Dehydrogenation catalyst and a process for its production

摘要

A catalyst, particularly suitable for the dehydrogenation of an alcohol to a carbonyl compound comprises: copper, nickel, and an alkaline-reacting alkali metal compound on a siliceous support; the alkali metal compound or compounds being present to the extent of from 1 to 30 per cent of the combined copper and nickel. The preferred support is kieselguhr and the preferred alkali metal compound is a potassium compound. Advantageously the support comprises 20 to 400 per cent of the combined weight of copper and nickel and the alkali metal compound advantageously comprises 3 to 20 per cent of the combined weight of copper and nickel. The copper and nickel are in the proportions of 2-1 to 1-2. The catalyst is prepared by precipitating the aqueous solution of a compound of copper and a compound of nickel by an alkaline-reacting alkali metal compound on to kieselguhr; washing the precipitate; impregnating with an alkali metal compound; drying and treating with hydrogen or hydrogen-containing gas. The catalyst may be activated by treatment, before reduction by hydrogen with an inert and/or an oxidizing gas for at least sixty minutes at 250 DEG to 600 DEG C. The catalyst may be regenerated by treatment with oxygen or oxygen - containing gas at temperatures below 300 DEG C.ALSO:Carbonyl compounds are prepared by the dehydrogenation of alcohols wherein is used as catalyst a composition comprising copper, nickel and one or more alkaline-reacting alkali metal compounds on a siliceous support, the alkali metal compound or compounds being present to the extent of from 1 to 30 per cent of the combined weight of copper and nickel. The preferred support is kieselguhr and the preferred alkali metal compound is a potassium compound. Advantageously the support comprises 20 to 400 per cent of the combined weight of copper and nickel and the alkali metal compound advantageously comprises 3 to 20 per cent of the combined weight of copper and nickel. The copper and nickel may be present in the proportions of 2-1 to 1-2. The preparation of the catalysts is described (see Group III). Alcohols, particularly secondary saturated aliphatic alcohols, may be converted into carbonyl compounds at a temperature in the range of 200 DEG to 300 DEG C., using a space velocity of 3 to 6 litres (liquid) of alcohol per litre of catalyst per hour. Spent catalyst may be regenerated by treatment with oxygen at temperatures below 300 DEG C. followed by reduction. Examples describe the conversion of isopropyl alcohol to acetone and sec.-butanol to methyl ethyl ketone by passing the alcohol or mixture thereof with hydrogen in the vapour phase over a catalyst obtained by adding a solution of copper and nickel nitrates to a solution of sodium carbonate containing kieselguhr, filtering, impregnating the solid residue with potassium carbonate and finally reducing with hydrogen at 300 DEG C. The potassium carbonate used may be replaced by an alkali metal hydroxide, silicate, phosphate, nitrate or borate.