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
1999-11-10
2001-08-07
Wu, David W. (Department: 1713)
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, C526S127000, C526S160000, C526S943000, C526S348600
Reexamination Certificate
active
06271164
ABSTRACT:
The present invention relates to a highly active, supported catalyst system which can advantageously be used in olefin polymerization and to a process for its preparation, and also to polymers which are prepared using the supported catalyst system.
Processes for preparing polyolefins with the aid of soluble, homogeneous catalyst systems comprising a transition metal component of the metallocene type and a cocatalyst component of the aluminoxane, Lewis acid or ionic type are known. These catalysts give polymers and copolymers having a narrow molar mass distribution with high activity.
In polymerization processes using soluble, homogeneous catalyst systems, heavy deposits form on reactor walls and stirrer if the polymer is obtained as a solid. These deposits are always formed by agglomeration of the polymer particles if metallocene and/or cocatalyst are present in dissolved form in the suspension. Such deposits in the reactor systems have to be removed regularly, since they quickly reach considerable thicknesses, have a high strength and prevent heat transfer to the cooling medium. Furthermore, homogeneous catalyst systems cannot be used for preparing polyolefins in the gas phase.
To avoid deposit formation in the reactor, the use of supported catalyst systems in which the metallocene and/or the aluminum compound serving as cocatalyst are fixed on an inorganic support material have been proposed.
EP 576 970 A1 discloses a catalyst system comprising a metallocene of the formula
where
M
a
is a metal of group IVb, Vb or VIb of the Periodic Table,
R
a
and R
b
are identical or different and are each a hydrogen atom, a C
1
-C
10
-alkyl group, a C
1
-C
10
-alkoxy group, a C
6
-C
10
-aryl group, a C
6
-C
10
-aryloxy group, a C
2
-C
10
-alkenyl group, a C
7
-C
40
-arylalkyl group, a C
7
-C
40
-alkylaryl group, a C
8
-C
40
-arylalkenyl group, an OH group or a halogen atom,
the radicals R
c
are identical or different and are each a hydrogen atom, a halogen atom, a C
1
-C
10
-alkyl group which may be halogenated, a C
6
-C
10
-aryl group, an —NR
P
2
, —SR
P
, —OSiR
P
3
— or —PR
P
2
radical, where R
P
is a halogen atom, a C
1
-C
10
-alkyl group or a C
6
-C
10
-aryl group,
R
d
to R
1
are identical or different and are as defined for R
c
, or adjacent radicals R
d
to R
1
together with the atoms connecting them form one or more aromatic or aliphatic rings, or the radicals R
e
and R
h
or R
1
together with the atoms connecting them form an aromatic or aliphatic ring,
R
m
is
where R
n
and R
o
are identical or different and are each a hydrogen atom, a halogen atom, a C
1
-C
10
-alkyl group, a C
1
-C
10
-fluoroalkyl group, a C
1
-C
10
-alkoxy group, a C
6
-C
10
-aryl group, a C
6
-C
10
-fluoroaryl group, a C
6
-C
10
-aryloxy group, a C
2
-C
10
-alkenyl group, a C
7
-C
40
-arylalkyl group, a C
7
-C
40
-alkylaryl group or a C
8
-C
40
-arylalkenyl group, or R
n
and R
o
, in each case together with the atoms connecting them, form one or more rings and
M
b
is silicon, germanium or tin,
and a supported cocatalyst.
An isotactic polypropylene having a melting point below 157° C. is obtained using this catalyst system.
EP 287 666 B1 discloses a process for the polymerization of olefins in the presence of a catalyst comprising a compound of a transition metal, an inorganic support, an aluminoxane and an organoaluminum compound having a hydrocarbon group different from n-alkyl groups as solid catalyst component, wherein the transition metal compound has the formula
R
q
k
R
r
l
R
s
m
R
t
n
Me,
where R
q
is a cycloalkadienyl group, R
r
, R
s
and R
t
are identical or different and are each a cycloalkadienyl group, an aryl group, an alkyl group, an arylalkyl group, a halogen atom or a hydrogen atom, Me is zirconium, titanium or hafnium, k is 1, 2, 3 or 4, 1, m and n are 0, 1, 2 or 3 and k+l+m+n=4.
This process gives polymers in good yields.
EP 336 593 B1 discloses a process for preparing a metallocene/aluminoxane catalyst provided with a support for olefin polymerization, in which trialkylaluminum and water are reacted in the presence of a water-absorbing solid material at a molar ratio of trialkylaluminum to water of from 10:1 to 1:1 and a metallocene of a transition metal is added to the reacted mixture, with the water being absorbed by the solid material in an amount of from 10 to 50% by weight prior to the reaction, the water-containing solid material being added to a solution of trialkylaluminum and the molar ratio of aluminum to metallocene transition metal being from 1000:1 to 1:1.
By this process, the cocatalyst is immobilized on the support. An advantageous molar ratio of aluminum to metallocene transition metal is obtained.
DE 4330667 A1 discloses a process for preparing catalyst systems using a pretreated support. In this process, the support material is reacted with a solution of triethylaluminum in heptane. Preference is given to using catalyst systems comprising a mixture of a plurality of metallocene complexes and/or a Ziegler-Natta catalyst system in the polymerization. When using metallocene complexes and Ziegler-Natta catalysts, polypropylenes having a melting point of >160° C. are obtained. Polypropylenes having melting points of <150° C. are prepared when only metallocenes are used as catalysts.
It is an object of the present invention to provide a highly active, supported catalyst system which gives polymers having a high regioregularity and stereoregularity and also an environmentally friendly and economical process for preparing the polymers.
We have found that this object is achieved by a catalyst system comprising at least one metallocene and at least one passivated support.
According to the present invention, the catalyst system is prepared by mixing at least one metallocene and at least one passivated support.
The metallocene component of the catalyst system of the present invention can be essentially any metallocene. The metallocene can be either bridged or unbridged and have identical or different ligands. Preference is given to metallocenes of group IVb of the Periodic Table of the Elements, viz. titanium, zirconium or hafnium, preferably zirconium.
The metallocenes preferably have the formula I
where
M
1
is a metal of group IVb of the Periodic Table of the Elements,
R
1
and R
2
are identical or different and are each a hydrogen atom, a C
1
-C
10
-alkyl group, a C
1
-C
10
-alkoxy group, a C
6
-C
20
-aryl group, a C
6
-C
20
-aryloxy group, a C
2
-C
10
-alkenyl group, an OH group, an NR
12
2
group, where R
12
is a C
1
-C
2
-alkyl group or a C
6
-C
14
-aryl group, or a halogen atom,
R
3
to R
8
and R
3
′ to R
8
′ are identical or different and are each a hydrogen atom, a C
1
-C
40
-hydrocarbon group which may be linear, cyclic or branched, e.g. a C
1
-C
10
-alkyl group, a C
2
-C
10
-alkenyl group, a C
6
-C
20
-aryl group, a C
7
-C
40
-arylalkyl group, a C
7
-C
40
-alkylaryl group or a C
8
-C
40
-arylalkenyl group, or adjacent radicals R
4
to R
8
and/or R
4
′ to R
8
′ together with the atoms connecting them form a ring system,
R
9
is a bridge, preferably
where R
10
and R
11
are identical or different and are each a hydrogen atom, a halogen atom or a C
1
-C
40
-group such as a C
1
-C
20
-alkyl group, a C
1
-C
10
-fluoroalkyl group, a C
1
-C
10
-alkoxy group, a C
6
-C
14
-aryl group, a C
6
-C
10
-fluoroaryl group, a C
6
-C
10
-aryloxy group, a C
2
-C
10
-alkenyl group, a C
7
-C
40
-arylalkyl group, a C
7
-C
40
-alkylaryl group or a C
8
-C
40
-arylalkenyl group, or R
10
and R
11
, in each case together with the atoms connecting them, form one or more rings and x is an integer from zero to 18, M
2
is silicon, germanium or tin, and the rings A and B are identical or different, saturated or unsaturated. R
9
can also link two units of the formula I to one another.
The 4,5,6,7-tetrahydroindenyl analogs corresponding to the compounds I are likewise of importance.
In formula I, it is preferred that
M
1
is zirconium,
R
1
and R
2
are identical and are methyl or chlorine, in particular chlorine, and R
9
&equa
Bachmann Bernd
Fritze Cornelia
Kuber Frank
Harlan R.
Wu David W.
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