Phenol modified polymerization catalyst and polymerization process
AssigneeUnion Carbide Corporation
InventorsAnthony David Hamer, Frederick John Karol
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Abstract
An improved chromate ester catalyst useful for preparing, at relatively low temperatures, ethylene polymers which have a relatively lower molecular weight and which are more stable against oxidation is prepared by treating a silica supported chromate ester first with a phenol compound and then with a strong reducing agent.
Claims31
In a process for polymerizing a monomer charge comprising at least a major amount of ethylene by contacting said charge with a catalyst comprising chromate ester deposited on a support comprising silica and treated with strong reducing agent, the improvement which comprises treating said catalyst, prior to said treatment with said reducing agent, with phenol compound, said chromate ester containing one or more groups of the formula
- CrO.sub.2 Y.sub.2
- wherein the Y's are the same or different and are radicals selected from the group consisting of halogen, --O--R--, --O--Ti--OR).sub.3, ##STR10## and --O--M--R.sub.3, and wherein R is a C.sub.1 to C.sub.14 hydrocarbyl group and M is selected from the group consisting of Si and Sn.
An ethylene polymerization catalyst which comprises chromate ester deposited on a support comprising silica and sequentially treated with phenol compound and strong reducing agent, said chromate ester containing one or more groups of the formula
- CrO.sub.2 Y.sub.2
- wherein the Y's are the same or different and are radicals selected from the group consisting of halogen, --O--R, --O--Ti--OR).sub.3, ##STR12## and --O--M--R).sub.3, and wherein R is a C.sub.1 to C.sub.14 hydrocarbyl grop and M is selected from the group consisting of Si and Sn.
Dependencies are inferred from the claim text.