GB434104A - Improvements in or relating to the manufacture of organic condensation products - Google Patents

Abstract

Condensation products of higher molecular weight, such as ketones, alcohols and hydrocarbons are obtained by treating a secondary alcohol with a dehydrogenating catalyst at temperatures from 200--500 DEG C. and pressures of from 2--750 atmospheres, the yield of condensation products such as higher alcohols increasing with the pressure. The process may be carried out either in the liquid or in the vapour phase. Suitable catalysts include difficultly reducible oxides, such as zinc oxide, manganese oxide or magnesium oxide or mixtures thereof or with other oxides which may be less active but more acidic than the above oxides, e.g. oxides of vanadium, tungsten, molybdenum or uranium which act as promoters. Preferably the catalyst contains one or more components having dehydrogenating characteristics and one or more dehydrating metal oxides, e.g. chromium oxide, aluminium oxide or thorium oxide. A preferred catalyst consists of chromium oxide and manganese oxide or zinc oxide. Preferably, the dehydrogenating components are in the combined state, e.g. as oxide or in the form of a compound with the dehydrating oxide. Suitable catalysts of this type are described in Specifications 272,555, 301,806, and 313,575, [all in Class 2 (iii)]. Examples of secondary alcohols which may be treated are isopropanol, secondary butanol, diethyl carbinol, methyl normal propyl carbinol, and methyl isopropyl carbinol. According to examples (1) isopropanol vapour is passed over a zinc-copper-cadmium chromite catalyst at a temperature of 390 DEG C. and a pressure of 200 atmospheres. The condensate contains acetone, low boiling hydrocarbons, higher alcohols and ketones and other higher condensation products; (2) secondary butyl alcohol is vaporized and passed over a zinc-copper-cadmium chromite catalyst at 350 DEG C. and 200 atmospheres pressure. The condensate contains higher products as in the above example in addition to methyl ethyl ketone. If the reaction is carried out under atmospheric pressure, low boiling ketones are chiefly obtained, free from condensation products.ALSO:Condensation products of higher molecular weight, such as ketones, alcohols and hydrocarbons, are obtained by treating a secondary alcohol with a dehydrogenating catalyst at temperatures from 200--500 DEG C. and pressures of from 2--750 atmospheres, the yield of condensation products such as higher alcohols increasing with the pressure. The process may be carried out either in the liquid or in the vapour phase. Suitable catalysts include difficulty reducible oxides such as zinc oxide, manganese oxide or magnesium oxide or mixtures thereof or with other oxides which may be less active but more acidic than the above oxides, e.g. oxides of vanadium, tungsten, molybdenum or uranium which act as promoters. Preferably the catalyst contains one or more components having dehydrogenating characteristics and one or more dehydrating metal oxides, e.g. chromium oxide, aluminium oxide or thorium oxide. A preferred catalyst consists of chromium oxide and manganese oxide or zinc oxide. Preferably the dehydrogenating components are in the combined state, e.g. as oxide or in the form of a compound with the dehydrating oxide. Suitable catalysts of this type are described in Specifications 272,555, 301,806, and 313,575, [all in Class 1 (i)]. Examples of secondary alcohols which may be treated are isopropanol, secondary butanol, diethyl carbinol, methyl normal propyl carbinol and methyl isopropyl carbinol. According to examples, isopropanol and secondary butyl alcohol are treated in the vapour phase in the presence of a zinc-copper-cadmium chromite catalyst at 200 atmospheres pressure and temperatures of 390 and 350 DEG C. respectively. The products are low boiling hydrocarbons, higher alcohols and ketones and other higher condensation products, in addition to acetone and methyl-ethyl ketone. If the reaction is carried out at atmospheric pressure, low-boiling ketones are chiefly obtained, free from condensation products.