GBL

γ-Butyrolactone (GBL) or gamma-butyrolactone is an organic compound with the formula O=CO(CH2)3. It is a hygroscopic, colorless, water-miscible liquid with a pleasant odor. It is the simplest 4-carbon lactone. It is mainly used as an intermediate in the production of other chemicals, such as N-methyl-2-pyrrolidone.