Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Plural component system comprising a - group i to iv metal...
Reexamination Certificate
1999-03-26
2002-07-30
Wood, Elizabeth D. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Plural component system comprising a - group i to iv metal...
C502S117000, C502S152000, C502S155000, C502S159000, C526S131000, C526S160000, C526S163000
Reexamination Certificate
active
06426313
ABSTRACT:
TECHNICAL FIELD
This invention relates to olefin polymerization with organometallic transition metal catalysts on polymeric supports wherein the transition metal catalysts are activated for polymerization by an ionizing reaction and stabilized in cationic form with a noncoordinating anion.
BACKGROUND ART
The use of ionic catalysts for olefin polymerization where organometallic transition metal cations are stabilized in an active polymerization state by compatible, non-coordinating anions is a well-recognized field in the chemical arts. Typically such organometallic transition metal cations are the chemical derivatives of organometallic transition metal compounds having both ancillary ligands which help stabilize the compound in an active electropositive state and labile ligands at least one of which can be abstracted to render the compound cationic and at least one of which is suitable for olefin insertion. Since inert supports are used industrially for insertion polymerization processes in both of gas phase polymerization and slurry polymerization, technology for supporting these ionic catalysts is also known.
U.S. Pat. No. 5,427,991 describes the chemical bonding of discrete non-coordinating anionic activators, such as described in the earlier U.S. Pat. No. 5,198,401, to supports so as to prepare polyanionic activators that when used with the metallocene compounds avoid problems of catalyst desorption experienced when ionic catalysts physically adsorbed on inert supports are utilized in solution or slurry polymerization. The supports are core components of inert monomeric, oligomeric, polymeric or metal oxide supports which have been prepared so as to incorporate chemically bound, discrete non-coordinating anions. The teaching of the preparation of polyanionic activators from hydrocarbyl compounds (FIGS. 1, 5-6) entails a number of reactions. A typical reaction for a polymeric core component is that of a treating with the lithiating agent n-BuLi, or optionally lithiating a polymerizable monomer followed by polymerization of monomers into a polymeric segment, to produce a polymer or cross-linked polymer having pendant hydrocarbyl lithium groups. These are subsequently treated with the bulky Lewis acid trisperfluorophenylboron (B(pfp)
3
) and subjected to an ion exchange reaction with dimethylanilinium hydrochloride ([DMAH]
+
[Cl]
−
) so as to prepare a polymer surface having covalently linked activator groups of [DMAH]
+
[(pfp)
3
BP]
−
, where P is the polymeric core component.
In addition to the attachment of anionic complexes to support substrates, patent literature describes the attachment of transition metal ligand groups to polymeric supports, the ligand groups then being reacted with transition metal compounds so as to form organometallic compounds bound through cyclopentadienyl ligands to polymeric supports. Such compounds can then be rendered suitable as olefin polymerization catalysts by the use of activating cocatalyst compounds, e.g., such as alkylalumoxanes and phenylborates. See U.S. Pat. Nos. 4,463,135, 5,610,115 and WO 96/35726. WO 96/35726 in particular notes the use of an acrylate-containing copolymer support having a surface area of less than about 15 m
2
/g, with examples illustrating 2.1 m
2
/g surface area. These catalysts are taught to be of benefit over metal oxide supports in requiring fewer preparation steps since polar moieties such as adsorbed water and hydroxyl groups are not typically present on the polymeric supports. However, this technology presents problems in that the preparation of the support bound ligands limits ligand selection available for subsequent bonding to the transition metal and gives rise to low reaction product yields and undesirable byproducts, some of which may either interfere or compete with subsequent reactions.
Also the functionalization of polymer resin beads for use with or preparation of heterogeneous catalytic species is known. See, e.g., Fréchet, J. M. J., Farrall, M. J., “Functionalization of Crosslinked Polystyrene by Chemical Modification”,
Chemistry and Properties of Crosslinked Polymers,
59-83 (Academic Press, 1977); and, Sun, L., Shariati, A., Hsu, J. C., Bacon, D. W.,
Studies in Surface Science and Catalysis
1994, 89, 81, and U.S. Pat. No. 4,246,134, this patent describing polymeric carriers of macroporous copolymers of vinyl and divinyl monomers with specific surface areas of 30 to 700 m
2
/g. and the use of such for vinyl monomer polymerization.
The use of supported or heterogeneous catalysts in gas phase polymerization is important as a means of increasing process efficiencies by assuring that the forming polymeric particles achieve shape and density that improves reactor operability and ease of handling. Ineffective catalyst supports permit the production of polymeric fines and resulting fouling of reactor walls or piping. This appears to be due to a number of possible reasons, including premature support particle fragmentation due to excessively rapid polymerization of monomer or catalyst desorption both of which can lead to decrease in the control of polymerization. Polymer particle size and density can be degraded and efficiencies lost. Additionally, ionic catalysts based on discrete non-coordinating anions provide significant industrial advantages in reducing the amounts of cocatalyst needed and in often providing safer and cheaper synthesis of those cocatalyst activator compounds. These catalysts however can be highly sensitive to polar impurities and accordingly methods of catalyst synthesis that can reduce the production of potential interfering byproducts are desirable.
SUMMARY OF THE INVENTION
The invention provides a low fouling, high particle density polymerization process using a supported olefin polymerization cocatalyst activator composition comprising a cross-linked polymer bead having a surface area of from about 1 to 20 m
2
/g to which are bound a plurality of non-coordinating anions, where the polymeric support comprises ligands covalently bound to the central metal or metalloid atoms of said anions, and an effective number of cationic species to achieve a balanced charge. The invention includes activated olefin polymerization catalysts derived as the reaction product of said cocatalyst activator composition and an organometallic transition metal compound having ancillary ligands, at least one labile ligand capable of abstraction by protonation by said cocatalyst activator composition and at least one labile ligand into which an olefinic monomer can insert for polymerization. In a preferred embodiment, the polymeric support has a surface area of ≦10 m
2
/g and is particularly suitable for use with high activity organometallic, transition metal catalyst compounds.
DESCRIPTION OF THE INVENTION
The olefin polymerization cocatalyst activator composition according to the invention is a stable polymeric supported activator that can be washed, stored, shipped or otherwise handled prior to introduction of the organometallic transition metal compounds without deleterious effects on its ability to activate by protonation those compounds and facilitate their placement throughout the polymeric, resin supports consisting of cross-linked polymer beads. It comprises a protonated salt functionality having a weakly coordinating anionic complex covalently bonded to the polymeric support, the salt functionality comprising a suitable cation, said polymeric support being substantially nonporous as reflected in its low surface area.
The invention polymeric, activator support can be represented by the formula A:
Polymer-D
n
—[NCA]
−
[Z]
+
A
where “Polymer” is a cross-linked polymeric backbone, D is an optional group linking the Polymer to NCA, n is 0 or 1, NCA refers to a compatible “noncoordinating anion” derived from a Lewis acid moiety (as further defined below), and Z is a suitable cation that electronically charge balances NCA. The linking group is a substantially hydrocarbyl diradical (—D—) con
Dias Anthony J.
Frechet Jean M J
Roscoe Stephen B.
Walzer, Jr. John F.
Exxon Mobil Chemical Patents Inc.
Muller William G.
Runyan, Jr. Charles Edwin
Wood Elizabeth D.
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