SILICA-BASED CHROMIUM-CONTAINING CATALYST, METHOD FOR PREPARATION THEREOF, AND POLYETHYLENE PRODUCTION PROCESS USING THIS CATALYST Russian patent published in 2005 - IPC

FIELD: polymer production and polymerization catalysts.

SUBSTANCE: invention provides and process of producing polyethylene or copolymers of ethylene with comonomers based on higher α-olefins via bringing ethylene into contact, under appropriate polymerization conditions, with catalytic system including chromium-containing catalyst, prepared in following steps: (1) interaction of inorganic oxide, namely silica-based carrier, with magnesium compound; (2) contacting resulting product with a base to form magnesium hydroxide on inorganic dioxide, namely silica; (3) drying product prepared in step (2); and (4) calcination of dry product in presence of oxygen, provided that such amount of magnesium compound being used as to provide larger surface area of the prepared catalyst than that of starting silica-containing inorganic oxide material. In thus prepared catalyst, chromium is available from following sources: (a) use, as silica-containing inorganic oxide, common silica- and chromium-containing gel from step (1); (b) adding chromium compound to dry combination of magnesium compound and silica-based carrier before calcination after step (3); (c) adding chromium compound to dried magnesium compound/silica combination before calcination; (d) adding chromium compound after calcination of silica-based carrier; or (e) adding chromium compound after drying step (3) by mixing additional magnesium compound with chromium compound solution.

EFFECT: expanded polymerization catalysts preparation possibilities.

15 cl, 8 tbl, 8 ex