GB734264A - Polymerisation of olefins - Google Patents

Abstract

Products of gasoline boiling range are obtained by polymerizing normally gaseous olefins in the vapour phase at 0-200 DEG , preferably 20-30 DEG C., in the presence of boron fluoride chemisorbed on a binary or ternary gel which is itself active as a catalyst for cracking hydrocarbon oils. Such gels include silica-alumina, magnesia, zirconia or titania, and silica-alumina-magnesia. The major component of the gel is preferably acidic. Thus, 60-90 per cent may be silica. A silica sol may be formed by acidifying water-glass solution, this being allowed to set to a gel, impregnated with a salt of the second metal, e.g. aluminium nitrate, precipitated with ammonia, washed, and heated to activate. Alternatively, the wet silica gel is mixed with a slurry of magnesia, dried, and activated. Particles of 2-10 mm. may be used and boron fluoride adsorbed equivalent, for example, to 5-40 per cent by weight. The feed gas such as cracked refinery gas is passed through a bed of the catalyst at atmospheric or higher pressure, e.g. up to 10 atmos. Make-up BF3 may be added, e.g. in the feed, or a guard bed used to adsorb volatilized BF3, the direction of flow being later reversed. In an example, a C4 feed is passed at 133 vols/vol. catalyst/hour over a commercial silica-alumina pre-dried at 200 DEG C. for 3 days and on which 20 per cent BF3 is adsorbed, the temperature being 20 DEG C. initially and rising to 100 DEG C. Specification 536,813 is referred to.ALSO:Catalysts for polymerizing normally gaseous olefins comprise boron fluoride chemisorbed on a binary or ternary gel which is itself active as a catalyst for cracking hydrocarbon oils. Such gels include silica-alumina, magnesia, zirconia or titania, and silica - alumina - magnesia. The major component of the gel is preferably acidic. Thus, 60-90 per cent may be silica. A silica sol may be formed by acidifying water glass solution, this being allowed to set to a gel, impregnated with a salt of the second metal, e.g. aluminium nitrate, precipitated with ammonia, washed, and heated to activate. Alternatively, the wet silica gel is mixed with a slurry of magnesia, dried, and activated. Particles of 2-10 mm. may be used and boron fluoride adsorbed equivalent, for example, to 5-40 per cent by weight. The feed gas such as cracked refinery gas is passed through a bed of the catalyst at atmospheric or higher pressure, e.g. up to 10 atmos. Make-up BF3 may be added, e.g. in the feed, or a guard bed used to adsorb volatilized BF3, the direction of flow being later reversed. In an example, a C4 feed is passed over a commercial silica-alumina pre-dried at 200 DEG C. for 3 days and on which 20 per cent BF3 is adsorbed. Specification 536,813, [Group IV], is referred to.