In the USA, this use of is second only to production of THE. It is formed by dehydrogenation cyclization, preferably in the gas phase, and generally over copper catalysts at 200-250°C and at slightly higher than atmospheric pressure, with yields of up to 93 %:



Industrial processes are operated by BASF and GAF in USA and Western Europe.

An alternative process for the manufacture of γ-butyrolactone, the partial hydrogenation of maleic anhydride, is carried out in Japan by Mitsubishi Kasei. Due to the low price of maleic anhydride, use of this process is increasing in many countries.

γ-Butyrolactone is a solvent as well as a precursor of another industrially important solvent- N-methylpyrrolidone (NMP). About 27000 tonnes of NMP are currently used annually worldwide. NMP is obtained by reacting y-butyrolactone with methylamine:



γ-Butyrolactam, usually known as 2-pyrrolidone, results from the reaction between y-butyrolactone and ammonia. This manufacturing method is, compared to several other processes,that used most often commercially.