Note: Descriptions are shown in the official language in which they were submitted.
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PROCESS FOR THE CO-P~rYMF~IZATION OF
5 AN OLEFIN AND A VINYL AROMATIC MONOMER
BACKGROUND OF THE INV~NTION
10 1.Field of the Invention
The present invention relates to a process for
the co-polymerization o~ an olefin, especially ethylene,
and a vinyl aromatic monomer. In particular, the present
invention relates to the co-polymerization process
conducted in the presence of a catalyst composition
comprising a transition metal complex and a co-catalyst.
2. Description of the Related Art
A process for the co-polymerization of ethylene
and a vinyl aromatic monomer is disclosed in EP-A-416,81S,
in which a so-called constrained-geometry catalyst is
applied. The catalysts disclosed in this reference have
had success, to some extent, in co-polymerizing vinyl
aromatic monomers with ethylene.
A disadvantage of the process disclosed in this
reference, however, is the unfavorable molecular weights
of the co-polymers obtained and the insufficient
percentage of vinyl aromatic monomers incorporated into
the resultant co-polymers under a given set of
polymerization conditions. It is known to enhance this
ratio by lowering the polymerization temperature; however,
the lowering of the polymerization temperature leads to
decreased catalyst activity and an inferior co-polymer
yield.
A need therefore exists to provide a process
that, under a given set of polymerization conditions,
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produces a co-polymer having, at a given molecular weight,
a higher concentration of co-polymerized vinyl aromatic
monomers than could be obtained via previously known
processes conducted under similar process conditions.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present
invention to solve the aforementioned problems associated
with the related art as well as to address the need
expressed above. In accordance with the principles of the
present invention, this object is obtained by providing a
process for the co-polymerization of at least one a-olefin
and at least one vinyl aromatic monomer in the presence of
the present catalyst composition. The catalyst composition
includes at least one complex comprising a reduced valency
transition metal (M) selected from groups 4-6 of the
Periodic Table of Elements, a multidentate monoanionic
ligand (X), two monoanionic ligands (L), and, optionally,
additional ligands (K). More specifically, the complex of
the catalyst composition of the present invention is
represented by the following formula (I):
X (I)
M - L2
I
Km
wherein the symbols have the following meanings:
M a reduced transition metal selected from group 4, 5
or 6 of the Periodic Table of Elements;
X a multidentate monoanionic ligand represented by the
formula: (Ar-Rt-)8Y(-Rt-DRIn)q;
Y a cyclopentadienyl, amido (-NR'-), or phosphido group
(-PR'-), which is bonded to the reduced transition
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metal M;
R at least one member selected from the group
consisting of (i) a connecting group between the Y
group and the DR'n group and (ii) a connecting group
between the Y group and the Ar group, wherein when
the ligand X contains more than one R group, the R
groups can be identical to or different from each
other;
D an electron-donating hetero atom selected from group
15 or 16 of the Periodic Table of Elements;
R' a substituent selected from the group consisting of a
hydrogen, hydrocarbon radical and hetero atom-
containing moiety, except that R' cannot be hydrogen
when R' is directly bonded to the electron-donating
hetero atom D, wherein when the multidentate
monoanionic ligand X contains more than one
substituent R', the substituents R' can be identical
or different from each other;
Ar an electron-donating aryl group;
L a monoanionic ligand bonded to the reduced transition
metal M, wherein the monoanionic ligand L is not a
ligand comprising a cyclopentadienyl, amido (-NR'-),
or phosphido (-PR'-) group, and wherein the
monoanionic ligands L can be identical or different
from each other;
K a neutral or anionic ligand bonded to the reduced
transition metal M, wherein when the transition metal
complex contains more than one ligand K, the ligands
K can be identical or different from each other;
m is the number of K ligands, wherein when the K ligand
is an anionic ligand m is 0 for M3+, m is 1 for M4+,
and m is 2 for M5+, and when K is a neutral ligand m
increases by one for each neutral K ligand;
- n the number of the R' groups bonded to the electron-
. 35 donating hetero atom D, wherein when D is selected
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from group 15 of the Periodic Table of Elements n is
2, and when D is selected from group 16 of the
Periodic Table of Elements n is li
q,s q and s are the number of (-Rt-DR'~) groups and (Ar-
Rt-) groups bonded to group Y, respectively, wherein
q + s is an integer not less than l; and
t the number of R groups connecting each of (i) the Y
and Ar groups and (ii) the Y and DR 'n groups, wherein
t is selected independently as 0 or 1.
A few non-limiting examples of transition metal
complexes according to the invention are presented below
in Table 1.
In the process according to the present
invention, a higher catalytic activity is observed in the
co-polymerization reaction between a process employing
ethylene and a vinyl aromatic monomer. Consequently, the
co-polymer prepared in accordance with the process of the
present invention also has a higher concentration of vinyl
aromatic monomers incorporated into the co-polymer than
could be obtained for a co-polymer, of the same molecular
weight, prepared in accordance with the above-mentioned
known process conducted under similar process conditions.
Another object of the present invention is the
provision of a copolymer of at least one ~-olefin and at
least one vinyl aromatic monomer obtained by means of the
above-mentioned polymerization process with utilization of
the catalyst composition according to the invention.
These and other objects, features, and
advantages of the present invention will become apparent
from the following detailed description when taken in
conjunction with the accompanying drawings which
illustrate, by way of example, the principles of the
present invention.
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BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings illustrate the present
invention. In such drawings:
FIG. 1 is a schematic view of a cationic active
site of a trivalent catalyst complex in accordance with an
embodiment of the present invention; and
FIG. 2 is a schematic view of a neutral active
site of a trivalent catalyst complex of a dianionic ligand
of a conventional catalyst complex according to WO-A-
93/19104.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Various components (groups) of the transitionmetal complex are discussed below in more detail.
(a) The Transition Metal (M)
The transition metal in the complex is selected
from groups 4-6 of the Periodic Table of Elements. As
referred to herein, all references to the Periodic Table
of Elements mean the version set forth in the new IUPAC
notation found on the inside of the cover of the Handbook
of Chemistry and Physics, 70th edition, 1989/1990, the
complete disclosure of which is incorporated herein by
reference. More preferably, the transition metal is
selected from group 4 of the Periodic Table of Elements,
and most preferably is titanium (Ti).
The transition metal is present in reduced form
in the complex, which means that the transition metal is
in a reduced oxidation state. As referred to herein,
"reduced oxidation state" means an oxidation state which
is greater than zero but lower than the highest possible
oxidation state of the metal (for example, the reduced
oxidation state is at most M3+ for a transition metal of
- group 4, at most M~+ for a transition metal of group ~ and
at most M5+ for a transition metal of group 6).
... . ... .. . .. . .... . . ... .... .. .
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(b) The X Ligand
The X ligand is a multidentate monoanionic
ligand represented by the formula: (Ar-Rt-)sY(-Rt-DR~n)g.
As referred to herein, a multidentate
monoanionic ligand is bonded with a covalent bond to the
reduced transition metal (M) at one site (the anionic
site, Y) and is bonded either (i) with a coordinate bond
to the transition metal at one other site (bidentate) or
(ii) with a plurality of coordinate bonds at several other
sites (tridentate, tetradentate, etc.). Such coordinate
bonding can take place, for example, via the D heteroatom
or Ar group(s). Examples of tridentate monoanionic ligands
include, without limitation, Y-Rt-DR'n_l-Rt-DR'n and Y(-R-
DR'n)2. It is noted, however, that heteroatom(s) or aryl
substituent(s) can be present on the Y group without
coordinately bonding to the reduced transition metal M, so
long as at least one coordinate bond is formed between an
electron-donating group D or an electron donating Ar group
and the reduced transition metal M.
R represents a connecting or bridging group
between the DR 'n and Y, and/or between the electron-
donating aryl (Ar) group and Y. Since R is optional, "t"
can be zero. The R group is discussed below in paragraph
(d) in more detail.
(c) The Y Group
The Y group of the multidentate monoanionic
ligand (X) is preferably a cyclopentadienyl, amido
(-NR'-), or phosphido (-PR'-) group.
Most preferably, the Y group is a
cyclopentadienyl ligand (Cp group). As referred to herein,
the term cyclopentadienyl group encompasses substituted
cyclopentadienyl groups such as indenyl, fluorenyl, and
benzoindenyl groups, and other polycyclic aromatics
containing at least one 5-member dienyl ring, so long as
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at least one of the substituents of the Cp group is an Rt-
DR'~ group or Rt-Ar group that replaces one of the
hydrogens bonded to the five-member ring of the Cp group
via an exocyclic substitution.
Examples of a multidentate monoanionic ligand
with a Cp group as the Y group (or ligand) include the
following (with the (-Rt-DR'n) or (Ar-Rt-) substituent on
the ring):
R' R' R' R'
R~ ~ R' R~ ~ R' (II)
R-DR ~n R-Ar
The Y group can also be a hetero
cyclopentadienyl group. As referred to herein, a hetero
cyclopentadienyl group means a hetero ligand derived from
a cyclopentadienyl group, but in which at least one of the
atoms defining the five-member ring structure of the
cyclopentadienyl is replaced with a hetero atom via an
endocyclic substitution. The hetero Cp group also includes
at least one Rt-DR'n group or Rt-Ar group that replaces
one of the hydrogens bonded to the five-member ring of the
Cp group via an exocyclic substitution. As with the Cp
group, as referred to herein the hetero Cp group
encompasses indenyl, fluorenyl, and benzoindenyl groups,
and other polycyclic aromatics containing at least one 5-
member dienyl ring, so long as at least one of thesubstituents of the hetero Cp group is an Rt-DR", group or
Rt-Ar group that replaces one of the hydrogens bonded to
the five-member ring of the hetero Cp group via an
exocyclic substitution.
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The hetero atom can be selected from group 14,
15 or 16 of the Periodic Table of Elements. If there is
more than one hetero atom present in the five-member ring,
these hetero atoms can be either the same or different
from each other. More preferably, the hetero atom(s)
is/are selected from group 15, and still more preferably
the hetero atom(s) selected is/are phosphorus.
~ y way of illustration and without limitation,
representative hetero ligands of the X group that can be
practiced in accordance with the present invention are
hetero cyclopentadienyl groups having the following
structures, in which the hetero cyclopentadienyl contains
one phosphorus atom (i.e., the hetero atom) substituted in
the five-member ring:
R' R' R' R-DR'n
R ~ O ~ R-DR ~ R~~ O ~ R' (III)
It is noted that, generally, the transition
metal group M is bonded to the Cp group via an ~5 bond.
The other R' exocyclic substituents (shown in
formula (III)) on the ring of the hetero Cp group can be
of the same type as those present on the Cp group, as
represented in formula (II). As in formula (II), at least
one of the exocyclic substituents on the five-member ring
of the hetero cyclopentadienyl group of formula (III) is
the Rt-DR'n group or the Rt-Ar group.
The numeration of the substitution sites of the
indenyl group is in general and in the present description
based on the IUPAC Nomenclature of Organic Chemistry 1979,
t ', ,, . , . . _ _ _ __~
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rule A 21.1. The numeration of the substituent sites for
indene is shown below. This numeration is analogous for an
indenyl group:
Indene 6 ~ Cl!2
The Y group can also be an amido (-NR'-) group
or a phosphido (-PR'-) group. In these alternative
embodiments, the Y group contains nitrogen (N) or
phosphorus (P) and is bonded covalently to the transition
metal M as well as to the (optional) R group of the
(-Rt-DR 'n) or (Ar-Rt-) substituent.
(d) The R Group
The R group is optional, such that it can be
absent from the X group. Where the R group is absent, the
DR ~n or Ar group is bonded directly to the Y group (that
is, the DR 'n or Ar group is bonded directly to the Cp,
amido, or phosphido group). The presence or absence of an
R group between each of the DR rn groups and/or Ar groups
is independent.
Where at least one of the R groups is present,
each of the R group constitutes the connecting bond
between, on the one hand the Y group, and on the other
hand the DR 'n group or the Ar group. The presence and size
of the R group determines the accessibility of the
transition metal M relative to the DR ~n or Ar group, which
gives the desired intramolecular coordination. If the R
group (or bridge) is too short or absent, the donor may
not coordinate well due to ring tension. The R groups are
each selected independently, and can generally be, for
example, a hydrocarbon group with 1-20 carbon atoms (e.g.,
alkylidene, arylidene, aryl alkylidene, etc.). Specific
~ . , . ~ , . .......
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examples of such R groups include, without limitation,
methylene, ethylene, propylene, butylene, phenylene,
whether or not with a substituted side chain. Preferably,
the R group has the following structure:
(-CR'2-)p (IV)
where p = 1-4. The R' groups of formula (IV) can each be
selected independently, and can be the same as the R'
groups defined below in paragraph (g).
In addition to carbon, the main chain of the R
group can also contain silicon or germanium. Examples of
such R groups are: dialkyl silylene (-SiR '2-)~ dialkyl
germylene (-GeR '2-)~ tetra-alkyl silylene (-SiR'2-SiR'2-),
or tetraalkyl silaethylene (-SiR'2CR'2-). The alkyl groups
in such a group preferably have 1-4 carbon atoms and more
preferably are a methyl or ethyl group.
(e) The DR' n Group
This donor group consists of an electron-
donating hetero atom D, selected from group 15 or 16 of
the Periodic Table of Elements, and one or more
substituents R' bonded to D. The number (n) of R' groups
is determined by the nature of the hetero atom D, insofar
as n being 2 if D is selected from group 15 and n being 1
if D is selected from group 16. The R' substituents bonded
to D can each be selected independently, and can be the
same as the R' groups defined below in paragraph (g), with
the exception that the R' substituent bonded to D cannot
be hydrogen.
The hetero atom D is preferably selected from
the group consisting of nitrogen (N), oxygen (O),
phosphorus (P) and sulphur (S); more preferably, the
hetero atom is nitrogen (N). Preferably, the R' group is
an alkyl, more preferably an n-alkyl group having 1-20
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carbon atoms, and most preferably an n-alkyl having 1-8
carbon atoms. It is further possible for two R' groups in
- the DR 'n group to be connected with each other to form a
ring-shaped structure tso that the DR'n group can be, for
example, a pyrrolidinyl group). The DR ~n group can form
coordinate bonds with the transition metal M.
f) The Ar Group
The electron-donating group (or donor) selected
1~ can also be an aryl group (C6R's), such as phenyl, tolyl,
xylyl, mesityl, cumenyl, tetramethyl phenyl, pentamethyl
phenyl, a polycyclic group such as triphenylmethane, etc.
The electron-donating group D of formula (I) cannot,
however, be a substituted Cp group, such as an indenyl,
benzoindenyl, or fluorenyl group.
The coordination of this Ar group in relation to
the transition metal M can vary from t~l to ~l6.
(g) The R' Group
The R' groups may each separately be hydrogen or
a hydrocarbon radical with 1-20 carbon atoms (e.g. alkyl,
aryl, aryl alkyl and the like as shown in Table 1).
Examples of alkyl groups are methyl, ethyl, propyl, butyl,
hexyl and decyl. Examples of aryl groups are phenyl,
mesityl, tolyl and cumenyl. Examples of aryl alkyl groups
are benzyl, pentamethylbenzyl, xylyl, styryl and trityl.
Examples of other R' groups are halides, such as chloride,
bromide, fluoride and iodide, methoxy, ethoxy and phenoxy.
Also, two adjacent hydrocarbon radicals of the Y group can
be connected with each other to define a ring system;
therefore the Y group can be an indenyl, a fluorenyl or a
benzoindenyl group. The indenyl, fluorenyl, and/or
benzoindenyl can contain one or more R' groups as
substituents. R' can also be a substituent which instead
of or in addition to carbon and/or hydrogen can comprise
.. . . . . .. . . . . . ...
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one or more hetero atoms of groups 14-16 of the Periodic
Table of Elements. Thus, a substituent can be, for
example, a Si-containing group, such as Si(CH3)3.
(h) The L Group
The transition metal complex contains two
monoanionic ligands L bonded to the transition metal M.
Examples of the L group ligands, which can be identical or
different, include, without limitation, the following: a
hydrogen atom; a halogen atom; an alkyl, aryl or aryl
alkyl group; an alkoxy or aryloxy group; a group
comprising a hetero atom selected ~rom group 15 or 16 of
the Periodic Table of Elements, including, by way of
example, (i) a sulphur compound, such as sulphite,
sulphate, thiol, sulphonate, and thioalkyl, and (ii) a
phosphorus compound, such as phosphite, and phosphate. The
two L groups can also be connected with each other to form
a dianionic bidentate ring system.
These and other ligands can be tested for their
suitability by means of simple experiments by one skilled
in the art.
Preferably, L is a halide and/or an alkyl or
aryl group; more preferably, L is a Cl group and/or a C1-
C4 alkyl or a benzyl group. The L group, however, cannot
be a Cp, amido, or phosphido group. In other words, L
cannot be one of the Y groups.
(i) The K Ligand
The K ligand is a neutral or anionic group
bonded to the transition metal M. The K group is a neutral
or anionic ligand bonded to M. When K is a neutral ligand
K may be absent, but when K is monoanionic, the following
holds for Km:
m = 0 for M3+
m = 1 for M4
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m = 2 for M5+
On the other hand, neutral K ligands, which by
definition are not anionic, are not subject to the same
rule. Therefore, for each neutral K ligand, the value of m
(i.e., the number of total K ligands) is one higher than
the value stated above for a complex having all
monoanionic R ligands.
The K ligand can be a ligand as described above
for the L group or a Cp group (-C5R'5), an amido group (-
NR'2) or a phosphido group (-PR'2). The K group can also
be a neutral ligand such as an ether, an amine, a
phosphine, a thioether, among others.
If two K groups are present, the two K groups
can be connected with each other via an R group to form a
bidentate ring system.
As can also be seen from formula (I), the X
group of the complex contains a Y group to which are
linked one or more donor groups (the Ar group(s) and/or
DR'n group(s)) via, optionally, an R group. The number of
donor groups linked to the Y group is at least one and at
most the number of substitution sites present on a Y
group.
With reference, by way of example, to the
structure according to formula (II), at least one
substitution site on a Cp group is made by an Rt-Ar group
or by an Rt-DR'n group (in which case q + s = 1). If all
the R' groups in formula (II) were Rt-Ar groups, Rt-DR'n
groups, or any combination thereof, the value of (q + s)
would be 5.
One preferred embodiment of the catalyst
composition according to the present invention comprises a
- transition metal complex in which a bidentate/monoanionic
ligand is present and in which the reduced transition
metal has been selected from group 4 of the Periodic Table
of Elements and has an oxidation state of +3.
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In this case, the catalyst composition according
to the invention comprises a transition metal complex
represented by formula (V):
M(III) ~ L2~ (V)
I m
where the symbols have the same meaning as described above
for formula (I) and where M(III) is a transition metal
selected from group 4 of the Periodic Table of Elements
and is in oxidation state 3~.
Such a transition metal complex has no anionic K
ligands (for an anionic K, m = 0 in case of M3+).
It should be pointed out that in WO-A-93/19104,
transition metal complexes are described in which a group
4 transition metal in a reduced oxidation state (3+) is
present. The complexes described in WO-A-93/19104 have the
general formula:
Cpa(ZY)bMLc (VI)
The Y group in this formula (VI) is a hetero atom, such as
phosphorus, oxygen, sulfur, or nitrogen bonded covalently
to the transition metal M (see p. 2 of WO-A-93/19104).
This means that the Cpa(ZY)b group is of a dianionic
nature, and has the anionic charges residing formerly on
the Cp and Y groups. Accordingly, the Cpa(ZY)b group of
formula (VI) contains two covalent bonds: the first being
between the 5-member ring of the Cp group and the
transition metal M, and the second being between the Y
group and the transition metal. By contrast, the X group
in the complex according to the present invention is of a
monoanionic nature, such that a covalent bond is present
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between the Y group (e.g., the Cp group) and transition
metal, and a coordinate bond can be present between the
transition metal M and one or more of the tAr-Rt-) and (-
Rt-DR rn) groups. This changes the nature of the transition
metal complex and consequently the nature of the catalyst
that is active in the polymerization. As referred to
herein, a caordinate bond is a bond (e.g., H3N-BH3) which
when broken, yields either (i) two species without net
charge and without unpaired electrons (e.g., H3N: and BH3)
or (ii) two species with net charge and with unpaired
electrons (e.g., H3N + and BH3 -). On the other hand, as
referred to herein, a covalent bond is a bond (e.g., CH3-
CH3) which when broken yields either (i) two species
without net charge and with unpaired electrons (e.g., CH3
and CH3 ) or (ii) two species with net charges and without
unpaired electrons (e.g., CH3' and CH3:-). A discussion of
coordinate and covalent bonding is set forth in Haaland et
al. (Angew. Chem Int. Ed. Eng. Vol. 28, 1989, p. 992), the
complete disclosure of which is incorporated herein by
reference.
The following explanation is proposed, although
it is noted that the present invention is in no way
limited to this theory.
Referring now more particularly to FIG. 2, the
transition metal complexes described in WO-A-93/19104 are
ionic after interaction with the co-catalyst. However, the
transition metal complex according to WO-A-93/19104 that
is active in the polymerization contains an overall
neutral charge (on the basis of the assumption that the
polymerizing transition metal complex comprises, a M(III)
transition metal, one dianionic ligand and one growing
- monoanionic polymer chain (POL)). By contrast, as shown in
FIG. 1, the polymerization active transition metal complex
of the catalyst composition according to the present
invention is of a cationic nature (on the basis of the
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assumption that the polymerizing transition metal complex -
based on the formula tV) structure - comprises, a M(III)
transition metal, one monoanionic bidentate ligand and one
growing monoanionic polymer chain (POL)).
Transition metal complexes in which the
transition metal is in a reduced oxidation state, but have
the following structure:
Cp - M(III) - L2 (VII)
are generally not active in co-polymerization reactions.
It is precisely the presence, in the transition metal
complex of the present invention, of the DR ~n or Ar group
(the donor), optionally bonded to the Y group by means of
the R group, that gives a stable transition metal complex
suitable for polymerization.
Such an intramolecular donor is to be preferred
over an external (intermolecular) donor on account of the
fact that the former shows a stronger and more stable
coordination with the transition metal complex.
It will be appreciated that the catalyst system
may also be formed in situ if the components thereof are
added directly to the polymerization reactor system and a
solvent or diluent, including li~uid monomer, is used in
said polymerization reactor.
The catalyst composition of the present
invention also contains a co-catalyst. For example, the
co-catalyst can be an organometallic compound. The metal
of the organometallic compound can be selected from group
1, 2, 12 or 13 of the Periodic Table of Elements. Suitable
metals include, for example and without limitation,
sodium, lithium, zinc, magnesium, and aluminum, with
aluminum being preferred. At least one hydrocarbon radical
is bonded directly to the metal to provide a carbon-metal
bond. The hydrocarbon group used in such compounds
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preferably contains 1-30, more preferably 1-10 carbon
atoms. Examples of suitable compounds include, without
limitation, amyl sodium, butyl lithium, diethyl zinc,
butyl magnesium chloride, and dibutyl magnesium.
Preference is given to organoaluminium compounds,
including, for example and without limitation, the
following: trialkyl aluminum compounds, such as triethyl
aluminum and tri-isobutyl aluminum; alkyl aluminum
hydrides, such as di-isobutyl aluminum hydride;
alkylalkoxy organoaluminium compounds; and halogen-
containing organoaluminium compounds, such as diethyl
aluminum chloride, diisobutyl aluminum chloride, and ethyl
aluminum sesquichloride. Preferably, linear or cyclic
aluminoxanes are selected as the organoaluminium compound.
In addition or as an alternative to the
organometallic compounds as the co-catalyst, the catalyst
composition of the present invention can include a
compound which contains or yields in a reaction with the
transition metal complex of the present invention a non-
coordinating or poorly coordinating anion. Such compounds
have been described for instance in EP-A-426,637, the
complete disclosure of which is incorporated herein by
reference. Such an anion is bonded sufficiently unstably
such that it is replaced by an unsaturated monomer during
the co-polymerization. Such compounds are also mentioned
in EP-A-277,003 and EP-A-277,004, the complete disclosures
of which are incorporated herein by reference. Such a
compound preferably contains a triaryl borane or a
tetraaryl borate or an aluminum equivalent thereof.
Examples of suitable co-catalyst compounds include,
without limitation, the following:
- dimethyl anilinium tetrakis (pentafluorophenyl)
borate [C6H5N(CH3)2H] [B(C6Fs) 4]
- dimethyl anilinium bis (7,8-dicarbaundecaborate)-
cobaltate (III);
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- tri(n-butyl)ammonium tetraphenyl borate;
- triphenylcarbenium tetrakis (pentafluorophenyl)
borate;
- dimethylanilinium tetraphenyl borate;
- tris(pentafluorophenyl) borane; and
- tetrakis(pentafluorophenyl) borate.
If the above-mentioned non-coordinating or
poorly coordinating anion is used, it is preferable for
the transition metal complex to be alkylated (that is, the
L group is an alkyl group). As described for instance in
EP-A-500,944, the complete disclosure of which is
incorporated herein by reference, the reaction product of
a halogenated transition metal complex and an
organometallic compound, such as for instance triethyl
aluminum (TEA), can also be used.
The molar ratio of the co-catalyst relative to
the transition metal complex, in case an organometallic
compound is selected as the co-catalyst, usually is in a
range of from about 1:1 to about 10,000:1, and preferably
is in a range of from about 1:1 to about 2,500:1. If a
compound containing or yielding a non-coordinating or
poorly coordinating anion is selected as co-catalyst, the
molar ratio usually is in a range of from about 1:100 to
about 1,000:1, and preferably is in a range of from about
1:2 to about 250:1.
As a person skilled in the art would be aware,
the transition metal complex as well as the co-catalyst
can be present in the catalyst composition as a single
component or as a mixture of several components. For
instance, a mixture may be desired where there is a need
to influence the molecular properties of the polymer, such
as molecular weight and in particular molecular weight
distribution.
The present invention relates to a process for
the co-polymerization of one or more a-olefins and one or
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more vinyl aromatic monomers. As referred to herein, the
term "monomer" as encompasses dimers, trimers, and
oligomers. The ~-olefin is preferably at least one member
selected from the group consisting of ethylene, propylene,
butene, pentene, heptene and octene, and any combination
thereof. More preferably, at least one member selected
from the group consisting of ethylene and propylene is
selected as the a-olefin. Suitable vinyl aromatic monomers
which can be polymerized in the process of the present
invention include, without limitation, those represented
by the formula:
Hl=CH2
\ C''' \ C"'
l l (VIII)
R2~ ~ C ~ ~ R 2
ll~2
wherein each R2 in formula (VIII) is, for example,
independently selected as one of the following: hydrogen;
an aliphatic, cycloaliphatic or aromatic hydrocarbon group
having from 1 to 10 carbon atoms, more suitably from 1 to
6 carbon atoms, most suitably from 1 to 4 carbon atoms;
and a halogen atom. Exemplary vinyl aromatic monomers
include, without limitation, styrene, chlorostyrene, n-
butyl styrene, and p-vinyl toluene. Especially preferred
is styrene.
The amount of vinyl aromatic monomer
incorporated in the copolymers of the present invention is
at least 0.1 mol%. Additional olefin monomers can be co-
polymerized in the same process to thereby yield ter-
polymers and higher polymers (which are also referred to
herein as being encompassed by the term ''co-polymerll and
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made by the "co-polymerization process"). Other olefin
monomers include, by way of example and without
limitation, ethylene, propylene, butene, pentene, hexene,
heptene, octene and dienes such as 1,4-hexadiene, 1,7-
octadiene, dicyclopentadiene (DCPD), 5-vinylidene-2-
norbornene, 5-ethylidene-2-norbornene, and 5-methylene-2-
norbornene, and polyenes such as polybutadiene.
The process according to the invention is also
suitable for the preparation of rubber-like copolymers
based on an ~-olefin, a vinyl aromatic monomer and a third
monomer. It is preferred to use a diene as the third
monomer. Suitable dienes for preparing rubber-like
copolymers include those specified above.
The catalyst can be used as is, or optionally
the catalyst can be supported on a suitable support or
carrier, such as alumina, MgCl2 or silica, to provide a
heterogeneous supported catalyst. The transition metal
complex or the co-catalyst can be supported on the
carrier. It is also possible to support both the
transition metal complex and co-catalyst on the same or
different carriers. Where more than one carrier is
provided, the carriers can be the same or different from
each other. The supported catalyst systems of the
invention can be prepared separately before being
introduced into the co-polymerization reaction, or can be
formed in situ, for example, before the co-polymerization
reaction commences.
By way of example, the co-polymerization
reaction can be conducted under solution or slurry
conditions, in a suspension utilizing a perfluorinated
hydrocarbon or similar liquid, in the gas phase (for
example, by utilizing a fluidized bed reactor), or in a
solid phase powder polymerization.
A catalytically effective amount of the present
catalyst and co-catalyst are any amounts that succesfully
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result in formation of the co-polymer. Such amounts can be
readily determined by the routine experimentation by the
skilled artisan. For instance, where the co-polymerization
is conducted in a liquid reaction medium via in solution
or suspension polymerization, which are preferred for the
process of the invention, the quantity of transition metal
complex to be used generally can be such that the
concentration of the transition metal in the solution or
dispersion agent is about 10-8 mol/l to about 10-3 mol/l,
and preferably about 10-7 mol/l to about 10-4 mol/l.
It is to be understood that the transition metal
complex described herein undergoes various transformations
or forms intermediate species prior to and during the
course of co-polymerization. Thus, other catalytically
active species or intermediates formed from the metal
complexes described herein and other metal complexes
(precursors) than those described herein that achieve the
same catalytic species as the complexes of the present
invention are herein envisioned without departing from the
scope or the present invention.
Any liquid that is inert relative to the
catalyst system can be used as a dispersion agent in the
co-polymerization process. Suitable inert liquids that can
be selected as the dispersion agent include, without
limitation, the following: one or more saturated,
straight or branched aliphatic hydrocarbons, including,
without limitation, butane, pentane, hexane, heptane,
pentamethyl heptane, and any combination thereof; and/or
one or more mineral oil fractions, including, without
limitation, light or regular petrol, naphtha, kerosine,
gas oil, and any combination thereof. Aromatic
hydrocarbons, for instance benzene, ethylbenzene and
toluene, can be also used; however, due to the high cost
associated with aromatic hydrocarbons, as well as safety
considerations, it is generally preferred not to use such
~ . .... . . . ..
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solvents for production on a technical (or commercial)
scale. In polymerization processes on a technical (or
commercial) scale, it is, therefore, preferred to use as
the solvent the low-priced aliphatic hydrocarbons or
mixtures thereof, as marketed by the petrochemical
industry.
Excess vinyl aromatic or olefin monomers,
including liquid vinyl aromatic or olefin monomers, can
also be applied in so-called bulk polymerization
processes. If an aliphatic hydrocarbon is used as the
solvent, the solvent can yet contain minor quantities of
aromatic hydrocarbons such as, for instance, toluene.
Thus, if, for instance, methyl aluminoxane (MA0) is
selected as the co-catalyst, toluene can be used as the
solvent for the MA0 in order to dissolve the MA0 into
solution and supply the solution to the polymerization
reactor. Drying or purification of the solvents is
desirable if such solvents are used; this can be done
without undue experimentation by the skilled artisan.
If solution or bulk polymerization is utilized,
the polymerization is preferably carried out at
temperatures well above the melting point of the polymer
to be produced. Suitable temperatures generally include,
without limitation, temperatures in a range of from about
120~C to about 260~C. In general, suspension or gas phase
polymerization takes place at lower temperatures, that is,
temperatures well below the melting temperature of the
polymer to be produced. Generally, temperatures suitable
for suspension or gas phase polymerization are below about
105~C.
The polymer solution resulting from the
polymerization can be worked up by a method known per se.
In general, the catalyst is de-activated at some point
during the processing of the polymer. The de-activation is
also effected in a manner known per se, e.g., by means of
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water or an alcohol. Removal of the catalyst residues can
generally be omitted, since the ~uantity of catalyst in
the co-polymer, in particular the content of halogen and
transition metal in the co-polymer, is very low due to the
use of the catalyst system according to the invention.
Co-polymerization can be effected at sub-
atmospheric, atmospheric and elevated pressure, and under
conditions where at least one of the monomers is a liquid,
which can be realized by application of suitable
combinations of pressure and temperature, continuously or
discontinuously. If the co-polymerization is carried out
under pressure, the polymer yield can be increased
substantially, resulting in an even lower catalyst residue
content. Preferably, the co-polymerization is performed at
pressures in a range of from about 0.1 MPa to about 25
MPa. Higher pressures, typically but not limited to 100
MPa and above, can be applied if the polymerization is
carried out in so-called high-pressure reactors. In such a
high-pressure process, the catalyst according to the
present invention can also be used with good results.
The co-polymerization can also be performed in
several steps, in series as well as in parallel. If
required, the catalyst composition, temperature, hydrogen
concentration, pressure, residence time, etc., or any
combination thereof can be varied from step to step. In
this way, products having a wide molecular weight
distribution can be obtained.
EXAMPLES
The process according to the invention will
hereafter be elucidated with reference to the following
examples, which serve to explain the present invention in
more detail. It will be appreciated that the invention is
- not restricted to these exemplary examples and processes.
All tests in which organometallic compounds were
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involved were carried out in an inert nitrogen atmosphere,
using standard Schlenk equipment. A method for synthesis
of (dimethylaminoethyl)-tetramethyl cyclopentadienyl is
published by P. Jutzi et al., Synthesis 1993, 684, the
complete disclosure of which is incorporated herein by
reference.
TiCl3, the esters, the lithium reagents, 2-
bromo-2-butene and 1-chlorocyclohexene each were supplied
by Aldrich Chemical Company. TiC13 3THF was obtained by
heating TiC13 for 24 hours in THF with reflux. In the
following example, THF refers to tetrahydrofuran, "Me"
refers to methyl, "(t)Bu" refers to ttertiary) butyl,
"Ind" refers to indenyl, "Flu" refers to fluorenyl, and
"iPr" refers to iso-propyl.
SYnthesis of bidentate monocYclopentadienyl transition
metal comPlexes
Examples I-IV set forth non-limiting processes
for preparing embodiments of the transition metal
complexes of the present invention.
ExamPle I
Synthesis of (dimethylaminoethyl)tetramethyl-
cyclopentadienyltitanium(III)dichloride
(CsMe4(cH2)2NMe2Ticl 2 ) -
(a) PreParation of 4-hYdroxY-4-(dimethYlamino-ethyl)-3,5-
dimethYl-2,5-hePtadiene
2-bromo-2-butene (108 g; 0.800 mol) was added to
10.0 g of lithium (1.43 mol) in diethyl ether (300 ml)
over the course of about 30 minutes with reflux. After
stirring overnight tl7 hours), ethyl-3-(N,N-
dimethylamino)propionate (52.0 g; 0.359 mol) was added to
the reaction mixture over a course of about 15 minutes.
After stirring for 30 minutes at room temperature, 200 ml
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of water was added dropwise. After separation, the water
phase was extracted two times with 50 ml of CH2C12. The
organic phase was boiled down and the residue was
distilled at reduced pressure. The yield was 51.0 g (67~).
(b) PreParation of (dimethYlaminoethyl)tetramethyl-
cyclopentadiene
The compound (21.1 g; 0.10 mol) prepared as
described above in Example I(a) was added in a single
portion to p-toluenesulphonic acid H2O (28.5 g; 0.15 mol)
dissolved in 200 ml of diethyl ether. After stirring for
30 minutes at room temperature, the reaction mixture was
poured out in a solution of 50 g of Na2CO3 10H2O in 250 ml
of water. After separation, the water phase was extracted
two times with 100 ml of diethyl ether. The combined ether
layer was dried (with Na2SO4), filtered and boiled down.
Then the residue was distilled at reduced pressure. The
yield was 11.6 g (60%).
(c) PreParation of (dimethYlaminoethyl)tetramethyl-
cycloPentadienYltitanium(III)dichloride
1.0 equivalent of n-BuLi (1.43 ml; 1.6 M) was
added (after cooling to -60~C) to a solution of the
C5Me4H(CH2)2NMe2 of Example I(b) (0.442 g; 2.29 mmol) in
THF (50 ml), after which the cooling bath was removed.
After warming to room temperature, the solution was cooled
to -100~C and then TiCL3 3THF (0.85 g; 2.3 mmol) was added
in a single portion. After stirring for 2 hours at room
temperature, the THF was removed at reduced pressure.
After addition of special boiling point gasoline (i.e., a
C6 hydrocarbon fraction with a boiling range of 65-70~C,
obtainable from Shell or Exxon, the complex (a green
solid) was purified by repeated washing of the solid,
- followed by filtration and backdistillation of the
solvent. It was also possible to obtain the pure complex
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through sublimation.
Example II
Synthesis of (dibutylaminoethyl)tetramethyl-
cyclopentadienyltitanium(III) dichloride
(c5Me4(cH2)2NBu2T iCl2)-
(a) PreParation of ethyl-3-(N,N-di-n-butYlamino)ProPionate
Ethyl 3-bromopropionate (18.0 g; 0.10 mol) was
added carefully to di-n-butylamine (25.8 g; 0.20 mol),
followed by stirring for 2 hours. Then, diethyl ether (200
ml) and pentane (200 ml) were added. The precipitate was
filtered off, the filtrate was boiled down and the residue
was distilled at sub-atmospheric pressure. The yield was
7.0 g (31%).
(b) Preparation of bis(2-butenYl~(di-n-butYlaminoethvl)-
methanol
2-Lithium-2-butene was prepared from 2-bromo-2-
butene (16.5 g; 0.122 mol) and lithium (2.8 g; 0.4 mol) asin Example I. To this, the ester of Example II(a) (7.0 g;
0.031 mol) was added with reflux over the course of
approximately 5 minutes, followed by stirring for about 30
minutes. Then (200 ml) of water was carefully added
dropwise. The water layer was separated off and extracted
twice with 50 ml of CH2C12. The combined organic layer was
washed once with 50 ml of water, dried with K2CO3,
filtered and boiled down. The yield was 9.0 g (100~).
(c) PreParation of (di-n-butYlaminoethyl)tetramethyl-
cYcloPentadiene ~
4.5 g (0.015 mol) of the compound of Example
II(b) was added dropwise to 40 ml of concentrated
sulphuric acid of 0~C, followed by stirring for another 30
minutes at 0~C. Then the reaction mixture was poured out
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in a mixture of 400 ml of water and 200 ml of hexane. The
mixture was made alkaline with NaOH (60 g) while being
cooled in an ice bath. The water layer was separated off
and extracted with hexane. The combined hexane layer was
dried with K2CO3, filtered and boiled down. The residue
was distilled at sub-atmospheric pressure. The yield was
2.3 g (55%)-
(d) Preparation of (di-n-butylaminoethvl)
tetramethvlcYclo-PentadienYltitaniumtIII)dichloride
1.0 eguivalent of n-BuLi (0.75 ml; 1.6 M) was
added (after cooling to -60~C) to a solution of the
CsMe4H(CH2)2NBu2 of Example II(c) (0.332 g; 1.20 mmol) in
THF (50 ml), after which the cooling bath was removed.
After warming to room temperature, the solution was cooled
to -100~C and then TiCL3 3THF (0.45 g; 1.20 mmol) was
added in a single portion. After stirring for 2 hours at
room temperature, the THF was removed at sub-atmospheric
pressure. The purification was performed as in Example I.
Example III
As another catalyst component,
(didecylaminoethyl)tetramethyl-cyclopentadienyl-
titanium(III) dichloride (CsMe4(CH2)2N(Cl0H2l)2TiCl2) was
prepared in an analoguous way as described in Example I,
the difference being that the corresponding di-decyl-
amino-propionate was applied in place of the ethyl-3-(N,N-
dimethylamino)propionate.
Example IV
Synthesis of [1,2,4-triisopropyl-3-(dimethyl-
aminoethyl)cyclopentadienyl]-titanium(III)dimethyl.
(a) Reaction of cvcloPentadiene with isoProPvl bromide
Aqueous KOH (50~; 1950g, about ca. 31.5 mol in
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2.483 L water) and as a phase transfer agent Adogen 464
(31.5 g) were placed in a 3L three-neck flask fitted with
a condenser, mechanical stirrer, heating mantle,
thermometer, and an inlet adapter. Freshly cracked
cyclopentadiene (55.3g, 0.79 mol) and isopropyl bromide
(364 g, 2.94 mol) were added and stirring was begun. The
mixture turned brown and became warm (50~C). The mixture
was stirred vigorously over night, after which the upper
layer containing the product was removed. Water was added
to this layer and the product was extracted with hexane.
The combined hexane layer was washed once with water and
once with brine, and after drying (with MgSO4) the solvent
was evaporated, leaving a yellow-brown oil. GC and GC-MS
analysis showed the product mixture to contain
diisopropylcyclopentadiene (iPr2-Cp, 40%) and
triisopropylcyclopentadiene (iPr3-Cp, 60~). iPr2-Cp and
iPr3-Cp were isolated by distillation at reduced (20 mmHg)
pressure. Yield depended on distillation accuracy (approx.
0.2 mol iPr2-Cp (25%) and 0.3 mol iPr3-Cp (40%)).
(b) Reaction of lithium 1,2,4-triisopropylcyclo-
pentadienYl with dimethYlaminoethYl chloride
In a dry 500 ml flask containing a magnetic
stirrer, under dry nitrogen, a solution of 62.5 mL of n-
butyllithium (1.6 M in n-hexane; 100 mmol) was added to a
solution of 19.2 g (100 mmol) of iPr3-Cp in 250 ml of THF
at -60 ~C. The solution was allowed to warm to room
temperature after which the solution was stirred
overnight. After cooling to -60~C, dimethylaminoethyl
chloride (11.3g, 105 mmol, freed from ~Cl (by the method
of ~ees W.S. Jr. ~ Dippel K.A. in OPPI BRIEFS vol 24, No
5, 1992, which is incorporated herein by reference) was
added via a dropping funnel over the course of 5 minutes.
The solution was allowed to warm to room temperature,
after which it was stirred overnight. The progress of the
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reaction was monitored by GC. After addition of water and
an alkane mixture, the organic layer was separated, dried
and evaporated under reduced pressure. Next to starting
material iPr3-Cp (30~), 5 isomers of the product
5 (dimethylaminoethyl)-triisopropylcyclopentadiene (LH; 70%)
are visible in GC. Two isomers are geminal (together 3096).
Removal of the geminal isomers was feasible by
precipitation of the potassium salt of the iPr3-Cp anion
and filtration and washing with an alkane mixture (3x).
The overall yield (relative to iPr3-Cp) was 30 mmol (30%).
(c) APPlied reaction sequence to rl,2,4-triisopropvl-3-
(dimethvlaminoethYl)-cycloPentadenyl1-
titanium(III)dimethyl
Solid TiCl3 3THF (18.53g, 50.0 mmol) was added
to a solution of K iPr3-Cp in 160 mL of THF at -60~C at
once, after which the solution was allowed to warm to room
temperature. The color changed from blue to green. After
all the TiCl3 3THF had disappeared, the reaction mixture
was cooled again to -60 ~C after which 2.0 equivalents of
MeLi (62.5 ml of a 1.6 M solution in Et2O) were added.
After warming to room temperature again, the black
solution was stirred for an additional 30 minutes after
which the THF was removed at reduced pressure.
PolYmerization exPeriments
Examples V-XVII set forth non-limiting processes
for preparing copolymers with the transition metal
complexes of the present invention.
Polymerization experiments were carried out
according to the procedure described in general terms
below. Unless otherwise indicated, the conditions
specified in Example V were applied in each of the
- individual examples.
...... ..
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Example V
Styrene was distilled from CaH2 under vacuum.
600 ml of an alkane mixture was introduced as a solvent
into a stainless steel reactor with a volume of 1.5 liters
under a dry N2 atmosphere. Then, the required amount of
dry styrene was introduced into the reactor. The reactor
was heated to 80~C, while stirring, at an absolute
ethylene pressure of 800 kPa.
25 ml of an alkane mixture was dosed as a
solvent into a catalyst premixing vessel having a volume
of 100 ml. The re~uired amount of the methyl aluminoxane
cocatalyst (MAO, from Witco, 10 wt.~ solution in toluene)
was premixed for 1 minute with the required amount of
transition metal compound
This mixture was subsequently dosed to the
reactor, after which the polymerization started. The
polymerization reaction was carried out isothermally. A
constant absolute ethylene pressure of 8 bar was
maintained. After the desired time, the ethylene supply
was stopped and the reaction mixture was drained and
quenched with the aid of methanol. The methanol-containing
reaction mixture was washed with water and HCl to remove
residual catalyst. Then the mixture was neutralized with
the aid of NaHCO3. Next, an antioxidant (Irganox 1076, TM)
was added to the organic fraction to stabilize the
polymer. The polymer was dried in a vacuum for 24 hours at
70~C.
ExamPle VI
The reactor was filled with 600 ml of alkane
mixture and 45 g of styrene according to the procedure set
forth above in Example V. The reactor was brought to a
temperature of 80~C and was saturated with 8 bar ethylene,
with stirrin~. 10 micromol EtCp(iPr)3NMe2TiCl2 (Example
IV) was premixed with 20 mmol MAO (Al/Ti=2000) for 1
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- 31 -
minute in a catalyst metering vessel. After 6 minutes of
polymerization, the reaction mixture was drained and
quenched with the aid of methanol. After being stabilized,
the polymer was dried in a vacuum. The polymer yield
amounted to 15.8 kg/mol Ti hour. The product was analyzed
by means of SEC-DV, lH-NMR and DSC. The formed polymer was
a copolymer with an Mw of 250,000 g/mol and a maximum
melting temperature (as determined via DSC) of 93~C.
Comparative exPeriment A
With the aid of the transition metal compound
Me2SiCp*NtBuTiCl2 known from EP-A-416,815 a
copolymerization reaction was carried out under the
conditions described in Example VI, using MAO as the
cocatalyst (Al:Ti ratio = 2000), for 7 minutes. The yield
was 14.6 kg/mol Ti.hour. The product had an Mw of 145,000
g/mol and a maximum melting temperature of 114~C.
ExamPle VII
Example VI was repeated, except that 75 g of
styrene was added to the reactor contents. 10 micromol of
the transition metal compound (CsMe4H(CH2)2N(ClOH2l)2Ticl2
(Example III) was mixed with 10 mmol MAO (Al:Ti = 1000:1)
for 1 minute in the catalyst metering vessel. The reaction
mixture was subjected to co-polymerization. The yield was
6.7 g. The styrene content as determined by lH-NMR
amounted to 7.5 mol.~. The Mw, as determined by means of
SEC-DV, was 180,000 g/mol.
Example VIII
Example VII was repeated, except that 10
micromol of the transition metal compound
(C5Me4(CH2)2NBu2TiCl2 (Example II) was premixed with 10
mmol MAO (Al:Ti = 1000:1) for 1 minute. The copolymer
formed had an Mw (as determined by means of SEC-DV) of
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- 32 -
180,000 g/mol. The styrene content was determined by means
of 1H-NMR and found to be 6. 3 mol.96.
Example IX
A co-polymerization process was carried out
using the transition metal compound (CsME4(CH2)2NMe2TiCl2
(Example I) under the conditions described in Example VII.
The copolymer formed contained 8.6 mol.% styrene, as
determined by means of lH-NMR. The polymer had an Mw of
130,000 g/mol (SEC-DV).
ComParative exPeriment B
The copolymerization of ethylene and styrene was
carried out as described in Example VII, with the
exception that the catalyst composition included 10
micromol Me2SiCp*NtBuTiCl2 and 20 mmol MAO (Al:Ti =
2000:1), which were mixed for 1 minute in the catalyst
metering vessel. The polymer formed (6.2 g) was found to
have an Mw of 82,000 g/mol (as determined by means of SEC-
DV) and to contain 4.2 mol.% styrene.
Example X
A catalyst on a carrier was synthesised by
adding 10 ml of dry toluene to 1.453 g of SiO2
(Grace/Davidson W952, dried for 4 hours at 400~C under dry
N2). Then 16 ml of MAO (Witco, 30~ by weight in toluene)
was added over the course of lO minutes, with stirring, at
300 K. The sample was dried for 2 hours in a vacuum, with
stirring, after which 25 ml of an alkane mixture was added
and the resultant mixture was stirred for 12 hours at
300K. Next, a suspension of 10-4 mol (C5Me4(CH2)2NMe2TiCl2
(~xample I) was added, with stirring. After drying, the
catalyst was found to contain 27.9 wt.~ Al and to have an
Al/Ti ratio of 328.
A co-polymerization experiment was carried out
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- 33 -
using the supported catalyst described above, under
conditions comparable with those of Example VI. 45 g of
styrene was added to the reactor. Then 20 micromol (based
on Ti) of supported catalyst was introduced into the
reactor. The co-polymerization reaction was carried out at
an ethylene pressure of 8 bar, at 80~C. The formed polymer
(1450 kg/mol Ti.hour) was analyzed by means of SEC-DV. The
Mw was found to be 490,000 g/mol at a styrene content of
3.1 mol.% (as determined via lH-NMR).
Example XI
A stainless steel reactor with a volume of 1.5
liters was filled with 600 ml of a mixed high-boiling
alkane solvent (with a boiling range starting at 180~C)
for a solution polymerization. The temperature was raised
to 150~C while stirring. Then the reactor was saturated
with ethylene and the ethylene pressure was brought to 21
bar. 45 g of dried styrene was introduced into the
reactor. Next, 0.4 mmol aluminium alkyl
(triethylaluminium) was introduced into the reactor as a
scavenger. The transition metal complex
(CsMe4(CH2)2NMe2TiMe2, obtained by methylating the compound
of Example I by a method similar to that described in
Example IV(c), was premixed with dimethylaniline tetrakis-
(pentafluorophenyl)borate (DMAHBF20) in 25 ml of high-
boiling alkane solvent (B/Ti ratio = 2) for 1 minute in a
100-ml catalyst metering vessel. The co-polymerization
reaction was started by introducing the reaction mixture
from the catalyst premixing vessel into the reactor.
A constant ethylene pressure of 21 bar was
maintained and the co-polymerization was carried out
isothermally at 150~C.
After 10 minutes the reaction mixture was
drained from the reactor, quenched with methanol and
stabilized with antioxidant (Irganox 1076 (TM)). After
... ... ... . ...
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- 34 -
drying in a vacuum, the product was analyzed by means of
SEC-DV. The product was found to have a molecular weight
of 82,000 g/mol. The product also contained 2.7 mol.%
styrene as determined by means of lH-NMR and the DSC curve
indicated a maximum melting temperature of 127~C.
Example XII
A co-polymerization reaction was carried out as
described in Example VII, with the exception that the
transition metal complex was (CsMe4(CH2)2NBu2TiMe2,
obtained by methylating the compound of Example II
according to the method described in Example IVc. The
polymer formed was analyzed by means of SEC-DV (Mw =
80,000 g/mol) and lH-NMR (4.0 mol.% styrene content).
Example XIII
A co-polymerization reaction was carried out as
described in Example VI, except that the transition metal
complex was EtCp(iPr)3NMe2TiMe2, obtained by methylating
the compound of Example IV. The polymer formed was
analyzed by means of SEC-DV (Mw = 105,000 g/mol) and lH-
NMR (styrene content 3.8 mol.~).
Example XIV
A co-polymerization reaction was carried out as
described in Example VI, with the difference being that
3.0 ml of dried 1,7-octadiene was additionally introduced
into the reactor as a third monomer after the styrene had
been introduced (terpolymerization).
Then the co-polymerization was carried out in
exactly the same manner as described in Example VI. The
polymer formed contained 1.6 mol.~ styrene and 0.6 mol.~
octadiene, both as determined by means of l3C-NMR and lH-
NMR, at a polymer yield of 12,000 kg/mol Ti.hour.
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ExamPle XV
An ethylene/styrene co-polymerization process
was carried out as described in Example VI, only now 225 g
of styrene was co-polymerized at an ethylene pressure of
600 KPa. The co-polymerization was carried out at 80~C
using (CsMe4)(CH2)2NMe2TiCl2 (Example I) and MAO (Al/Ti =
1000). The product formed was purified and analyzed by
means of SEC-DV. The Mw was found to be 100 kg/mol and the
Mn 53,000 g/mol. lH-NMR analysis showed that the polymer
contained 19.9 mol.~ styrene.
Example XVI
A co-polymerization experiment was carried out
as described in Example XII, with the exception that the
transition metal compound was EtCp(iPr)3NMe2TiCl2 (Example
IV), which was used in combination with MAO (Al/Ti = 1000)
and 135 g of styrene was added as the second monomer.
SEC-DV analysis of the polymer formed revealed
an Mw of 150,000 g/mol. The Mn was 47,000 g/mol. The co-
polymer contained 12.3 mol.~ styrene as determined bymeans of lH-NMR.
ComParative exPeriment C
A co-polymerization experiment was carried out
as described in Example XIII, except that the catalyst
composition included the transition metal compound
Me2SiCp~NtBuTiCl2 in combination with MAO (Al/Ti = 1000).
At a styrene content comparable with that obtained in
Example 12, the Mw and Mn were found to be only 24,000
g/mol and 9,000 g/mol, respectively.
..~ . . .
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W O 97/42240 -36- PCTANL97/00239
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CA 022~3381 1998-10-30
W097/42240 PCT~L97/00239
- 37 -
It will thus be seen that the objectives and
principles of this invention have been fully and
effectively accomplished. It will be realized, however,
that the foregoing preferred specific embodiments have
been shown and described for the purpose of this
invention and are subject to change without departure
from such principles.
