GB396681A - An improved method of preparing catalytic materials - Google Patents

Abstract

A catalyst for the hydrogenation of carbonaceous materials, especially under high pressure, is obtained by dissolving molybdic acid in an alkali, preferably a 6-7 per cent solution of ammonia, and concentrating the resulting solution to a specific gravity greater than 1,0, and preferably between about 1,2 and 1,4. The molybdic acid is then precipitated by means of an acid such as hydrochloric acid which is added until the mixture contains an excess of 1-4 per cent, preferably about 3 per cent. If other acids are used, the hydrogen ion concentration of the resulting mixture should be substantially equivalent to that of mixtures containing the above excess of hydrochloric acid. The precipitated acid is then separated, washed with water or ammonium chloride solution, and dried at 200-212 DEG F. The acid is then heated at an elevated temperature until rodshaped crystals of the desired size are formed. Temperatures between 750-1500 DEG F. may be used, but between 780-840 DEG F. are preferred. The molybdic acid thus prepared may be moulded into shapes, or mixed with a bonding agent such as magnesium or zinc oxides and pressed into lumps. It may also be mixed with other catalytic materials such as tungsten or chromium oxides or sulphides, or may be deposited on inert materials having a large surface, such as alumina, silica, pumice or active charcoal. The catalyst mixtures may be used in the form of lumps or be finely ground and suspended in the material to be treated.