Covalently supported chemical compound which can be neutral...

Details Covalently supported chemical compound which can be neutral... Covalently supported chemical compound which can be neutral...

1997-08-12

2001-12-11

Gupta, Yogendra N. (Department: 1751)

Catalyst, solid sorbent, or support therefor: product or process

Catalyst or precursor therefor

Boron or compound containing same

C502S103000, C502S118000, C502S232000, C556S007000, C556S008000, C556S011000, C556S014000, C568S001000, C568S003000

Reexamination Certificate

active

06329313

ABSTRACT:

The present invention relates to a covalently supported chemical compound which can be neutral or ionic in composition and which is able in combination with a transition metal compound such as a metallocene to form a catalyst system which is suitable for the polymerization of olefins. With this system it is possible to forego the use of aluminoxanes such as methylaluminoxane as cocatalyst and yet still to obtain high catalyst activity.
The role of cationic complexes in Ziegler-Natta polymerization using metallocenes has been generally recognized (M. Bochmann, Nachr. Chem. Lab. Techn. 1993, 41, 1220).
Hitherto the most effective cocatalyst, MAO has the disadvantage of being employed in a high excess. The preparation of cationic alkyl complexes in opens up the way to MAO-free catalysts having comparable activity. Cationic alkyl complexes are synthesized by
a) protolysis of metallocene compounds with, for example, weakly acidic ammonium salts of the highly stable nonbasic tetra(pentafluorophenyl)borate (e.g. [PhMe
2
NH]
+
[B(C
6
F
5
)
4
]
−
),
b) abstraction of an alkyl group from metallocene compounds with the aid of strong Lewis acids, possible Lewis acids including both salts of the form (Ph
3
C
+
BR
4
−
) and strong, neutral Lewis acids such as B(C
6
F
5
)
3
, or
c) oxidation of metallocene-dialkyl complexes with, for example, AgBPh
4
or [Cp
2
Fe][BPh
4
].
The synthesis of “cation-like” metallocene polymerization catalysts is described in J. Am. Chem. Soc. 1991, 113, 3623. In that document, abstraction of alkyl from a metallocene-dialkyl compound takes place by means of tris(pentafluorophenyl)borane. EP 427 697 claims this synthetic principle and a corresponding catalyst system, consisting of a neutral 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 general formula LMX
+
XA
−
in accordance with the above-described principle is claimed in EP 520 732.
EP 558 158 claims zwitterionic catalyst systems which are prepared from metallocene-dialkyl compounds and salts of the form [R
3
NH]
+
[BPh
4
]
−
. The reaction of such a salt with, say, Cp*
2
ZrMe
2
, via protolysis with elimination of methane, produces a zirconocene-methyl cation as intermediate. This intermediate reacts by way of C—H activation to form the zwitterion Cp*
2
Zr
+
—(m—C
6
H
4
)—BPh
3
−
.
In accordance with this reaction principle, following the protolysis of a metallocene-dialkyl species with a perfluorinated [R
3
NH]
+
[B(C
6
F
5
)
4
]
−
salt in the first step, a cationic species is likewise formed, although now the follow-on reaction (C—H activation) to form zwitterionic complexes is not possible. Consequently, salts of the form [Cp
2
Zr—R—RH]
+
[B(C
6
F
5
)
4
]
−
are formed. U.S. Pat. No. 5,348,299 claims corresponding systems in which dimethylanilinium salts with perfluorinated tetraphenylborate anions are used. The supporting of such systems is aimed at better morphology of the polymer and is described in WO 91/09882.
The disadvantage of previous supporting techniques, as are described in WO 91/09882, is that the ionic catalyst system is attached only physically to the support. It can therefore easily be removed from the surface of the support by solvents. The homogeneous polymerization which is then carried out leads to a poorer morphology of the polymer.
The present invention therefore provides a supported chemical compound, and a process for preparing this supported chemical compound, which is bonded covalently to a support material. It also provides a catalyst system comprising at least one transition metal compound and at least one novel, supported chemical compound as cocatalyst. Also described is a process for preparing polyolefins in the presence of the supported chemical compound.
The supported chemical compound consists of a support T, y units N of the formula (II) given below, which are bonded covalently to the support, and b units A.
The supported chemical compound has the formula (I)
in which
A
c+
is a cation,
c is an integer from 1 to 10,
b is an integer ≧0,
T is a support,
y is an integer ≧1,
a is an integer from 0 to 10, where a·y=c·b, and
N is a unit of the formula (II)
 in which
R independently at each occurrence is an identical or different substituent of M, such as a halogen atom or a C
1
-C
40
carbon-containing group, such as a C
1
-C
40
-alkyl, C
1
-C
40
-haloalkyl, C
6
-C
40
-aryl, C
6
-C
40
-haloaryl, C
7
-C
40
-arylalkyl or C
7
-C
40
-halo-arylalkyl group,
X independently at each occurrence is identical or different and is a C
1
-C
40
carbon-containing group, for example a divalent, carbon-containing group such as a C
1
-C
40
-alkylene, C
1
-C
40
-haloalkylene, C
6
-C
40
-arylene, C
6
-C
40
-haloarylene, C
7
-C
40
-arylalkylene or C
7
-C
40
-halo-arylalkylene, C
2
-C
40
-alkynylene, C
2
-C
40
-haloalkynylene, C
2
-C
40
-alkenylene or C
2
-C
40
-haloalkenylene group, or a trivalent, carbon-containing group, such as a C
1
-C
40
-alkanetriyl, C
1
-C
40
-haloalkanetriyl, C
6
-C
40
-arenetriyl, C
6
-C
40
-haloarenetriyl, C
7
-C
40
-arenalkanetriyl, C
7
-C
40
haloarenealkanetriyl, C
2
-C
40
-alkynetriyl, C
2
-C
40
haloalkynetriyl, C
2
-C
40
-alkenetriyl or C
2
-C
40
-haloalkenetriyl group,
M independently at each occurrence is identical or different and is an element of group IIa, IIIa, IVa or Va of the Periodic Table of the Elements,
d is 0 or 1, e is 0 or 1, f is 0 or 1,
g is an integer from 0 to 10, h is an integer from 0 to 10, k is an integer from 0 to 10, r is an integer from 0 to 10,
i is an integer from 0 to 1000,
j is an integer from 1 to 6,
S at each occurrence is identical or different and is a spacer which links M covalently with T,
w is identical or different at each occurrence and is 0, 1 or 2, and z is 0, 1 or 2.
If a=0, then unit N is neutral; if a≧1, N is a negatively charged unit.
Each of the y units N of the formula (II) can be bonded covalently to the support T, starting from M, directly or by way of one or more spacers S. In this case, each M and each spacer S can have one or more covalent bonds to the support T. This is symbolized in the formulae (I), (II), (III) and (IV) by the sign
. For clarity in formula (II) the bond to the support (i.e.
) is shown by way of example only for one group MRS, although the other groups MRS can also bond to the support. In the groups MRS in which z is 0 and/or w is 0, M is bonded directly and covalently to the support.
Where the supported chemical compound of the formula (I) has two or more groups MRS these groups can be identical or different from one another. The number of substituents R in a group MRS depends on the (co)valence of M. Preferably, z is 1 and all w are 0. The spacer S preferably has the formula (III)
—R′
n
—Q
q
B
p
  (III)
in which R′ is identical or different at each occurrence and is a C
1
-C
40
carbon-containing group, such as a C
1
-C
40
-alkylene, C
1
-C
40
-haloalkylene, C
6
-C
40
-arylene, C
6
-C
40
-haloarylene, C
7
-C
40
-arylalkylene or C
7-
C
40
-halo-arylalkylene, C
2
-C
40
-alkynylene, C
2
-C
40
-haloalkynylene, C
2
-C
40
-alkenylene, C
2
-C
40
-haloalkenylene, C
1
-C
40
-aryleneoxy, C
1
-C
40
-alkylaryleneoxy or C
1
-C
40
-arylalkyleneoxy group, —NR″—, —PR″—, —P(O)R″—, —Si(R″)
2
—O—Si(R″)
2
—, —C—O—SiR″
2
— or —CONR″—, where R″ is a C
1
-C
40
carbon-containing group, such as a C
1
-C
40
alkyl, C
1
-C
40
-haloalkyl, C
6
-C
40
-aryl, C
6
-C
40
-haloaryl, C
7
-C
40
-arylalkyl or C
7
-C
40
-halo-arylalkyl, C
2
-C
40
-alkynyl, C
2
-C
40
-haloalkynyl, C
2
-C
40
alkenyl, C
2
-C
40
-haloalkenyl, C
1
-C
40
-aryloxy, C
1
-C
40
-alkylaryloxy or C
1
-C
40
-arylalkyloxy group,
or R′ is a heteroatom-containing group, such as —SO—, —SO
2
—, —S—, —CO—, —CO
2
—, —O—, —NH—or —PH—,
n is an integer ≧0, preferably 0 or 1,
Q is Si, N, P, S or O

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