GB842998A - Process for the production of carboxylic acids by the oxidation of organic compounds - Google Patents

Abstract

A process for the production of carboxylic acids of aromatic character comprises oxidising a hydrocarbon of aromatic character substituted by at least one alkyl or haloalkyl group or a partially oxidised derivative thereof and by at least one polar group selected from halogen, -SO2NR1R11(R1R11=alkyl, aryl or H); -OR (R = alkyl, aryl); -NHCOR (R = alkyl, aryl or H); -O.OC.R, (R = alkyl, aryl or H); -SO 3R (R = alkyl, aryl or H); -CONR 1R11 (R1, R11 = alkyl, aryl or H); -NR 1R11 (R1, R11 = alkyl, aryl); benzoyl; substituted benzoyl and alkyl carboxylic ester in the liquid phase by means of molecular oxygen or ozone in the presence of a catalyst comprising the manganese bromide and/or cobalt bromide. The term "a hydrocarbon of aromatic character" includes also heterocyclic compounds of aromatic character containing one or more alkyl groups connected to nuclear carbon atoms. The partially oxidised derivatives which may be employed are carboxylic, aldehydo, keto and alcohol derivatives. The starting material may be an ester formed by the interaction of two partially oxidised derivatives e.g. an ester. Examples of heterocyclic starting materials are b -picolines substituted with the above defined polar groups in the b -position. Primary, secondary and tertiary alkyl groups which may be oxidised to carboxyl are mentioned. The metal bromides may be introduced as such or may be produced e.g. by introducing metal salts soluble in the reaction mixture e.g. the acetates or naphthenates and e.g. bromine, hydrobromic acid or sodium bromide. Cobalt may be introduced as reduced metal or as carboxyl or oxide. Halogen lost during the process may be replaced by introducing hydrogen bromide, bromine or a bromo derivative of the aromatic starting material. The process may be carried out at elevated temperatures and pressures. Ozone may be employed to accelerate the oxidation of difficulty oxidisable compounds and the oxygen may be produced in situ by decomposition of hydrogen peroxide. Solvents mentioned include aliphatic carboxylic acids containing from 2 to 4 carbon atoms, aromatic hydrocarbons, halobenzenes, e.g. o-dichlorobenzene, aromatic acids and water. Examples relate to the production of p-sulphonamido-benzoic acid, m- and pbenzoxy-benzoic acid and anisic acid. Additional products mentioned include m-sulphonamido-benzoic acid, p-carboxy benzene sulphonic acid, p-carboxybenzene methyl sulphonate and terephthalomonoamide. Additional starting materials mentioned include p-toluene sulphonic acid, methyl p-toluene sulphonate and p-toluamide. Specifications 832,995, 833,438 and 833,440 are referred to.