n,n-dimethylcyclohexylamine: properties, applications, and industrial significance

introduction

n,n-dimethylcyclohexylamine (dmcha) is a tertiary amine with the molecular formula c₈h₁₇n. it is a colorless to pale yellow liquid with a characteristic amine odor. dmcha is a versatile chemical intermediate finding widespread applications in various industries, including polyurethane production, pharmaceuticals, agrochemicals, and more. its reactivity stems from the lone pair of electrons on the nitrogen atom, making it a useful catalyst, reagent, and building block for complex molecules. this article provides a comprehensive overview of dmcha, covering its physical and chemical properties, synthesis methods, applications, safety considerations, and industrial significance, drawing upon both domestic and international research.

table of contents

1. chemical identity & nomenclature
2. physical and chemical properties
3. synthesis methods
4. applications
   • 4.1 polyurethane catalysis
   • 4.2 pharmaceutical synthesis
   • 4.3 agrochemicals
   • 4.4 corrosion inhibitors
   • 4.5 other applications
5. handling and storage
6. safety and toxicity
7. environmental impact
8. quality control and analysis
9. market overview and suppliers
10. future trends
11. conclusion
12. references

1. chemical identity & nomenclature

property	value
iupac name	n,n-dimethylcyclohexylamine
common name	dmcha
cas registry number	98-94-2
molecular formula	c8h17n
molecular weight	127.23 g/mol
smiles notation	cn(c)c1ccccc1
pubchem cid	7424

2. physical and chemical properties

dmcha exhibits a range of physical and chemical properties that influence its applications and handling requirements.

property	value	reference
appearance	colorless to pale yellow liquid
odor	amine-like
melting point	-60 °c (-76 °f; 213 k)
boiling point	160 °c (320 °f; 433 k)
density	0.845 g/cm3 at 20 °c
vapor pressure	2.7 mmhg at 20 °c
refractive index	1.446 at 20 °c
flash point	46 °c (115 °f; 319 k)
solubility in water	slightly soluble
solubility in organic solvents	soluble in most common organic solvents (e.g., alcohols, ethers)
pka	10.2 (approximate)

dmcha is a relatively stable compound under normal conditions. however, it is flammable and should be kept away from open flames and oxidizing agents. it can react with strong acids, forming salts. the basicity of dmcha is crucial to its catalytic activity.

3. synthesis methods

several methods can be employed to synthesize dmcha. the most common industrial route involves the reductive amination of cyclohexanone with dimethylamine.

• reductive amination: cyclohexanone reacts with dimethylamine in the presence of a reducing agent, such as hydrogen gas and a metal catalyst (e.g., nickel or palladium). this is the most prevalent industrial method. the reaction can be represented as follows:

  c₆h₁₀o + (ch₃)₂nh + h₂ → c₈h₁₇n + h₂o

  this reaction typically requires elevated temperatures and pressures. optimized catalysts and reaction conditions are crucial for achieving high yields and selectivity.

• alkylation of cyclohexylamine: cyclohexylamine can be alkylated with methyl halides (e.g., methyl iodide or methyl bromide) in the presence of a base. however, this method is less common due to the cost and handling concerns associated with methyl halides.

  c₆h₁₁nh₂ + 2 ch₃x + 2 b → c₈h₁₇n + 2 bhx (where x is a halogen and b is a base)

• other methods: less common methods include the reaction of cyclohexanol with dimethylamine over a catalyst at high temperatures. these methods are generally less efficient and not suitable for large-scale production.

the choice of synthesis method depends on factors such as cost, availability of raw materials, and desired product purity. reductive amination is generally preferred for industrial-scale production due to its efficiency and cost-effectiveness.

4. applications

dmcha finds diverse applications across various industries, leveraging its unique chemical properties.

4.1 polyurethane catalysis

the most significant application of dmcha is as a catalyst in the production of polyurethane foams, coatings, adhesives, and elastomers. polyurethanes are formed through the reaction of polyols (compounds containing multiple hydroxyl groups) and isocyanates (compounds containing the -nco group). this reaction requires a catalyst to proceed at a reasonable rate.

dmcha acts as a tertiary amine catalyst, accelerating both the polyol-isocyanate reaction (gelation) and the blowing reaction (reaction of isocyanate with water to generate carbon dioxide, which expands the foam).

• mechanism of catalysis: dmcha increases the nucleophilicity of the hydroxyl group in polyol, making it more reactive towards the electrophilic isocyanate group. it also facilitates the formation of the urea linkage in the blowing reaction. the tertiary amine acts as a base, deprotonating the hydroxyl group and promoting the reaction.

• types of polyurethane: dmcha is used in the production of various types of polyurethane, including:

  • rigid foams: used for insulation in refrigerators, buildings, and other applications.
  • flexible foams: used in mattresses, furniture, and automotive seating.
  • coatings and adhesives: used for surface protection and bonding applications.
  • elastomers: used for durable and flexible components in various industries.

• advantages of using dmcha:

  • high catalytic activity.
  • relatively low cost.
  • good solubility in polyurethane formulations.
  • contributes to desirable foam properties.

4.2 pharmaceutical synthesis

dmcha is a valuable building block and reagent in the synthesis of various pharmaceuticals. its cyclohexyl ring and dimethylamino group provide opportunities for introducing structural complexity and functionality into drug molecules.

• intermediate for active pharmaceutical ingredients (apis): dmcha can be used as an intermediate in the synthesis of drugs targeting various conditions, including:

  • antihistamines: some antihistamines contain a cyclohexyl ring and a tertiary amine moiety, which can be derived from dmcha.
  • antidepressants: certain antidepressants utilize similar structural motifs, making dmcha a potential precursor.
  • analgesics: dmcha can be incorporated into analgesic compounds to modify their pharmacokinetic properties or improve their binding affinity to target receptors.

• chiral resolution: dmcha can be used as a chiral resolving agent for separating enantiomers of chiral carboxylic acids or other chiral compounds. this is crucial in pharmaceutical synthesis, as enantiomers often exhibit different biological activities.

• examples of pharmaceutical applications: while specific examples are often proprietary, dmcha’s role in pharmaceutical synthesis typically involves:

  • acting as a protecting group for carboxyl or amino groups.
  • serving as a catalyst in specific reactions.
  • being incorporated as a structural component into the final drug molecule.

4.3 agrochemicals

dmcha finds applications in the agrochemical industry as an intermediate in the synthesis of pesticides, herbicides, and fungicides.

• pesticide synthesis: dmcha can be used to synthesize insecticides that target various insect pests affecting crops. the cyclohexyl ring and amine functionality contribute to the insecticidal activity or improve the compound’s stability and delivery.

• herbicide synthesis: dmcha can be incorporated into herbicide molecules to enhance their selectivity or improve their uptake by target weeds.

• fungicide synthesis: some fungicides utilize dmcha-derived building blocks to inhibit fungal growth and protect crops from fungal diseases.

• examples of agrochemical applications: specific examples are often confidential, but dmcha’s role in agrochemical synthesis often involves:

  • modifying the lipophilicity of the active ingredient.
  • improving the compound’s ability to penetrate plant tissues.
  • enhancing the stability of the active ingredient in the environment.

4.4 corrosion inhibitors

dmcha can be used as a corrosion inhibitor in various industrial applications. its amine functionality allows it to adsorb onto metal surfaces, forming a protective layer that prevents corrosion.

• mechanism of corrosion inhibition: dmcha inhibits corrosion by:

  • adsorption: the nitrogen atom in dmcha has a lone pair of electrons that can interact with the metal surface, forming a protective adsorbed layer.
  • neutralization: dmcha can neutralize acidic environments, which are often corrosive.
  • barrier protection: the adsorbed layer acts as a barrier, preventing corrosive agents (e.g., oxygen, water, chloride ions) from reaching the metal surface.

• applications:

  • oil and gas industry: used in pipelines and equipment to prevent corrosion caused by sour gas (hydrogen sulfide) and other corrosive substances.
  • water treatment: used in cooling water systems and other water treatment applications to prevent corrosion of metal components.
  • metalworking fluids: added to metalworking fluids to protect metal parts from corrosion during machining and other metalworking processes.

4.5 other applications

in addition to the major applications listed above, dmcha is also used in:

• rubber production: as an accelerator in rubber vulcanization.
• textile industry: as a dyeing assistant and leveling agent.
• water treatment: as a component in flocculants and coagulants.
• laboratory reagent: used in various chemical reactions and analytical techniques.

5. handling and storage

proper handling and storage of dmcha are crucial to ensure safety and maintain product quality.

• storage:

  • store in a cool, dry, and well-ventilated area.
  • keep containers tightly closed to prevent evaporation and contamination.
  • store away from incompatible materials, such as strong acids, oxidizing agents, and open flames.
  • use corrosion-resistant containers (e.g., stainless steel or polyethylene).
  • avoid direct sunlight and extreme temperatures.

• handling:

  • wear appropriate personal protective equipment (ppe), including gloves, safety glasses, and a respirator if necessary.
  • avoid breathing vapors or mist. use in a well-ventilated area or with local exhaust ventilation.
  • avoid contact with skin, eyes, and clothing.
  • wash thoroughly after handling.
  • do not eat, drink, or smoke in areas where dmcha is handled.
  • follow established safety procedures and guidelines.

• spills:

  • contain spills immediately.
  • absorb with inert materials (e.g., sand, vermiculite).
  • collect and dispose of contaminated materials in accordance with local regulations.
  • ventilate the area to remove vapors.

6. safety and toxicity

dmcha is a hazardous substance and should be handled with care.

• acute toxicity:

  • oral: moderately toxic if swallowed.
  • dermal: may be harmful in contact with skin.
  • inhalation: harmful if inhaled. may cause respiratory irritation.

• skin corrosion/irritation: causes skin irritation. prolonged contact may cause burns.

• serious eye damage/eye irritation: causes serious eye irritation. may cause corneal damage.

• respiratory or skin sensitization: may cause respiratory irritation. skin sensitization is possible but less common.

• germ cell mutagenicity: no evidence of mutagenicity has been reported in standard tests.

• carcinogenicity: not classified as a carcinogen by iarc, ntp, or osha.

• reproductive toxicity: no evidence of reproductive toxicity has been reported.

• specific target organ toxicity (single exposure): may cause respiratory irritation and central nervous system depression.

• specific target organ toxicity (repeated exposure): no data available.

• aspiration hazard: not classified as an aspiration hazard.

• first aid measures:

  • eye contact: immediately flush with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. seek medical attention.
  • skin contact: immediately wash with soap and water. remove contaminated clothing. 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 medical attention immediately.

7. environmental impact

the environmental impact of dmcha should be considered, particularly in relation to its release into the environment.

• persistence and degradability: dmcha is expected to be biodegradable in the environment, but the rate of degradation may vary depending on environmental conditions.

• bioaccumulation: the potential for bioaccumulation is expected to be low due to its relatively low octanol-water partition coefficient (log kow).

• ecotoxicity: dmcha can be toxic to aquatic organisms. releases to aquatic environments should be minimized.

• environmental regulations: local and national regulations may govern the handling, storage, and disposal of dmcha to minimize its environmental impact.

• waste management: waste dmcha should be disposed of in accordance with applicable environmental regulations. incineration is a common method for disposal.

8. quality control and analysis

quality control is essential to ensure that dmcha meets the required specifications for its intended applications.

• analytical methods:

  • gas chromatography (gc): used to determine the purity and identify impurities.
  • titration: used to determine the amine content and basicity.
  • spectroscopy (ir, nmr): used to confirm the chemical structure.
  • water content analysis (karl fischer titration): used to determine the water content.
  • density measurement: used to verify the density.
  • refractive index measurement: used to verify the refractive index.

• specifications: typical specifications for dmcha include:

  • purity: ≥ 99.0% (by gc)
  • water content: ≤ 0.5%
  • color: apha color ≤ 20
  • density: within specified range
  • refractive index: within specified range

• quality assurance: manufacturers should implement a robust quality assurance program to ensure that dmcha consistently meets the required specifications. this includes regular testing, process control, and documentation.

9. market overview and suppliers

the global market for dmcha is driven by the demand for polyurethane products, particularly in the construction, automotive, and furniture industries.

• major suppliers: several companies worldwide manufacture and supply dmcha, including:

  • [hypothetical supplier a]
  • [hypothetical supplier b]
  • [hypothetical supplier c]
  • [hypothetical supplier d]

• market trends: the market for dmcha is expected to grow in line with the growth of the polyurethane industry. factors driving the growth include:

  • increasing demand for polyurethane foams for insulation and comfort applications.
  • growing demand for polyurethane coatings and adhesives in the construction and automotive industries.
  • development of new applications for polyurethanes in various industries.

• pricing: the price of dmcha can vary depending on factors such as supply and demand, raw material costs, and geographic location.

10. future trends

several trends are shaping the future of dmcha and its applications.

• development of sustainable catalysts: research is ongoing to develop more sustainable catalysts for polyurethane production, including bio-based catalysts and catalysts with lower toxicity.

• new applications in pharmaceuticals and agrochemicals: continued research is exploring new applications for dmcha in the synthesis of pharmaceuticals and agrochemicals.

• improved manufacturing processes: efforts are focused on improving the efficiency and sustainability of dmcha manufacturing processes.

• stricter environmental regulations: increasingly stringent environmental regulations are driving the development of more environmentally friendly handling and disposal methods for dmcha.

11. conclusion

n,n-dimethylcyclohexylamine (dmcha) is a versatile tertiary amine with significant industrial importance. its primary application lies in polyurethane catalysis, but it also serves as a crucial intermediate in the synthesis of pharmaceuticals, agrochemicals, and corrosion inhibitors. understanding its physical and chemical properties, synthesis methods, applications, safety considerations, and environmental impact is crucial for its safe and effective use. as the polyurethane industry continues to grow and new applications for dmcha emerge, its role as a key chemical building block will remain significant. future trends will likely focus on developing more sustainable and environmentally friendly alternatives and improving the efficiency of its production and use.

12. references

(note: these are examples and should be replaced with actual citations)

1. sutton, d. microwave synthesis: methods and protocols. humana press, 2006.
2. olah, g. a. introduction to aromatic chemistry. wiley-interscience, 1971.
3. march, j. advanced organic chemistry: reactions, mechanisms, and structure. 4th edition, wiley-interscience, 1992.
4. vollhardt, k. p. c., & schore, n. e. organic chemistry: structure and function. 5th edition, w. h. freeman, 2007.
5. kirk-othmer encyclopedia of chemical technology. john wiley & sons.
6. ullmann’s encyclopedia of industrial chemistry. wiley-vch.
7. european chemicals agency (echa). registered substances database.
8. [hypothetical research article a] – investigating the catalytic activity of dmcha in polyurethane foam formation. journal of applied polymer science, [volume], [page numbers], [year].
9. [hypothetical research article b] – synthesis of novel pharmaceutical compounds using dmcha as a building block. organic letters, [volume], [page numbers], [year].
10. [hypothetical research article c] – dmcha as a corrosion inhibitor for steel in acidic environments. corrosion science, [volume], [page numbers], [year].
11. [hypothetical chinese publication a] – a study on the reductive amination of cyclohexanone using a novel nickel catalyst. chinese journal of chemistry, [volume], [page numbers], [year].
12. [hypothetical chinese publication b] – application of dmcha in the synthesis of a new herbicide. acta chimica sinica, [volume], [page numbers], [year].

this article provides a comprehensive overview of n,n-dimethylcyclohexylamine, drawing upon established knowledge and hypothetical research examples. remember to replace the bracketed information with actual supplier names, journal citations, and specific research details when creating your final document.

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