Patent GB-888635-A (GB)
Title: Improvements in or relating to the isomerisation of úe-pentane or úe-hexane
Inventor: CARR NORMAN L
IPC: B01J23/96
Filed: 1960-02-22
Abstract: A hydrocarbon isomerization catalyst comprises 0,1-1% of palladium or rhodium on a silica-alumina support containing 50-95% of silica and 0,1-5% of combined fluorine.  The fluorine may be incorporated as hydrogen fluoride, ammonium fluoride, fluorine-substituted organic acids (preferably perfluoro C2-C5 aliphatic acids), alcohols or ethers, aluminium or zirconium fluoride, or fluorine-containing perhalogenated hydrocarbons.  In one method of preparation the palladium or rhodium is combined with the dried silicaalumina base by impregnation, the fluorine compound being added before or simultaneously or by precipitation on to or with the original silica-alumina gel.  The water content is not allowed to fall below 20% by weight before extrusion and is adjusted to 50-65% during extrusion which may be effected before or after impregnation.  The catalyst is dried to 107 DEG -117 DEG C. and reduced at 450 DEG -524 DEG C. with 0,36-0,93 m3 of hydrogen per hour per litre of catalyst for 2-24 hours.  In a modified method of preparation the metal is incorporated by impregnation in the support which is then wetted with a solution consisting of 0,1-5%, by weight of the support, of the desired fluorine compound in a mixture of water and a volatile, water-soluble organic liquid having a critical temperature below 316 DEG C. and a boiling point below 100 DEG C., e.g. methanol, ethanol, isopropanol, tert.-butanol, methyl ethyl ketone, acetaldehyde, propionaldehyde or sec.-butyraldehyde.  The organic liquid may constitute 10-60% of the volume of solution and amount to at least 50% of the weight of catalyst.  The catalyst is heated and pressurized to just below the critical temperature and pressure of the organic liquid and gases are removed until the pressure starts to drop.  The pressure is reduced to atmospheric and the catalyst is dried at 110 DEG -232 DEG C., pelleted and reduced.  In another method of preparation a silicaalumina cracking catalyst is calcined at 510 DEG -593 DEG C. for 1-24 hours in nitrogen, air or helium, impregnated with the fluorine compound and the metal, dried, reduced and pelleted or extruded.  Alternatively the cracking catalyst is contacted with anhydrous hydrogen fluoride at 35 DEG -538 DEG C. (other than 343 DEG -454 DEG C.) before impregnation and the resultant catalyst, after reduction, may be contacted with a mixture of hydrogen and hydrogen sulphide.  Regeneration may be effected by purging and oxidizing at 371 DEG -510 DEG C. and 6-10 atmospheres, followed by reduction at 399 DEG -510 DEG C.  Specifications 823,010 and 825,353 are referred to.ALSO:The isomerisation of n-pentane or n-hexane is effected at 343 DEG C.-421 DEG C., 8-69 atmospheres with a hydrogen to hydrocarbon mol ratio of 0.5-5.1 in the presence of a catalyst comprising a silica-alumina support containing 50%-95% of silica with 0.1%-1% of palladium or rhodium and 0.1%-5% of combined fluorine.  The fluorine may be incorporated as hydrogen fluoride, ammonium fluoride, fluorine-substituted carboxylic acids (particularly perfluorinated C2-C5 aliphatic acids), alcohols or ethers, aluminium or zirconium fluoride or a fluorinecontaining perhalogenated hydrocarbon.  The content of sulphur (y p.p.m.) and higher-boiling hydrocarbons (x% by weight) is preferably adjusted so that 3.0x + 15y = 45 Space velocities of 0.5-25 vol./vol./hr. are used.  Specification 823,010 and 825,353 are referred to.