Organo zirconium-chromium mixtures, catalyst prepared therefrom and polymerization of olefins therewith
AssigneeThe Dow Chemical Company
InventorRandall S. Shipley
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Abstract
Ziegler-type catalysts are modified using zirconium compounds such as zirconium octoate and/or chromium compounds such as chromium octoate. These compounds are useful in modifying the catalysts for the polymerization of .alpha.-olefins to produce polymers having a high molecular weight and a narrow molecular weight distribution. Synergistic effects are observed when both the chromium and zirconium compounds are present. No special heating or reaction of these compounds is required prior to their use with the catalyst.
Claims9
As a composition of matter, the product resulting from mixing (1) at least one zirconium compound represented by the empirical formula ##STR3## with (2) at least one organic soluble chromium compound represented by the empirical formula ##STR4## in a mole ratio of component (2) to component (1) of from about 0.05:1 to about 10:1 and wherein each R is independently a hydrocarbon group having from 1 to about 20 carbon atoms and a has a value equal to the valence of Cr.
A catalyst composition which comprises
- (A) at least one member of the group consisting of
- (1) at least one zirconium compound, represented by the empirical formula ##STR5## wherein R is a hydrocarbon group having from 1 to about 12 carbon atoms;
- (2) at least one hydrocarbon soluble chromium compound represented by the empirical formula ##STR6## wherein R is a hydrocarbon group having from 1 to about 12 carbon atoms and has a value equal to the valence of Cr;
- and
- (3) a mixture of components (1) and (2) in a mole ratio of component (2) to component (1) of from about 0.05:1 to about 10:1;
- (B) a solid catalyst support containing magnesium prepared by reacting a magnesium compound with a halide source;
- (C) a tetrahydrocarbyloxy titanium or titanium halide compound;
- and
- (D) an organometallic activating agent;
- wherein (a) the Mg:(Cr+Zr) atomic ratio is from about 1:1 to about 100:1, (b) the Al:(Cr+Zr) atomic ratio is from about 1:1 to about 200:1;
- (c) the (Cr+Zr):Ti atomic ratio is from about 0.5:1 to about 20:1;
- (d) the excess X:Al atomic ratio is from about 0.0005:1 to about 5:1;
- (e) excess X is the excess halide above that which would be theoretically required to convert the magnesium compound to the dihalide;
- and (f) said catalyst is prepared at a temperature in the range of from about -100.degree. C. to about 200.degree. C.
Dependencies are inferred from the claim text.