Catalyst system

Details Catalyst system Catalyst system

2000-06-09

2002-12-31

Wu, David W. (Department: 1713)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S170000, C526S129000, C526S159000

Reexamination Certificate

active

06500908

ABSTRACT:

The present invention relates to a catalyst system comprising a chemical compound having cocatalytic activity in combination with a metallocene and an aluminum compound. The cocatalytically active chemical compound is uncharged and has a plurality of Lewis acid centers. The catalyst system can advantageously be used for the polymerization of olefins. Here, the use of aluminoxanes such as methylaluminoxane (MAO) as cocatalyst can be dispensed with while still achieving high catalyst activities. The catalyst system can be used either in homogeneous form or supported form for the polymerization.
The role of cationic complexes in Ziegler-Natta polymerization using metallocenes is generally known (H. H. Brintzinger, D. Fischer, R. Mülhaupt, R. Rieger, R. Waymouth, Angew. Chem. 1995, 107, 1255-1283). MAO as cocatalyst has the disadvantage of being used in a high excess. The preparation of cationic alkyl complexes opens up the route to MAO-free catalysts which have comparable activity and in which the cocatalyst can be used in an almost stoichiometric amount.
The synthesis of “cation-like” metallocene polymerization catalysts is described in J. Am. Chem. Soc. 1991, 113, 3623. Here, abstraction of an alkyl group from an alkyl-metallocene compound is achieved by means of trispentafluorophenylborane. EP 427 697 describes this synthetic principle and a corresponding catalyst system comprising an uncharged metallocene species (e.g. Cp
2
ZrMe
2
), a Lewis acid (e.g. B(C
6
F
5
)
3
) and aluminum alkyls. A process for preparing salts of the formula LMX
+
XA
−
by the above-described principle is described in EP 520 732.
EP 558 158 describes zwitterionic catalyst systems which are prepared from dialkyl-metallocene compounds and salts of the formula [R
3
NH]
+
[B(C
6
H
5
)
4
]
−
. The reaction of such a salt with, for example, Cp
2
ZrMe
2
results in protolysis with elimination of methane to give a methyl-zirconocene cation as intermediate. This reacts via C—H activation to form the zwitterion Cp
2
Zr
+
—(m—C
6
H
4
)—BPh
3
−
. In this compound, the Zr atom is covalently bound to a carbon atom of the phenyl ring and is stabilized via agostic hydrogen bonds. U.S. Pat. No. 5,348,299 describes zwitterionic catalyst systems which are prepared from dialkyl-metallocene compounds and salts of the formula [R
3
NH]
+
[B(C
6
F
5
)
4
]
−
by protolysis. The C—H activation as subsequent reaction does not occur. EP 426 637 utilizes a process in which the Lewis acid CPh
3
+
cation is used for abstracting the methyl group from the metal center. The function of the weakly coordinating anion is likewise fulfilled by B(C
6
F
5
)
4
−
.
Disadvantages of the catalyst systems known hitherto are the high sensitivity toward catalyst poisons and the problem of leaching in application of the catalyst systems to a support.
It is an object of the present invention to provide an alternative catalyst system which avoids the disadvantages of the prior art and nevertheless achieves high polymerization activities.
We have found that this object is achieved by a catalyst system comprising a) at least one cocatalytically active chemical compound A, b) at least one metallocene B and c) at least one aluminum compound C, and also by a process for preparing this catalyst system. The catalyst system can be used both for the homogeneous polymerization and the heterogeneous polymerization of olefins. In the heterogeneous polymerization, additional use is made of a support material which may have been pretreated. In addition, a process for preparing polyolefins in the presence of the catalyst system of the present invention is described.
The catalyst system of the present invention comprises as cocatalytically active chemical compound A an organoboron-aluminum compound comprising units of the formula I
where
R
1
are identical or different and are each a hydrogen atom, a halogen atom, a C
1
-C
40
-group such as C
1
-C
20
-alkyl, C
1
-C
20
-haloalkyl, C
1
-C
10
-alkoxy, C
6
-C
20
-aryl, C
6
-C
20
-haloaryl, C
6
-C
20
-aryloxy, C
7
-C
40
-arylalkyl, C
7
-C
40
-haloarylalkyl, C
7
-C
40
-alkylaryl or C
7
-C
40
-haloalkylaryl or R
1
can be an OSiR
3
3
group, where R
3
are identical or different and are each a hydrogen atom, a halogen atom, a C
1
-C
40
-group such as C
1
-C
20
-alkyl, C
1
-C
20
-haloalkyl, C
1
-C
10
-alkoxy, C
6
-C
20
-aryl, C
6
-C
20
-haloaryl, C
6
-C
20
-aryloxy, C
7
-C
40
-arylalkyl, C
7
-C
40
-haloarylalkyl, C
7
-C
40
-alkylaryl or C
7
-C
40
-haloalkylaryl,
R
2
is a hydrogen atom, a halogen atom, a C
1
-C
40
-group such as C
1
-C
20
-alkyl, C
1
-C
20
-haloalkyl, C
1
-C
10
-alkoxy, C
6
-C
20
-aryl, C
6
-C
20
-haloaryl, C
6
-C
20
-aryloxy, C
7
-C
40
-arylalkyl, C
7
-C
40
-haloarylalkyl, C
7
-C
40
-alkylaryl or C
7
-C
40
-haloalkylaryl or R
2
can be an OSiR
3
3
group, where R
3
are identical or different and are each a hydrogen atom, a halogen atom, a C
1
-C
40
-group such as C
1
-C
20
-alkyl, C
1
-C
20
-haloalkyl, C
1
-C
10
-alkoxy, C
6
-C
20
-aryl, C
6
-C
20
-haloaryl, C
6
-C
20
-aryloxy, C
7
-C
40
-arylalkyl, C
7
-C
40
-haloarylalkyl, C
7
-C
40
-alkylaryl or C
7
-C
40
-haloalkylaryl,
i is 0, 1 or 2, and
j is 0 or 1.
The chemical compound A comprising units of the formula I can be in the form of a monomer or a linear, cyclic or cage-like oligomer in which i are identical or different and are 0, 1 or 2 and j is 0 or 1. It is also possible for two or more chemical compounds comprising units of the formula I to form dimers, trimers or higher associates by means of Lewis acid-base interactions with one another.
Preference is given to cocatalytically active chemical compounds A of the formula VI
where
R
1
are identical or different and are each a hydrogen atom, a halogen atom, a C
1
-C
40
-group such as C
1
-C
20
-alkyl, C
1
-C
20
-haloalkyl, C
1
-C
10
-alkoxy, C
6
-C
20
-aryl, C
6
-C
20
-haloaryl, C
6
-C
20
-aryloxy, C
7
-C
40
-arylalkyl, C
7
-C
40
-haloarylalkyl, C
7
-C
40
-alkylaryl or C
7
-C
40
-haloalkylaryl or R
1
can be an OSiR
3
3
group, where R
3
are identical or different and are each a hydrogen atom, a halogen atom, a C
1
-C
40
-group such as C
1
-C
20
-alkyl, C
1
-C
20
-haloalkyl, C
1
-C
10
-alkoxy, C
6
-C
20
-aryl, C
6
-C
20
-haloaryl, C
6
-C
20
-aryloxy, C
7
-C
40
-arylalkyl, C
7
-C
40
-haloarylalkyl, C
7
-C
40
-alkylaryl or C
7
-C
40
-haloalkylaryl,
R
2
is a hydrogen atom, a halogen atom, a C
1
-C
40
-group such as C
1
-C
20
-alkyl, C
1
-C
20
-haloalkyl, C
1
-C
10
-alkoxy, C
6
-C
20
-aryl, C
6
-C
20
-haloaryl, C
6
-C
20
-aryloxy, C
7
-C
40
-arylalkyl, C
7
-C
40
-haloarylalkyl, C
7
-C
40
-alkylaryl or C
7
-C
40
-haloalkylaryl or R
2
can be an OSiR
3
3
group, where R
3
are identical or different and are each a hydrogen atom, a halogen atom, a C
1
-C
40
-group such as C
1
-C
20
-alkyl, C
1
-C
20
-haloalkyl, C
1
-C
10
-alkoxy, C
6
-C
20
-aryl, C
6
-C
20
-haloaryl, C
6
-C
20
-aryloxy, C
7
-C
40
-arylalkyl, C
7
-C
40
-haloarylalkyl, C
7
-C
40
-alkylaryl or C
7
-C
40
-haloalkylaryl.
Cocatalytically active chemical compounds A are obtainable by reacting dihydroxyorganoboranes of the formula III or triorganoboroxins of the formula IV with organoaluminum compounds of the formula V.
In these formulae, R
4
is a halogen atom, a C
1
-C
40
-group such as C
1
-C
20
-alkyl, C
1
-C
20
-haloalkyl, C
1
-C
10
-alkoxy, C
6
-C
20
-aryl, C
6
-C
20
-haloaryl, C
6
-C
20
-aryloxy, C
7
-C
40
-arylalkyl, C
7
-C
40
-haloarylalkyl, C
7
-C
40
-alkylaryl or C
7
-C
40
-haloalkylaryl or R
4
can be an OSiR
3
3
group, where R
3
are identical or different and are each a hydrogen atom, a halogen atom, a C
1
-C
40
-group such as C
1
-C
20
-alkyl, C
1
-C
20
-haloalkyl, C
1
-C
10
-alkoxy, C
6
-C
20
-aryl, C
6
-C
20
-haloaryl, C
6
-C
20
-aryloxy, C
7
-C
40
-arylalkyl, C
7
-C
40
-haloarylalkyl, C
7
-C
40
-alkylaryl or C
7
-C
40
-haloalkylaryl. Preference is here given to, for example, the following radicals: pentafluorophenyl, 3,5-bis(trifluoromethyl)phenyl, phenyl, methyl, ethyl, propyl, butyl, 3,4,5-trifluorophenyl, 3,5-difluorophenyl,

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