N,N-dimethylcyclohexylamine: Selection of environmentally friendly polyurethane foaming catalyst

Introduction

Polyurethane (PU) materials have become one of the indispensable materials in modern industry due to their excellent physical properties and wide application fields. Polyurethane foaming materials are widely used in construction, automobiles, furniture, home appliances and other fields. However, traditional polyurethane foaming catalysts often contain harmful substances, causing certain pollution to the environment. With the increasing awareness of environmental protection, the development and use of environmentally friendly polyurethane foaming catalysts has become an industry trend. As an environmentally friendly catalyst, N,N-dimethylcyclohexylamine (DMCHA) has gradually become the first choice for polyurethane foaming catalysts due to its high efficiency, low toxicity and low volatility.

1. Basic properties of N,N-dimethylcyclohexylamine

1.1 Chemical structure

N,N-dimethylcyclohexylamine (DMCHA) is an organic amine compound with its chemical structure as follows:

 CH3
       |
  C6H11-N-CH3

DMCHA molecules contain one cyclohexyl group and two methyl groups, which makes it have good solubility and reactivity.

1.2 Physical Properties

Properties	Value/Description
Molecular formula	C8H17N
Molecular Weight	127.23 g/mol
Appearance	Colorless to light yellow liquid
Boiling point	160-162°C
Density	0.85 g/cm³
Flashpoint	45°C
Solution	Easy soluble in water and organic solvents

1.3 Chemical Properties

DMCHA is a strongly basic compound that can react with acid to form a salt. Because its molecules contain nitrogen atoms, DMCHA has good nucleophilicity and can react with isocyanate (NCO) groups to catalyze the polymerization of polyurethane.

2. Application of DMCHA in polyurethane foaming

2.1 Basic principles of polyurethane foaming

Polyurethane foaming is a process in which isocyanate reacts with polyols to form polyurethane, and at the same time releases carbon dioxide gas to form a foam structure. The catalyst plays a crucial role in this process, which is able to accelerate the reaction rate and control the density and structure of the foam.

2.2 Catalytic mechanism of DMCHA

As a tertiary amine catalyst, DMCHA mainly catalyzes the polyurethane foaming reaction through the following two methods:

Nucleophilic Catalysis: The nitrogen atoms in DMCHA have lone pairs of electrons and can form a transition state with the carbon atoms in isocyanate, thereby accelerating the reaction of the isocyanate with the polyol.
Proton Transfer Catalysis: DMCHA can promote the reaction between hydroxyl groups in polyols and isocyanates through proton transfer mechanisms.

2.3 Advantages of DMCHA

Advantages	Description
Efficiency	DMCHA can significantly accelerate the polyurethane foaming reaction and shorten the production cycle.
Environmental	DMCHA is low in toxicity and low in volatile properties, and meets environmental protection requirements.
Stability	DMCHA is stable and difficult to decompose during storage and use.
Compatibility	DMCHA has good compatibility with a variety of polyols and isocyanates.

3. Comparison of DMCHA with other catalysts

3.1 Disadvantages of traditional catalysts

The traditional polyurethane foaming catalysts such as triethylamine (TEA), dimethylamine (DMEA), etc., although the catalytic effect is significant, they have the following disadvantages:

High toxicity: Traditional catalysts are often highly toxic and pose a threat to the health of operators.
Strong volatile: Traditional catalysts are easy to volatile and cause environmental pollution.
Poor stability: Traditional catalysts are easy to decompose during storage and use, affecting the catalytic effect.

3.2 Comparison between DMCHA and traditional catalysts

Catalyzer	Toxicity	Volatility	Stability	Catalytic Efficiency
Triethylamine (TEA)	High	High	Poor	High
Dimethylamine (DMEA)	in	in	in	in
N,N-dimethylcyclohexylamine (DMCHA)	Low	Low	High	High

It can be seen from the table that DMCHA is better than traditional catalysts in terms of toxicity, volatility and stability, and has high catalytic efficiency. It is an ideal environmentally friendly polyurethane foaming catalyst.

4. Application examples of DMCHA

4.1 Building insulation materials

Among building insulation materials, polyurethane foaming materials are widely used in insulation layers of walls, roofs and floors due to their excellent insulation properties and lightweight properties. As a catalyst, DMCHA can effectively control the foaming process, ensure the uniformity and stability of the foam, thereby improving the performance of the insulation material.

4.2 Car interior

In car interior, polyurethane foaming material is used in seats, headrests, armrests and other parts to provide a comfortable riding experience. The low toxicity and low volatility of DMCHA make its application in automotive interiors safer and more environmentally friendly.

4.3 Furniture Manufacturing

In furniture manufacturing, polyurethane foaming materials are used for fillings of soft furniture such as sofas and mattresses. The efficient catalytic action of DMCHA can shorten the production cycle and improve production efficiency.

5. Production and storage of DMCHA

5.1 Production process

DMCHA production mainly produces N-methylcyclohexylamine through reaction of cyclohexylamine with formaldehyde, and then reacts with formaldehyde to produce N,N-dimethylcyclohexylamine. The specific reaction equation is as follows:

Cyclohexylamine reacts with formaldehyde to form N-methylcyclohexylamine:
```
C6H11NH2 + HCHO → C6H11NHCH3 + H2O
```
N-methylcyclohexylamine reacts with formaldehyde to form N,N-dimethylcyclohexylamine:
```
C6H11NHCH3 + HCHO → C6H11N(CH3)2 + H2O
```

5.2 Storage conditions

Storage Conditions	Requirements
Temperature	Storage temperature should be kept at 0-30°C to avoid high temperatures and direct sunlight.
Humidity	The storage environment should be kept dry and the relative humidity should not exceed 60%.
Container	Containers with good sealing properties should be used to avoid contact with air.
Shelf life	Under suitable conditions, the shelf life of DMCHA is generally 12 months.

6. Safety and environmental protection of DMCHA

6.1 Safe use

Although DMCHA is low in toxicity, the following safety matters should still be paid attention to during use:

Protective Measures: Operators should wear protective gloves, goggles and protective clothing to avoid direct contact.
Ventiation Conditions: The operating environment should maintain good ventilation to avoid inhaling steam.
Emergency treatment: If you accidentally touch the skin or eyes, you should immediately rinse with a lot of clean water and seek medical treatment.

6.2 Environmental performance

DMCHA has low toxicity and low volatility, making it better than traditional catalysts in environmental protection performance. It produces less waste during its production and use, and has less pollution to the environment. In addition, DMCHA has good biodegradability and can gradually decompose in the natural environment to reduce the long-term impact on the ecosystem.

7. DMCHA market prospects

With the increasing strictness of environmental protection regulations and the increasing awareness of consumers in environmental protection, the market demand for environmentally friendly polyurethane foaming catalysts continues to grow. As an efficient and environmentally friendly catalyst, DMCHA has broad market prospects. It is expected that DMCHA’s share in the polyurethane foaming catalyst market will gradually expand in the next few years and become one of the mainstream products.

8. Conclusion

N,N-dimethylcyclohexylamine (DMCHA) is an environmentally friendly polyurethane foaming catalyst, which has the characteristics of high efficiency, low toxicity and low volatility., automobiles, furniture and other fields have broad application prospects. Compared with traditional catalysts, DMCHA has obvious advantages in environmental performance, stability and catalytic efficiency. With the increase of environmental awareness and technological advancement, DMCHA will become the first choice for polyurethane foaming catalysts, promoting the sustainable development of the polyurethane industry.

Appendix: DMCHA product parameter table

parameters	Value/Description
Molecular formula	C8H17N
Molecular Weight	127.23 g/mol
Appearance	Colorless to light yellow liquid
Boiling point	160-162°C
Density	0.85 g/cm³
Flashpoint	45°C
Solution	Easy soluble in water and organic solvents
Storage temperature	0-30°C
Storage humidity	Relative humidity does not exceed 60%
Shelf life	12 months

Through the detailed introduction of the above content, I believe that readers have a deeper understanding of the choice of N,N-dimethylcyclohexylamine (DMCHA) as an environmentally friendly polyurethane foaming catalyst. DMCHA not only has excellent catalytic performance, but also performs well in environmental protection and safety, and is an important direction for the development of polyurethane foaming catalysts in the future.