Organic compounds -- part of the class 532-570 series – Organic compounds – Heavy metal containing
Reexamination Certificate
2002-03-15
2004-01-27
Nazario-Gonzalez, Porfirio (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heavy metal containing
C556S007000, C556S009000, C556S028000, C502S152000, C526S132000, C526S134000, C526S163000
Reexamination Certificate
active
06683199
ABSTRACT:
BACKGROUND INFORMATION
The present invention relates to compounds that are useful, inter alia, as catalysts or catalyst components. More particularly, the present invention relates to dicationic compounds comprising a Group 4 metal atom (Ti, Zr, Hf) that are particularly adapted for use in the coordination polymerization of unsaturated compounds. Such compounds are particularly advantageous for use in a polymerization process wherein at least one polymerizable monomer is combined under polymerization conditions with a catalyst or catalyst composition to form a polymeric product.
It is previously known in the art to activate Ziegler-Natta polymerization catalysts, particularly such catalysts comprising Group 3-10 metal complexes containing delocalized &pgr;-bonded ligand groups, using Lewis acids to form catalytically active derivatives of such Group 3-10 metal complexes. Examples of suitable Lewis acids include tris(perfluorophenyl)borane and tris(perfluorobiphenyl)borane. Examples of such processes are disclosed in U.S. Pat. No. 5,721,185 and
J. Am. Chem. Soc.,
118, 12451-12452 (1996), and elsewhere.
According to
J. Chem. Soc. Chem. Commun.,
1999, 115-116, certain specifically substituted bis-Cp zirconocenedimethyl complexes may be converted to a dicationic derivative at −60° C. using multiple equivalents of trispentafluorophenylborane. The resulting metallocenes required the presence of either pendant phosphine moieties or benzyl groups on the cyclopentadienyl ring system and two equivalents of the methyltris(pentafluorophenyl)borate anion for charge balance. Upon heating even to −40° C. the product decomposed to give the corresponding monocationic complex and free tris(pentafluorophenyl)borane, thereby indicating the complexes would be unsuited for use as polymerization catalyst components.
In U.S. Pat. No. 5,318,935 metal complexes containing two amido groups optionally linked by means of a bridging group are disclosed.
Finally, in
Orpanometallics,
1998, 17, 5908-5912, the reaction of the strongly Lewis acidic compound, tris(pentafluorophenyl)aluminum, with bis(cyclopentadienyl)zirconium dimethyl was shown to form an unstable (&mgr;-methyl) derivative via methide abstraction, which rapidly collapsed through a back exchange reaction at temperatures above 0° C. to form bis(cyclopentadienyl)methylpentafluoro-phenyl zirconium. These compounds also would find little use as catalyst components for addition polymerizations due to the lack of temperature stability.
All of the foregoing attempts have failed to prepare a metal complex that is useful in catalytic applications, especially in the polymerization of one or more ethylenically unsaturated monomers under addition polymerization conditions.
SUMMARY OF THE INVENTION
According to the present invention there are now provided dicationic Group 4 metal compounds corresponding to the formula:
wherein:
Y
1
and Y
2
independently each occurrence is an anionic ligand group that is covalently bonded to M by means of a sigma bond through an oxygen, phosphorus or nitrogen atom, and containing up to 50 atoms, not counting hydrogen, said Y
1
and Y
2
optionally being joined through bridging group, J, and further optionally, Y
1
and Y
2
may also contain a coordinate/covalent bound to M;
J is an optional divalent bridging group having up to 20 atoms not counting hydrogen;
j is 0 or 1;
M is a Group 4 metal;
X
1
independently each occurrence is a Lewis base;
x
1
is 0, 1 or 2; and
A
−
independently each occurrence is an anion of up to 50 atoms other than hydrogen, derived or derivable from a Lewis acid, said A
−
optionally forming an adduct with the metal complex by means of a &mgr;bridging group, and further optionally two A
−
groups may be joined together thereby forming a single dianion, optionally containing one or more &mgr;-bridging groups.
The compounds of the invention may be formed by contacting a charge-neutral Group 4 metal coordination complex having two monovalent, anionic ligand groups, X (or optionally the two X groups together form a single divalent, anionic ligand group), or precursor(s) thereof (catalyst) with at least 2 molar equivalents of a charge-neutral, Lewis acid compound (activator), A, or a mixture thereof, such that the X groups of the Group 4 metal coordination complex are abstracted or partially abstracted, thereby forming a charge separated cation/anion pair, a zwitterionic metal complex, or a complex having both cation/anion and zwitteron functionality. Preferably the molar ratio of catalyst:activator employed in the foregoing process is from 1:2 to 1:10, more preferably the ratio is from 1:2 to 1:3, and most preferably from 1:2 to 1:2.5.
The foregoing process is illustrated by the following schematic drawing:
wherein
Y
1
, Y
2
, M, J, j, X, X
1
, x
1
, A, and A
−
, are as previously defined.
The present invented compounds are stable at elevated temperatures of at least 0° C., preferably at least 20° C. up to as high as 150° C. or higher and are usefully employed in a process for polymerization of ethylenically unsaturated monomers under solution, slurry, high pressure, or gas phase polymerization conditions. Relatively high molecular weight polymers may be readily obtained by use of the present metal complexes in the foregoing polymerization processes. Additionally, the foregoing metal complexes are suitably employed as initiators or catalysts for cationic polymerizations, such as the cationic polymerization of styrene or isobutylene, ring opening polymerizations, such as the polymerization of oxiranes or epoxides, especially propylene oxide, and the copolymerization of an olefin, especially ethylene, with a ring openable monomer.
Accordingly, the present invention additionally provides a process for the polymerization of one or more ethylenically unsaturated, addition polymerizable monomers comprising contacting the same, optionally in the presence of an inert aliphatic, alicyclic or aromatic hydrocarbon, under polymerization conditions with the above metal complex, or alternatively, forming the above metal complex in situ in the presence of or prior to addition to, a reaction mixture comprising one or more ethylenically unsaturated, polymerizable compounds.
DETAILED DESCRIPTION OF THE INVENTION
All references herein to elements belonging to a certain Group refer to the Periodic Table of the Elements published and copyrighted by CRC Press, Inc., 1995. Also any reference to the Group or Groups shall be to the Group or Groups as reflected in this Periodic Table of the Elements using the IUPAC system for numbering groups. Where any reference is made herein to any publication, patent application or provisional patent application, the contents thereof are incorporated herein in its entirety by reference. By the term “Lewis acid”, in reference to activator compounds herein, is meant compounds that are sufficiently electrophilic, such that a fully charge separated cation/anion pair, a &mgr;-bridged complex or a zwiterionic complex is formed upon combination of the respective catalyst and activators. Preferred anionic ligand groups, X, are hydrocarbyl, silyl, N,N-dialkylamido and alkanediylamido groups of up to 20 atoms not counting hydrogen, or two such X groups together are an alkanediyl or alkenediyl group which together with M form a metallocycloalkane or metallocycloalkene. By the term “partially dicationic” is meant that at least one A
−
group (or the entity formed from two A
−
groups collectively) is not fully charge separated from the metal center, M, or that at least one A
−
group (or the entity formed from two A
−
groups collectively) form a zwitterionic complex.
Preferred activators, A, are aluminum compounds containing at least one halohydrocarbyl ligand, preferably a fluoroaryl ligand. More preferred are tri(halohydrocarbyl)aluminum compounds having up to 50 atoms other than hydrogen, especially tri(fluoroaryl) aluminum compounds, most preferably tris(perfluoroaryl)aluminum compounds, and most highly preferably tris(pentafluo
Chen Eugene Y.
Kruper, Jr. William J.
Dow Global Technology Inc.
Nazario-Gonzalez Porfirio
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