GB706009A - Improvements in and relating to the production of aliphatic carboxylic acids - Google Patents

Abstract

Saturated aliphatic monocarboxylic acids are obtained from mixtures containing olefins and saturated aliphatic aldehydes by preparing the aldehydes substantially free of olefins and oxidizing in the liquid phase with oxygen or gas containing it. Nonanoic acids may be prepared from crude nonaldehydes obtained by the Oxo synthesis and containing, for example, 5-40 per cent. of the initial olefin. Thus, 3, 5, 5-, 3, 4, 4-, 3, 4, 5-, and 4, 5, 5- trimethyl hexanoic-1 acids are obtained from mixtures of the corresponding hexanols and the original olefins. The olefin may be removed by distillation or by hydrogenating the mixture to convert the aldehyde to alcohol, separating the alcohol by fractionation, and then dehydrogenating to the aldehyde, for example, as described in Specification 704,943. The oxidation may be effected at 50-75 DEG C. with cobalt, lead or manganese as catalyst, preferably in the form of soluble salts, e.g. naphthenates, acetates, and nonanoates. Acids may also be obtained from other crude aldehydes produced by the Oxo synthesis from di-isobutene, and mixed olefins from the cracking of paraffin wax. Salts of the acids, for example the Co, Mn, Pb and Zn salts, are of use as paint and oil siccatives, and wood and textile preservatives. In an example, a crude carbonylated product containing di-isobutene is distilled in vacuo to give 3, 5, 5- trimethyl hexanol-1 to which is added manganese naphthenate in nonanoic acid before oxidation with oxygen in continuous co-current up-flow.