Oblon, Spivak, McClelland, Maier & Neustadt
Preparation of aromatic hydroxycarboxylic acids
 Aromatic hydroxycarboxylic acids of the formula EQU (HO--).sub.n A--COOH where n is 1 or 2 and A is a radical from the benzene, naphthalene, biphenyl, diphenyl ether, diphenyl sulfide or diphenyl sulfone series, are prepared by a process in which an acylated aromatic compound of the formula EQU (R.sup.1 --CO--O--).sub.n A--CO--R.sup.2 where R.sup.1 and R.sup.2 independently of one another are each unsubstituted or substituted C.sub.1 -C.sub.4 -alkyl and n and A each have the abovementioned meanings, is oxidized with oxygen in the presence of a catalyst and of a solvent at from 20.degree. to 250.degree. C. to give a carboxylic acid of the formula EQU (R.sup.1 --CO--O--).sub.n A--COOH where R.sup.1, n and A have the abovementioned meanings, and the acyl group or groups is or are then eliminated. 
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Ulrich Peter
Eichenauer Neumann