| 摘要 |
A new catalyst and a method of polymerizing olefins in which the catalyst is prepared (1) by forming a mixture by dispersing on a finely divided, difficult to reduce, inorganic support of silica, alumina, thoria, zirconia, titania, magnesia or mixtures of these a tetravalent or lower valent organic chromium compound, (2) calcining the mixture of (1) in an oxidizing or inert atmosphere and at an elevated temperature to produce a chromium compound on the support, (3) reacting the product of (2) with an alkyl ester of titanium, boron, vanadium or mixtures thereof or boric acid at an elevated temperature, and (4) activating the product of (3) with a dry gas that contains oxygen by heating at an elevated temperature the product of (3) in this dry gas.
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