GB610166A - Improvements in and relating to the production of gamma-butyrolactone - Google Patents

Abstract

Gamma-butyrolactone is obtained by oxidizing tetrahydrofuran, or a 2-alkyl substituted tetrahydrofuran wherein the alkyl radical contains not more than six carbon atoms, at a temperature below its boiling point by means of nitrogen tetroxide. The conditions of the reaction are preferably anhydrous and at atmospheric pressure. A temperature of not less than 20 DEG C. is used, and the molar ratio of nitrogen tetroxide to tetrahydrofuran is not more than 1.5:1. The nitrogen tetroxide is mixed with air or oxygen advantageously, and is bubbled through the reaction mixture or produced in situ, e.g. from nitrogen trioxide or nitric oxide and oxygen or air. Specified solvents are ether, dionan. The process may be continuous. In examples: (1) 92 gm. of nitrogen tetroxide is entrained in a stream of oxygen and passed into 72 gm. tetrahydrofuran at 40 DEG to 50 DEG C. and at the end of the reaction oxygen is blown through the liquid product to remove the nitrogen trioxide to obtain gammabutyrolactone; (2) 43.4 gm. tetrahydrosyloan in ether solution is oxidized by a stream of nitrogen tetroxide and oxygen at 30 DEG to 40 DEG C., the reaction product is stripped of N2O4 and distilled to obtain gamma-butyrolactone, with gamma-aceto-propanol as a by-product.