GB991413A - Improvements in or relating to the production of hydrogen peroxide - Google Patents

Abstract

A process for regenerating the hydrogen peroxide producing capacity of a solution comprising an anthraquinone dissolved in an organic solvent therefor which capacity has become diminished through use in a process for synthesizing hydrogen peroxide involving hydrogenating the anthraquinone, oxidizing the resultant anthrahydroquinone, separating by aqueous extraction the H2O2 so formed and recycling the so treated solution to the hydrogenation step, or for regenerating the H2O2 producing capacity of solids derived from the anthraquinone and separated from such a solution and redissolved, wherein at least a portion of the solution while in the oxidized anthraquinone state or of said redissolved solids being of the chemical composition which obtains in the cycle after aqueous extraction and before hydrogenation, is contacted with an aqueous solution of sodium hydroxide or potassium hydroxide of a concentration between 8N and 17N in the presence of an oxidizing agent capable of supplying oxygen to the solution or said redissolved solids. The solution after treatment may be washed with water prior to returning to the cycle. The oxidizing agent may be used in amount sufficient to yield a weight of oxygen at least equal to 3.5% of the solid material other than anthraquinone and tetrahydroanthraquinone. The process is preferably carried out in conjunction with treatment of the degraded solution with a bed of particulate solid material, e.g. artificial aluminosilicate or activated alumina. Quinones mentioned are methyl, ethyl, isopropyl and butyl anthraquinones, e.g. 2 ethyl-anthraquinone and 2 tertbutylanthraquinone. Solvents specified: methyl naphthalene with diisobutyl carbinol, esters of cyclohexanol with aromatic hydrocarbons, e.g. xylene and cyclohexyl acetate, aliphatic ketones, chlorinated hydrocarbons, aromatic ketones, and aromatic alcohols and their esters. Hydrogenation catalysts may be Raney nickel or palladium or an inert support, e.g. alumina, silica gel, sodium aluminium silicate, silica alumina, calcium phosphate, magnesium oxide or hydroxide. The oxidizing agent may be oxygen or a gas containing free oxygen, or hydrogen peroxide supplied to the alkali treatment by lowering the efficiency of the H2O2 extraction. Specifications 465,070 and 838,939 are referred to.