Dilute process for the polymerization of ethylene/.alpha.-olefin copolymer using metallocene catalyst systems
AssigneeExxon Chemical Patents Inc.
InventorsAlbert Rossi, Salvatore Rea, Jon Edmond Stanat, Linda Kay Wright, Kenneth Lee Kaufman, Harold Wilbur Margo, Jeffery William Frederick, Robert Martin Koros
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Abstract
An improved process for the copolymerization of ethylene and .alpha.-olefins utilizing highly dilute .alpha.-olefin feedstreams to effect high conversions and catalyst productivities. The instant invention is particularly adaptable to copolymerizing the .alpha.-olefin content of commercially available refinery feedstreams such as Raffinate-2.
Claims30
A process for continuously producing copolymer comprising polymerizing ethylene and .alpha.-olefin monomers in the presence of a metallocene catalyst system and in a reaction zone containing liquid phase which comprises:
- (A) continuously providing a dilute liquefied .alpha.-olefin feed stream from a refinery or a steam cracking plant comprising at least one .alpha.-olefin reactant and diluent admixed therewith wherein the amount of diluent in said feed stream is at least 30 weight percent thereof wherein said stream is selected from those which contain butene-1, propylene or C.sub.5 .alpha.-olefin;
- (B) providing a feed stream comprising ethylene in liquid, vapor, or liquid/vapor form;
- (C) admixing, the feed streams of steps (A) and (B) in amounts sufficient to provide a reactant feed stream having an .alpha.-olefin/ethylene weight ratio effective to yield a co-polymer containing between about 5 to about 70 weight percent units from ethylene;
- (D) continuously introducing reactant feed stream derived in accordance with step (C) and metallocene catalyst system into the liquid phase of the reaction zone in a manner and under conditions sufficient to:
- (i) polymerize the ethylene and .alpha.-olefin to obtain a polymer product having a number average molecular weight of from about 300 to about 15,000;
- (ii) obtain an .alpha.-olefin conversion of at least 30%;
- (iii) obtain an ethylene conversion of at least 70%
- (E) continuously withdrawing copolymer product from the reactor.
A process for continuously producing copolymer comprising polymerizing ethylene and .alpha.-olefin monomers in the presence of a metallocene catalyst system in an evaporatively cooled reactor containing vapor phase and liquid phase which comprises:
- (A) continuously providing a dilute liquefied .alpha.-olefin feed stream from a refinery or a steam cracking plant comprising at least one .alpha.-olefin reactant and diluent admixed therewith wherein said stream is selected from those which contain butene-1, propylene or C.sub.5 .alpha.-olefin;
- (i) the amount of diluent in said feed stream is at least 30 weight percent thereof;
- and
- (ii) at least 50 weight percent of the constituents of said diluent possess a boiling point under reaction conditions within about .+-.20.degree. C. of the average boiling point of the .alpha.-olefin constituents of the feed stream;
- (B) providing an ethylene feed stream in liquid, vapor, or liquid/vapor form;
- (C) admixing, the feed streams of steps (A) and (B) to provide a reactant feed stream;
- (D) continuously introducing reactant feed stream derived in accordance with step (C) and metallocene catalyst system into the liquid phase of the evaporatively cooled reactor in a manner and under conditions sufficient to polymerize ethylene and .alpha.-olefin at a rate such that the ratio of the weight % of ethylene in the vapor phase to the weight % of ethylene in the reactant feed stream is no more than about 1.2;
- (E) continuously at least partially condensing the vapor above the liquid phase and returning the condensate to the liquid phase;
- (F) continuously withdrawing copolymer product from the reactor.
A process for continuously producing copolymer comprising polymerizing ethylene and .alpha.-olefin monomers in the presence of a metallocene catalyst system, comprising:
- (A) continuously providing a dilute liquefied .alpha.-olefin feed stream from a refinery or it steam cracking plant comprising at least one .alpha.-olefin reactant and diluent admixed therewith, wherein said stream is selected from those which contain butene-1, propylene or C.sub.5 .alpha.-olefin, wherein:
- (i) the amount of diluent in said feed stream is about 30 weight percent thereof;
- and
- (ii) about 50 weight percent of the constituents of said diluent possess a boiling point under reaction conditions within about .+-.20.degree. C. of the average boiling point of the .alpha.-olefin constituents of the feed stream;
- (B) providing a feed stream comprising ethylene in liquid, vapor, or liquid/vapor form;
- (C) continuously introducing the feed streams of steps (A) and (B) and metallocene catalyst system into the liquid phase of a reaction zone in a manner and under conditions sufficient to:
- (i) obtain an .alpha.-olefin conversion of about 30%,
- (ii) obtain an ethylene conversion of about 70%;
- and
- (D) continuously withdrawing copolymer product from the reactor.
Dependencies are inferred from the claim text.