Thermally stable coprecipitated catalysts useful for methanation and other reactions

Claim 1

In a process wherein a chemical conversion is carried out by contacting at least one fluid reactant with a solid catalyst under reducing conditions in the presence of hydrogen and/or carbon monoxide, and at temperatures between about 300° and 2000° F. to produce a product chemically different from said reactant, said catalyst consisting essentially of a composite of alumina and one or more iron group metals, and wherein progressive thermal deactivation of said catalyst takes place, the improvement which comprises using as said catalyst a composite of improved thermal stability prepared by the steps of: (1) forming at a relatively low temperature a homogeneous aqueous solution of an aluminum salt, a salt or salts of at least one divalent iron group metal and a delayed precipitant, said delayed precipitant being a water-soluble compound which, at said relatively low temperature, does not bring about precipitation of the metal salts dissolved in said solution, but which will hydrolyze at a relatively higher temperature to form ammonia and carbon dioxide; (2) heating said aqueous solution to a sufficiently high temperature and for a sufficient time to bring about hydrolysis of said delayed precipitant with resultant gradual increase in pH of said solution and formation of a homogeneous coprecipitate of basic compounds of aluminum and of the divalent metal content of said solution; (3) separating said coprecipitate from said solution before the latter reaches a pH above about 8; and (4) drying and calcining said coprecipitate.