GB918900A - Production of cyclohexanone and cyclohexanol - Google Patents

Abstract

Cyclohexane is oxidised in liquid phase with an oxygen-containing gas at 120-170 DEG C. and at a pressure up to 70 atmospheres; the oxidation mixture containing 30-98% by weight of cyclohexane is contacted with a 10-30% aqueous solution of an alkali hydroxide or carbonate at 60-150 DEG C. for 2-60 minutes; the aqueous phase is separated from the oxidation mixture; the cyclohexane is distilled off from the oxidation mixture until the content thereof is less than 20% by weight; alkali hydroxide or carbonate is added in an amount corresponding to 0.20-0.95 equivalents of the esters contained in the oxidation mixture and the mixture is then heated for 0.1-10 minutes at 130-160 DEG C.; pure cyclohexanol and pure cyclohexanone are then recovered by fractional distillation of the oxidation mixture, preferably under reduced pressure without previous separation of the alkali compound. Oxidation may be effected in two or three stages, and an oxidation catalyst such as cobalt naphthenate may be present. Water formed during the oxidation may be left in the reaction mixture or distilled off continuously. After the oxidation or after one or more oxidation stages, the reaction mixture may be subjected to water washing e.g. at 60-120 DEG C. If desired, the cyclohexanol obtained may be dehydrogenated and converted to cyclohexanone by heating in gas phase with a catalyst such as an oxide of Cu, Cr, Ni, Zn, Mo, or V. Specifications 776,803 and 815,162 are referred to.