PRODUCTION OF HYDROGEN PEROXIDE BY ANTHRAQUINONE PROCESS

1,273,280. Palladium-containing catalysts. FMC CORP. 15 June, 1970 [16 June, 1969], No. 28803/70. Heading B1E. [Also in Division C1] A hydrogenation catalyst comprises at least 0.05, for example from 0.1 to 5, weight per cent metallic palladium distributed evenly over the surface of alumina spheres which (a) comprise delta-alumina and/ortheta-alumina, (b) are substantially free from alpha -alumina, alpha-alumina monohydrate (boehmite) and gamma-alumina, (c) have a diameter of from 0.074 to 6.35 mm (200 to 3 U.S. Standard mesh size), (d) have a BET surface area of at least 20, for example from 20 to 200 m2/g and (e) are substantially free from pores having a diameter larger than 0.06 microns, the palladium penetrating no more than 50 microns into the surface pores of the spheres, which surface pores may have a diameter of from 0.035 to 0.06 microns. As exemplified, catalyst comprising 0.3 or 2.0 weight per cent palladium is prepared by forming an aqueous slurry containing amorphous alumina and boehmite from aluminium metal and formic acid, mixing calcined gamma-alumina with the slurry, forming the slurry into spheres by the oil drop method, drying and calcining the spheres until the alumina thereof is converted to a mixture of delta-alumina and thetaalumina, impregnating the calcined spheres with an aqueous solution of sodium palladium chloride, treating the impregnated spheres with formaldehyde, washing the treated spheres with water and drying the washed spheres. Comparative catalysts comprise 0.28 or 0.3 weight per cent palladium supported on dolomite or corundum or activated alumina (boehmite).