Patent GB-1345612-A (GB)
Title: Dehydrogenation catalyst method of manufacture thereof and use  thereof in the dehydrogenation of hydrocarbons
IPC: C07C5/333
Filed: 1971-05-28
Abstract: 1345612 Hydrocarbon dehydrogenation catalysts UNIVERSAL OIL PRODUCTS CO 28 May 1971 [11 June 1970] 17719/71 Heading B1E [Also in Division C5] Hydrocarbon dehydrogenation catalyst comprising alumina carrier material, a germanium component, a Group VIII noble metal component and an alkali metal component is prepared by a method which comprises (a) contacting alumina with an impregnation solution comprising an alcoholic solution of a germanium tetrahalide in admixture with a Group VIII noble metal compound and an alkali metal compound in aqueous solution, (b) evaporating liquid from the resulting mixture, for example in a steam dryer, and (c) drying the resulting impregnated alumina in a steamcontaining atmosphere under oxidising ;onditions, for example initially for 1 to 3 hours at a temperature of from 204 to 371‹C and thereafter for 3 to 5 hours at a temperature of from 482 to 649‹C. The impregnation solution preferably contains from 0.02 to 0.1 moles of mineral acid, for example hydrochloric acid or nitric acid, per mole of alumina to be impregnated. The impregnated alumina resulting from step (b) has a loss on ignition (1.01) at 900‹C preferably of less than 60 weight per cent, more preferably of from 50 to 55 weight per cent; the dried impregnated alumina resulting from step (c) has a halogen content preferably of less than 0.1 weight per cent. The alumina, which preferably has a surface area of from 150 to 500 m<SP>2</SP>/g, may be gammaalumina, eta-alumina or theta-alumina, may be naturally occuring or synthetically prepared, for example by a conventional oil drop procedure, and may be in the form of spheres, pills, granules, extrudates or powder; a preferred alumina is gamma-alumina having a surface area of from 125 to 400 m<SP>2</SP>/g, an apparent bulk density of from 0.20 to 0.60 g/cm<SP>3</SP>, an average pore diameter of from 20 to 300 Angstroms and an average pore volume of from 0.10 to 1.0 cm<SP>3</SP>/g. The germanium tetrahalide solution, which preferably is aged for at least 24 hours prior to forming the impregnation solution, may be prepared from germanium tetrafluoride, tetrachloride, tetrabromide or tetraiodide and methanol, ethanol, propanol or isopropanol. Exemplified Group VIII noble metal compounds are chloropalladic acid, chloroplatinic acid, ammonium chloroplatinate, dinitrodiamino platinum and water-soluble chlorides of ruthenium, rhodium, palladium, osmium, iridium and platinum; exemplified alkali metal compounds are the chlorides, sulphates, nitrates and acetates of lithium, sodium, potassium, rubidium and caesium. The catalyst preferably contains, expressed on an elemental basis, from 0.0 to 5 weight per cent germanium, from 0.05 to 5 weight per cent Group VIII noble metal and from 0.01 to 1.5 weight per cent alkali metal. As exemplified, catalyst comprising 0.45 weight per cent germanium, 0.378 weight per cent platinum, 0.59 weight per cent lithium and 0.06 weight per cent chlorine is prepared by adding 1/16 inch spheres of gamma-alumina to a solution prepared from a solution of chloroplatinic acid in aqueous nitric acid, a 48 hour-aged solution of germanium tetrachloride in reagent grade ethanol and an aqueous solution of lithium nitrate, maintaining the spheres in contact with the solution under quiescent conditions for about 10 minutes at ambient temperature, evaporating liquid from the mixture to provide particles having a LO1 at 900‹C of 50 weight per cent and drying the particles in a stream of air containing 20 weight per cent steam initially for 2 hours at 316‹C and thereafter for 4 hours at 538‹C.