Ethylene polymerization catalysts
AssigneeGulf Oil Corporation
InventorsWilliam L. Kehl, Thomas J. Lynch
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Abstract
Novel catalysts are provided for the polymerization of olefins such as ethylene. The catalysts consist essentially of a chromium compound supported upon an inorganic carrier containing aluminum and arsenate moieties. The inorganic carrier is an amorphous precipitate of aluminum arsenate, or an amorphous coprecipitate containing aluminum and arsenate moieties in proportions such that the aluminum and arsenic are present in an atomic ratio in the range of 5:1 to 1:1. The catalysts are particularly useful for polymerizng ethylene in a Particle Form Process in that the catalysts have essentially no induction period and provide ethylene polymers having a desirably-broad molecular weight distribution and a desirably-high melt flow shear ratio.
Claims7
A process for preparing an olefin polymerization catalyst which consists essentially of depositing a chromium compound upon an inorganic carrier containing aluminum and arsenate moieties and activating the catalyst by heating the material to a temperature of at least about 350.degree. C., the inorganic carrier being selected from the group consisting of:
- a. an amorphous precipitate of aluminum arsenate,
- b. an amorphous coprecipitate containing aluminum and arsenate moieties in proportions such that the aluminum and arsenic are present in an atomic ratio of between 5:1 and 1:1, and
- c. mixtures of (a) and (b);
- said carrier having been prepared by neutralizing a strongly acidic solution containing aluminum and arsenic ions in proportions such that the aluminum and arsenic are present in an atomic ratio in the range of 5:1 to 1:1 to form a solid precipitate containing aluminum and arsenate moieties, and recovering the precipitate.
Dependencies are inferred from the claim text.