GB712043A - Process for the preparation of higher aliphatic alcohols - Google Patents

Abstract

An aliphatic alcohol containing twice the number of carbon atoms per molecule compared with the number of carbon atoms in the starting material molecule is obtained from a primary or secondary monohydric aliphatic alcohol having from 9 to 20 carbon atoms in the molecule and possessing a methylene group next to the hydroxylated carbon atom by heating the said alcohol with technical potassium hydroxide in the presence of boric anhydride or a boric ester at a temperature of from 250 DEG to 300 DEG C. When the alcohols used as starting materials have a boiling range (at atmospheric pressure) above 250 DEG C. the reaction is preferably effected at atmospheric pressure. The alcohols used as starting materials are preferably the alcohols or mixtures of alcohols derived from natural vegetable or animal sources, e.g. the mixture of wax esters in the oils of the sperm whale, the dolphins and porpoises. Thus sperm oil, both head and blubber oil, furnishes by saponification or reduction a mixture of aliphatic alcohols having from 14 to 20 carbon atoms partly saturated and partly unsaturated. Saturated alcoholic starting material may be obtained by first submitting the crude sperm oil to hydrogenation. Other suitable starting materials can be obtained by the total reduction of wax esters or of the glycerides from vegetable oils such as coconut oil, or of the fatty acids derived there-from, by one of the modifications of the Bouveault-Blanc process or by catalytic high-pressure hydrogenation. The reaction product may be recovered by adding water and then separating the product either as a liquid layer or as a crystalline product and then directly, or after drying, isolating the alcoholic condensation product by distillation. The aqueous solution may be worked up for the recovery of the boron compound. Alternatively the reaction product may be submitted directly to fractional distillation. The alcohol products are stated to be susceptible to oxidation to the corresponding acids, to dehydrogenation, to ketonization, and to esterification. In examples: (1) 3.3 mol. lauryl alcohol is heated with technical potassium hydroxide (corresponding to 1 mol. KOH) and 0.5 mol. boric anhydride, the heating being carried out either in a sealed autoclave for 5 hours at 290 DEG C. or under reflux at atmospheric pressure for seven hours at 255 DEG C.; (2) cetyl alcohol (1 mol.), technical potassium hydroxide (corresponding to 0.3 mol. KOH) and 0.15 mol. boric anhydride, are heated under reflux at atmospheric pressure for five hours at 300 DEG C.; (3) the alcohols prepared by the saponification of hydrogenated sperm oil with solid caustic soda followed by distillation are heated under reflux with technical potassium hydroxide and boric anhydride for 5 hours at 300 DEG C. The products in each case are aliphatic alcohols containing twice the number of carbon atoms as the starting alcohol. Specification 655,864 is referred to.