| 摘要 |
A C2-C8 alpha -alkene particularly ethylene, is polymerized in the presence of a catalyst which is obtained by reacting a chromium-1,3-diketo compound of formula Cr(OCR1CR2CR3O)3 wherein R1, R2 and R3 are C1-C10 alkyl groups and wherein R2 may be H, with an organometallic compound of a metal of Group II or Group III of the Periodic Table of Elements, heating the product thus obtained between 200 and 1200 DEG C in a non-reducing atmosphere and combining the resulting product with an organo-metallic compound of an element of Group II or Group III of the Periodic Table of Elements; characterized in that a catalyst support is used which is a silica having a pore volume of at least 1.5 cm<3>/g and a sodium content not greater than 200 p.p.m. The selection of such a silica support provides excellent activity for the polymerization reaction. |
