Ciba-geigy Corporation

Junkuan Wang

Paul Rys

Martin Clausen

Process for the preparation of compounds of the formula HO-Ar-COOH in which Ar is a substituted or unsubstituted aromatic ring system, by oxidizing, by means of oxygen or compounds which donate oxygen, compounds of the formula HO-Ar-R.sub.1 in which R.sub.1 is alkyl having 1 to 5 carbon atoms and Ar is as defined above, or the O-acyl derivatives of these compounds, in an organic solvent at 80.degree. to 130.degree. C. and in the presence of an acylating agent, a cobalt and/or manganese compound and a compound which donates bromide, ions, and subsequently hydrolysing the products in a conventional manner. In the presence of the acylating agent, a selective oxidation of the hydroxyl-substituted aromatic compounds to carboxylated hydroxy compounds, which are obtained in a good state of purity and yield, is obtained without the application of pressure. The compounds obtained in accordance with the process are, for example, valuable intermediates for the preparation of dyes, plastics and pharmaceuticals.

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Zurich, Switzerland

Junkuan Wang