Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Organic compound containing
Reexamination Certificate
1995-06-07
2002-10-15
Wu, David W. (Department: 1713)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Organic compound containing
C502S103000, C502S117000, C502S104000, C556S011000, C556S053000, C526S160000, C526S943000
Reexamination Certificate
active
06465384
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to certain biscyclopentadienyl Group 4 transition metal complexes possessing diene ligands and to polymerization catalysts obtained from such. In one form this invention relates to bisoyclopentadienyl and substituted bis(cyclopentadienyl)titanium, zirconium or hafnium complexes possessing diene ligands in which the metal is either in the +2 or +4 formal oxidation state which can be activated to form catalysts for the polymerization of olefins and to methods for preparing such complexes and catalysts.
The preparation and characterization of certain biscyclopentadienyl (Cp
2
) zirconium and hafnium diene complexes is described in the following references: Yasuda, et al.,
Organometallics
, 1982, 1, 388 (Yasuda I); Yasuda, et al.
Acc. Chem. Res
., 1985, 18 120 (Yasuda II); Erker, et al.,
Adv. Organomet. Chem
., 1985, 24, 1 (Erker I); Erker et al.
Chem. Ber
., 1994, 127, 805 (Erker II); and U.S. Pat. No. 5,198,401. The last reference describes the use of CP
2
Zr(diene) where the Zr is in the +4 formal oxidation state as an olefin polymerization catalyst in combination with ammonium borate cocatalysts.
Biscyclopentadienyl Group 4 transition metal complexes in which the metal is in the +4 formal oxidation state, and olefin polymerization catalysts formed from such complexes by combination with an activating agent, e.g., alumoxane or ammonium borate, are known in the art. Thus, U.S. Pat. No. 3,242,099 describes the formation of olefin polymerization catalysts by the combination of biscyclopentadienyl metal dihalides with alumoxane. U.S. Pat. No. 5,198,401 discloses tetravalent biscyclopentadienyl Group 4 transition metal complexes and olefin polymerization catalysts obtained by converting such complexes into cationic form in combination with a non-coordinating anion. Particularly preferred catalysts are obtained by the combination of ammonium borate salts with the biscyclopentadienyl titanium, zirconium or hafnium complexes. Among the many suitable complexes disclosed are bis(cyclopentadienyl)zirconium complexes containing a diene ligand attached to the transition metal through &sgr;-bonds where the transition metal is in its highest (+4) formal oxidation state.
Copending applications, Ser. No. 08/082,197 filed Jun. 24, 1993, Ser. No. 08/230,051 filed Apr. 19, 1994 ABN and Ser. No. 08/241,523 filed May 12, 1994 U.S. Pat. No. 5,470,993 disclose monocyclopentadienyl diene complexes with titanium or zirconium in which the metal is in the +2 formal oxidation state and the formation of olefin polymerization catalysts from such complexes by the combination of the complex with activator compounds such as alumoxane, ammonium borate salts or strong Lewis acids such as tris(pentafluorophenyl)borane capable of converting the complexes to active forms.
The present invention provides novel olefin polymerization catalysts which can be employed over a wide range of physical conditions and with a wide range of olefin monomers and combinations of such monomers, thus providing an outstanding opportunity of tailor making polyolefins having specifically desired properties.
SUMMARY OF THE INVENTION
The present invention relates to metal complexes containing two cyclopentadienyl groups or substituted cyclopentadienyl groups, said complex corresponding to the formula:
CpCp′MD
wherein:
M is titanium, zirconium or hafnium in the +2 or +4 formal oxidation state;
Cp and Cp′ are each substituted or unsubstituted cyclopentadienyl groups bound in an &eegr;
5
bonding mode to the metal, said substituted cyclopentadienyl group being substituted with from one to five substituents independently selected from the group consisting of hydrocarbyl, silyl, germyl, halo, cyano, hydrocarbyloxy, and mixtures thereof, said substituent having up to 20 nonhydrogen atoms, or optionally, two such substituents (except cyano or halo) together cause Cp or Cp′ to have a fused ring structure, or wherein one substituent on Cp and Cp′ forms a linking moiety joining Cp and Cp′;
D is a stable, conjugated diene, optionally substituted with one or more hydrocarbyl groups, silyl groups, hydrocarbylsilyl groups, silylhydrocarbyl groups, or mixtures thereof, said D having from 4 up to 40 nonhydrogen atoms and forming a &pgr;-complex with M when M is in the +2 formal oxidation state, and forming a &sgr;-complex with M when M is in the +4 formal oxidation state. In the diene complexes in which M is in the +2 formal oxidation state, the diene is associated with M as a &pgr;-complex in which the diene normally assumes an s-trans configuration or an s-cis configuration in which the bond lengths between M and the four carbon atoms of the conjugated diene are nearly equal (&Dgr;d as defined hereafter ≧−0.15 Å) whereas in the complexes in which M is in the +4 formal oxidation state, the diene is associated with the transition metal as a &sgr;-complex in which the diene normally assumes a s-cis configuration in which the bond lengths between M and the four carbon atoms of the conjugated diene are significantly different (&Dgr;d<−0.15 Å). The formation of the complex with M in either the +2 or +4 formal oxidation state depends on the choice of the diene, the specific metal complex and the reaction conditions employed in the preparation of the complex. The complexes wherein the diene is &pgr;-bound and M is in the +2 formal oxidation state constitute the preferred complexes of the present invention.
The present invention also relates to novel methods of preparing the CpCp′MD complexes involving the reaction of the biscyclopentadienyl dihydrocarbyl, dihydrocarbyloxy, dihalide or diamide Group 4 metal complexes wherein the metal is in the +4 or +3 formal oxidation state, with a diene, D, and a reducing agent. The use of a reducing agent is optional when starting with biscyclopentadienyl dihydrocarbyl complexes.
Stated more particularly, the diene metal complexes of the present invention may be formed by reacting in any order the following components:
1) a complex of the formula:
CpCp′M*X or CpCp′M**X
2
wherein;
Cp and Cp′ are as previously defined;
M* is titanium, zirconium or hafnium in the +3 formal oxidation state;
M** is titanium, zirconium or hafnium in the +4 formal oxidation state; and
X is a C
1-6
hydrocarbyl, halide, C
1-6
hydrocarbyloxy or diC
1-6
hydrocarbylamide group;
2) a diene corresponding to the formula, D; and
3) optionally when X is C
1-6
hydrocarbyl, otherwise, not optionally, a reducing agent.
Uniquely, the process when used with diastereomeric mixtures of rac and meso isomers of metallocenes, can result information of only the rac diene metal complex.
Further according to the present invention there are provided catalysts for polymerization of addition polymerizable monomers comprising a combination of one or more of the above metal complexes and one or more activating cocatalysts. The metal complexes wherein the metal is in the +2 formal oxidation state are preferred in the formation of the novel catalysts of this invention.
Finally according to the present invention there is provided a polymerization process comprising contacting one or more addition polymerizable monomers and particularly one or more &agr;-olefins with a catalyst comprising one or more of the above metal complexes and one or more activating cocatalysts.
Generally speaking, the present diene containing complexes are more soluble in hydrocarbon solvents compared to the corresponding dihalide complexes and they are more stable to reductive elimination and other side reactions than are the corresponding dihydrocarbyl complexes. Catalyst systems comprising such diene containing complexes are accordingly better adapted to commercial use than are such alternative systems.
DETAILED DESCRIPTION
All reference to the Periodic Table of the Elements herein shall refer to the Periodic Table of the Elements, published and copyrighted b
Devore David D.
Neithamer David R.
Patton Jasson T.
Rosen Robert K.
Stevens James C.
Choi Ling-Siu
The Dow Chemical Company
Wu David W.
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