Polymerization process
AssigneeExxonMobil Chemical Patents Inc.
InventorsRobert O. Hagerty, Chia S. Chee, Randall B. Laird, Michael A. Risch, Pradeep P. Shirodkar, Zerong Lin, Larry L. Iaccino
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Abstract
This invention is directed to processes of making polymer in the presence of a hydrofluorocarbon or perfluorocarbon and recovering the polymer. The processes provided enable polymerization processes to be practiced with minimal fouling in the reaction system, and to the recovery of the hydrofluorocarbon and other hydrocarbons such as hydrocarbons for reuse in the process or hydrocarbon by-products from the polymerization process. The invention is particularly beneficial in the production of ethylene based polymers using bulky ligand metallocene-type catalyst systems.
Claims54
A process for producing polymer comprising polymerizing ethylene and optionally one or more comonomers at a temperature of from 30° C. to 200° C. in the presence of a supported bulky ligand metallocene-type catalyst system and a diluent to form a slurry of polymer solids, wherein the diluent comprises at least 5 volume percent of a fluorinated hydrocarbon based on the total volume of the diluent, wherein the fluorinated hydrocarbon is not a perfluorocarbon, and wherein the bulky ligand metallocene-type catalyst system comprises an activator and a bulky ligand metallocene-type compound is represented by the formula:
- LALBMQn (I) or
- LAALBMQn (II)
- where M is a metal from Group 3 to 12 of the Periodic Table of Elements,
- LA and LB are selected from the group consisting of cyclopentadienyl ligands, cyclopentaphenanthreneyl ligands, indenyl ligands, benzindenyl ligands, fluorenyl ligands, octahydrofluorenyl ligands, cyclooctatetraendiyl ligands, cyclopentacyclododecene ligands, azenyl ligands, azulene ligands, pentalene ligands, pyrrolyl ligands, pyrozolyl ligands, carbazolyl ligands, borabenzene ligands and hydrogenated versions thereof;
- Q is a monoanionic labile ligand having a sigma-bond to M, and depending on the oxidation state of M, the value for n is 0, 1 or 2 such that Formula I or II above represents a neutral bulky ligand metallocene-type catalyst compound;
- and
- A is a bridging group containing carbon, germanium or silicon.
Dependencies are inferred from the claim text.