Polymerization of olefins from catalysts prepared from organo zirconium-chromium compounds
AssigneeThe Dow Chemical Company
InventorsRandall S. Shipley, Fred L. Vance
Life of this patent
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Abstract
Alpha-Olefins are polymerized in the presence of a catalyst which comprises (A) the reaction product of (1) a tetrahydrocarbyloxy zirconium compound such as tetraisopropoxy zirconium or a tetravalent hydrocarbyloxy zirconium halide such as triisopropoxy zirconium halide with (2) a chromium compound such as CrO.sub.3 ; (B) a solid catalyst support; (C) an organometallic activating agent or cocatalyst and (D) a trivalent or tetravelent titanium compound. The resultant polymers have a high molecular weight and a narrow molecular weight distribution.
Claims13
A process for polymerizing one or more .alpha.-olefins which comprises conducting polymerization under Ziegler polymerization conditions in the presence of a catalyst which comprises
- (A) the reaction product of
- (1) at least one zirconium compound represented by the empirical formula (RO).sub.m ZrX.sub.4-m wherein R is a monovalent hydrocarbyl group having from 1 to about 20 carbon atoms, X is chlorine or bromine and m has a value from 0 to 4;
- and
- (2) an inorganic oxygen-containing chromium compound in a mole ratio of component (2) to component (1) of from about 0.05:1 to about 6:1;
- (B) a solid catalyst support containing magnesium;
- (C) a tetrahydrocarbyloxy titanium or titanium halide compound;
- and
- (D) an organometallic activating agent;
- wherein the Mg:Cr atomic ratio is from about 1:1 to about 200:1, the Al:Cr atomic ratio is from about 1:1 to about 250:1;
- the Cr:Ti atomic ratio is from about 0.1:1 to about 50:1;
- and the excess X:Al atomic ratio is from about 0.005 to about 10:1.
Dependencies are inferred from the claim text.