Catalyst system comprising supported alumoxane and unsupported alumoxane particles
AssigneeExxonMobil Chemical Patents Inc.
InventorLubin Luo
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Abstract
The invention is directed to a supported olefin polymerization catalyst system comprising catalyst compound, silica support and alumoxane activator, where part of the alumoxane is present on the support and part of the alumoxane is not associated with the support, wherein the silica comprises silica particles having an average surface area of greater than about 400 m2/g, an average pore diameter of less than about 70 Angstroms, and wherein alumoxane is present on the support in an amount of less than 7 mmol Al/g silica and at least 1 wt % of alumoxane particles not associated with the support are present in the catalyst system, based upon the weight of the catalyst system.
Claims49
A catalyst system comprising catalyst compound, silica support and alumoxane activator, where part of the alumoxane is present on the support, supported alumoxane, and part of the alumoxane is not associated with the support, unsupported alumoxane,
- wherein:
- i) the support comprises silica particles having, prior to combination with the alumoxane, an average surface area of greater than about 400 m2/g and an average pore diameter of less than about 70 Angstroms;
- ii) alumoxane is present on the support in an amount of less than 7 mmol Al/g silica;
- and
- iii) the catalyst system comprises at least 1 wt % of unsupported alumoxane particles, based upon the weight of the catalyst system.
A process of making a catalyst system, the process comprising:
- (a) providing a support, wherein the support comprises silica particles having, prior to combination with the alumoxane, an average surface area of greater than about 400 m2/g and an average pore diameter of less than about 70 Angstroms;
- (b) contacting alumoxane and the support at a temperature of from 0 to 120° C. to form particles of alumoxane on the support, supported alumoxane, and particles of the alumoxane not associated with the support, unsupported alumoxane,
- wherein alumoxane is present on the support in an amount of less than 7 mmol Al/g silica, and the catalyst system comprises at least 1 wt % of unsupported alumoxane particles, based upon the weight of the catalyst system;
- and
- (c) contacting the supported alumoxane and unsupported alumoxane particles with a single site catalyst precursor compound to form the catalyst system.
Dependencies are inferred from the claim text.