GB850536A - Improvements in and relating to the oxidation of organic compounds - Google Patents

Abstract

Cyclic carboxylic acids are prepared by oxidising an alkyl or haloalkyl substituted compound of aromatic character or a closely related oxygenated derivative thereof, i.e. where the substituent is an aldehyde, hydroxy- or alkoxymethyl, acyl or hydroperoxy group, or one of the alkyl substituted or oxygenated compounds containing a polar substituent inert to oxidation under the reaction conditions, the reaction being carried out in the liquid phase by means of molecular oxygen or ozone in the presence as catalyst of a compound of a metal of variable valence and of hydrogen chloride and in the absence of bromine and bromine-containing compounds. The hydrogen chloride is preferably carried in the oxygen-containing gas in a concentration of from 0,001 to 1 gm. mole per 100 litres of oxygen at N.T.P. and the total amount of chlorine introduced is preferably 0,1 to 10 gm. atoms per mole of starting material. The process is said to be applicable to aromatic and heterocyclic compounds containing up to three substituents convertable to carboxyl groups and which may also contain as inert substituents halogen, nitro, sulphonamide, alkoxy, aryloxy, acylamino, acyloxy, carboxy, sulphonic acid or ester, amido, amino or benzoyl groups. In examples p-toluic acid is oxidised to terephthalic acid in benzoic acid or phthalic anhydride and in the presence of cobalt and manganese acetate. The Provisional Specification refers to the process where the hydrogen chloride is obtained from a metal chloride or an organic chloride which yields hydrogen chloride under the reaction conditions and two further examples describe the oxidation of p-toluic acid (1) in the presence of lithium chloride together with a catalyst and (2) in the presence of cobalt and manganese chlorides as catalyst. Specifications 840,009 and 842,998 are referred to.