Branched carboxylic acids from long‐chain unsaturated compounds and carbon monoxide at atmospheric pressure

Abstract

AbstractCarbon monoxide at atmospheric pressure adds readily to the double bonds of certain long‐chain unsaturated compounds in concentrated sulfuric acid to produce branehed carboxylic acids. Unsaturated compounds studied were oleic acid, 10‐hendecenoic acid, oleyl alcohol, methyl ricinoleate, and linoleic acid. A major component from the reactions of the last two compounds is the same.Infrared spectrophotometry and gas‐liquid chromatography have been the major tools employed in determining composition and structure of the products in addition to the usual chemical and physical determinations.Both the concentration and quantity of sulfuric acid are critically important variables in determining the yields. Water is an essential reactant also and must be available throughout the reaction.Carbon monoxide has been prepared and utilizedin situ by a modification of Koch's (1) method in which the unsaturated compound mixed with formic acid is added to concentrated sulfuric acid or carbon monoxide from a cylinder is passed through sulfuric acid to which the unsaturated compound is added. A method for preparing methyl and butyl esters of carboxyl groups which are difficult to esterify is described.Reaction mechanisms involving intermediate carbonium and oxoearbonium ions are proposed to account for the products.