Product Name: gamma-Butyrolactone/GBL/γ-Butyrolactone CAS Number: 96-48-0 Molecular Formula: C4H6O2 γ-Butyrolactone is principally a precursor to other chemicals. Reaction with methylamine gives NMP. Ammonia gives pyrrolidone. It is also used as a solvent in lotions and some polymers.Butyrolactone, with its wide liquid range, chemical stability and high dielectric constant, is used in some batteries but primarily is found in electrolytic capacitors as the organic solvent. In this capacity, it is frequently mixed with a small ratio of ethylene glycol, "9:1" being common, to vary internal resistivity.