Hydrogenolysis: I. Nickel-kieselguhr as catalyst for the conversion of alcohols to ethers and hydrocarbons

Abstract

The hydrogenolysis of alcohols in the presence of nickel-kieselguhr catalysts has been investigated in a micropulse reactor at 150–190 ° and at atmospheric pressure. Three main reactions occurred with primary aliphatic alcohols: reductive dehydroxymethylation, dehydroxylation, and the formation of ethers. The nickel-catalyzed conversion of alcohols to ethers is a novel reaction and can be applied even for the synthesis of neopentyl ether. The methods of preparation of nickel-kieselguhr affects the composition of the products. For the preferential formation of ethers the catalyst was prepared by precipitating the nickel from an aqueous nickel nitrate solution with ammonium carbonate. When potassium carbonate was used as the precipitating agent the yield of ether was lower. The intrinsic acidic sites of the catalyst appear to be responsible for the reductive dehydroxylation and for the formation of the ethers. Kieselguhr as such was not a catalyst for these reactions, while a nonsupported nickel under certain conditions could influence the ether formation.