GB380486A - Improvements in or relating to catalytic agents - Google Patents

Abstract

The invention relates to catalytic agents consisting of a highly porous adsorbent carrier (e.g. silica gel) in the pores of which catalytically active material is deposited by reaction between a metal compound solution and a precipitating solution. According to the invention the metal compound solution is employed in excess, and the strength of the precipitating solution is so chosen that there is formed a plural precipitate consisting of two or more compounds of the catalytic metal. The compounds may be precipitated in concentric rings within the pores of the gel. Activators may be precipitated simultaneously with the catalyst. The carrier may be a hydrogel composed of an oxide of silicon, germanium, chromium, tungsten, titanium, aluminium, tin, &c., or a partly dehydrated hydrogel or a fully dried hard porous gel, or a material such as fullers earth, kieselguhr, &c. The precipitating solution may be a hydroxide of an alkali or alkaline-earth metal, or ammonium hydroxide, or a hydroxyl-containing amine, or an alkali carbonate or carbamate, or it may be a metallic salt such as potassium vanadite which is capable of reacting with a salt of another metal to form an active compound, or a non-hydroxyl-containing amine. Suitable concentrations are 0,25-1 per cent in the case of a hydroxyl-bearing compound and 0,5-10 per cent in the case of a metallic salt. The metal compound solution may be a salt of any catalytic metal, specified examples being iron, chromium, aluminium, gallium, indium, thorium, copper, cobalt, nickel, silver, gold, beryllium, magnesium, zinc, cadmium, mercury, lead, germanium, tin, titanium, zirconium, cerium, terbium, yttrium, bismuth, molybdenum, tungsten, uranium, manganese, ruthenium, rhodium, palladium, caesium, iridium, platinum, and vanadium, the last being preferred. The Specification contains several specific examples, all relating to vanadium catalysts, of which the following is typical: a silica hydrogel is soaked in a 0,3 normal solution of potassium vanadite, then rinsed with water and immersed in a 0,1 N. solution of chromium chloride in slight excess of that required for precipitation. The product is again rinsed and dried in air, first at 75-120 DEG C. and finally at 300-400 DEG C. Specification 212,034, [Class 1 (i), Chemical processes &c.], is referred to.