Ciba-geigy Corporation

Martin Clausen

Paul Rys

Wang Junkuan

Junkuan Wang

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.

Process for the preparation of carboxylated aromatic hydroxy compounds

Process for the preparation of alkyl-substituted phenols or naphthols by oxidizing the corresponding dialkylbenzenes or dialkylnaphthalenes, respectively, at elevated temperatures of, for example, 70.degree. to 130.degree. C. by means of oxygen or oxygen donors, in the absence of solvents and in the presence of an alkali metal salt or alkaline earth metal salt of an organic carboxylic acid having 5 to 14 carbon atoms, to give the corresponding 2,6-dialkylnaphthalene-or 1,4-dialkylphenyl monohydroperoxides and subsequently hydrolysing the latter in a customary manner. The process results in pure, easily isolatable products in a good yield. The products of the process according to the invention are valuable precursors and intermediates for, inter alia, dyes, plastics or pharmaceuticals.

Process for the preparation of alkyl-substituted phenols or naphthols

Process for the preparation of 2,6-dihydroxynaphthalene from 2,6-dialkylnaphthalenes, which are dissolved in an inert solvent and are oxidized at temperatures from 50.degree. to 150.degree. C. by means of oxygen or oxygen donors, in the presence of an alkali metal salt or alkaline earth metal salt of an organic carboxylic acid having 5 to 14 carbon atoms, to give the corresponding 2,6-dialkylnaphthalene dihydroperoxides, and the latter are subsequently hydrolysed. The process results in pure, easily isolatable products in a good yield. The process products according to the invention are valuable intermediates for, inter alia, dyes, plastics, synthetic fibres, polymeric liquid crystals or pharmaceuticals.

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Zurich, Switzerland

Martin Clausen