Patent GB-496267-A (GB)
Title: Improvements in the polymerisation of gaseous olefines
IPC: C07C2/18
Filed: 1937-05-24
Abstract: A catalyst for polymerizing olefines contains a salt of a phosphoric acid, and a free phosphoric acid or anhydride in amounts corresponding approximately to 1 molecular proportion of primary orthophosphate to 0,5-1 molecular proportion of orthophosphoric acid. Phosphates of the light metals of Group 2, e.g. Ca, Mg, Sr, Ba, are suitable.  A preferred composition has a ratio of P2O5 to CaO between about 3 and 4.  Primary or secondary phosphates can be mixed with phosphoric acid, heated at about 200-300 DEG  C., comminuted, and sieved.  Tertiary phosphates or metal oxides can be used with appropriately larger amounts of acid.  Other phosphates, e.g. copper phosphate or zinc pyrophosphate, may be used, but preferably in addition to those mentioned above and in small amounts such as 1-10 per cent by weight of the acid.  These can be supplied by adding other salts such as chlorides, carbonates or acetates which are converted into phosphates by the free acid.  Substances such as kieselguhr, active charcoal, starch, linseed oil or tonsil may be incorporated.  The mixed catalysts can be made without heating by crystallization from aqueous solutions containing phosphates and free acid.  The proportion of free acid may be in excess of the required ratio, e.g. a solution containing 1 mol. of secondary calcium phosphate to 2-4 of phosphoric acid gives on evaporation a crystalline precipitate of the desired composition which is dried and shaped.  Suitable initial olefines are propylene and butylenes or gases containing them.  Examples describe the preparation of catalysts by heating calcium or magnesium phosphates or calcium oxide with phosphoric acid at 250 or 300 DEG  C. or by crystallization from a solution containing secondary calcium phosphate and phosphoric acid.ALSO:Gaseous olefines are polymerized to liquids by contact at 100 to 300, advantageously 200 to 250 DEG  C. with a catalyst containing a salt of a phosphoric acid, and a free phosphoric acid or anhydride in amounts corresponding approximately to 1 molecular proportion of primary orthophosphate to 0,5-1 molecular proportion of orthophosphoric acid.  Phosphates of the light metals of Group 2, e.g. Ca, Mg, Sr, Ba, are suitable.  A preferred composition has a ratio of P2O5 to CaO between about 3 and 4.  Primary or secondary phosphates can be mixed with phosphoric acid, heated at about 200-300 DEG  C., comminuted, and sieved.  Tertiary phosphates or metal oxides can be used with appropriately larger amounts of acid.  Other phosphates, e.g. copper phosphate or zinc pyrophosphate, may be used, but preferably in addition to those mentioned above and in small amounts such as 1-10 per cent by weight of the acid.  These can be supplied by adding other salts such as chlorides, carbonates or acetates which are converted into phosphates by the free acid. Substances such as kieselguhr, active charcoal, starch, linseed oil or tonsil may be incorporated.  The mixed catalysts can be made without heating by crystalization from aqueous solutions containing phosphates and free acid.  The proportion of free acid may be in excess of the required ratio, e.g. a solution containing 1 mol. of secondary calcium phosphate to 2-4 of phosphoric acid gives on evaporation a crystalline precipitate of the desired composition which is dried and shaped.  Suitable initial olefines are propylene and butylenes or gases containing them.  Examples describe the preparation of catalysts by heating calcium or magnesium phosphates or calcium oxide with phosphoric acid at 250 or 300 DEG  C. or by crystallization from a solution containing secondary calcium phosphate and phosphoric acid.  These are used to polymerize moist propylene or isobutylene at 200 DEG  C. and 1 atmos. or an industrial gas containing 32 per cent olefines, mainly propylene, at 200 DEG  C. and 50 atmos.