GB492595A - Improvements in or relating to the manufacture of soap-forming carboxylic acids - Google Patents

Abstract

Soap-forming carboxylic acids or their salts are made by fusing with alkali metal or alkaline earth metal bases the mixtures of glycols or products containing oxide groups obtained by oxidation of technical mixtures of aliphatic, aliphatic-alicyclic or aliphatic-aromatic hydrocarbons containing, besides one or more unsaturated linkages in an aliphatic chain, at least one saturated aliphatic chain of at least 6 carbon atoms. Suitable hydrocarbon mixtures are unsaturated tar oils boiling at 200-350 DEG C. obtained by distillation of lignite, cracking gas oil fractions boiling at 200-325 DEG C. and containing 70-75 per cent of olefines having 12-18 C atoms, and olefinic products of the hydrogenation of carbon monoxide. The oxidation at the unsaturated linkage may be effected with permanganates, persulphates, hypochlorites, hydrogen peroxide, chlorine, oxygen or air, preferably in the presence of solvents or diluents such as acetic acid or anhydride, dioxane, acetone, mineral oils, or saturated hydrocarbons present in the initial mixtures. The hydrocarbons may first be converted into aqueous emulsions with soaps, fatty alcohol sulphonates and the like. The oxidation products are melted with the bases, either in anhydrous form or with addition of small amounts of water, at above 200, e.g. 250-300 DEG C. In examples: (1) a benzine obtained by hydrogenation of carbon monoxide, containing about 50 per cent higher olefines is emulsified with soap, and oxidized with hydrogen peroxide at 90 DEG C. The dried product is melted with caustic alkali at 250-280 DEG C. and the melt decomposed with mineral acid; (2) a gas oil fraction is similarly oxidized while dissolved in acetic acid and the product fused with alkali; (3) the olefines obtained by dehydration of a mixture of cetyl and stearyl alcohols are oxidized to the glycols which are converted to acids; (4) cracking benzine is similarly oxidized to glycol and autoclaved with caustic soda and water. The soap formed gives caproic acid on acidification.