| 摘要 |
Substituted phenols, aromatic carboxylic acids, aromatic ketones and/or aromatic peroxides are made by reacting one or more alkylated aromatic hydrocarbons or halogenated alkylated aromatic hydrocarbons containing at least one replaceable hydrogen atom, with oxygen in the presence of hydrogen bromide at an elevated temperature below that at which spontaneous combustion or substantial decomposition of the carbon structure occurs. The hydrogen bromide may be produced from a compound capable of yielding hydrogen bromide under the operating conditions. Specified compounds which may be oxidised by the process are toluene, xylenes, ethyl benzene, hemimellithene, mesitylene, n-propyl benzene, cymene, durene, tertiary butyl benzene, diphenylmethane, diphenylethane, and their homologues, and derivatives thereof partially halogenated in the ring or in the alkyl chain, e.g. benzyl chloride and benzyl bromide. The oxidation may be effected in presence of inert diluents such as steam, nitrogen, carbon dioxide or methane, and oxygen containing mixtures, such as air, may be used instead of oxygen. In examples: (1) toluene, oxygen, nitrogen and hydrogen bromide are heated to about 200 DEG C. at atmospheric pressure to give benzoic acid; (2) ethyl benzene, oxygen, nitrogen and hydrogen bromide are heated to about 195 DEG C. at atmospheric pressure to give acetophenone, carboxylic acids (chiefly phenylacetic acid) and a mixture of bromophenols. Rapid neutralisation of the products with sodium carbonate or hydroxide increases the yields. Aralkyl bromides formed by side reaction may be oxidised by the process of the invention and any hydrogen bromide regenerated may be re-used. The Specification as open to inspection under Sect. 91 comprises also the oxidation of non-alkylated aromatic hydrocarbons, e.g. benzene, naphthalene and phenanthrene, and their halogenated derivatives, and the use, as catalysts, of hydrogen halides in general (hydrogen chloride being additionally specified) or of chlorine or bromine. This subject-matter does not appear in the Specification as accepted.
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