| 摘要 |
The invention comprises a process for the production of benzene carboxylic acids, or their nitro, halogen, or hydroxy substituted derivatives, by the oxidation of benzene compounds having at least one alkyl group containing up to three carbon atoms, or the corresponding oxidation products thereof in so far as they are poorer in oxygen than the corresponding carboxylic acid, with an aqueous solution of a hypochlorite to form the corresponding benzene carboxylic acids, which process comprises working in the presence of finely divided solid emulsifiers, which are insoluble in water. Solid emulsifiers specified are barium sulphate, calcium sulphate, kieselguhr, titanium dioxide, aluminium silicates, tricalcium phosphate, calcium carbonate and magnesium carbonate. The emulsifiers may be removed at the end of the reaction by e.g. filtration, decantation or centrifuging and reused. Examples are given of the preparation of terephthalic acid using barium sulphate as the emulsifier and (1) para-diisopropylbenzene which has been partially oxidized with air in the presence of cobalt salts, and (2) paradiacetylbenzene, as starting materials. Specifications 770,521 and 783,286 are referred to. |
