GB1009083A - Chemical process - Google Patents

Abstract

Butene, pentene, cyclohexene, ethyl-benzene and cumene are obtained by the selective hydrogenation of the corresponding more unsaturated compound which may be a conjugated diene, such as butadiene, using hydrogen in the presence of an aqueous solution of pH at least 7 containing cyanide complexes of a cobalt group metal. The reduction may be carried out under mild conditions, e.g. at room temperature, and at a pressure of 1 atmosphere but a temperature up to 180 DEG C. and a hydrogen pressure up to 3000 p.s.i. may be used. The cobalt group metal ions for the complex may be produced from the corresponding nitrates, acetates, sulphates, carbonates or chloride in conjunction with sodium or potassium cyanide.ALSO:The invention relates to the use of a reduction medium comprising hydrogen in the presence of an aqueous solution of pH at least 7 containing cyanide complexes of a cobalt group metal for the selected reduction of certain functional groups. The reduction may be carried out under mild conditions, e.g. at room temperature and a pressure of 1 atmosphere, but a temperature up to 180 DEG C. and a hydrogen pressure up to 3000 p.s.i. may be used. The cobalt group metal ions for the complex may be produced from the corresponding nitrates, acetates, sulphates, carbonates or chlorides in conjunction with sodium or potassium cyanide. Preferably from 0.3 to 0.6 mol. of the reactant is used per mol. of the complex. Classes of compounds which may be selectively reduced include vinyl compounds, particularly conjugated compounds, compounds containing an epoxide group, a nitro group, nitroso group, an aldehyde group or a quinone group. In examples, the following compounds are prepared: butene, pentene, cyclohexene, ethylbenzene, cumene, hydrocinnamyl alcohol, methyl succinic acid, 2-hexenoic acid, isobutyric acid, 2-methylvaleraldehyde, 2-methylbutyraldehyde, isobutyric acid, isobutyramide, methyl isopropylketone, hydrazobenzene, 2,21 - dichloroazoxybenzene, 2,21-dichloroazobenzene, 2,21-dichlorohydrazobenzene, p-tolylhydroxylamine, p-azoxytoluene, dimethylamine, hydrochloride, benzyl alcohol, hydroquinone and 4-phenyl-2-butamine.ALSO:A selective reduction medium comprises hydrogen in the presence of an aqueous solution of pH of at least 7 containing cyanide complexes of a cobalt group metal. The reduction may be carried out at room temperature and at one atmosphere pressure of hydrogen, but a temperature up to 180 DEG C. and a pressure up to 3,000 p.s.i. may be employed. The complex is produced by mixing the nitrate, acetate, sulphate, carbonate or chloride of a cobalt group metal with potassium or sodium cyanide. The complex may be used selectively to reduce vinyl compounds, especially conjugated compounds, compounds containing epoxide or nitro or nitroso or aldehyde groups or quinone as described in Division C2.