N-methyl-pyrrolidone that is also called N-methyl-2-pyrrolidone is written NMP for short. The molecular formula is C5H9NO. N-methyl-pyrrolidone, which is a liquid with little ammonia odor, can mix with almost all solvents such as ethyl alcohol, acetaldehyde, ketone, aromatic hydrocarbons and chlorohydro carbons etc. Its boiling point 204¡ã and flash point 95¡ã. NMP which is a polar non proton transfer solvent possesses little toxicity, high boiling point, powerful solvency, good selectivity and stability properties. The product is widely applied to aromatic hydrocarbons extracting, acetylene, and diolefine purification. It can be also used as polymer solvents and polymerization process medium, such as polyamides, polyimides and polyphenyl thioether(PPS) , etc. which are called engineering plastics. Besides these, it can be used as aromatic fibre, insulate pesticide, pigment and detergent, etc.