to one of the carbons.
  • appearance: colorless to light yellow liquid
  • odor: amine-like odor
  • boiling point: 160-162 °c
  • melting point: -60 °c
  • density: 0.85 g/cm³ at 20 °c
  • refractive index: 1.447-1.449 at 20 °c
  • viscosity: low viscosity
  • solubility: soluble in most organic solvents, slightly soluble in water.
  • flash point: 45 °c (closed cup)
  • vapor pressure: low vapor pressure

table 1: summary of key physicochemical properties of dmcha

property value unit
molecular weight 127.23 g/mol
boiling point 160-162 °c
melting point -60 °c
density 0.85 g/cm³ (at 20 °c)
refractive index 1.447-1.449 (at 20 °c)
flash point 45 °c (closed cup)

2. reaction mechanism as a gelling catalyst

dmcha, as a tertiary amine, acts as a catalyst in the isocyanate-polyol reaction, which is the fundamental reaction in polyurethane formation. the mechanism can be summarized as follows:

  1. proton abstraction: dmcha, possessing a lone pair of electrons on the nitrogen atom, acts as a base, abstracting a proton from either the hydroxyl group of the polyol or from a water molecule. this proton abstraction forms a reactive alkoxide ion or a hydroxyl ion, respectively.

  2. nucleophilic attack: the resulting alkoxide or hydroxyl ion, now a strong nucleophile, attacks the electrophilic carbon atom of the isocyanate group (-n=c=o).

  3. urethane formation (polyol reaction): when the alkoxide ion attacks the isocyanate, it forms a urethane linkage (-nh-co-o-), extending the polymer chain and contributing to the gelling process.

  4. urea formation (water reaction): when the hydroxyl ion attacks the isocyanate, it forms an unstable carbamic acid intermediate. this intermediate decomposes to form an amine and carbon dioxide. the amine then reacts with another isocyanate molecule to form a urea linkage (-nh-co-nh-), which also contributes to chain extension and the formation of hard segments in the polyurethane. the carbon dioxide generated acts as a blowing agent in foam production.

  5. catalyst regeneration: the dmcha molecule is regenerated in the process, allowing it to participate in further catalytic cycles.

the relative rates of the urethane and urea reactions are influenced by the catalyst type and concentration, as well as other factors such as temperature and reactant composition. dmcha tends to favor the gelling (urethane) reaction more strongly than the blowing (urea) reaction, making it a useful catalyst for applications where a faster gel time is desired.

3. performance parameters and evaluation methods

the performance of dmcha as a gelling catalyst is evaluated based on several key parameters:

  • cream time: the time elapsed between the mixing of the reactants (isocyanate, polyol, catalyst, etc.) and the point at which the mixture starts to rise or cream. shorter cream times indicate faster reaction rates.
  • gel time: the time it takes for the mixture to transition from a liquid to a semi-solid or gelled state. gel time is a crucial indicator of the rate of chain extension and crosslinking. shorter gel times are generally desirable for faster processing and improved productivity.
  • tack-free time: the time required for the surface of the polyurethane material to become non-sticky or tack-free. this parameter is important for applications such as coatings and adhesives.
  • rise time: the total time it takes for a polyurethane foam to reach its maximum height. this parameter is relevant for foam applications and is influenced by both the gelling and blowing reactions.
  • demold time: the minimum time required before a molded polyurethane part can be removed from the mold without deformation.
  • tensile strength: a measure of the material’s resistance to breaking under tension.
  • elongation at break: the percentage increase in length of the material before it breaks under tension.
  • hardness: a measure of the material’s resistance to indentation. typically measured using shore a or shore d durometers.
  • density (for foams): the mass per unit volume of the foam.
  • cell structure (for foams): the size, shape, and uniformity of the cells in the foam. a fine and uniform cell structure generally leads to better physical properties.
  • compressive strength (for foams): a measure of the foam’s resistance to compression.

table 2: common evaluation methods for dmcha catalyst performance

parameter evaluation method
cream time visual observation, stopwatch
gel time visual observation (stirring rod test), automatic gel timer
tack-free time touch test, visual observation
rise time visual observation, measuring height of rising foam
demold time trial and error, observing for deformation upon demolding
tensile strength astm d412, iso 37
elongation astm d412, iso 37
hardness astm d2240 (shore a or d), iso 868
density (foam) astm d1622, iso 845
cell structure microscopic analysis (optical or scanning electron microscopy)
compressive strength (foam) astm d1621, iso 844

the choice of evaluation methods depends on the specific application and the properties of interest.

4. factors influencing catalyst performance

several factors can influence the performance of dmcha as a gelling catalyst:

  • concentration: the concentration of dmcha directly affects the reaction rate. higher concentrations generally lead to faster gel times, but excessive amounts can cause undesirable side reactions or affect the final properties of the polyurethane. an optimal concentration range should be determined experimentally for each specific formulation.
  • temperature: reaction rates are generally temperature-dependent. higher temperatures typically accelerate the reaction, leading to shorter cream and gel times. however, excessively high temperatures can also lead to premature gelling or degradation of the reactants.
  • moisture content: moisture can react with isocyanates to form urea linkages and carbon dioxide, affecting the gelling and blowing balance. high moisture content can lead to uncontrolled foaming or reduced mechanical properties.
  • type of polyol: the type of polyol used (e.g., polyether polyol, polyester polyol) influences the reactivity and compatibility of the system. polyols with higher hydroxyl numbers generally react faster with isocyanates.
  • type of isocyanate: different isocyanates (e.g., tdi, mdi, hdi) exhibit different reactivities. aromatic isocyanates (tdi, mdi) are generally more reactive than aliphatic isocyanates (hdi, ipdi).
  • additives: other additives, such as surfactants, blowing agents, and stabilizers, can also affect the catalyst’s performance by influencing the miscibility of the reactants, the foam cell structure, or the stability of the polyurethane material.
  • presence of co-catalysts: dmcha is often used in conjunction with other catalysts, such as metal catalysts (e.g., tin catalysts), to achieve a specific balance of gelling and blowing. the combination of catalysts can provide synergistic effects, allowing for greater control over the reaction profile.
  • steric hindrance: the steric hindrance around the nitrogen atom in dmcha can affect its ability to abstract protons. while dmcha is less sterically hindered than some other tertiary amine catalysts, it still exhibits some degree of steric hindrance, which can influence its selectivity for different reactions.
  • ph of the system: while not a primary concern in typical polyurethane formulations, extreme ph values can affect the catalyst’s activity.

table 3: impact of factors on dmcha catalyst performance

factor impact on gel time impact on cream time impact on foam rise time (if applicable)
dmcha concentration decreases decreases decreases
temperature decreases decreases decreases
moisture content can vary (usually decreases slightly for gelling) can vary (usually decreases slightly) increases (due to co2 formation)
polyol type varies (depends on reactivity) varies (depends on reactivity) varies
isocyanate type varies (depends on reactivity) varies (depends on reactivity) varies
co-catalysts varies (synergistic or antagonistic) varies (synergistic or antagonistic) varies

5. applications of dmcha in polyurethane production

dmcha is widely used in the production of various polyurethane materials, including:

  • flexible polyurethane foams: used in furniture, bedding, automotive seating, and packaging. dmcha helps to achieve the desired gel time and cell structure in these foams.
  • rigid polyurethane foams: used in insulation for buildings, appliances, and transportation. dmcha contributes to the rapid gelling required for efficient production of rigid foams.
  • semi-rigid polyurethane foams: used in automotive parts, shoe soles, and other applications where a balance of flexibility and rigidity is needed.
  • polyurethane elastomers: used in seals, gaskets, tires, and other applications requiring high elasticity and durability. dmcha helps to control the reaction rate and achieve the desired mechanical properties.
  • polyurethane coatings and adhesives: used in a wide range of applications, including automotive coatings, wood finishes, and industrial adhesives. dmcha accelerates the curing process and improves the adhesion of the coating or adhesive.
  • spray polyurethane foam (spf): used for insulation and roofing applications. dmcha is crucial for achieving the fast reaction and rapid curing required for spf application.
  • reaction injection molding (rim): used for manufacturing large, complex polyurethane parts. dmcha helps to control the reaction rate and ensure proper mold filling.

table 4: applications of dmcha in various polyurethane products

polyurethane product function of dmcha benefits
flexible foam gelling catalyst controls gel time, influences cell structure, improves foam properties
rigid foam gelling catalyst accelerates reaction, enables efficient production, contributes to insulation properties
elastomers gelling catalyst controls reaction rate, achieves desired mechanical properties (tensile strength, elongation, hardness)
coatings/adhesives curing catalyst accelerates curing process, improves adhesion, enhances durability
spray foam gelling catalyst enables fast reaction and rapid curing, ensures proper adhesion to substrate
rim parts reaction rate control ensures proper mold filling, improves part quality, reduces cycle time

6. safety and handling

dmcha is a flammable and corrosive liquid. it is important to handle it with care and follow appropriate safety precautions:

  • personal protective equipment (ppe): wear appropriate ppe, including gloves, safety glasses, and a respirator, when handling dmcha.
  • ventilation: use adequate ventilation to prevent inhalation of vapors.
  • storage: store dmcha in a tightly closed container in a cool, dry, and well-ventilated area.
  • fire hazards: keep dmcha away from heat, sparks, and open flames.
  • first aid: in case of skin or eye contact, flush with plenty of water for at least 15 minutes and seek medical attention. if inhaled, move to fresh air and seek medical attention.

7. alternatives to dmcha

while dmcha is a widely used catalyst, there are several alternatives available, depending on the specific application and desired properties:

  • other tertiary amines: examples include triethylenediamine (teda), dimethylbenzylamine (dmba), and bis(2-dimethylaminoethyl) ether. these amines offer different reactivities and selectivity for the gelling and blowing reactions.
  • metal catalysts: examples include tin catalysts (e.g., dibutyltin dilaurate – dbtdl) and bismuth catalysts. metal catalysts are often used in combination with amine catalysts to achieve a specific balance of properties.
  • delayed-action catalysts: these catalysts are designed to provide a delayed onset of catalytic activity, allowing for better control over the reaction process.
  • environmentally friendly catalysts: research is ongoing to develop more environmentally friendly catalysts for polyurethane production, with a focus on reducing voc emissions and improving the sustainability of the materials.

table 5: comparison of dmcha with alternative catalysts

catalyst type advantages disadvantages
dmcha good gelling catalyst, relatively low cost, widely available amine odor, potential voc emissions, may require co-catalysts
teda strong blowing catalyst, can improve foam cell structure strong amine odor, may require co-catalysts
dmba good balance of gelling and blowing, lower odor than some other amines may be more expensive than dmcha, potential voc emissions
dbtdl (tin catalyst) strong gelling catalyst, can improve mechanical properties toxicity concerns, potential for hydrolysis
bismuth catalyst less toxic than tin catalysts, good gelling activity may be more expensive than dmcha or tin catalysts, may require higher loading levels

the selection of the appropriate catalyst depends on a variety of factors, including the desired reaction rate, the target properties of the polyurethane material, and environmental considerations.

8. conclusion

n,n-dimethylcyclohexylamine (dmcha) remains a valuable and widely used gelling catalyst in the production of polyurethane materials. its ability to accelerate the isocyanate-polyol reaction, along with its relatively low cost and availability, makes it a popular choice for a wide range of applications. however, it’s crucial to understand the factors influencing its performance, handle it safely, and consider potential alternatives to meet specific requirements and address environmental concerns. further research and development efforts are focused on improving the sustainability and performance of polyurethane catalysts, ensuring the continued advancement of this important class of materials.

literature sources (example references – actual citations would need to be found and inserted):

  1. oertel, g. (ed.). polyurethane handbook. hanser gardner publications. (this is a general reference for polyurethane chemistry)
  2. randall, d., & lee, s. the polyurethanes book. john wiley & sons. (another general reference)
  3. saunders, j. h., & frisch, k. c. polyurethanes: chemistry and technology. interscience publishers. (classic text on polyurethane chemistry)
  4. specific journal articles on polyurethane catalysis (e.g., journal of applied polymer science, polymer, european polymer journal) – search for articles focusing on amine catalysts and their performance in polyurethane systems. these articles would need to be located and cited specifically.
  5. technical data sheets from dmcha manufacturers (e.g., , , etc.) – these provide specific information on product properties and handling.
  6. patents related to polyurethane catalysts and formulations.

sales contact：sales@newtopchem.com

n,n-dimethylcyclohexylamine dosage recommendations for pu foam
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n,n-dimethylcyclohexylamine (dmcha) in polyurethane (pu) foam production: a comprehensive guide

introduction:

n,n-dimethylcyclohexylamine (dmcha), a tertiary amine catalyst, plays a crucial role in the production of polyurethane (pu) foams. it is primarily employed to accelerate the blowing reaction, contributing significantly to the foam’s cell structure, density, and overall mechanical properties. this article aims to provide a comprehensive overview of dmcha in pu foam applications, covering its properties, mechanism of action, dosage recommendations, influencing factors, safety considerations, and comparative analysis with other catalysts. this guide is intended for pu foam manufacturers, researchers, and anyone seeking a deeper understanding of dmcha’s role in pu foam chemistry.

1. product overview:

dmcha is a colorless to pale yellow liquid with a characteristic amine odor. it’s an effective catalyst primarily used in rigid and semi-rigid pu foam formulations. its bicyclic structure contributes to its reactivity and selectivity.

1.1 chemical structure and properties:

property value
chemical name n,n-dimethylcyclohexylamine
cas number 98-94-2
molecular formula c8h17n
molecular weight 127.23 g/mol
appearance colorless to pale yellow liquid
density (20°c) 0.845 – 0.855 g/cm3
boiling point 160-162 °c
flash point 45-50 °c
refractive index (n20/d) 1.449 – 1.453
water solubility slightly soluble
amine value 435-445 mg koh/g

1.2 key advantages of dmcha:

  • strong blowing reaction catalysis: dmcha effectively promotes the reaction between isocyanate and water, generating carbon dioxide (co2) for foam expansion.
  • good flowability improvement: enhances the flow of the pu mixture during the foaming process, leading to a more uniform cell structure.
  • relatively low odor: compared to some other amine catalysts, dmcha exhibits a relatively lower odor profile, which is beneficial for indoor applications.
  • compatibility: good compatibility with most polyols and isocyanates used in pu foam formulations.
  • cost-effectiveness: dmcha offers a balanced cost-performance ratio, making it a popular choice in various pu foam applications.

2. mechanism of action:

dmcha, as a tertiary amine catalyst, primarily accelerates the blowing reaction (isocyanate-water reaction) in pu foam formation. the general mechanism can be simplified into the following steps:

  1. amine activation: dmcha, acting as a lewis base, abstracts a proton from the water molecule, forming an activated water-amine complex.

  2. nucleophilic attack: the activated water molecule, now a stronger nucleophile, attacks the electrophilic carbon atom of the isocyanate group (-nco).

  3. carbamic acid formation: this attack leads to the formation of a carbamic acid intermediate.

  4. decarboxylation: the carbamic acid spontaneously decomposes, releasing carbon dioxide (co2), the blowing agent, and regenerating the amine catalyst.

  5. polymerization: simultaneously, the isocyanate group reacts with the polyol hydroxyl groups (-oh), forming urethane linkages and contributing to the polymer network.

dmcha’s structure, particularly the presence of the cyclohexyl ring, influences its activity and selectivity. the steric hindrance caused by the ring can affect the catalyst’s interaction with the isocyanate and water molecules. this can lead to a balance between the blowing and gelling reactions, influencing the final properties of the pu foam.

3. dosage recommendations:

determining the optimal dmcha dosage is crucial for achieving the desired foam properties. the dosage depends on several factors, including the type of polyol, isocyanate index, presence of other catalysts, ambient temperature, and desired foam density.

3.1 general dosage range:

the typical dosage range for dmcha in pu foam formulations is 0.1 to 1.0 parts per hundred parts polyol (pphp). however, this is a general guideline, and adjustments are necessary based on specific formulation requirements.

3.2 dosage guidelines based on foam type:

foam type typical dmcha dosage (pphp) notes
rigid pu foam 0.3 – 1.0 higher dosages may be needed for formulations with high water content or low isocyanate index.
semi-rigid pu foam 0.2 – 0.7 moderate dosages are sufficient to achieve the desired cell structure and density.
flexible pu foam 0.1 – 0.5 lower dosages are typically used, often in combination with other amine or organometallic catalysts to balance blowing and gelling.

3.3 considerations for dosage adjustment:

  • isocyanate index: a higher isocyanate index may require a slightly higher dmcha dosage to ensure complete reaction and avoid residual isocyanate.
  • water content: formulations with higher water content will generally require more dmcha to catalyze the blowing reaction effectively.
  • polyol type: the reactivity of the polyol influences the catalyst dosage. more reactive polyols might require lower dmcha concentrations.
  • temperature: higher temperatures can accelerate the reaction, potentially requiring a lower dmcha dosage. conversely, lower temperatures may necessitate a higher dosage.
  • other catalysts: the presence of other amine or organometallic catalysts will affect the overall catalytic activity, requiring adjustments to the dmcha dosage. synergistic effects can occur, allowing for lower overall catalyst loadings.

3.4 example formulations (illustrative):

the following table provides examples of starting formulations for different pu foam types. these are simplified examples and should be adjusted based on specific requirements and experimental results.

component rigid pu foam (pphp) semi-rigid pu foam (pphp) flexible pu foam (pphp)
polyol 100 100 100
isocyanate as required (index 110) as required (index 105) as required (index 100)
water 2.0 – 4.0 1.0 – 3.0 3.0 – 5.0
dmcha 0.5 – 0.8 0.3 – 0.5 0.2 – 0.4
surfactant 1.0 – 2.0 1.0 – 2.0 1.0 – 2.0
flame retardant (optional) as required as required as required

important note: these are just examples. proper optimization of the formulation requires careful experimentation and monitoring of foam properties.

4. factors influencing dmcha performance:

several factors can influence the effectiveness of dmcha in pu foam formulations. understanding these factors is critical for achieving consistent and predictable results.

4.1 temperature:

temperature significantly affects the rate of the catalytic reaction. higher temperatures generally accelerate the reaction, potentially leading to faster rise times and shorter demold times. however, excessively high temperatures can cause premature blowing and collapse of the foam structure. conversely, lower temperatures can slow n the reaction, resulting in longer rise times and potentially incomplete foaming.

4.2 humidity:

humidity can influence the water content in the formulation, which directly affects the blowing reaction. high humidity can lead to increased water content, potentially requiring adjustments to the dmcha dosage to maintain the desired foam density.

4.3 raw material quality:

the quality of the polyol, isocyanate, and other additives can significantly impact the performance of dmcha. impurities or inconsistencies in the raw materials can interfere with the catalytic reaction and affect the final foam properties.

4.4 mixing efficiency:

proper mixing of the components is essential for ensuring uniform distribution of dmcha and other additives. inadequate mixing can lead to localized variations in reaction rates, resulting in uneven cell structure and inconsistent foam properties.

4.5 isocyanate index:

the isocyanate index (the ratio of isocyanate groups to hydroxyl groups) plays a crucial role in determining the foam’s properties. deviations from the optimal isocyanate index can affect the crosslinking density and the overall mechanical properties of the foam. adjustments to the dmcha dosage may be necessary to compensate for variations in the isocyanate index.

5. safety considerations:

dmcha is a chemical substance and should be handled with care. it is essential to follow proper safety procedures to minimize the risk of exposure and potential health hazards.

5.1 hazard identification:

  • irritant: dmcha can cause irritation to the skin, eyes, and respiratory tract.
  • flammable: dmcha is a flammable liquid and should be kept away from sources of ignition.
  • harmful if swallowed: ingestion of dmcha can be harmful.

5.2 safety precautions:

  • personal protective equipment (ppe): wear appropriate ppe, including gloves, safety glasses, and a respirator, when handling dmcha.
  • ventilation: ensure adequate ventilation in the work area to minimize exposure to vapors.
  • storage: store dmcha in a cool, dry, and well-ventilated area, away from incompatible materials.
  • first aid: in case of contact with skin or eyes, flush immediately with plenty of water and seek medical attention. if swallowed, do not induce vomiting and seek medical attention immediately.

5.3 regulatory information:

consult the safety data sheet (sds) for detailed information on the hazards, handling, and storage of dmcha. comply with all applicable local, regional, and national regulations regarding the use and disposal of dmcha.

6. dmcha vs. other catalysts:

dmcha is one of many amine catalysts used in pu foam production. each catalyst possesses unique properties and advantages. comparing dmcha to other common catalysts can help in selecting the most suitable option for a specific application.

6.1 comparison table:

catalyst primary effect activity odor advantages disadvantages common applications
dmcha blowing moderate to high relatively low good balance of blowing and gelling, relatively low odor, cost-effective. can cause yellowing in some formulations, may require careful dosage control. rigid and semi-rigid pu foams, spray foams.
triethylenediamine (teda) gelling high strong strong gelling catalyst, promotes rapid curing, good for improving dimensional stability. strong odor, can lead to shrinkage in some formulations, may be more expensive than dmcha. flexible pu foams, high-resiliency foams.
dimethylaminoethanol (dmea) blowing & gelling moderate moderate balanced blowing and gelling activity, promotes good cell structure. can be more sensitive to moisture, may require careful formulation. flexible and rigid pu foams, integral skin foams.
dabco 33-lv® gelling high moderate delayed action catalyst, provides longer cream time, good for complex mold filling. can be more expensive than dmcha, requires careful handling. automotive seating, molded foams.
pentamethyldiethylenetriamine (pmdeta) blowing & gelling very high strong highly active catalyst, promotes rapid reaction rates, good for low-density foams. can be difficult to control the reaction, may cause shrinkage, strong odor. microcellular foams, specialty foams.

6.2 considerations for catalyst selection:

  • desired foam properties: the choice of catalyst should be based on the desired foam properties, such as density, cell structure, and mechanical strength.
  • reaction rate: the desired reaction rate will influence the selection of catalyst. faster-reacting catalysts are suitable for applications requiring rapid curing.
  • odor profile: the odor of the catalyst is an important consideration, especially for indoor applications. dmcha has a relatively low odor compared to some other amine catalysts.
  • cost: the cost of the catalyst is a significant factor in the overall formulation cost. dmcha offers a good balance of cost and performance.
  • regulatory requirements: compliance with environmental regulations may restrict the use of certain catalysts.

7. troubleshooting common issues:

proper use of dmcha requires an understanding of potential problems that can arise during the foaming process. here are some common issues and troubleshooting tips:

issue possible cause solution
slow reaction time low dmcha dosage, low temperature, inactive polyol, high humidity, incorrect isocyanate index. increase dmcha dosage (gradually), increase temperature, check polyol activity, adjust water content, verify isocyanate index.
foam collapse excessive dmcha dosage, high temperature, excessive water content, poor mixing, unstable surfactant. reduce dmcha dosage, decrease temperature, reduce water content, improve mixing efficiency, use a more stable surfactant.
non-uniform cell structure inadequate mixing, uneven temperature distribution, incorrect surfactant dosage, poor raw material quality. improve mixing efficiency, ensure uniform temperature distribution, adjust surfactant dosage, check raw material quality.
shrinkage excessive gelling catalyst, low isocyanate index, insufficient crosslinking. reduce gelling catalyst dosage, increase isocyanate index, use a crosslinking agent.
yellowing high dmcha dosage, exposure to uv light, incompatible additives. reduce dmcha dosage, use uv stabilizers, select compatible additives.
surface tackiness incomplete reaction, insufficient catalyst, low temperature. increase dmcha dosage, increase temperature, ensure complete mixing.

8. future trends:

the pu foam industry is constantly evolving, with ongoing research and development efforts focused on improving foam properties, reducing environmental impact, and enhancing processing efficiency. future trends related to dmcha and other amine catalysts include:

  • development of bio-based catalysts: research is underway to develop amine catalysts derived from renewable resources, reducing reliance on fossil fuels.
  • catalyst blends with enhanced selectivity: combining different catalysts to achieve a synergistic effect, allowing for more precise control over the blowing and gelling reactions.
  • low-emission catalysts: developing catalysts with lower volatile organic compound (voc) emissions to improve air quality and reduce environmental impact.
  • catalysts for specific applications: tailoring catalyst formulations to meet the specific requirements of niche applications, such as high-performance insulation foams and biomedical foams.
  • use of modeling and simulation: employing computational modeling to predict catalyst performance and optimize formulations, reducing the need for extensive experimental trials.

9. conclusion:

n,n-dimethylcyclohexylamine (dmcha) remains a widely used and effective catalyst in polyurethane foam production. its ability to selectively promote the blowing reaction, coupled with its relatively low odor and cost-effectiveness, makes it a valuable tool for pu foam manufacturers. understanding the properties, mechanism of action, dosage recommendations, influencing factors, safety considerations, and comparative advantages of dmcha is essential for achieving optimal foam properties and consistent results. as the pu foam industry continues to evolve, ongoing research and development efforts will likely lead to further advancements in catalyst technology, improving foam performance and reducing environmental impact. by carefully considering the various factors discussed in this article, pu foam manufacturers can effectively utilize dmcha to produce high-quality foams that meet the demands of diverse applications.

10. references:

  • oertel, g. (ed.). (1993). polyurethane handbook. hanser publishers.
  • woods, g. (1990). the ici polyurethanes book. john wiley & sons.
  • rand, l., & frisch, k. c. (1962). polyurethanes: chemistry and technology. interscience publishers.
  • szycher, m. (1999). szycher’s handbook of polyurethanes. crc press.
  • ashida, k. (2006). polyurethane and related foams: chemistry and technology. crc press.
  • provisional patent application (cn 202111430960.2). a polyurethane foam catalyst composition and a preparation method and application thereof.
  • chinese patent application (cn 110734559 a). method for preparing polyurethane foam with high opening cell rate.
  • zhang, x., et al. (2018). effects of amine catalysts on the properties of rigid polyurethane foams. journal of applied polymer science, 135(15), 46164.

disclaimer: this article provides general information and should not be considered as professional advice. the information provided is based on available literature and general industry practices. users are responsible for conducting their own research and testing to determine the suitability of dmcha for their specific applications. the authors and publisher disclaim any liability for any damages arising from the use of this information. always consult with a qualified professional before making any decisions related to pu foam formulation or production. ⚙️🧪

sales contact：sales@newtopchem.com

n,n-dimethylcyclohexylamine catalyst for pu foam production
Published by BDMAEE on | Permalink

n,n-dimethylcyclohexylamine: a catalyst for polyurethane foam production

introduction

n,n-dimethylcyclohexylamine (dmcha), with the chemical formula c8h17n, is a tertiary amine widely used as a catalyst in the production of polyurethane (pu) foams. it is a colorless to slightly yellow liquid with a characteristic amine odor. dmcha’s efficacy stems from its ability to accelerate both the polyol-isocyanate (gelling) and water-isocyanate (blowing) reactions, thereby influencing the foam’s structure, density, and overall properties. this article provides a comprehensive overview of dmcha, covering its properties, applications, catalytic mechanism, handling precautions, and market trends, with particular emphasis on its role in pu foam synthesis.

1. physical and chemical properties

dmcha exhibits a unique set of physical and chemical properties that contribute to its effectiveness as a pu foam catalyst. these properties are summarized in the table below:

property value unit reference
molecular weight 127.23 g/mol [1]
appearance colorless to slightly yellow liquid – [1]
odor amine-like – [1]
boiling point 160-165 °c [1]
melting point -70 °c [2]
flash point 41 °c [1]
density (20°c) 0.845-0.855 g/cm³ [1]
refractive index (20°c) 1.448-1.452 – [1]
solubility in water slightly soluble – [2]
solubility in organic solvents soluble in most organic solvents – [2]
vapor pressure (20°c) 2.7 mm hg [3]
ph (1% aqueous solution) 10.5-11.5 – [3]

2. synthesis and production

dmcha is typically synthesized through the catalytic reductive alkylation of cyclohexanone with dimethylamine. the reaction is generally carried out in the presence of a hydrogenation catalyst, such as nickel or palladium supported on a suitable carrier. the reaction scheme can be represented as follows:

cyclohexanone + dimethylamine + h2 → dmcha + h2o

the reaction conditions, including temperature, pressure, and catalyst loading, are carefully controlled to optimize the yield and selectivity of the reaction. different production methods exist, each with varying efficiency and environmental impact. improvements in catalyst design and process optimization continue to be areas of active research. for instance, novel catalysts that operate at lower temperatures and pressures, potentially reducing energy consumption and waste generation, are under investigation [4].

3. applications in polyurethane foam production

dmcha’s primary application lies in the production of polyurethane foams. pu foams are versatile materials used in a wide range of applications, including:

  • insulation: building insulation, refrigerators, freezers. 🏠
  • furniture: mattresses, cushions, upholstery. 🪑
  • automotive: seats, dashboards, sound insulation. 🚗
  • packaging: protective packaging for fragile goods. 📦
  • footwear: shoe soles and insoles. 👟

in pu foam synthesis, dmcha acts as a catalyst, accelerating the reaction between polyols and isocyanates to form the polyurethane polymer. simultaneously, it promotes the reaction between water and isocyanates, generating carbon dioxide (co2), which acts as a blowing agent to create the cellular structure of the foam.

3.1. role as a catalyst:

dmcha’s catalytic activity stems from its tertiary amine structure. tertiary amines act as nucleophiles, facilitating the reaction between the isocyanate group (-nco) and the hydroxyl group (-oh) of the polyol. the proposed mechanism involves the following steps:

  1. complex formation: dmcha initially forms a complex with either the polyol or the isocyanate. this complexation activates the reactant, making it more susceptible to nucleophilic attack.
  2. proton abstraction: dmcha abstracts a proton from the hydroxyl group of the polyol, increasing its nucleophilicity. this activated polyol then attacks the electrophilic carbon of the isocyanate.
  3. polymerization: the reaction between the activated polyol and the isocyanate forms a urethane linkage, extending the polymer chain.
  4. regeneration: dmcha is regenerated after the reaction, allowing it to participate in further catalytic cycles.

similarly, dmcha catalyzes the water-isocyanate reaction, leading to the formation of an amine and co2. the amine further reacts with isocyanate to form a urea linkage. the co2 gas expands the reacting mixture, creating the foam structure. the balance between these two reactions (gelling and blowing) is crucial for achieving the desired foam properties.

3.2. impact on foam properties:

the concentration of dmcha, along with other factors like temperature and reactant ratios, significantly influences the properties of the resulting pu foam.

  • cell size and structure: dmcha influences the rate of gas generation (co2) and the rate of polymer crosslinking. by controlling these rates, the cell size and uniformity of the foam can be tailored. higher concentrations of dmcha generally lead to finer cell structures and increased foam density [5].
  • density: the amount of co2 generated directly affects the foam density. dmcha’s influence on the blowing reaction contributes to the overall density of the foam.
  • hardness and flexibility: by influencing the crosslinking density of the polymer matrix, dmcha can affect the hardness and flexibility of the foam.
  • open vs. closed cell content: dmcha can influence the ratio of open cells (interconnected cells) to closed cells (isolated cells). open-cell foams are generally softer and more breathable, while closed-cell foams offer better insulation properties.
  • cream time, rise time, and tack-free time: dmcha affects the reaction kinetics and, hence, the cream time (time until the mixture starts to cream), rise time (time until the foam reaches its maximum height), and tack-free time (time until the foam surface is no longer sticky).

3.3. formulation considerations:

the optimal concentration of dmcha in a pu foam formulation depends on several factors, including:

  • type of polyol: different polyols have varying reactivity, requiring adjustments in catalyst concentration.
  • type of isocyanate: the isocyanate index (ratio of isocyanate to polyol) influences the reaction rate and the amount of co2 generated.
  • desired foam properties: the target cell size, density, and mechanical properties dictate the required catalyst concentration.
  • other additives: surfactants, flame retardants, and other additives can interact with the catalyst, requiring further adjustments.

formulators carefully balance these factors to achieve the desired foam characteristics. it is common practice to use dmcha in combination with other catalysts, such as tin catalysts, to achieve a synergistic effect and optimize the reaction profile [6].

4. safety and handling

dmcha is a hazardous chemical and requires careful handling to ensure safety.

  • toxicity: dmcha is a skin and eye irritant. inhalation of dmcha vapors can cause respiratory irritation. prolonged or repeated exposure can lead to skin sensitization.
  • flammability: dmcha is a flammable liquid and should be kept away from heat, sparks, and open flames.
  • storage: dmcha should be stored in tightly closed containers in a cool, dry, and well-ventilated area.
  • personal protective equipment (ppe): when handling dmcha, it is essential to wear appropriate ppe, including safety glasses, gloves, and a respirator if ventilation is inadequate.
  • first aid: in case of skin contact, wash thoroughly with soap and water. in case of eye contact, flush with plenty of water for at least 15 minutes and seek medical attention. if inhaled, move to fresh air and seek medical attention if symptoms persist. if swallowed, do not induce vomiting and seek immediate medical attention.

safety data sheet (sds): a comprehensive sds should be consulted before handling dmcha. this document provides detailed information on the chemical’s hazards, handling precautions, and emergency procedures.

5. environmental considerations

the use of amine catalysts in pu foam production has raised environmental concerns, primarily due to the release of volatile organic compounds (vocs) and potential odor issues. dmcha, being a relatively volatile amine, can contribute to these concerns.

  • voc emissions: dmcha can evaporate from the foam during production and use, contributing to voc emissions. vocs can contribute to smog formation and other environmental problems.
  • odor: the characteristic amine odor of dmcha can be unpleasant, especially in enclosed spaces.
  • alternative catalysts: research is ongoing to develop alternative catalysts with lower voc emissions and reduced odor. these alternatives include:
    • reactive amine catalysts: these catalysts are designed to be incorporated into the polymer matrix, reducing their volatility [7].
    • blocked amine catalysts: these catalysts are deactivated during the initial stages of the reaction and are only activated under specific conditions, reducing premature emissions [8].
    • metal catalysts: certain metal catalysts, such as bismuth carboxylates, can also catalyze the pu reaction with lower voc emissions than amine catalysts [9].

6. market trends

the global market for pu foam catalysts is driven by the growing demand for pu foams in various applications. the market is characterized by increasing demand for more environmentally friendly and sustainable solutions.

  • growing demand for pu foams: the increasing demand for pu foams in construction, automotive, and furniture industries is driving the growth of the pu foam catalyst market.
  • shift towards low-emission catalysts: due to growing environmental concerns and stricter regulations, there is a shift towards the use of low-emission catalysts, such as reactive amines, blocked amines, and metal catalysts.
  • regional market trends: the asia-pacific region is expected to be the fastest-growing market for pu foam catalysts, driven by the rapid growth of the construction and automotive industries in countries like china and india.

7. quality control and standards

ensuring the quality of dmcha is crucial for consistent pu foam production. standard quality control measures include:

  • gas chromatography (gc): used to determine the purity of dmcha and identify any impurities.
  • titration: used to determine the amine content of dmcha.
  • water content analysis: determines the amount of water present in the dmcha sample, as water can interfere with the pu reaction.
  • refractive index measurement: used to verify the identity and purity of dmcha.
  • density measurement: used to verify the identity and purity of dmcha.

8. comparison with other catalysts

dmcha is just one of many catalysts used in pu foam production. other common catalysts include:

catalyst type examples advantages disadvantages
tertiary amines triethylenediamine (teda), dimethylaminoethanol (dmea) efficient, versatile, relatively inexpensive can have strong odor, contribute to voc emissions
organotin catalysts dibutyltin dilaurate (dbtdl), stannous octoate strong gelling catalysts, promote rapid curing toxic, environmentally harmful, can cause yellowing of foam
metal carboxylate catalysts bismuth carboxylates, zinc carboxylates lower voc emissions, less toxic than organotin catalysts can be less reactive than amine catalysts, may require higher concentrations
reactive amine catalysts various modified amines lower voc emissions, incorporated into the polymer matrix can be more expensive than traditional amine catalysts, may have limited availability
blocked amine catalysts various blocked amine compounds lower voc emissions, delayed action allows for better processing can be more expensive than traditional amine catalysts, require specific activation conditions

the choice of catalyst depends on the specific application and the desired foam properties. often, a combination of catalysts is used to achieve the optimal balance of reactivity, foam properties, and environmental impact.

9. future trends and research

future research in the field of dmcha and pu foam catalysts is focused on:

  • developing more sustainable catalysts: research is focused on developing catalysts based on renewable resources and with lower environmental impact.
  • improving catalyst efficiency: researchers are working to develop catalysts that can be used at lower concentrations and still achieve the desired foam properties.
  • developing catalysts for specific applications: research is focused on developing catalysts that are tailored for specific pu foam applications, such as high-resilience foams or flame-retardant foams.
  • understanding the catalytic mechanism in detail: detailed kinetic studies and computational modeling are being used to gain a deeper understanding of the catalytic mechanism, leading to the design of more effective catalysts.

conclusion

n,n-dimethylcyclohexylamine (dmcha) remains a significant catalyst in the production of polyurethane foams, contributing to the formation of the desired cellular structure and overall foam properties. while its efficacy is well-established, environmental concerns regarding voc emissions are driving the development and adoption of alternative, lower-emission catalysts. future research will continue to focus on creating more sustainable and efficient catalytic systems for pu foam production, balancing performance with environmental responsibility.

references

[1] sigma-aldrich. n,n-dimethylcyclohexylamine. product information. (accessed: [date]).

[2] pubchem. n,n-dimethylcyclohexylamine. national center for biotechnology information. (accessed: [date]).

[3] . technical data sheet: n,n-dimethylcyclohexylamine. (accessed: [date]).

[4] zhang, l., et al. "novel catalysts for polyurethane synthesis: a review." journal of applied polymer science, vol. 135, no. 45, 2018.

[5] randall, d., and s. lee. the polyurethanes book. john wiley & sons, 2002.

[6] szycher, m. szycher’s handbook of polyurethanes. crc press, 2013.

[7] rosthauser, j. w., and k. b. hayes. "reactive amine catalysts for polyurethane foams." journal of cellular plastics, vol. 32, no. 6, 1996, pp. 521-542.

[8] mark, h. f., et al. encyclopedia of polymer science and technology. john wiley & sons, 2002.

[9] melchiors, m., et al. "bismuth carboxylates as catalysts for polyurethane production." polymer chemistry, vol. 5, no. 2, 2014, pp. 435-442.

disclaimer: this article is for informational purposes only and should not be considered as professional advice. always consult with qualified professionals for specific applications and safety procedures.

sales contact：sales@newtopchem.com

n,n-dimethylcyclohexylamine cas 98-94-2 technical specifications
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n,n-dimethylcyclohexylamine: a comprehensive overview

introduction

n,n-dimethylcyclohexylamine (dmcha), with the chemical abstracts service (cas) registry number 98-94-2, is a tertiary amine characterized by a cyclohexyl ring substituted with two methyl groups attached to the nitrogen atom. this compound is a clear to pale yellow liquid at room temperature and atmospheric pressure. dmcha is a versatile chemical intermediate widely employed in various industrial applications, particularly in the production of polyurethane foams, epoxy resins, and as a catalyst in organic synthesis. this article provides a comprehensive overview of dmcha, covering its physical and chemical properties, specifications, synthesis methods, applications, safety information, and regulatory status. the information presented aims to offer a detailed understanding of dmcha for researchers, industrial professionals, and anyone seeking information on this important chemical compound.

basic information

property value/description
iupac name n,n-dimethylcyclohexanamine
common name n,n-dimethylcyclohexylamine (dmcha)
cas registry number 98-94-2
molecular formula c8h17n
molecular weight 127.23 g/mol
structural formula (cyclohexyl)-n(ch3)2
appearance clear to pale yellow liquid

physical and chemical properties

understanding the physical and chemical properties of dmcha is crucial for its safe handling, storage, and application. these properties determine its behavior in different environments and its reactivity with other chemicals.

property value reference
boiling point 159-161 °c (at 760 mmhg) [1, 2]
melting point -60 °c [1, 2]
flash point 43 °c (closed cup) [1, 2]
density 0.845 g/cm3 at 20 °c [1, 2]
refractive index 1.446-1.448 at 20 °c [1, 2]
vapor pressure 2.7 mmhg at 20 °c [3]
solubility in water slightly soluble (approximately 2 g/l at 20°c) [1, 4]
solubility in organic solvents soluble in most common organic solvents [1, 4]
pka 10.2 (conjugate acid) [5]
viscosity 1.4 cp at 25 °c [6]
auto-ignition temperature 220 °c [7]

explanation of key properties:

  • boiling point: dmcha’s boiling point of approximately 160 °c indicates that it is a relatively volatile liquid.
  • flash point: the flash point of 43 °c signifies that dmcha is flammable and requires careful handling to avoid fire hazards.
  • density: its density of 0.845 g/cm3 means it is less dense than water and will float on water.
  • solubility: the limited solubility in water makes it necessary to use organic solvents for many applications. the good solubility in organic solvents facilitates its incorporation into various formulations.
  • pka: the pka value indicates the basicity of the amine. dmcha is a relatively strong base, which is crucial for its catalytic activity in various reactions.

technical specifications

the technical specifications of dmcha define the quality and purity requirements for its various applications. different grades of dmcha may exist depending on the intended use. here’s a typical example of technical specifications:

parameter specification test method
appearance clear to pale yellow liquid visual inspection
assay (gc) ≥ 99.0% gas chromatography
water content (kf) ≤ 0.5% karl fischer titration
color (apha) ≤ 20 astm d1209
cyclohexylamine ≤ 0.1% gas chromatography
n-methylcyclohexylamine ≤ 0.1% gas chromatography
refractive index (20°c) 1.446 – 1.448 refractometry

explanation of specifications:

  • assay (gc): this specification ensures the purity of the dmcha, indicating the percentage of the desired compound present in the sample. gas chromatography (gc) is a common analytical technique for determining the composition of volatile organic compounds.
  • water content (kf): the water content specification limits the amount of water present in the dmcha. excessive water can interfere with certain reactions and degrade the product. karl fischer titration is a standard method for determining water content.
  • color (apha): the apha color scale measures the yellowness of the liquid. a lower apha value indicates a clearer, less colored product.
  • cyclohexylamine and n-methylcyclohexylamine: these are potential impurities that may be present in the dmcha. their concentrations are limited to ensure the quality and performance of the product.
  • refractive index: this is a physical property that can be used to verify the identity and purity of the dmcha.

synthesis methods

dmcha can be synthesized through various methods, including reductive amination and alkylation of cyclohexylamine.

1. reductive amination:

this method involves the reaction of cyclohexanone with dimethylamine in the presence of a reducing agent. the reaction proceeds through an intermediate imine or enamine, which is subsequently reduced to the desired amine.

cyclohexanone + dimethylamine + reducing agent → dmcha + byproducts

common reducing agents include:

  • hydrogen gas with a metal catalyst (e.g., ni, pd, pt) [8]
  • sodium borohydride (nabh4) [9]
  • sodium cyanoborohydride (nabh3cn) [10]

advantages: this method offers relatively high yields and can be conducted under mild conditions.

disadvantages: the use of metal catalysts or specialized reducing agents can increase the cost of production.

2. alkylation of cyclohexylamine:

this method involves the alkylation of cyclohexylamine with methylating agents.

cyclohexylamine + 2 methylating agents → dmcha + byproducts

common methylating agents include:

  • methyl iodide (ch3i) [11]
  • dimethyl sulfate ((ch3)2so4) [12]

advantages: this method is relatively straightforward and can be conducted in a variety of solvents.

disadvantages: the use of highly toxic methylating agents requires careful handling and disposal. the reaction may also produce unwanted byproducts.

3. catalytic amination:

this method involves reacting cyclohexanol with dimethylamine over a heterogeneous catalyst.

cyclohexanol + dimethylamine → dmcha + water

the reaction typically uses catalysts based on copper, nickel, or other transition metals supported on alumina or silica. [13, 14]

advantages: this method can be performed in the gas phase and may offer a more sustainable route compared to methods using stoichiometric reducing agents.

disadvantages: the catalyst activity and selectivity can be affected by reaction conditions and catalyst poisoning.

reaction mechanism (reductive amination with hydrogen):

  1. imine formation: cyclohexanone reacts with dimethylamine to form an imine intermediate, releasing water.
  2. adsorption: the imine adsorbs onto the surface of the metal catalyst.
  3. hydrogenation: hydrogen gas dissociates on the catalyst surface and reduces the imine to dmcha.
  4. desorption: dmcha desorbs from the catalyst surface.

applications

dmcha finds widespread applications in various industries due to its unique chemical properties. the main applications include:

  1. polyurethane production: dmcha is primarily used as a catalyst in the production of polyurethane foams, elastomers, and coatings. it acts as a tertiary amine catalyst, accelerating the reaction between isocyanates and polyols. [15, 16]

    • foam production: dmcha promotes both the blowing (reaction of isocyanate with water) and gelling (reaction of isocyanate with polyol) reactions, which are essential for the formation of polyurethane foams.

    • elastomers and coatings: dmcha is also used in the production of polyurethane elastomers and coatings, where it contributes to the crosslinking and curing processes.

  2. epoxy resin curing: dmcha can act as a curing agent or accelerator for epoxy resins. it promotes the polymerization of epoxy resins, leading to the formation of crosslinked networks with desirable mechanical and thermal properties. [17, 18]

  3. organic synthesis: dmcha is used as a base catalyst and a reagent in various organic reactions. [19]

    • esterification: it can catalyze the esterification of carboxylic acids.
    • transesterification: dmcha can facilitate the transesterification of esters.
    • michael addition: it can promote michael addition reactions.
    • wittig reactions: dmcha can be used as a base in wittig reactions.

  4. pharmaceuticals: dmcha derivatives have found applications in the synthesis of various pharmaceutical compounds. [20]

  5. corrosion inhibitors: dmcha and its derivatives can be used as corrosion inhibitors for metals. [21]

  6. water treatment: dmcha can be used as a neutralizer and scale inhibitor in water treatment processes. [22]

safety information

dmcha is classified as a hazardous chemical and requires careful handling and storage. understanding its hazards and implementing appropriate safety measures is crucial to prevent accidents and protect human health and the environment.

hazard class description
flammable liquids (category 3) dmcha is a flammable liquid and vapor.
acute toxicity (oral, category 4) harmful if swallowed.
acute toxicity (dermal, category 4) harmful in contact with skin.
skin corrosion/irritation (category 1b) causes severe skin burns and eye damage.
serious eye damage/eye irritation (category 1) causes serious eye damage.
specific target organ toxicity – single exposure (category 3) may cause respiratory irritation.

safety precautions:

  • handling:
    • wear appropriate personal protective equipment (ppe), including gloves, safety goggles, and a respirator if necessary.
    • handle in a well-ventilated area.
    • avoid contact with skin, eyes, and clothing.
    • avoid breathing vapors or mist.
    • wash thoroughly after handling.
  • storage:
    • store in a tightly closed container in a cool, dry, and well-ventilated area.
    • keep away from heat, sparks, and open flames.
    • store away from incompatible materials (e.g., strong oxidizing agents, strong acids).
    • ground containers to prevent static electricity buildup.
  • first aid:
    • eye contact: rinse immediately with plenty of water for at least 15 minutes and seek medical attention.
    • skin contact: wash affected area with soap and water. remove contaminated clothing and shoes. seek medical attention if irritation persists.
    • inhalation: remove to fresh air. if breathing is difficult, administer oxygen. seek medical attention.
    • ingestion: do not induce vomiting. rinse mouth with water. seek immediate medical attention.
  • firefighting:
    • use water spray, alcohol-resistant foam, dry chemical, or carbon dioxide to extinguish fires.
    • wear self-contained breathing apparatus (scba) and protective clothing to prevent exposure to vapors and combustion products.
  • spill response:
    • contain the spill and prevent it from entering waterways or sewers.
    • absorb the spill with an inert material (e.g., sand, vermiculite).
    • collect the absorbed material in a sealed container for disposal.
    • ventilate the area and wash the spill site with water.

personal protective equipment (ppe):

  • gloves: chemical-resistant gloves (e.g., nitrile, neoprene)
  • eye protection: safety goggles or face shield
  • respiratory protection: respirator with an organic vapor cartridge if ventilation is inadequate
  • clothing: chemical-resistant apron or coveralls

regulatory information

the regulatory status of dmcha varies depending on the country and region. it is important to comply with all applicable regulations regarding the manufacture, transportation, storage, use, and disposal of dmcha.

  • globally harmonized system (ghs): dmcha is classified under the ghs and is assigned hazard statements and precautionary statements as described in the safety information section.
  • european union (eu): dmcha is subject to reach (registration, evaluation, authorisation and restriction of chemicals) regulations. manufacturers and importers are required to register dmcha with the european chemicals agency (echa).
  • united states (us): dmcha is subject to regulations under the toxic substances control act (tsca).
  • china: dmcha is listed in the inventory of existing chemical substances in china (iecsc).

environmental considerations

dmcha can pose environmental risks if released into the environment. it is important to minimize its release and to properly dispose of waste containing dmcha.

  • biodegradability: dmcha is not readily biodegradable.
  • aquatic toxicity: dmcha is toxic to aquatic organisms.
  • waste disposal: dispose of dmcha waste in accordance with local, state, and federal regulations. incineration is a common method for disposing of dmcha waste.

conclusion

n,n-dimethylcyclohexylamine (dmcha) is a versatile chemical compound with a wide range of applications in various industries. its key properties, including its boiling point, flash point, and basicity, make it suitable for use as a catalyst in polyurethane production, an epoxy resin curing agent, and a reagent in organic synthesis. however, dmcha is also a hazardous chemical and requires careful handling and storage to prevent accidents and protect human health and the environment. by understanding the properties, applications, safety information, and regulatory status of dmcha, users can ensure its safe and responsible use. continuous research and development efforts are focused on improving the synthesis methods, expanding the applications, and enhancing the safety profile of dmcha.

literature references

[1] sigma-aldrich. n,n-dimethylcyclohexylamine. safety data sheet.

[2] alfa aesar. n,n-dimethylcyclohexylamine. safety data sheet.

[3] yaws, c.l. the yaws handbook of vapor pressure: antoine coefficients. gulf professional publishing, 2015.

[4] riddick, j.a.; bunger, w.b.; sakano, t.k. organic solvents: physical properties and methods of purification, 4th edition. wiley-interscience, 1986.

[5] perrin, d.d. dissociation constants of organic bases in aqueous solution. iupac chemical data series, butterworths, london, 1965.

[6] daubert, t.e.; danner, r.p. physical and thermodynamic properties of pure chemicals data compilation. hemisphere publishing corp, 1989.

[7] bretherick, l. bretherick’s handbook of reactive chemical hazards. butterworth-heinemann, 2016.

[8] smith, m. b., & march, j. march’s advanced organic chemistry: reactions, mechanisms, and structure. john wiley & sons, 2007.

[9] hutchins, r. o., et al. "sodium borohydride in trifluoroacetic acid: a mild and selective reagent for the reduction of imines to amines." the journal of organic chemistry, 1975, 40(26), 3734-3736.

[10] borch, r. f., bernstein, m. d., & durst, h. d. "cyanohydridoborate anion as a selective reducing agent." journal of the american chemical society, 1971, 93(12), 2897-2904.

[11] vogel, a.i. vogel’s textbook of practical organic chemistry. longman, 1989.

[12] furniss, b.s., et al. vogel’s textbook of practical organic chemistry, 5th edition. longman scientific & technical, 1989.

[13] shimizu, k.-i., et al. "catalytic amination of alcohols with ammonia over metal oxides." catalysis surveys from asia, 2011, 15(3-4), 109-123.

[14] opanasenko, m. v., et al. "selective amination of alcohols with ammonia over supported copper catalysts." journal of catalysis, 2014, 311, 106-116.

[15] oertel, g. polyurethane handbook. hanser gardner publications, 1994.

[16] rand, l.; reegen, s.l. "amine catalysts in urethane chemistry." advances in urethane science and technology, 1971, 3, 1-52.

[17] ellis, b. chemistry and technology of epoxy resins. springer science & business media, 1993.

[18] lee, h.; neville, k. handbook of epoxy resins. mcgraw-hill, 1967.

[19] carey, f.a.; sundberg, r.j. advanced organic chemistry: part b: reactions and synthesis. springer science & business media, 2007.

[20] lednicer, d. organic chemistry of drug synthesis. john wiley & sons, 2007.

[21] roberge, p.r. handbook of corrosion engineering. mcgraw-hill, 1999.

[22] nalco chemical company. the nalco water handbook. mcgraw-hill, 1988.

sales contact：sales@newtopchem.com

n,n-dimethylcyclohexylamine use in rigid polyurethane systems
Published by BDMAEE on | Permalink

n,n-dimethylcyclohexylamine (dmcha) in rigid polyurethane systems: properties, applications, and performance

introduction

n,n-dimethylcyclohexylamine (dmcha), represented by the chemical formula c8h17n, is a tertiary amine catalyst widely employed in the production of rigid polyurethane (pur) foams. its efficacy stems from its ability to accelerate both the urethane (polyol-isocyanate) and blowing (isocyanate-water) reactions, thereby influencing the foam’s cell structure, density, and overall mechanical properties. this article provides a comprehensive overview of dmcha, encompassing its properties, mechanism of action, typical applications in rigid pur systems, factors affecting its performance, and comparative analysis with other amine catalysts.

1. properties of n,n-dimethylcyclohexylamine (dmcha)

dmcha is a colorless to slightly yellow liquid with a characteristic amine odor. its chemical structure features a cyclohexyl ring directly attached to a dimethylamino group. key physical and chemical properties are summarized in table 1.

table 1: physical and chemical properties of dmcha

property value reference
molecular weight 127.23 g/mol manufacturer sds
cas number 98-94-2 pubchem
boiling point 160-162 °c merck index
melting point -60 °c merck index
density (at 20°c) 0.845-0.855 g/cm3 manufacturer sds
flash point 41 °c (closed cup) manufacturer sds
vapor pressure (at 20°c) 1.33 hpa manufacturer sds
solubility in water slightly soluble merck index
appearance colorless to slightly yellow liquid visual observation
refractive index (at 20°c) 1.445-1.448 manufacturer sds
amine value typically between 435-455 mg koh/g titration method

2. mechanism of action in polyurethane formation

dmcha acts as a catalyst in both the polyol-isocyanate (urethane) and isocyanate-water (blowing) reactions. its catalytic activity arises from the lone pair of electrons on the nitrogen atom, which facilitates nucleophilic attack and proton abstraction.

  • urethane reaction (polyol-isocyanate): dmcha enhances the reaction between polyols and isocyanates by:

    • activating the polyol: dmcha can abstract a proton from the hydroxyl group of the polyol, creating a more nucleophilic alkoxide ion. this alkoxide ion readily attacks the electrophilic carbon atom of the isocyanate group, forming the urethane linkage.

    • activating the isocyanate: dmcha can also coordinate with the isocyanate group, increasing the polarization of the n=c bond and making it more susceptible to nucleophilic attack by the polyol.

  • blowing reaction (isocyanate-water): in the presence of water, isocyanates react to form carbamic acid, which subsequently decomposes into carbon dioxide (co2) and an amine. this co2 acts as the blowing agent, creating the cellular structure of the foam. dmcha accelerates this reaction by:

    • facilitating carbamic acid formation: dmcha acts as a general base catalyst, promoting the formation of carbamic acid by abstracting a proton from water.

    • promoting carbamic acid decomposition: dmcha can also facilitate the decomposition of carbamic acid into co2 and an amine.

the relative rates of the urethane and blowing reactions significantly influence the foam’s properties. a balanced catalysis is crucial for achieving optimal cell structure, foam density, and overall performance.

3. applications in rigid polyurethane systems

dmcha finds widespread use in various rigid pur foam applications, including:

  • insulation boards and panels: rigid pur foams are extensively used for thermal insulation in buildings, refrigerators, and other appliances. dmcha contributes to the foam’s excellent insulation properties by promoting the formation of a fine and closed-cell structure, which minimizes heat transfer.

  • spray foam insulation: dmcha is also used in spray foam applications, where the foam is applied directly onto surfaces for insulation and air sealing. the rapid reaction times facilitated by dmcha are crucial for achieving a uniform and consistent foam layer.

  • structural foam: rigid pur foams are sometimes used for structural applications, such as in sandwich panels and composite materials. dmcha helps to control the foam’s density and mechanical properties, ensuring that it can withstand the required loads.

  • appliances (refrigerators, freezers): rigid pur foams provide excellent thermal insulation in refrigerators and freezers, contributing to energy efficiency. dmcha plays a role in achieving the desired foam properties within these applications.

table 2: typical applications of dmcha in rigid pur systems

application key performance requirements dmcha’s contribution
insulation boards & panels high thermal insulation, low density promotes fine, closed-cell structure, reducing thermal conductivity.
spray foam insulation rapid cure, good adhesion, uniformity accelerates reaction, ensures uniform foam application and strong adhesion to substrates.
structural foam high compressive strength, dimensional stability controls foam density and cell structure, enhancing mechanical properties.
appliance insulation high thermal resistance, low odor contributes to efficient insulation with optimized cell size; careful formulation minimizes odor.

4. factors affecting dmcha performance

several factors can influence the performance of dmcha in rigid pur systems:

  • concentration: the concentration of dmcha directly affects the reaction rates. higher concentrations generally lead to faster reaction times, but excessive amounts can result in undesirable side reactions, such as trimerization of isocyanate or scorching of the foam. therefore, the optimal concentration needs to be carefully determined based on the specific formulation and application.

  • temperature: temperature significantly affects the kinetics of the urethane and blowing reactions. higher temperatures generally accelerate both reactions. however, the relative rates of the two reactions may change with temperature, potentially affecting the foam’s cell structure and properties.

  • water content: the water content of the formulation is critical for the blowing reaction. insufficient water can lead to a dense foam with poor cell structure, while excessive water can result in foam collapse or instability. the dmcha concentration needs to be adjusted accordingly to maintain a balanced reaction.

  • polyol type and molecular weight: the type and molecular weight of the polyol influence the reactivity of the hydroxyl groups and the overall viscosity of the system. dmcha’s catalytic activity may need to be adjusted to compensate for these variations.

  • isocyanate index: the isocyanate index, defined as the ratio of isocyanate groups to hydroxyl groups, affects the crosslinking density and the overall mechanical properties of the foam. an appropriate isocyanate index is essential for achieving the desired foam characteristics. dmcha concentration can influence the speed with which the optimal crosslinking density is achieved.

  • presence of other additives: the presence of other additives, such as surfactants, flame retardants, and stabilizers, can also influence dmcha’s performance. some additives may interact with dmcha or affect the reaction kinetics.

table 3: factors influencing dmcha performance

factor effect on reaction rates potential impact on foam properties mitigation strategies
concentration proportional fast reaction, potential scorching, poor cell structure if excessive optimize concentration based on formulation and application.
temperature exponential altered reaction balance, cell structure variations control temperature during processing; use temperature-stable catalysts.
water content direct correlation density variations, foam collapse (excess), poor cell structure (deficit) control water content accurately; adjust dmcha concentration accordingly.
polyol type/mw variable altered reactivity, viscosity changes adjust dmcha concentration based on polyol characteristics.
isocyanate index affects crosslinking changes in mechanical properties, dimensional stability maintain optimal isocyanate index for desired foam properties.
other additives variable potential interactions with dmcha, altered reaction kinetics evaluate additive compatibility; adjust dmcha concentration if necessary.

5. comparison with other amine catalysts

dmcha is often compared with other tertiary amine catalysts, such as triethylenediamine (teda) and bis-(2-dimethylaminoethyl)ether (bdmaee), in terms of their catalytic activity, selectivity, and impact on foam properties.

  • triethylenediamine (teda): teda is a strong gelling catalyst that primarily promotes the urethane reaction. it generally leads to faster reaction times and higher crosslinking density compared to dmcha. however, teda can also result in a more brittle foam with a less uniform cell structure.

  • bis-(2-dimethylaminoethyl)ether (bdmaee): bdmaee is a blowing catalyst that primarily promotes the isocyanate-water reaction. it generally leads to a lower density foam with a finer cell structure compared to dmcha. however, bdmaee can also result in a slower cure time and a more open-cell structure.

the choice of catalyst depends on the specific requirements of the application. dmcha offers a good balance between gelling and blowing catalysis, making it a versatile option for a wide range of rigid pur foam applications. it is often used in combination with other amine catalysts to achieve the desired foam properties.

table 4: comparison of dmcha with other amine catalysts

catalyst primary effect advantages disadvantages typical applications
dmcha balanced gelling & blowing versatile, good cell structure, balanced properties can be less reactive than teda, slower cure than teda in some systems insulation panels, spray foam, structural foam
teda gelling fast reaction, high crosslinking density brittle foam, less uniform cell structure high-density foam, structural components
bdmaee blowing low density foam, fine cell structure slower cure time, open-cell structure low-density insulation, flexible foam applications (sometimes in blends)

6. safety and handling

dmcha is a corrosive and flammable liquid. it should be handled with care and appropriate personal protective equipment (ppe) should be worn, including gloves, safety glasses, and a respirator. dmcha should be stored in a cool, dry, and well-ventilated area, away from incompatible materials such as strong acids and oxidizers. refer to the manufacturer’s safety data sheet (sds) for detailed safety information.

7. future trends and development

research efforts are focused on developing new and improved amine catalysts that offer enhanced performance, reduced emissions, and improved safety profiles. some of the ongoing research areas include:

  • reduced emissions catalysts: efforts are being made to develop catalysts with lower volatility and odor, reducing emissions during foam production and improving indoor air quality.

  • blocked amine catalysts: blocked amine catalysts are designed to be inactive at room temperature and become active only at elevated temperatures. this allows for better control over the reaction kinetics and improved foam properties.

  • metal-based catalysts: metal-based catalysts, such as tin and bismuth compounds, are also used in polyurethane production. these catalysts can offer different catalytic activities and selectivity compared to amine catalysts.

  • bio-based catalysts: research is being conducted on developing bio-based amine catalysts derived from renewable resources. these catalysts offer a more sustainable alternative to traditional petroleum-based catalysts.

conclusion

n,n-dimethylcyclohexylamine (dmcha) remains a widely used and effective tertiary amine catalyst in the production of rigid polyurethane foams. its balanced catalytic activity, promoting both urethane and blowing reactions, contributes to the desirable cell structure, density, and mechanical properties of the foam. understanding the factors that influence dmcha performance, along with the comparison with other amine catalysts, allows for optimized formulation and processing to meet the specific requirements of various applications. ongoing research efforts are focused on developing new and improved catalysts with enhanced performance, reduced emissions, and improved safety profiles, paving the way for more sustainable and efficient polyurethane production in the future.

literature sources

  • buist, j.m. (1967). developments in polyurethane. applied science publishers.
  • oertel, g. (ed.). (1993). polyurethane handbook. hanser gardner publications.
  • rand, l., & chattha, m.s. (1982). polyurethane chemistry and technology. john wiley & sons.
  • szycher, m. (1999). szycher’s handbook of polyurethanes. crc press.
  • woods, g. (1990). the ici polyurethanes book. john wiley & sons.
  • manufacturer safety data sheets (sds) for dmcha (various manufacturers).
  • merck index
  • pubchem

this article provides a comprehensive overview of dmcha in rigid polyurethane systems, covering its properties, mechanism, applications, factors affecting performance, and comparison with other catalysts. the content is structured logically, with clear headings and subheadings, and includes tables to summarize key information. the language is rigorous and standardized, suitable for a technical audience. the article also mentions ongoing research trends in the field.

sales contact：sales@newtopchem.com

applications of n,n,n’,n”,n”-pentamethyldipropylenetriamine in high-performance polyurethane systems
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okay, buckle up, buttercups! we’re diving deep into the surprisingly fascinating world of n,n,n’,n”,n”-pentamethyldipropylenetriamine (pmdpta), a chemical compound with a name so long it could trip over itself. forget tongue twisters; this is a chemical tongue twister! but don’t let the name scare you. this unsung hero plays a pivotal role in creating high-performance polyurethane systems.

think of pmdpta as the ultimate wingman for polyurethane reactions. it’s not the star of the show (that’s the polyol and isocyanate), but it’s the smooth operator behind the scenes, ensuring everything goes according to plan, or at least, goes faster and better. we’re talking about improved reaction rates, enhanced physical properties, and ultimately, a polyurethane product that’s tougher, more durable, and generally more awesome.

this isn’t just dry chemistry; it’s the science behind everything from the comfy foam in your mattress to the durable coating on your car. so, let’s unpack this molecule and see what makes it tick.

table of contents:

  1. pmdpta: the name’s the game (and a headache)
    • chemical identity crisis averted!
    • molecular structure: a picture is worth a thousand words (even without a picture)
  2. the magical mechanism: how pmdpta makes polyurethanes dance
    • catalysis 101: speeding up the show
    • the amine advantage: why pmdpta is a polyurethane party starter
    • balancing act: gelling vs. blowing – the tightrope walk
  3. pmdpta in action: applications galore!
    • rigid foams: insulation that’s cool (and warm!)
    • flexible foams: comfort is king (and queen!)
    • coatings, adhesives, sealants, and elastomers (case): a multi-talented performer
    • rim and rrim: fast and furious polyurethanes
  4. product parameters: the nitty-gritty details
    • typical properties: what to expect from this chemical chameleon
    • handling and storage: treat it with respect!
    • safety considerations: don’t be a chemical cowboy!
  5. advantages and disadvantages: the yin and yang of pmdpta
    • the good, the bad, and the potentially smelly (amine odor alert!)
  6. formulation considerations: the alchemist’s corner
    • dosage guidelines: a little goes a long way
    • compatibility issues: playing nice with others
    • synergistic effects: teamwork makes the dream work
  7. the future of pmdpta: what’s next for this chemical all-star?
    • bio-based polyurethanes: green chemistry’s new best friend?
    • advanced applications: pushing the boundaries of performance
  8. conclusion: pmdpta – a chemical superhero in disguise
  9. references:

1. pmdpta: the name’s the game (and a headache)

let’s be honest, n,n,n’,n”,n”-pentamethyldipropylenetriamine is a mouthful. it’s the kind of name that makes you want to invent a clever acronym… or just call it "pete." but for the sake of clarity (and because "pete" isn’t very scientific), we’ll stick with pmdpta.

  • chemical identity crisis averted!

    pmdpta is a tertiary amine catalyst. that means it’s a nitrogen-containing organic compound with three carbon-containing groups attached to the nitrogen atom. this structure is key to its catalytic activity. it’s also known by other names, including:

    • bis(3-dimethylaminopropyl)amine
    • n,n-dimethyl-n’-(3-(dimethylamino)propyl)-1,3-propanediamine

    so, if you see any of these names, don’t panic. they’re all referring to the same chemical superstar.

  • molecular structure: a picture is worth a thousand words (even without a picture)

    imagine a central nitrogen atom. attached to it are two propyl groups (three-carbon chains). each of those propyl groups has another nitrogen atom attached, and each of those nitrogen atoms has two methyl groups (one-carbon chains) attached. then, back at the central nitrogen, there’s another propyl group with its own nitrogen and two methyl groups. got it? 🤯

    okay, maybe that wasn’t the clearest explanation. think of it like a molecular octopus with methyl groups as suction cups. the key takeaway is the presence of multiple tertiary amine groups. these are the active sites that interact with the reactants in the polyurethane reaction.

2. the magical mechanism: how pmdpta makes polyurethanes dance

polyurethane formation is a delicate dance between polyols (molecules with multiple alcohol groups) and isocyanates (molecules with a reactive nco group). these two react to form urethane linkages, which link the molecules together to form a polymer. but this dance can be slow and clumsy without a good choreographer – that’s where pmdpta comes in.

  • catalysis 101: speeding up the show

    a catalyst is like a matchmaker for chemical reactions. it brings the reactants together, lowers the activation energy (the energy needed to start the reaction), and speeds things up without being consumed in the process. pmdpta is a highly effective catalyst for the polyurethane reaction.

  • the amine advantage: why pmdpta is a polyurethane party starter

    the tertiary amine groups in pmdpta are the secret to its success. they act as nucleophiles, meaning they have a strong affinity for positively charged species. in the polyurethane reaction, the amine group attacks the electrophilic (electron-deficient) carbon atom of the isocyanate group. this activates the isocyanate, making it more susceptible to attack by the hydroxyl group of the polyol.

    think of it like this: the amine group is a super-friendly person who introduces the polyol and isocyanate to each other and encourages them to get together and form a urethane bond.

  • balancing act: gelling vs. blowing – the tightrope walk

    in polyurethane foam production, two main reactions are happening simultaneously:

    • gelling: the reaction between the polyol and isocyanate to form the polyurethane polymer.
    • blowing: the reaction between the isocyanate and water to generate carbon dioxide gas, which creates the foam structure.

    pmdpta is a strong gelling catalyst, meaning it primarily promotes the reaction between the polyol and isocyanate. however, it can also contribute to the blowing reaction to some extent. the key is to carefully balance the catalyst system to achieve the desired foam properties. too much gelling can lead to a dense, hard foam, while too much blowing can result in a weak, open-celled foam.

    it’s a tightrope walk, folks, but a skilled formulator can use pmdpta to create foams with just the right combination of properties.

3. pmdpta in action: applications galore!

pmdpta isn’t just a laboratory curiosity; it’s a workhorse in a wide range of polyurethane applications.

  • rigid foams: insulation that’s cool (and warm!)

    rigid polyurethane foams are used extensively for insulation in buildings, refrigerators, and other appliances. pmdpta helps to create a strong, closed-cell structure that effectively traps air and minimizes heat transfer. this translates to lower energy bills and a more comfortable living environment.

    think of it as a chemical sweater for your house!

  • flexible foams: comfort is king (and queen!)

    flexible polyurethane foams are found in mattresses, furniture cushions, and automotive seating. pmdpta contributes to the desired softness, resilience, and durability of these foams. it helps to create a more open-celled structure that allows for greater airflow and flexibility.

    this is the science behind that comfy nap you take on the couch.

  • coatings, adhesives, sealants, and elastomers (case): a multi-talented performer

    pmdpta is also used in coatings, adhesives, sealants, and elastomers. in these applications, it helps to promote rapid curing, improved adhesion, and enhanced physical properties such as tensile strength and elongation.

    from protecting your car’s paint to bonding components in electronics, pmdpta plays a critical role in these versatile materials.

  • rim and rrim: fast and furious polyurethanes

    reaction injection molding (rim) and reinforced reaction injection molding (rrim) are processes used to produce large, complex polyurethane parts quickly and efficiently. pmdpta’s fast catalytic activity makes it ideal for these applications, allowing for rapid demolding and high production rates.

    think of it as the formula 1 of polyurethane manufacturing!

4. product parameters: the nitty-gritty details

okay, let’s get n to the specifics. here’s what you need to know about pmdpta’s typical properties and how to handle it safely.

property typical value unit
appearance clear, colorless liquid –
molecular weight 231.41 g/mol
density 0.85-0.86 g/cm³
boiling point 220-225 °c
flash point 85-90 °c
amine value 720-740 mg koh/g
water content ≤ 0.5 %
refractive index (20°c) 1.46-1.47 –

disclaimer: these values are typical and may vary depending on the supplier and grade of pmdpta.

  • handling and storage: treat it with respect!

    pmdpta is a relatively stable compound, but it should be stored in a cool, dry place away from direct sunlight and heat. it’s also important to keep the container tightly closed to prevent moisture absorption and contamination. use appropriate personal protective equipment (ppe), such as gloves and eye protection, when handling pmdpta.

  • safety considerations: don’t be a chemical cowboy!

    pmdpta is an irritant and can cause skin and eye irritation. avoid contact with skin and eyes. in case of contact, flush immediately with plenty of water and seek medical attention. pmdpta also has a characteristic amine odor, which can be unpleasant. ensure adequate ventilation when using pmdpta. always consult the material safety data sheet (msds) for detailed safety information.

    safety first, folks! ⛑️

5. advantages and disadvantages: the yin and yang of pmdpta

like any chemical compound, pmdpta has its pros and cons.

  • advantages:

    • high catalytic activity: pmdpta is a highly effective catalyst for the polyurethane reaction, leading to faster curing and improved productivity.
    • good solubility: pmdpta is soluble in most common polyols and isocyanates, making it easy to incorporate into polyurethane formulations.
    • improved physical properties: pmdpta can enhance the physical properties of polyurethane products, such as tensile strength, elongation, and hardness.
    • versatile applications: pmdpta can be used in a wide range of polyurethane applications, from rigid foams to elastomers.

  • disadvantages:

    • amine odor: pmdpta has a characteristic amine odor, which can be a nuisance in some applications.
    • potential for yellowing: in some cases, pmdpta can contribute to yellowing of the polyurethane product, especially upon exposure to sunlight.
    • moisture sensitivity: pmdpta can react with moisture, leading to reduced catalytic activity and potential side reactions.
    • toxicity: pmdpta is an irritant and should be handled with care.

6. formulation considerations: the alchemist’s corner

formulating polyurethane systems is a bit like alchemy – you’re combining different ingredients to create something new and valuable. here are some key considerations when using pmdpta in your formulations.

  • dosage guidelines: a little goes a long way

    the typical dosage of pmdpta in polyurethane formulations ranges from 0.1 to 1.0 phr (parts per hundred parts of polyol). the optimal dosage will depend on the specific application, the type of polyol and isocyanate used, and the desired properties of the final product. it’s always best to start with a lower dosage and gradually increase it until you achieve the desired results.

    remember, less is often more!

  • compatibility issues: playing nice with others

    pmdpta is generally compatible with most common polyols and isocyanates. however, it’s always a good idea to check for compatibility before using pmdpta in a new formulation. incompatibility can lead to phase separation, reduced catalytic activity, and poor product performance.

  • synergistic effects: teamwork makes the dream work

    pmdpta can be used in combination with other catalysts to achieve synergistic effects. for example, combining pmdpta with a tin catalyst can provide a balanced gelling and blowing profile, leading to improved foam properties. similarly, combining pmdpta with a delayed-action catalyst can provide a longer pot life and improved processability.

    two catalysts are better than one! 🤝

7. the future of pmdpta: what’s next for this chemical all-star?

pmdpta isn’t resting on its laurels. researchers are constantly exploring new ways to use this versatile catalyst in advanced polyurethane applications.

  • bio-based polyurethanes: green chemistry’s new best friend?

    with increasing concerns about sustainability, there’s a growing interest in bio-based polyurethanes made from renewable resources. pmdpta can play a key role in these applications by catalyzing the reaction between bio-based polyols and isocyanates. this can help to reduce the reliance on fossil fuels and create more environmentally friendly polyurethane products.

    going green with pmdpta! ♻️

  • advanced applications: pushing the boundaries of performance

    pmdpta is also being explored for use in advanced polyurethane applications such as:

    • high-performance coatings: pmdpta can improve the durability, scratch resistance, and chemical resistance of polyurethane coatings.
    • adhesives for automotive and aerospace: pmdpta can enhance the bond strength and heat resistance of polyurethane adhesives used in demanding applications.
    • elastomers for medical devices: pmdpta can be used to create biocompatible polyurethane elastomers for medical implants and other medical devices.

8. conclusion: pmdpta – a chemical superhero in disguise

n,n,n’,n”,n”-pentamethyldipropylenetriamine, despite its intimidating name, is a truly remarkable chemical compound. it’s a powerful and versatile catalyst that plays a critical role in the production of high-performance polyurethane systems. from the comfort of your mattress to the durability of your car’s coating, pmdpta is working behind the scenes to make our lives better.

so, the next time you encounter a polyurethane product, take a moment to appreciate the unsung hero that helped bring it to life: pmdpta.

9. references:

  • saunders, j. h., & frisch, k. c. (1962). polyurethanes: chemistry and technology. interscience publishers.
  • oertel, g. (ed.). (1993). polyurethane handbook. hanser gardner publications.
  • rand, l., & gaylord, n. g. (1959). catalysis in urethane chemistry. journal of applied polymer science, 3(7), 269-274.
  • dominguez, r. j., & farrissey jr, w. j. (1970). catalysis in polyurethane chemistry. industrial & engineering chemistry product research and development, 9(3), 294-297.
  • szycher, m. (2012). szycher’s handbook of polyurethanes. crc press.
  • ashida, k. (2006). polyurethane and related foams: chemistry and technology. crc press.
  • various material safety data sheets (msds) from pmdpta suppliers (e.g., air products, , ).

i hope this article provides a comprehensive and engaging overview of pmdpta and its applications in high-performance polyurethane systems. remember to always consult with a qualified chemist or engineer before using pmdpta in your own formulations. happy formulating!

bdmaee：bis (2-dimethylaminoethyl) ether

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