GB867751A - Process for the hydrogenation of unsaturated fatty acids - Google Patents

Abstract

Unsaturated fatty acids are catalytically hydrogenated in the vapour phase in the presence of water vapour, the hydrogenation vapour mixture containing from 2 to 200 molecules of water for each 100 molecules of hydrogen. The hydrogenation may be partial (in which case it may be selective) or complete. In practice the water is introduced into the hydrogenation vapour mixture before it contacts the catalyst. Preferably from 5 to 50 molecules of water are used for each 100 molecules of hydrogen employed, the total amount of hydrogen and water being usually 20 to 200 molecules for each molecule of fatty acid. The preferred pressure is from 600 to 2280 mm. Hg, with a partial pressure of fatty acid of 10 to 40 mm. A temperature of above 150 DEG C. is used in practice, conveniently from 200 to 280 DEG C. when C10-24 acids are being hydrogenated. Fixed bed or fluidised catalysts may be used; nickel and alumina catalysts suitably deposited on alumina or silica may be used. Dissolved air is preferably removed from the acid before hydrogenation. The hydrogen may be first passed through water at a temperature to give the desired water content, then through a vapouriser containing the unsaturated material at a temperature to provide the desired acid content and then over the catalyst. In examples, oleic acid and fish oil fatty acids are hydrogenated. Specification 828,661 is referred to.