Patent GB-951192-A (GB)
IPC: B01J31/04
Abstract: 951,192. Oxidation of aralkyl compounds. GENERAL ELECTRIC CO. March 9, 1960, No. 8313/60. Heading C2C. Aralkyl compounds are oxidized in the side chain by treatment in the liquid phase with an oxygen-containing gas at a temperature between room temperature and 160‹C. in the presence of a solvent and of a catalyst containing bromine, cobalt and a carboxylic acid, the atomic ratio of bromine to cobalt in the catalyst being from 0À1 to 1À2 and the concentration of cobalt in the solvent being at least 0À05 molar. The solvent must not contain more than 5% of water by weight, and the reaction may be effected under conditions promoting the removal of water. The preferred solvent is a carboxylic acid, a number of which are specified, and the preferred sources of bromine and cobalt are hydrogen bromide and cobaltous acetate tetrahydrate respectively, although in both cases other sources are also specified. The process is preferably effected at atmospheric pressure, but the use of lower or higher pressures is also metioned. The products are generally ketones or carboxylic acids, but if it is desired to oxidize ketonic products further to yield carboxylic acids, the oxygen-containing gas may be used in admixture with ozone. The starting materials may be (1) mono-, di- and tri-alkyl substituted benzenes, e.g. toluene, the xylenes, ethyltoluene and mesitylene, (2) mono-, di-, tri- and tetra-alkyl diphenyls or diphenylalkanes, e.g. diphenylmethanes, (3) mono-, di- and tri-alkyl substituted naphthalenes, e.g. 1-methylnaphthalene and amylnaphthalene, (4) the isomeric toluic acids, (5) alkyl-substituted acetophenones, (6) alkylsubstituted diphenyl ketones, e.g. 4, 4<SP>1</SP>-dimethyldiphenyl ketone, (7) alkyl-substituted diphenyl sulphones, (8) bromotoluene and bromotoluic acid, and (9) dialkyldiphenyl ethers. Examples are given in which (1) o-xylene yields phthalic acid, (2) ethylbenzene yields acetophenone, (3) p-xylene yields terephthalic acid, (4) a mixture of o-, m- and p-xylene and ethylbenzene yields mixed dibasic acids and acetophenone, (5) ptoluic acid yields terephthalic acid, (6) o-bromotoluene yields o-bromobenzoic acid, (7) p-xylene yields p-toluic acid, (8) mesitylene yields a mixture of mono-, di- and tri-benzene carboxylic acids, (9) 2, 5-dimethylacetophenone yields a mixture of acetophenone mono- and di-carboxylic acids, (10) p-methylacetophenone yields p-acetylbenzoic acid, (11) 4, 41-dimethyldiphenyl ketone yields 4, 4<SP>1</SP>-diphenylketone dicarboxylic acid, (12) 4, 41-dimethyldiphenyl ether yields 4, 4<SP>1</SP>- diphenyl ether dicarboxylic acid, (13) ethylbenzene yields acetophenone, (14) ethylbenzene, with the addition of ozone to the gas containing oxygen, yields benzoic acid and acetophenone, (15) propylbenzene yields propiophenone and benzoic acid, (16) p-ethylacetophenone yields p-diacetylbenzene, (17) 1-methylnaphthalene yields 1-naphthoic acid, (18) 1-amylnaphthalene yields naphthalyl -1- butyl ketone and 1-naphthoic acid, and (19) p-ethyltoluene yields pacetylbenzoic acid. Reference is made also to the production of isophthalic acid from m-xylene, benzoic acid from toluene, o- and m-diacetylbenzenes from o-, and m-diethylbenzenes and 1- acetylnaphthalene from 1-ethylnaphthalene. Mention is made also of the use of peroxides or hydroperoxides as reaction promoters.