GB1269764A - Hydrocarbon reforming catalyst - Google Patents

Abstract

1,269,764. Hydrocarbon reforming catalysts. ENGELHARD MINERALS & CHEMICALS CORP. 20 March, 1970 [21 March, 1969], No. 13706/70. Heading B1E. [Also in Division C5] A hydrocarbon reforming catalyst comprises catalytic amounts of rhenium and of Group VIII noble metal, for example platinum, palladium or rhodium, supported upon material which comprises "gamma-family alumina modifications" (including eta-alumina) formed by calcination of a mixture of (a) alumina trihydrate and (b) alumina monohydrate (boehmite) and/or amorphous hydrous alumina, from 50 to 95 weight per cent of the dry solids content of the mixture being alumina trihydrate, for example selected from bayerite, gibbsite and nordstrandite (randomite). The catalyst has a surface area of at least 150 m<SP>2</SP>/g, for example at least 400 m<SP>2</SP>/g, and a pore volume preferably of from 0.4 to 0.8 cm<SP>3</SP>/g; at least 0.1 cm<SP>3</SP>/g of the pore volume may be constituted by pores having a pore size of at least 100 Angstroms and at least 0.05 cm<SP>3</SP>/g of the pore volume may be constituted by pores having a pore size greater than 300 Angstroms. The catalyst, which preferably is substantially free of crystallites and crystals of rhenium and of Group VIII noble metal having a size greater than 50 Angstroms, may contain from 0.1 to 2 weight per cent of rhenium and from 0.1 to 1 weight per cent of Group VIII noble metal; it is preferred that the catalyst contains rhenium and Group VIII noble metal is a molar ratio of between 1:5 and 5:1. The catalyst also may comprise sulphur, for example in an amount constituting up to 1 weight per cent of the catalyst, and/or acidic promoter selected from halogen, for example fluorine and/or chlorine in an amount constituting from 0.05 to 2 weight per cent of the catalyst, silica, zirconia and tungstic acid. The catalyst may be prepared by a process which comprises forming a slurry of a mixture of alumines as aforedefined, the slurry having dissolved therein a water-soluble compound of rhenium and a water-soluble compound of a Group VIII noble metal, spray drying the slurry to form a mass, forming the mass into particles, for example by tabletting or extruding, and calcining the particles, for example at a temperature of from 600 to 1200‹F in an inert atmosphere, for example nitrogen, an oxidizing atmosphere, for example dry air, or a reducing atmosphere, for example an atmosphere containing hydrogen. Sulphur may be incorporated in the catalyst by treating the slurry, prior to drying, with a water-soluble ionic sulphiding agent, for example hydrogen sulphide or ammonium sulphide; chlorine may be incorporated in the catalyst by treating the calcined particles with gaseous hydrogen chloride or with an aqueous solution containing hydrogen chloride or ammonium chloride. As exemplified, catalysts containing 0.35 weight per cent rhenium, 0.35 weight per cent platinum and chlorine in a varying amount constituting up to 0.6 weight per cent of the catalyst are prepared from perrhenic acid, chloroplatinic acid and alumina having a dry solids composition of 38 weight per cent bayerite, 18 weight per cent gibbsite, 29 weight per cent nordstrandite, 13 weight per cent boehnite and 2 weight per cent amorphous hydrous alumina. Reference is made to Specifications 735,390, 837,907 and 1,269,765.