Patent GB-722262-A (GB)
Title: Improvements in or relating to the polymerization of olefins
Inventor: FELL WILLIAM KING
IPC: C07C2/18
Filed: 1951-10-02
Abstract: Normally gaseous olefins are polymerized at elevated temperature and pressure in the presence of a finely-divided solid catalyst comprising phosphoric acid deposited on a non-carbonaceous carrier, together with a divided solid adsorbent diluent for the catalyst. Said diluent is preferably impregnated with phosphoric acid, the amount of acid in the diluent, expressed as a percentage by weight thereof based on diluent+acid being at least 20 per cent less than the amount of acid in the catalyst expressed as a percentage by weight based on carrier+acid.  The adsorbent diluent may be silica gel, bauxite, activated alumina, carbon or activated carbon.  Silica gel is preferably de-activated before use to reduce the surface area to from 50-300 sq. m. per g., e.g. by heating at 1800 DEG  F. for 3/4 -2 hours. Carbon should have a density near that of the catalyst.  It may be treated with phosphoric acid solution, dried, and heated at 400-500 DEG  F.  The amount of diluent is generally 5-50 per cent by weight of the catalyst, i.e. phosphoric acid+carrier.  The carrier is preferably siliceous, e.g. kieselguhr, silica gel, and aluminium silicates; and the phosphoric acid usually comprises 50-90 per cent of the combined weight.  Promoters such as metal salts may be present.  The catalyst is used in powder form, generally 20-200 mesh, and fluidized in the feed or formed into a slurry with the feed or a heavy oil, Reaction conditions may be 300-650 DEG  F.. 500-1500 p.s.i.g. or above, and 0.5-15 vols. liquid feed/vol./hr.  Pressure above the critical to give a single fluid phase is preferred.  Water may be injected.  In examples: (1) the ease of fluidization is compared using C3 and C3+C4 feeds, the catalyst being 80 per cent phosphoric acid on 20 per cent kieselguhr, alone or mixed with silica gel equal to 50 or 15 per cent of the total or sand equal to 35 per cent; (2) catalyst agglomeration is compared in a series of slurry operations in a stirred autoclave using the catalyst of (1) alone or with 20 per cent silica gel; (3) the effects of adding to the p  same catalyst, silica gel, alone or containing 7.6 or 39 per cent free acid, in a fluidized operation, are compared; (4) propylene is polymerized, using a suspended catalyst alone or with 20 per cent of activated carbon or activated carbon impregnated with 20 per cent phosphoric acid; (5) the effect of adding silica gels of different surface areas to the same catalyst used for polymerizing a C4 feed is illustrated, those of intermediate values giving optimum results.ALSO:A finely-divided solid catalyst for olefin polymerization comprises phosphoric acid deposited on a non-carbonaceous carrier, together with a finely-divided solid adsorbent diluent for the catalyst.  Said diluent is preferably impregnated with phosphoric acid, the amount of acid in the diluent expressed as a percentage by weight thereof based on diluent + acid being at least 20 less than the amount of acid in the catalyst expressed as a percentage by weight based on carrier + acid.  The adsorbent diluent may be silica gel, bauxite, activated alumina, carbon or activated carbon.  Silica gel is preferably de-activated before use to reduce the surface area to from 50-300 sq. m.p.g., e.g. by heating at 1,800 DEG F. for three-quarters to two hours.  Carbon should have a density near that of the catalyst.  It may be treated with phosphoric acid solution, dried, and heated at 400-500 DEG  F. The amount of diluent is generally 5-50 per cent. by weight of the catalyst, i.e. phosphoric acid + carrier.  The carrier is preferably siliceous, e.g. kieselguhr, silica gel, and aluminium silicates, and the phosphoric acid usually comprises 50-90 per cent. of the combined weight.  Promoters such as metal salts may be present.  The catalyst is used in powder form, generally 20-200 mesh, and fluidized in the feed or formed into a slurry with the feed or a heavy oil.  Pressure above the critical to give a single fluid phase is preferred.  Water may be injected. In Examples: (1) The ease of fluidization is compared using C3 and C3 + C4, the catalyst being 80 per cent. phosphoric acid on 20 per cent. kieselguhr, alone or mixed with silica gel equal to 50 or 15 per cent. of the total or sand equal to 35 per cent.; (2) catalyst agglomeration is compared in a series of slurry operations in a stirred autoclave using the catalyst of (1) alone or with 20 per cent. silica gel; (3) the effects of adding to the same catalyst, silica gel, alone or containing 7.6 or 39 per cent. free acid, in a fluidized operation, are compared; (4) propylene is polymerized using a suspended catalyst alone or with 20 per cent. of activated carbon or activated carbon impregnated with 20 per cent. phosphoric acid; (5) the effect of adding silica gels of different surface areas to the same catalyst used for polymerizing a C4 feed is illustrated, those of intermediate values giving optimum results.