N-methylpyrrolidone, abbreviated as NMP, molecular formula: C5H9NO， English: 1-Methyl-2-pyrrolidone, appearance is a colorless to light yellow transparent liquid with a slight ammonia odor. It is miscible with water in any ratio and soluble in various organic solvents such as ether, acetone and esters, halogenated hydrocarbons, aromatic hydrocarbons, etc. It is almost completely mixed with all solvents, with a boiling point of 204 ℃ and a flash point of 91 ℃. It has strong hygroscopicity, stable chemical properties, and is not corrosive to carbon steel and aluminum, but slightly corrosive to copper. It has the advantages of low viscosity, good chemical and thermal stability, high polarity, low volatility, and infinite miscibility with water and many organic solvents. This product belongs to micro drugs, and the maximum allowable concentration in the air is 100PPM.