款-butyrolactone is an important chemical raw material and intermediate for medicine, and also the intermediate of the synthesize N-methyl pyrrolidone, 慣-pyrrolidone, polyvinyl pyrrolidone, 慣-acetyl-款-butyrolactone, methionine and the butyric acid compound . Colorless and transparent oily liquid with a smell similar to that of acetone, the boiling point is 204째C. It can dissolve mutually with water, acetone, benzene, carbon tetrachloride and alcohol at any proportion.