PRODUCTION OF SILICON DIOXIDES WITH LARGE PORES AND THEIR USE IN CHROME CATALYSTS FOR OLEFIN POLYMERIZATION Russian patent published in 2023 - IPC C08F110/02 C08F4/02 C08F4/22 C08F4/69 

FIELD: chemistry.

SUBSTANCE: invention relates to chrome catalysts on a carrier (options) and methods for polymerization of olefins in the presence of the specified catalysts (options). The catalyst contains composite based on silicon dioxide and from 0.1 to 15% by wt. of chrome. The specified catalyst is characterized by: volume density from 0.08 to 0.4 g/ml; total pore volume from 0.4 to 2.5 ml/g; specific surface area according to BET method from 175 to 375 m²/g, and maximum pore diameter from 10 to 80 nm, where the maximum pore diameter relates to a location, according to a pore diameter scale, of the highest point on a pore size distribution curve; and (1) where from 0.5 to 40% of the total pore volume of the catalyst is for pores with diameters ranging from 30 to 100 nm, or (2) from 40 to 85% of the total pore volume of the catalyst is fore pores with diameters ranging from 10 to 50 nm, or (3) from 1 to 25% of the total pore volume of the catalyst is for pores with diameters less than or equal to 5 nm; and less than or 4% of the total pore volume of the catalyst is for pores with diameters less than or equal to 3 nm.

EFFECT: invention allows for modification of some physical parameters of a catalyst and substrate, such as a surface area and a pore volume, for regulation or control of important parameters of the molecular weight and branching of polymer, while maintaining high catalytic activity.

34 cl, 11 dwg, 11 tbl, 3 ex