| 摘要 |
<p>A process and catalyst for polymerizing olefins, especially ethylene or a mixture of ethylene with up to 40 % (based on total monomer) of other 1-olefinic monomer, the process comprising (a) supporting a chromium compound on a refractory oxide support material, (b) adding one or more tetravalent titanium compounds, (c) heating the product under such conditions that an active polymerisation catalyst is formed, (d) and contacting the monomer with the active polymerisation catalyst in the presence of one or more organometallic compounds wherein the metal is of groups 1A, 2A, 2B or 3A of the Periodic Table (Mendeleef), especially aluminium trialkyls. Step (d) is preferably carried out in the presence of a polyene modifier. The refractory oxide support material is preferably silica. The produced polyolefins are also claimed.</p> |
