Process for the production of quinols and for the manufacture of hydrogen peroxide therewith

In a process for the production of a solution of a substituted anthraquinol or of a substituted tetrahydroanthraquinol in an organic solvent by the reduction of a substituted anthraquinone or of a substituted tetrahydranthraquinone in solution in that organic solvent by means of hydrogen in the presence of a hydrogenation catalyst, such organic solvent is a liquid solvent consisting of a mixture of a ketone having the structure R-CO-R1 and containing from 7 to 15 carbon atoms, R and R1 being hydrocarbon radicals each containing from 1 to 8 carbon atoms and at least one halogenated aromatic hydrocarbon having the halogen atom or atoms linked to carbon atom or carbon atoms in an aromatic ring, the amount of ketone being at least 20% by weight of the liquid solvent. Hydrogen peroxide is obtained by subjecting solutions of substituted anthraquinols or of substituted tetrahydroanthraquinol obtained by the above process, to oxidation with elemental oxygen in a manner known per se (see Group III). Halogenated aromatic hydrocarbons specified for use in the process include o-, m- and p-dichlorobenzenes, 1, 2, 3-, 1, 2, 4- and 1, 3, 5-trichlorobenzenes, chlorinated diphenyls e.g. 2- and 4-chlorodiphenyls, chlorinated naphthalenes e.g. 1-chloro-and 1, 6-dichloronaphthalenes and the corresponding bromides or fluorides e.g. 2-fluoro-, and 4-fluoro-diphenyl and 2-bromonaphthalene. Ketones specified include diisobutyl-, di-n-propyl-, diamyl-, dihexyl-, ethyl hexyl- and ethyl amyl ketones. Quinones specified include 2-ethyl-, 2-isopropyl-, 2-sec-butyl-, 2-tert.-butyl-, 2-sec.-amyl-, 1, 2-, 1, 3- and 1, 4-dimethyl-, and 2, 7 dimethyl anthraquinones. Catalysts specified include spongy nickel, metallic palladium and other metals of the eighth group of the Periodic Classification which are hydrogenation catalysts. In a specific process 2-ethyl anthraquinone is hydrogenated in solution in a mixture of diisobutyl, ketone and o-dichlorobenzene in the presence of a palladium-or-alumina catalyst. The 2-ethyl anthraquinol is either oxidised with air to form hydrogen peroxide or is isolated by evaporating the hydrogenated solution. Specification 465,070 is referred to. Reference has been directed by the Comptroller to Specifications 758,235, 799,099 and 820,512.ALSO:Hydrogen peroxide is produced by oxidation in a manner known per se of a solution of a substituted anthraquinol or a substituted tetrahydroanthraquinol in an organic solvent produced by reduction of a substituted anthraq