Patent GB-1263258-A (GB)
Title: Preparation of heterogeneous catalysts
Inventor: KROLL WOLFRAM RAINER
IPC: B01J37/16
Filed: 1968-10-09
Abstract: 1,263,258. Preparation of catalysts. ESSO RESEARCH & ENG. CO. 9 Oct., 1968 [10 Oct., 1967], No. 47954/68. Heading B1E. [Also in Divisions C1, C2 and C5] Heterogeneous catalyst is prepared by a method which comprises impregnating support material under an inert atmosphere and under anhydrous conditions either with a non-aqueous solution of a compound of a transition metal selected from Groups IV, V, VI, VII and VIII and with a non-aqueous solution of a reducing agent for the transition metal compound, which reducing agent is an organometallic compound or metal hydride and the metal constituent of which reducing agent is a metal selected from Groups I, II and III, or with a non-aqueous solution of a reaction product obtained by reacting, for example in a non-aqueous solvent, such transition metal compound and such reducing agent, and thereafter heating the impregnated support material, after removing therefrom either excess reducing agent and excess solvent for the transition metal compound and for the reducing agent or excess solvent for the reaction product of such transition metal compound and such reducing agent, under an inert atmosphere and under anhydrous conditions at a temperature above 100‹C for at least 0.1 hour, for example at a temperature of from above 100‹C to 600‹C for from 0.1 to 4 hours. The support material may be impregnated with the solution of the transition metal compound either before or after being impregnated with the solution of the reducing agent; in the latter case, excess reducing agent may be removed from the support material before impregnation thereof with the solution of the transition metal compound. It is preferred that the transition metal compound and the reducing agent are used, either when directly impregnating the support material or when preparing a reaction product for subsequent impregnation of the support material, in amounts such that the mole ratio, calculated on a metal basis, of reducing agent to transition metal compound is at least 1 to 1, for example between 1 to 1 and 10 to 1. The support material may be boria, silica or an oxide of a metal selected from Groups II, III, IV, V and VI, for example magnesia, calcium oxide, strontium oxide, barium oxide, zinc oxide, alumina, titania, zirconia or vanadia; a combination thereof, for example silica-alumina; a natural or synthetic clay, for example an attapulgite clay; a diatomaceous earth, for example kieselguhr; a molecular sieve, for example zeolite X or zeolite Y; or carbon, for example activated carbon, coke, charcoal, furnace black, channel black, graphite or alkali graphite. The transition metal may be titanium, zirconium, vanadium, chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium or platinum. The transition metal compound may be any compound, either polar or non- polar, which is soluble in non-aqueous solvents, for example a silicofluoride, cyanide, azide, chloride, bromide, carboxylate, alcoholate, alkoxide or chelate such as an acetylacetonate, tropolonate, salicylaldehyde or dimethyl dioxime derivative. Catalysts comprising two or more such transition metals may be prepared by the method according to the invention; reference is made in the specification to catalysts comprising cobalt and molybdenum; cobalt and tungsten; cobalt and platinum; and nickel and palladium. The reducing agent may be a compound having the formula MR n  wherein M is a metal selected from Groups I, II and III, for example lithium, magnesium, calcium, strontium, zinc, cadmium, boron or aluminium, n is the valency of the metal M and the or each R is a monovalent radical, for example a hydrogen atom, a halogen atom, a hydrocarbon radical or an alkoxy radical, with the proviso that at least one radical R is a hydrogen atom or a hydrocarbon radical; examples of suitable hydrocarbon radicals are listed in the specification. Preferred reducing agents have the formula AlR' 3  wherein each R' is a hydrogen atom, a hydrocarbon radical having from 1 to 20 carbon atoms or an alkoxy radical with the proviso that at least. one radical R' is a hydrogen atom or such hydrocarbon radical; exemplified reducing agents are trimethylaluminium, triethylaluminium, triisobutylaluminium, tri-n-hexylaluminium, diethylaluminium hydride and propylaluminium dihydride. The specification includes numerous examples which relate to the preparation from transition metal acetylacetonate or chloride of catalysts comprising iron on charcoal or "doped" alumina; cobalt on carbon (for example charcoal) or alumina (for example calcined alumina or eta alumina) or silica; nickel on carbon (for example charcoal) or eta alumina or silica-alumina; rhodium on charcoal or silica; and platinum on alumina (for example gamma or eta alumina) or silica, trimethylaluminium or triisobutylaluminium being used as reducing agent.