【Background and Overview】
Dimethylformamide (DMF) is relatively common in chemical production, but there are few introductions about dimethylacetamide (DMA). Dimethylacetamide is N,N-dimethylacetamide, also known as acetyl dimethyl amine, dimethyl amine acetate, and the English name is Dimethylacetamide (abbreviated as DMAC or DMA). Dimethylacetamide is a colorless transparent liquid that can be mixed with organic solvents such as water, alcohol, ether, etc., and is a polar solvent. It has the characteristics of high thermal stability, resistance to hydrolysis, low corrosiveness, and low toxicity. It is an excellent polar solvent for the synthesis of natural resins. It is used in the synthesis of polyimide, polysulfone amide and other polymer compounds, as well as in the synthesis Film formation and spinning of resins, synthetic drugs, crystallization and purification of aromatic dicarboxylic acids (such as terephthalic acid). It can also be used as a catalyst in certain organic reactions. Compared with the same series of dimethylformamide, it has high thermal stability, high hydrolytic stability, low corrosion and toxicity, and can replace dimethylformamide. Especially in recent years, the demand for pharmaceutical intermediates and pesticides has increased rapidly. The demand for high-quality dimethylacetamide in the electronics industry has also increased significantly, and the market usage of solvents such as polyacrylonitrile spinning, imine resin and insulating materials is gradually expanding. Because DMA has good solubility for a variety of resins, it is mainly used as a solvent for heat-resistant fibers, plastic films, coatings, pharmaceuticals, catalysts, and acrylonitrile spinning. Dimethylacetamide has a promising market prospect.
【Nature and structure】
Relative molecular mass of dimethylacetamide: 87.12, boiling point: 164-166°C (1xl&Pa), melting point: -20°C, flash point (open): 66°C, ignition point: 490°C, relative density: 0.9429 (20/4°C) ), refractive index: 1.4373. It is a colorless and transparent liquid that can be mixed with water, alcohol, ether and other organic solvents. It is a polar solvent. It has good thermal stability and is stable without decomposition even at the boiling point. It can be refined by distillation; it is stable in aqueous solution, but it will promote hydrolysis in the presence of acid and alkali. Dimethylacetamide should be sealed and stored in a cool, ventilated, dry place, and avoid water absorption and sunlight. It should not be close to the fire source. Please handle with care when transporting, and transport it in accordance with the regulations for toxic substances. Wear protective equipment when operating on site, and rinse with plenty of water after touching the skin.
【application】
1. Pharmaceutical intermediates
Dimethylacetamide is an important pharmaceutical raw material and is widely used in the production of drugs such as amoxicillin and cephalosporins. As a solvent or co-catalyst, dimethylacetamide can improve product quality and yield compared with traditional organic solvents. In 2000, the demand for dimethylacetamide in the pharmaceutical industry was about 6 kt. The demand for dimethylacetamide in 2006 was about 9.6 kt.
2. Acrylic production
In acrylic fiber production, some use the dimethylacetamide route. At present, domestic acrylic fiber production mainly includes sodium thiocyanate two-step method, dimethyl formamide one-step method and dimethyl acetamide organic wet method according to solvents. From the characteristics of process and equipment, material consumption, environmental impact, product quality, Many factors such as processing performance, localization rate, and foreign development trends have been intensified to increase application research and promotion. Dimethylacetamide is used as a comprehensive comparison. Sodium thiocyanate two-step method and dimethylacetamide organic wet method are the best Have development prospects. At present, many acrylic fiber devices in China adopt wet process with dimethylacetamide as solvent.
3. Polymer synthesis
Dimethylacetamide has good solubility for various resins, especially polyurethane resins and polyimide resins. It is mainly used as a solvent for heat-resistant synthetic fibers, plastic films, coatings, medicine, and acrylonitrile spinning. At present, it is mostly used in foreign countries to produce polyimide film, soluble polyimide, polyimide-polyperfluoroethylene propylene composite film, polyimide film, soluble polyimide molding powder, etc. The main domestic use molecule Good solvent for synthetic fiber spinning and other organic synthesis.
4. Organic Pigments
In the production of organic pigments, many devices use dimethylformamide as the solvent, but the chroma is far from that of foreign products. After some devices switch to dimethylacetamide as the solvent, the product quality and chroma have been significantly improved to meet Export requirements.
5. Petrochemical
In the petrochemical process, dimethylacetamide is an excellent catalyst, it can accelerate the reaction of cyclization, halogenation, cyanation, alkylation and dehydrogenation, and can increase the yield of main products.
6. Other aspects
There are many solvents for extracting butadiene from ethylene cracking gas. Among them, there are many sets of devices at home and abroad that use dimethylacetamide as the solvent. Dimethylacetamide is widely used as a solvent for separating pure benzene, cyclohexane and cyclohexene in nylon 66 salt cyclohexanol plant. Dimethylacetamide can also be used as a solvent or co-catalyst in the production of pesticides. Compared with traditional organic solvents, it can improve product quality and yield.