Studies on Alkaline Oxidation of Alcohols

Abstract

It has been known that alcohols are oxidized into corresponding salts of carboxylic acids by the action of alkali metal hydroxides.
As a method for making fatty acids from easily obtainable synthetic alcohols, the alkaline oxidation is very attractive from the industrial points of view. In order to obtain data for the commercial plant, alcohols were heated in the temperature range of 210320°C with alkali metal hydroxides in an autoclave of 2, 300ml.
The alcohols used for the reaction were as follows; straight-chain alcohols having even number carbon atoms from 6 to 18, branched chain alcohols obtained by the oxo-alcohol process, glycols, oleyl alcohol and benzyl alcohol.
In general, the reaction proceeded smoothly with evolution of hydrogen, and the conversion to the alkali metal salts of the corresponding acids was more than 90%.
2-Ethyl-1-hexanal was also converted into the corresponding acid by the alkaline oxidation, 2-ethyl-hexylether, however, was not oxidized under the similar conditions.
Lithium hydroxide and alkaliearth metal hydroxides did not react with alcohols in the present experimental conditions.
A small amount of water in the reaction mixture decreased the yields of acids and the reaction rates.
Secondary alcohols, such as 2-octanol and 1, 2-propanediol, were also oxidized for comparison.