N-Methylallylamine: Properties, Preparation and Applications

N-Allylmethylamine, also known as N-allylmethylamine and N-methylpropylamine, is an important aliphatic organic amine compound with active chemical properties and broad industrial application potential. Its unique molecular structure (containing allyl and methylamino groups) enables it to play an irreplaceable role in the fields of organic synthesis, pharmaceutical chemicals, and polymer materials. This article will systematically elaborate on N-methylallylamine from the aspects of basic information, physical and chemical properties, preparation methods, application fields and safety protection.
1. Basic information

The core chemical information of N-methylallylamine is as follows:

- Chinese name: N-methylallylamine

- English name: N-Allylmethylamine

- Alias: N-allylmethylamine, N-methacrylamine

- CAS number: 627-37-2

- EINECS number: 210-996-0

- Molecular formula: C₄H₉N

- Molecular weight: 71.12

- Chemical structure: CH₂=CHCH₂NHCH₃ (containing carbon-carbon double bonds and amino functional groups)

- Exact mass: 71.07350

- PSA (Polar Surface Area): 12.03000

- LogP (oil-water distribution coefficient): 0.78270

2. Physical and chemical properties

N-methylallylamine is a typical organic amine liquid with distinct physical and chemical properties, as follows:

- Appearance and form: It is a colorless to light yellow transparent liquid at room temperature. It easily absorbs carbon dioxide in the air and deteriorates, so it needs to be sealed and stored.

- Density: Density is 0.741 g/mL at 25°C, slightly lighter than water.

- Boiling point and melting point: The boiling point is 64-66°C and the melting point is 76°C. The low boiling point makes it easy to separate during distillation and purification.

-Refractive index: The refractive index at 20℃ is 1.412, which is an important physical parameter characterizing its purity.

- Flash point: The flash point is as low as -19 ℉ (approximately -28.3℃). It is a highly flammable liquid and requires strict control of fire sources.

- Solubility: Miscible with water, and easily soluble in organic solvents such as ethanol and ether, providing a good dissolving environment for multi-phase reactions.

- Acidity and alkalinity: The predicted pKa value is 9.88±0.10, which is weakly alkaline and can neutralize with acids to generate corresponding salts.

3. Preparation method

The industrial preparation of N-methylallylamine mainly uses the nucleophilic substitution reaction of monomethylamine and allyl chloride, supplemented by liquid caustic soda as an acid binding agent. The process route is mature and the raw materials are easily available. The specific steps are as follows:

1. Raw material selection

Using industrial pure monomethylamine (usually formulated into 25% aqueous solution), industrial pure propylene chloride and industrial pure liquid alkali (sodium hydroxide aqueous solution) as reaction raw materials, the cost is controllable and easy to purchase on a large scale.

2. Preparation of crude product

Add 25% monomethylamine aqueous solution to the reaction kettle, control the temperature in the kettle at 5-15°C through chilled brine, and then add propylene chloride and liquid caustic soda by alternating dropwise addition or simultaneous dropwise addition. During the dropwise addition process, the temperature is strictly controlled not to exceed 20°C. After the dropwise addition is completed, stir for half an hour, raise the temperature to 40-60°C and react for 4-10 hours. After the reaction is completed, the temperature is lowered and the liquid is separated to obtain crude N-methylallylamine. This step is optimized through temperature control and dripping methods to reduce the occurrence of side reactions and improve the conversion rate of raw materials.

3. Pure product purification

Perform normal pressure distillation of the crude product and collect the fractions at 109-113°C to obtain a high-purity N-methylallylamine product. After gas chromatography detection, the purity can reach more than 97.5%, meeting the needs of industry and scientific research.

4. Application areas

N-methylallylamine has important applications in many fields due to its active functional group structure. The core scenarios are as follows:

1. Pharmaceutical and chemical intermediates

As a key pharmaceutical intermediate, it can be used to synthesize drugs such as N-methylpyrrolidone. It can also be used to prepare N-ethyl methacrylamide through reaction with acryloyl chloride, providing raw material support for the synthesis of fine chemical products such as antibiotics and anti-tumor drugs.

2. Organic synthesis and polymer materials

The allyl group in its molecule can participate in the polymerization reaction and copolymerize with monomers such as dimethyldiallylammonium chloride to prepare water-soluble polymers. This type of polymer is widely used in water treatment, papermaking additives, surfactants and other fields. In addition, it can also be used to modify materials such as resin and rubber to improve product performance.

3. Laboratory R&D and fine chemicals

In laboratory research and development, it is used as a nitrogen-containing organic reagent for the exploration of various organic reactions; in industrial production, it can also be used to prepare fine chemicals such as formaldehyde-free fixatives and corrosion inhibitors, meeting the research and development needs of environmentally friendly chemical products.

5. Safety protection and emergency response

N-Methylallylamine is a flammable and toxic chemical and must strictly abide by safe operating regulations. The specific requirements are as follows:

1. Hazardous characteristics

The dangerous goods signs are F (flammable) and T (toxic), and the hazard category codes are R11 (highly flammable), R23/24/25 (toxic by inhalation, skin contact, and ingestion), and R34 (causing burns); the packaging level is Class II, and the dangerous goods transportation code is UN 3286.

2. Operation and storage

The operation must be carried out in a well-ventilated place. Operators must wear gas masks, anti-static clothing, and rubber and oil-resistant gloves. Smoking is strictly prohibited. Use explosion-proof ventilation and lighting equipment to avoid contact with oxidants. Store in a cool and ventilated warehouse at 2-8°C, sealed and stored separately from oxidants and food chemicals. The warehouse must be equipped with lightning protection and static conduction removal devices, and be equipped with corresponding fire-fighting equipment.

3. Emergency treatment

- Leakage treatment: Small leaks should be absorbed with sand and activated carbon, and flushing into the sewer is prohibited; large leaks should be contained by building dikes, covered with foam to inhibit evaporation, and transferred to special containers for recycling through explosion-proof pumps to prevent contamination of water bodies and soil.

- First aid measures: After inhalation, move to fresh air, rinse thoroughly with soapy water if exposed to skin, rinse immediately with running water and seek medical attention if exposed to eyes, rinse mouth and seek medical attention immediately after ingestion, and present chemical safety data sheet when rescuing.

- Firefighting measures: Use water mist, dry powder, foam or carbon dioxide to extinguish the fire. Avoid direct flow of water. Firefighters must wear breathing apparatus to extinguish the fire in the upwind direction. Evacuate immediately if the container changes color or there is a pressure release sound.

6. Conclusion

As a multifunctional organic amine compound, N-methylallylamine has both reactivity and application flexibility, and its demand continues to be stable in the fields of medicine, chemical industry, polymer materials and other fields. With the improvement of environmental protection requirements and the development of fine chemical technology, its preparation process has been continuously optimized, and high-purity products and derivative application scenarios will be further expanded. In the future, while improving production efficiency and reducing safety risks, it is necessary to tap its application potential in emerging fields such as new energy and electronic chemicals to promote the continuous release of its industrial value.