GB1080133A - Hydrogen peroxide - Google Patents

Abstract

In the production of hydrogen peroxide by the catalytic hydrogenation of alkylanthraquinones or mixtures thereof with tetrahydroanthraquinone and/or tetrahydroalkylanthraquinones in organic solvents, oxidation of the resultant alkylanthrahydroquinones or mixtures thereof with tetrahydroanthrahydroquinone and/or tetrahydroalkylanthrahydroquinones, and extraction of the resultant hydrogen peroxide, the hydrogenation catalyst is obtained by leaching a nickel-aluminium alloy, which leaching includes treatment with aqueous alkali solution at a temperature of from 120 DEG to 160 DEG C. The treatment preferably is carried out for between 1 and 3 hours at a temperature of from 130 DEG to 150 DEG C. To prevent deposition of aluminate on the catalyst, the leaching may take place in two stages, a fresh solution of alkali being used in the second stage, which is operated at a temperature of from 120 DEG to 160 DEG C. to constitute the above treatment. As exemplified, nickel-aluminium alloy is first leached by 20% by weight aqueous caustic soda solution at the boiling point (105 DEG to 107 DEG C.) of the solution for 1 hour and, after removal of the aluminate-containing solution by decanting, is further treated under pressure with fresh aqueous sodium hydroxide solution having a specific gravity of 1.24 for 2 hours at a temperaure either of 130 DEG C. or of 140 DEG C. The subsequent catalytic hydrogenation step in the production of hydrogen peroxide preferably is carried out at a temperature of from 40 DEG to 65 DEG C.; the working solution may comprise a mixture of alpha-methylnaphthalene and sec-octanol solvent containing 2-ethylanthraquinone (2-EAQ) and tetrahydro-2-ethylanthraquinone (TH-2-EAQ) (Example 1); 2-EAQ, TH-2-EAQ and tetrahydroanthraquinone (Examples 2 and 4); or 2-EAQ, TH-2-EAQ and tetrahydro-2-methylanthraquinone (Example 3).