GB723280A - Improvements in or relating to the production of ketones - Google Patents

Abstract

A higher ketone is produced by a method comprising passing a mixture containing an aliphatic or cycloaliphatic secondary alcohol containing from 3 to 7 carbon atoms and an aliphatic ketone containing from 3 to 7 carbon atoms in the vapour-phase over an alumina-copper catalyst at a temperature between 240 DEG and 300 DEG C. and at a pressure above 175 lb. per square inch. Suitable alcohols for starting materials are, for example, isopropyl alcohol, sec. - butyl alcohol, 2 - hydroxypentane, 3 - hydroxypentane, 2-hydroxyhexane, cyclohexanol, 4 - methylcyclohexanol and 2 - hydroxy heptane. Suitable ketones are acetone, methylethyl ketone, methyl n-propyl ketone, diethyl ketone, hexanone-2, hexanone-3, methyl tert.-butyl ketone, di-n-propyl ketone and diiso-propyl ketone. Preferably the alcohol is one which on reduction yields a ketone identical with the ketone reactant, e.g. when methyl ethyl ketone is reacted with sec.-butyl alcohol. The catalyst used preferably contains a major proportion of alumina, which has been rendered catalytically active, together with about 2-20 per cent of copper and optionally about 5 to 30 per cent of a difficultly reducible metal oxide having dehydrogenating characteristics, e.g. zinc oxide, manganese oxide, iron oxide, calcium oxide or magnesium oxide. In the examples methyl ethyl ketone is reacted with sec.-butyl alcohol to give 5-methyl-3-heptanone and about 3,5-dimethyl-3-hexanone.ALSO:A catalyst used in the production of a higher ketone from an aliphatic or cycloaliphatic secondary alcohol and a ketone consists of an alumina-copper catalyst preferably including a major proportion of alumina which has been rendered catalytically active together with from about 2 to 20 per cent copper and optionally with from about 5 to 30 per cent. of a difficultly reducible metal oxide having dehydrogenating characteristics such as zinc oxide, manganese oxide, iron oxide, calcium oxide or magnesium oxide. Preferably the alumina is first impregnated with a solution of a zinc salt, e.g. zinc nitrate, followed by roasting to convert the zinc salt to zinc oxide; the roasted catalyst is then impregnated with a solution of a copper salt, e.g. copper nitrate, and then roasted again to convert the copper salt to copper oxide; the copper oxide is then reduced to copper in a hydrogen atmosphere at elevated temperature. In the examples the catalyst is prepared by (a) impregnating activated alumina with a concentrated aqueous solution of copper nitrate, followed by drying and roasting and then reducing it to a pure hydrogen at 250 DEG C.; (b) impregnating activated alumina with aqueous zinc nitrate, evaporating excess water and roasting; impregnating with aqueous copper nitrate solution, drying and roasting again and then reducing in an atmosphere of hydrogen at 280 DEG C.