GB769515A - Improvements in or relating to the production of hydrogen peroxide - Google Patents

Abstract

<PICT:0769515/III/1> In the production of hydrogen peroxide from an alkyl anthraquinone by successive reduction and oxidation, a solution of the alkyl anthraquinone is substantially saturated with hydrogen, the hydrogen saturated solution is partially reduced in the presence of particle form hydrogenation catalyst, at least part of the partially reduced solution is oxidized by contact with a free oxygen-bearing gas, and hydrogen peroxide is recovered from the oxidized solution. 8-15 per cent solution of an alkyl anthraquinone, e.g. 2 - isopropyl, 2 - tert - butyl, tetramethylene, 2 - methyl, or 2 - ethyl anthraquinone, in solvents comprising benzene or alkylated benzenes, or in a mixture of light oils, e.g. a mixture of tetralin and methyl cyclohexanol, may be used. Hydrogen is compressed, e.g. to 250-750 psia and passed through 11 into saturator 12, where it is dissolved in a mixture of recycled partially reduced anthraquinone solution from 13 and recycled oxidized solution from 14 in a ratio say 5 to 0.8:1. The hydrogen-saturated solution passes to reducer 16, preferably containing a fixed bed of, e.g. Raney nickel, or palladium or platinum on alumina, to effect 50-75 per cent reduction at 30-80 DEG C. The major portion of the reduced solution is recycled to the saturator through 17, 13 and the remainder passes through further reducer 20 to oxidizer 22 where it is contacted with air entering at 25. The oxidation may be as described in Specification 768,675 by concurrent or countercurrent contact at 30-80 DEG C. and 15-300 psia. in a tower packed with inert solid. The oxidized solution passes to water extraction system 27, with water entering at 30. Strong hydrogen peroxide is withdrawn at 31 and separted intermediate solution is recycled through 14. The extraction may be in 3 stages with concentration by vacuum distillation. Extraction may be effected by distillation in the presence of steam at 70-105 DEG C. and 5-65 mm. Hg. as described in Specification 769,514. Compression of the hydrogen to above 750 psia renders the recycling of reduced and oxidized solution unnecessary.