Note: Descriptions are shown in the official language in which they were submitted.
CA 02494611 2010-12-14
Catalyst Comprising Bridged Indeno[1,2-b]indolyl Metal Complex
FIELD OF THE INVENTION
The invention relates to a process for making polyolefins. The process,
which uses catalysts having a bridged indenoindolyl ligand with "open
architecture," is valuable for making polyolefins with exceptionally low
densities.
BACKGROUND OF THE INVENTION
While Ziegler-Natta catalysts are a mainstay for polyolefin manufacture,
single-site (metallocene and non-metallocene) catalysts represent the
industry's
future. These catalysts are often more reactive than Ziegler-Natta catalysts,
and
they produce polymers with improved physical properties. The improved
properties include narrow molecular weight distribution, reduced low molecular
weight extractables, enhanced incorporation of a-olefin comonomers, lower
polymer density, controlled content and distribution of long-chain branching,.
and
modified melt rheology and relaxation characteristics.
Single-site olefin polymerization catalysts having "open architecture" are
generally known. Examples include the so-called "constrained geometry"
catalysts developed by scientists at Dow Chemical Company (see, e.g., U.S.
Pat. No. 5,064,802), which have been used to produce a variety of polyolefins.
"Open architecture" catalysts differ structurally from ordinary bridged
metallocenes, which have a bridged pair of pi-electron donors. In open
architecture catalysts, only one group of the bridged ligand donates pi
electrons
to the metal; the other group is sigma bonded to the metal. An advantage of
this
type of bridging is thought to be a more open or exposed locus for olefin
complexation and chain propagation when the complex becomes catalytically
active. Simple examples of complexes with open architecture are tert-
butylamido(cyclopentadienyl)dimethyl-silylzirconium dichloride and methyl-
amido(cyclopentadienyl)-1,2-ethanediyltitanium dimethyl:
i
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WO 2004/013194 PCT/US2003/021540
CI CI
Zr H3 \ . /CH3
N \-cH3
Si
Organometallic complexes that incorporate "indenoindolyl" ligands are
known (see U.S. Pat. No. 6,232,260 and PCT Int. Appl. WO 99/24446
("Nifant'ev")). The '260 patent demonstrates the use of non-bridged
bis(indenoindolyl) complexes for making HDPE in a slurry polymerization.
Versatility is an advantage of the complexes; by modifying the starting
materials,
a wide variety of indenoindolyl complexes can be prepared. "Open architecture"
complexes are neither prepared nor specifically discussed. Nifant'ev teaches
the use of bridged indenoindolyl complexes as catalysts for making
polyolefins,
io including polypropylene, HDPE and LLDPE. The complexes disclosed by
Nifant'ev do not have open architecture.
PCT Int. Appl. WO 01/53360 (Resconi et al.) discloses bridged
indenoindolyl complexes having open architecture and their use to produce
substantially amorphous propylene-based polymers. Resconi teaches many
is open architecture complexes but none that are bridged through the indolyl
nitrogen. Moreover, all of the complexes are used only to make propylene
polymers; their use to produce low-density ethylene polymers is not disclosed.
Resconi's teachings are also limited to indeno[2,1-b]indolyl complexes; the
reference includes no disclosure of indeno[1,2-b]indolyl complexes or their
use
20 for making propylene polymers.
As noted earlier, the indenoindolyl framework is versatile. The need
continues, - however, for new ways to make polyolefins--especially ethylene
copolymers--with very low densities. In particular, it is difficult to make
ethylene
polymers having densities less than about 0.915 g/cm3 using known
25 indenoindolyl complexes. On the other hand, ethylene polymers having such
low densities are valuable for special applications requiring elastomeric
properties. The industry would also benefit from the availability of new
catalysts
that capitalize on the inherent flexibility of the indenoindolyl framework.
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SUMMARY OF THE INVENTION
The invention is a process for making ethylene copolymers. The process
comprises copolymerizing ethylene with an a-olefin in the presence of a
catalyst
system comprising an activator and a silica-supported organometallic complex.
The complex, which has "open architecture," includes a Group 4 to 6 transition
metal and a bridged indenoindolyl ligand. Because the supported complex
incorporates comonomers with exceptional efficiency, the process enables the
production of ethylene copolymers having high molecular weights (Mw > 100K)
and very low densities (< 0.910 g/cm3). The invention includes new open
io architecture catalysts that take advantage of bridging through the indolyl
nitrogen of the indenoindolyl framework.
The invention also includes catalysts based on open architecture
indeno[1,2-b]indolyl complexes. We found that supported and unsupported
varieties of these catalysts are exceptionally valuable for making elastomeric
polypropylenes and ethylene copolymers.
DETAILED DESCRIPTION OF THE INVENTION
In the process of the invention, ethylene polymerizes with one or more a-
olefins to give a copolymer having very low density. Suitable a-olefins are 1-
butene, 1-hexene, 1-octene, and mixtures thereof. 1-Hexene is particularly
preferred.
Catalyst systems useful for the process comprise an activator and a
silica-supported, indenoindolyl Group 4-6 transition metal complex having open
architecture. More preferred complexes include a Group 4 transition metal such
as titanium or zirconium.
"Indenoindolyl" ligands are generated by deprotonating an indenoindole
compound using a potent base. By "indenoindole compound," we mean an
organic compound that has both indole and indene rings. The five-membered
rings from each are fused, i.e., they share two carbon atoms. Preferably, the
rings are fused such that the indole nitrogen and the only spa-hybridized
carbon
on the indenyl ring are "trans" to each other. Such is the case in an
indeno[1,2-
b] ring system such as:
3
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3
/ c 2
NA
H
Suitable ring systems also include those in which the indole nitrogen and
the spa-hybridized carbon of the indene are beta to each other, i.e., they are
on
the same side of the molecule. This is an indeno[2,1-b]indole ring system:
b N
z \H
3
The ring atoms can be unsubstituted or substituted with one or more groups
such as alkyl, aryl, aralkyl, halogen, silyl, nitro, dialkylamino,
diarylamino, alkoxy,
aryloxy, thioether, or the like. Additional fused rings can be present, as
long as
an indenoindole moiety is present.
Numbering of indenoindoles follows IUPAC Rule A-22. The molecule is
oriented as shown below, and numbering is done clockwise beginning with the
ring at the uppermost right of the structure in a manner effective to give the
lowest possible number to the heteroatom. Thus, 5,10-dihydroindeno[1,2-
b]indole is numbered as follows:
10 1
9 2
8~ ~ l
3
4
7 NS
6
H
while 5,6-dihydroindeno[2,1-b]indole has the numbering:
4
CA 02494611 2005-02-03
Printed: 08-12-2004 ; DESCPAMD L US0321540'
EPO - DUI
2 3 0 9. go. 2004
4
52
9
H
14-1
8
7 6
For correct nomenclature and numbering of these ring systems, see the Ring
Systems Handbook (1998), a publication of Chemical Abstracts Service, Ring
Systems File II: RF 33986-RF 66391 at RF 58952 and 58955. (Other examples
5 of correct numbering appear in PCT Int. Appl. WO 99124446.)
Methods for making indenoindole compounds are well known. Suitable
methods and compounds are disclosed, for example, in U.S. Pat. No. 6,232,260
and references cited therein, including the method of Buu-Hoi and Xuong, J.
Chem. Soc. (1952) 2225. Suitable procedures also appear in PCT Int. Appis.
io WO 99/24446 and WO 01/53360.
Indenoindolyl complexes useful for the process of the invention have
open architecture. By "open architecture" or "constrained geometry," we mean
a complex having a fixed geometry that enables generation of a highly exposed
active site when the catalyst is combined with an activator. The metal of the
is complex is pi-bonded to the indenyl Cp ring and is also sigma-bonded
through
two or more atoms to the indolyl nitrogen or the indenyl methylene carbon. (In
contrast, many of the bridged indenoindolyl complexes described in the
literature
have a transition metal that is pi-bonded to the indenyl Cp ring and pit-
bonded to
another Cp-like group. See, e.g., U.S. Pat. No. 6,232,260 or WO 99/24446).
Preferably, the metal is sigma-bonded to a heteroatom, i.e., oxygen, nitrogen,
phosphorus, or sulfur; most preferably, the metal is sigma-bonded to nitrogen.
The heteroatom is linked to the indenoindolyl group through a bridging group,
which is preferably dialkylsilyl, diarylsilyl, methylene, ethylene,
isopropylidene,
diphenylmethylene, or the like. Particularly preferred bridging groups are
dimethylsilyl, methylene, ethylene, and isopropylidene. The bridging group is
covalently bonded to either the indolyl nitrogen atom or the indenyl methylene
carbon.
5
AMENDED SHEET 09-08-2004
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Printed: 08-12-20041 [b, US0321540
In addition to the bridged indenoindolyl ligand, the organometallic
complex usually includes one or more labile anionic ligands such as halides,
alkoxys, aryloxys, alkyls, alkaryls, aryls, dialkylaminos, or the like.
Particularly
preferred are halides, alkyls, and alkaryls (e.g., chloride, methyl, benzyl).
In a preferred process of the invention, the indenoindolyl complex has the
general structure:
N
O
0 O or /N0
a a
M
xri 1-11 \L xn \
L
in which M is a Group 4-6 transition metal, G is a linking group, L is a
ligand that
is covalently bonded to G and M, R is alkyl, aryl, or trialkylsilyl, X is
alkyl, aryl,
alkoxy, aryloxy, halide, dialkylamino, or siloxy, and n satisfies the valence
of M.
More preferably, M is a Group 4 transition metal, L is alkylamido, G is
dialkylsilyl,
and X is halide or alkyl.
io In another preferred process, the indenoindolyl complex has the general
0 structure:
O
00 a or (~
N a
G-~ \xn G Mix
in which M is a Group 4-6 transition metal, G is a linking group, L is a
ligand that
is covalently bonded to G and M, X is alkyl, aryl, alkoxy, aryloxy, halide,
dialkylamino, or siloxy, and n satisfies the valence of M. Preferably, M is a
Group 4 transition metal, L is alkylamido, G is dialkylsilyl, and X is halide
or alkyl.
Exemplary organometallic complexes useful for the process of the
invention: .
6
,27' AMENDED SHEET 109-08-2004:
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H3C Sl h CI H3C /N CH
i 3
ZrCI H3C. T/CH3
H3C
0 0 1~
~1(1 0
&-0
H3C Ph
H3C
H'c W~o
H2C -Cl CI
H Si,NTi-C 33
Oo O 'C
O
H3C
H3C HA
N H3C\ N"CH3
H3C . Tj /Si-CH 3 H3C,Si ~CH3
3C N CH3 N ~Ti CH3
The complexes can be made by any suitable method; those skilled in the
art will recognize a variety of acceptable synthetic strategies. See
especially
PCT Int. Appl. WO 01/53360 for suitable routes. Often, the synthesis begins
with preparation of the desired indenoindole compound from particular indanone
and arylhydrazine precursors. In one convenient approach, the indenoindole is
deprotonated and reacted with dichlorodimethylsilane to attach a
chlorodimethylsilyl group to the indenyl methylene carbon. Subsequent reaction
io with an amine or, more preferably, an alkali metal amide compound such as
lithium tert-butylamide (from tert-butylamine and n-butyllithium), displaces
chloride and gives the desired = silylamine product. Double deprotonation and
reaction with a transition metal source gives the target indenoindolyl metal
complex having open architecture. A typical reaction sequence follows:
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H H H3C\ Si OCI
H3C H3C H3C, H
O 1D-1O n-BuLi O O 0 t-BuNH Li
N 2) Me2SiCl2
N
Me I
Me
H3C NH 1) n-BuLi (2 eq) H3C
\ / \ / \ /CH3
2) McLi (2.5 eq) Si
Ti-CH3
'Si HO
H3C 3) TiCl4(THF)2 H3C
H3C0 O
0
UT.N. 0 O
N
MI Mle
A similar complex can be generated by amine elimination, which may or
may not require heating, with a method explored by Professor Richard F. Jordan
and coworkers at the University of Iowa:
H3C /NH N NMe2
H3 H3C' C'Si H TI(NMe2)4 3C-Si \ Ti/ NMe
-Me2
H3C (-HNMe2) H3C
uo O. OO 0
MI MI
For additional examples of this approach to making organometallic complexes,
see U.S. Pat. No. 5,495,035; J. Am. Chem. Soc. 118 (1996) 8024; and
Organometallics 15 (1996) 4045.
The process of the invention can also utilize complexes in which bridging
to the indenoindolyl group occurs through the indolyl nitrogen atom. A
convenient route to an N-Si-N bridged complex is shown below:
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WO 2004/013194 PCT/US2003/021540
H H H3C
H3C ~
O O O +
00 O 1) 2 eq. n-BULi t-BuNHLi
Za -XC
2) Me2SiGI2
H3C~Si'CI
H3C
H H
H3C H3C
Zoe* 2)25eq McLi 00 O
3) TiCl4(THF)2 Ti-CH3
H3C7Si' NH H3C/Si'N/ ~CH3
---k H3C H3C I
Or with amine elimination to form a similar complex:
H H
H3C H3C
00 Ti(NMe2)4 00 O
(-,NMe2) Ti-NMe2
H3C/SI'NH H3CS' ,N/ NMe2
H3C H3C
Similar strategies can be used to make a wide variety of indenoindolyl metal
complexes having open architecture.
Any convenient source of the transition metal can be used to make the
complex. As shown above, the transition metal source conveniently has labile
ligands such as halide or dialkylamino groups that can be easily replaced by
the
1o indenoindolyl and amido anions of the bridged indenoindolyl ligand.
Examples
are halides (e.g., TiCl4, ZrC14), alkoxides, amides, and the like.
Catalyst systems useful in the process include, in addition to the
indenoindolyl metal complex, an activator. The activator helps to ionize the
organometallic complex and activate the catalyst. Suitable activators are well
is known in the art. Examples include alumoxanes (methyl alumoxane (MAO),
PMAO, ethyl alumoxane, diisobutyl alumoxane), alkylaluminum compounds
(triethylaluminum, diethyl aluminum chloride, trimethylaluminum, triisobutyl
aluminum), and the like. Suitable activators include acid salts that contain
non-
9
CA 02494611 2010-12-14
nucleophilic anions. These compounds generally consist of bulky ligands
attached to boron or aluminum. Examples include lithium
tetrakis(pentafluorophenyl)borate, lithium
tetrakis(pentafluorophenyl)aluminate,
anilinium tetrakis(penta-fluorophenyl)borate, and the like. Suitable
activators
also include organoboranes, which include boron and one or more alkyl, aryl,
or
aralkyl groups. Suitable activators include substituted and unsubstituted'
trialkyl
and triarylboranes such as tris(pentafluorophenyl)borane, triphenylborane, tri-
n-
octylborane, and the like. These and other suitable boron-containing
activators
are described in U.S. Pat. Nos. 5,153,157, 5,198,401, and 5,241,025. Suitable
io activators also include aluminoboronates--reaction products of alkyl
aluminum
compounds and organoboronic acids--as described in U.S. Pat. Nos: 5,414,180
and 5,648,440. Alumoxane activators, such as MAO, are preferred.
Other preferred activators are ionic borates, ionic aluminates,
alkylaluminums, and aluminoboronates.
. The optimum amount of activator needed relative to the amount of
organometallic complex depends on many factors, including the nature.. of the
is complex and activator, the desired reaction rate, the kind of polyolefin
product,
the reaction conditions, and other factors. Generally, however, when the
activator is an alumoxane or an alkyl aluminum compound, the amount used will
be within the range of about 0.01 to about 5000 moles, preferably from about
10
to about 500 moles, and more preferably from about 10 to about 200 moles, of
20 aluminum per mole of transition metal, M. When the activator is an
organoborane or an ionic borate or aluminate, the amount used will be within
the
range of about 0.01 to about 5000 moles, preferably from about 01 to about
500 moles, of activator per mole of M. The activator can be combined with the
complex and added to the reactor as a mixture, or the components can be
25 added to the reactor separately.
The process uses a silica-supported catalyst system. The silica is
preferably treated thermally, chemically, or both prior to use to reduce the
concentration of surface hydroxyl groups. Thermal treatment consists of
heating
(or "calcining") the silica in a dry atmosphere at elevated temperature,
preferably
30 greater than about 100 C, and more preferably from about 150 to about 600
C,
prior to use. A variety of different chemical treatments can be used,
including
reaction with organo-aluminum, -magnesium, -silicon, or -boron compounds.
See, for example, the techniques described in U.S. Pat. No. 6,211,311.
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While there are many ways to practice the ethylene copolymerization
process of the invention, the process is preferably a slurry or gas-phase
process. These processes are well-suited to the use of supported catalysts.
Suitable methods for polymerizing olefins using the catalysts of the invention
are
described, for example, in U.S. Pat. Nos. 5,902,866, 5,637,659, and 5,539,124.
The polymerizations can be performed over a wide temperature range,
such as about -30 C to about 280 C. A more preferred range is from about
30 C to about 180 C; most preferred is the range from about 60 C to about
100 C. Olefin partial pressures normally range from about 15 psia to about
io 50,000 psia. More preferred is the range from about 15 psia to about 1000
psia.
Catalyst concentrations used for the olefin polymerization depend on
many factors. Preferably, however, the concentration ranges from about 0.01
micromoles per liter to about 100 micromoles per liter. Polymerization times
depend on the type of process, the catalyst concentration, and other factors.
Generally, polymerizations are complete within several seconds to several
hours.
The invention includes a catalyst system. The catalyst system comprises
an activator, as described above, and a bridged indenoindolyl Group 4-6
transition metal complex. The complex has an open architecture in which
bridging to the indenoindolyl group occurs through the indolyl nitrogen. The
complexes are produced as described earlier. In preferred catalyst systems of
the invention, the indenoindolyl complex has the general structure:
O
00 r 00
\
G-
L/ xn M
GAL/ xn
in which M is a Group 4-6 transition metal, G is a linking group, L is a
ligand that
is covalently bonded to G and M, X is alkyl, aryl, alkoxy, aryloxy, halide,
dialkylamino, or siloxy, and n satisfies the valence of M. Preferably, M is a
Group 4 transition metal, L is alkylamido, G is dialkylsilyl, and X is halide
or alkyl.
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Exemplary indenoindolyl complexes for catalyst systems of the invention:
H3C H3C
O moo
00
_
H3C-sip ,Ti CH3 H3G . T. /Si-CH3
H3 C N CH3 H3C N CH3
H3C H3C
O O o Q C=
N I I
H3C-Sim Ti NMe2 Ch~Zr' /CGH3
H3C N NMe2 CIS N ~CH3
The invention enables the preparation of ethylene copolymers having
very low densities. Generally, the copolymers can have densities less than
about 0.930 g/cm3. An advantage of the invention, however, is the ability to
depress densities to much lower values, i.e., less than 0.910 g/cm3, and even
less than 0.890 g/cm3. As shown in Table 1, achieving very low densities is
1o difficult for indenoindolyl metal catalysts that lack an open architecture
(see
Comparative Examples 2 and 3). We found that an open architecture catalyst
incorporates comonomers more efficiently (see Example 1).
The catalyst system and process of the invention can be used to produce
ethylene polymers having high molecular weights. For example, very low
1s density polyolefins having weight average molecular weights (Mw) greater
than
400,000, or even greater than 1,000,000, can be easily produced (see Example
4). When desirable, hydrogen or other chain-transfer agents can be introduced
into the reactor to regulate polymer molecular weight.
Polyolefins produced by the process of the invention usually have narrow
20 molecular weight distributions, preferably less than about 3.5, more
preferably
less than about 3Ø When a comonomer is included, a high level of short-chain
branching is evident by FT-IR analysis. When the goal is to make polyolefins
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with very low density, the copolymers have more then about 20, preferably
more than about 30, branches per 1000 carbons.
In another aspect, the invention is a catalyst system useful for making
elastomeric polypropylene and ethylene copolymers. The catalyst system
s comprises an activator and a bridged indeno[1,2-b]indolyl Group 4-6
transition
metal complex having open architecture. We surprisingly found that the bridged
[1,2-b] complexes are much more active than their counterpart [2,1-b]
complexes in both propylene polymerizations and ethylene copolymerizations.
Activators useful in these catalyst systems are the same ones described
1o earlier. The complex includes a bridged indeno[1,2-b]indolyl ligand and a
Group
4-6, preferably a Group 4, transition metal. Suitable indeno[1,2-b]indolyl
complexes have already been described. As shown below in the preparation of
complex 4, the indeno[1,2-b]indolyl_ ligands are conveniently prepared by
reacting arylhydrazines and 1-indanones. Preferred indeno[1,2-b]indolyl
15 complexes have the structure:
R
I
N
0
xn '- M \ /G
L.
in which M is a Group 4-6 transition metal, G is a linking group, L is a
ligand that
is covalently bonded to G and M, R is alkyl, aryl, or trialkylsilyl, X is
alkyl, aryl,
alkoxy, aryloxy, halide, dialkylamino, or siloxy, and n satisfies the valence
of M.
20 More preferably, M is a Group 4 transition metal, L is alkylamido, G is
dialkylsilyl,
and X is halide or alkyl.
Methods for preparing the complexes and exemplary structures have
already been described. Complex 4 (below) and its method of preparation are
illustrative.
25 Indeno[1,2-b]indolyl complexes are exceptionally useful for making
elastomeric polypropylene. While both the [1,2-b] and [2,1-b] complexes give
polypropylene with elastomeric properties (i.e., the resulting polymers are
neither highly isotactic nor highly syndiotactic), the unsupported [1,2-b]
complexes are an order of magnitude (about 10 times) more active at the same
13
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reaction temperature than their [2,1-b] counterparts in propylene
polymerizations
(see Table 3). A similar activity advantage in propylene polymerizations is
seen
with supported indeno[1,2-b]indolyl complexes (see Example 20 and
Comparative Example 21).
Similar results are achieved in copolymerizations of ethylene with alpha-
olefins. As shown in Example 18 and Comparative Example 19, supported
indeno[1,2-blindolyl complexes with open architecture have three times the
activity of their [2,1-b] counterparts in copolymerizations of ethylene and 1-
hexene.
to The following examples merely illustrate the invention. Those skilled in
the art will recognize many variations that are within the spirit of the
invention
and scope of the claims.
PREPARATION of COMPLEX A
Open Architecture Complex 4
(a) Preparation of Indenofl,2-blindole 1. A mixture of 1-indanone (30.6
g, 232 mmol) and p-tolylhydrazine hydrochloride (37.0 g, 233 mmol) in EtOH
(350 ml-) and aqueous HCI (12 N, 18 ml-) are heated to reflux for 90 min. The
mixture is cooled and filtered, and the solid is washed with EtOH (600 mL)
followed by 20% aqueous EtOH (400 ml-) and finally hexanes (200 mL). The
off-white solid is dried under vacuum (36.5 g, 72%).
(b) N-Methylation of 1. A mixture of 1 (36.5 g, 166 mmol), aqueous
NaOH solution (112 mL, 20 M, 2.2 mol), C16H33NMe3Br (0.65 g, 1.78 mmol), and
toluene (112 ml-) is vigorously stirred at room temperature. A solution of Mel
(17.0 mL, 273 mmol) in toluene (15 mL) is added dropwise, and the mixture is
stirred at room temperature for 4 h and refluxed for 3 h. A crystalline solid
forms
upon cooling and is filtered and washed with cold (-78 C) EtOH (300 ml-)
followed by hexanes (100 mL). The layers are separated and the aqueous
fraction is washed with toluene (2 x 100 mL). The organics are combined and
dried over Na2SO4 and filtered. The volatiles are removed under vacuum and
the precipitate is dried and combined with the crystalline product 2 (total
yield
25.7 g, 66%).
(c) Bridged ligand preparation (3). n-Butyllithium (8 mL, 2.5 M in hexane,
20 mmol) is added dropwise to a solution of 2 (4.66 g, 21 mmol) in dry ether
(70
mL). After 2 h, this solution is slowly added to a solution of
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CA 02494611 2010-12-14
dichlorodimethylsilane (5.20 g) in ether (30 mL). After 2 h of stirring at
room
temperature, the mixture is filtered and evaporated. The residue is
redissolved
in ether (60 ml), and an ethereal solution of lithium t-butylamide (prepared
in the
usual manner from t-butylamine (1.46 g) and n-butyllithium (8 mL of 2.5 M
solution)) is added dropwise. The mixture is stirred for 3 h, and is then
filtered
through CeliteTM filter aid. After concentrating the filtrate, the residue is
collected
with pentane and chilled to -30 C. Yield of bridged ligand 3: 6 g (82%).
(d) Preparation of open architecture complex 4. Bridged ligand 3 (6 g) is
dissolved in ether (120 mL) and n-butyllithium (13.5 mL of 2.5 M solution in
io hexane) is added. After stirring overnight at room temperature,
methyllithium
(24.5 mL of 1.4 M solution in ether) is--added, and the mixture is cooled to -
30 C.
Titanium tetrachloride bis(tetrahydrofuran) complex (5.66 g) is added, and
stirring continues for 3 h. The mixture is filtered and the filtrate is
concentrated.
The residue is extracted with hot heptane (2 X 100 mL). The combined filtrates
are evaporated, and the residue is crystallized with pentane and cooled to -30
C.
The product, complex 4, is a dark brown solid. Yield: 4.67 g.
The 1H NMR spectrum is consistent with the proposed structure:
H3C\ =/N\ CH3
H3c - $i r'--CHs
H3C
OO
H3C
4
PREPARATION of COMPLEX B -- Comparative Example
Bridged Indeno[2,1-b]indolylzirconium Complex 9
(a) Preparation of Indenol2,1-bIindole S. A mixture of 2-indanone (51.0
g, 0.39 mol) and p-tolylhydrazine hydrochloride (61.4 g, 0.39 mol) is
dissolved in
glacial acetic acid (525 mL) and is vigorously stirred and heated to reflux.
The
mixture turns red and is heated for 2,h. After cooling to room temperature, it
is
2s poured into ice water (1 L). The precipitate is filtered to afford a solid,
which is
washed with water (about 1 Q. The solid is dissolved in ethyl acetate (1.4 L),
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activated charcoal is added, and the mixture is gently warmed. The mixture is
then cooled and filtered over a pad of Celite. The filtrate is dried over
Na2SO4
filtered, and is then concentrated to 450 mL and cooled to -30 C for 3 days.
The crystalline solid is filtered and washed with chilled (-78 C) hexanes (2 x
500
mL). The beige solid is collected and dried under vacuum (47.1 g, 56%).
(b) N-Methylation of 5 to give 6. A slurry of aqueous Na,OH (42 mL, 21.5
M, 903 mmol), C16H33NMe3Br (0.36 g, 0.97 mmol), and 5 (15.0 g, 68.4 mmol) is
combined with toluene (50 mL). A solution of Mel (8.0 mL, 129 mmol) in toluene
(15 mL) is added dropwise at room temperature. The mixture is stirred at room
1o temperature for 2.5 h and then refluxed for an hour. The mixture turns red
and
is cooled to room temperature and filtered. The crystalline solid is washed
with
chilled (-30 C) EtOH (200 mL) followed by chilled hexanes (200 mL) to afford a
pale red solid (10.3 g, 65%).
(c) Anion generation: Preparation of 7. n-Butyllithium (13.0 mL, 2.5 M
in hexanes, 32.5 mmol) is added at room temperature to a slurry of 6 (4.94 g,
21.1 mmol) in toluene (125 mL). The mixture is maintained at room temperature
and turns pale yellow. A precipitate forms after 2 h. After 2 days, the
mixture is
filtered to give a pale beige solid. The solid is washed with toluene (60 mL),
followed by hexanes (30 mL), and is then collected and dried under vacuum
(4.37 g, 87%).
(d) Preparation of Dianion 8. Product 7 (4.57 g, 19.1 mmol) is
suspended in toluene (100 mL). Diethyl ether (40 mL) is added dropwise to
afford an orange solution, which is added to a solution of SiCl2Me2 (12.0 mL,
98.9 mmol) in Et20 (100 mL) at room temperature. The mixture turns cloudy
and dirty beige and is stirred for 3 days and filtered to give a dark red-
orange
solution. Volatiles are removed under reduced pressure to afford an oily
solid.
An aliquot is analyzed by 1H NMR, revealing formation of the desired product;
100% conversion is presumed. The oily solid is dissolved in Et20 (140 mL), and
NaCp (11.0 mL, 2.0 M in THF, 22 mmol) is added. A precipitate forms
immediately, and stirring continues for 2 days. The mixture is washed with
water
(3 x 50 mL), and the organic phase is dried over Na2SO4 and filtered.
Volatiles
are removed under vacuum to give an oily residue, and 100% conversion is
assumed. The residue was dissolved in Et20 (75 mL) and cooled to -78 C. n-
Butyllithium (18.0 mL, 2.5 M in hexanes, 45.0 mmol) is added by syringe, and
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the mixture is warmed to room temperature slowly. A yellow solid precipitates
overnight, and volatiles are removed under vacuum. The crude material is
washed with hexanes (100 ml-) and filtered to afford a yellow powder. The
powder is collected and dried under vacuum (6.73 g, 93%).
(e) Preparation of Complex 9. Zirconium tetrachloride (3.15 g, 13.5
mmol) is combined with toluene (100 ml-) and dissolved in Et20 (50 mL) to
produce a cloudy suspension. Dianion 8 (5.02 g, 13.7 mmol) is added as a solid
in portions over the course of 30 min. The color turns from yellow to dark
orange, and a precipitate forms. The mixture is maintained at room temperature
to for 2 days and is filtered to give a dirty yellow solid. The solid is
washed with
toluene (50 ml-) and hexanes (50 mL). The yellow powder is collected and dried
under vacuum (3.72 g, 53%).
The 1 H NMR spectrum is consistent with the proposed structure:
H3c O ci
O ~/ Cl
Z
O ~--
N si
H3C H3C \CH3
9
PREPARATION of COMPLEX C -- Comparative Example
Unbridged Indeno[1,2-b]indolylzirconium Complex 10
In a glovebox under nitrogen, N-methylated indeno[1,2-b]indole 2 (14.2 g,
60.9 mmol), prepared as described earlier, is dissolved in toluene (175 mL). n-
2o Butyllithium (38.0 mL of 2.5 M solution in hexanes, 95 mmol) is added
carefully
under vigorous stirring at room temperature to give a red solution. After one
hour, - a precipitate forms. The mixture is kept at room temperature
overnight,
and is then filtered and washed with toluene (100 ml-) and then heptane (200
mL). The sticky product is dried under nitrogen in the glovebox and is
collected
and dried under vacuum.
A sample of the indeno[1,2-b]indolyl lithium salt produced above (10 g, 42
mmol) is dissolved in toluene (95 ml-) to produce an orange slurry. Diethyl
ether
(35 ml-) is added slowly to give an orange solution. This solution is added
over
17
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15 min. at room temperature with stirring to a slurry of
cyclopentadienyizirconium
trichloride (11 g, 42 mmol) in toluene (190 mL) and diethyl ether (190 mL).
The
mixture turns deep red and is kept at room temperature overnight. The slurry
is
filtered to recover a red solid, which is washed with toluene (200 mL) and
dried
under vacuum. Yield of complex 10: 16.5 g. The 1H NMR spectrum is consistent
with the proposed structure:
zr-SCI
H3C
N
H3C
Preparation of Silica-Supported Complexes
Crossfield ES757 silica is calcined at 250 C for 12 h. In a glovebox under
io nitrogen, a 30 wt.% solution of methylalumoxane (MAO) in toluene (0.8 mL)
is
slowly added to a sample (1.0 g) of the calcined silica at room temperature
with
efficient stirring. After the MAO-addition is complete, stirring continues for
0.5 h.
Volatiles are removed under vacuum (about 28.5 inches Hg, 1 hour) at room
temperature. Yield: 1.25 g of MAO-treated silica.
Also in. the glovebox, 30 wt.% MAO/toluene solution (1.18 mL) is added to
an amount of organometallic complex (A, B, or C) equal to 0.11 mmol of
transition metal. The resulting solution is added slowly at room temperature
with
stirring to the dry, MAO-treated silica described above. After stirring for an
additional 0.5 h, the supported complex is dried under vacuum to give a
supported complex (about 1.75 g).
EXAMPLE I and COMPARATIVE EXAMPLES 2-3
Copolymerization of'Ethylene and 1-Hexene
A one-liter, stainless-steel reactor is charged with 1-hexene (35 mL).
Triisobutylaluminum (1.0 mL of 1.0 M solution in heptane, 1.0 mmol) and
ArmostatTM 710 fatty amine (1 mg, product of Akzo Noble) is heptane solution
(0.25 mL) are mixed in one sidearm of the injector. This mixture is then
flushed
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into the reactor with nitrogen pressure and isobutane (about 450 mL). Hydrogen
is added (10 dpsig from a 90-mL stainless-steel cylinder pressurized initially
to
500 psig H2) to the reactor, which is then pressurized with ethylene to 320
psig.
The reactor contents are allowed to equilibrate at 80 C. The supported
catalyst
(30 mg) is loaded into the other injector arm and then flushed into the
reactor
with isobutane (100 mL) and nitrogen pressure. The polymerization proceeds
for 0.5 h. The reactor is vented and the olefin polymer is collected and dried
under vacuum at 60 C prior to testing. Results of polymer testing appear in
Table 1.
Table 1. Effect of Open Architecture on Polymer Density
Ex. Complex Type SCB density Mw Mw/Mn
(g/cm3)
I A open architecture Ti 30.3 0.889 784K 3.0
[1,2-b] complex
C2 B bridged Zr 17.0 0.913 100K 3.1
[2,1-b] complex
C3 C unbridged Zr 6.2 0.932 94K 2.8
[1,2-b] complex
SCB=short-chain branches per 1000 carbons as measured by FT-IR.
EXAMPLE 4
Copolymerization of Ethylene and 1-Hexene
A one-liter, stainless-steel reactor is charged with 1-hexene (35 mL).
Triisobutylaluminurn (0.20 mL of 1.0 M solution in heptane, 0.20 mmol) is
flushed into the reactor from one sidearm of the injector with isobutane (450
mL)
and nitrogen pressure. The reactor is then pressurized with ethylene to 320
psig. The reactor contents are allowed to equilibrate at 80 C. The supported
catalyst (34 mg of silica-supported complex A) is loaded into the other
injector
arm and then flushed into the reactor with isobutane (100 mL) and nitrogen
pressure. The polymerization proceeds for 0.5 h. The reactor is vented and the
olefin polymer is collected and dried under vacuum at 60 C prior to testing.
Activity: 6120 g polyolefin per g catalyst per hour. Mw/Mn (GPC)=2.44.
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Mw=1,180,000; intrinsic viscosity (by GPC): 9.57; short-chain branches per
1000
carbons (by FT-IR): 32.8; density: 0.888 g/cm3.
Example 4 demonstrates the use of an open architecture indenoindolyl
catalyst in a process of the invention for making ethylene copolymers. As
shown
in Table 1, the copolymers have very low densities, high molecular weight
(even
though hydrogen was present in the reactor), and narrow molecular weight
distributions (2.8-3.0).
Preparation of Supported Catalyst D
With Complex A and Borate Co-catalyst
Grace Davison silica 955 is calcined at 250 C for 12 h. In a glovebox
under nitrogen, a 0.5 M solution of triethylaluminum (TEAL) in heptane (8 mL)
is
slowly added to 2 g of the calcined silica at room temperature with efficient
stirring. After one hour stirring, the treated silica is dried by vacuum at
room
temperature.
Complex A (29 mg, 0.066 mmol), toluene (5 mL), and triphenylcarbenium
tetrakis(pentafluorophenyl)borate [(C6H5)3CB(C6F5)4] (85 mg, 0.092 mmol) are
mixed with a sample of the TEAL-treated silica (1.0 g) and the mixture is
stirred
for 0.5 h. Volatiles are removed under vacuum (about 28.5 inches Hg, 1 hour)
at room temperature. Yield: 1.12 g of catalyst D.
EXAMPLE 5
Copolymerization of Ethylene and 1-Hexene
A one-liter, stainless-steel reactor is charged with 1-hexene (35 mL).
Triisobutylaluminum (0.20 mL of 1.0 M solution in heptane, 0.20 mmol) is
flushed into the reactor from one sidearm of the injector with isobutane (450
mL)
and nitrogen pressure. The reactor is then pressurized with ethylene to 320
psig. The reactor contents are allowed to equilibrate at 80 C. Supported
catalyst D (20 mg) is loaded into the other injector arm and is then flushed
into
the reactor with isobutane (100 mL) and nitrogen pressure. The polymerization
proceeds for 0.5 h. The reactor,is vented and the olefin polymer is collected
and
3o dried under vacuum at 60 C prior to testing. Activity: 2680 g polyolefin
per g
catalyst per hour. Mw/Mn (GPC)=2.32. Mw=923,360; intrinsic viscosity (by
GPC): 8.1; short-chain branches per 1000 carbons (by FT-IR): 33.2; density:
0.882 g/cm3.
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Example 5 demonstrates the use of a borate-activated, open architecture
indenoindolyl catalyst in a process of the invention for making ethylene
copolymers with very low densities and high molecular weight.
EXAMPLE 6
Preparation of an N-Si-N Bridged Complex
2-Methyl-5,6-dihydroindeno[1,2-b]indole (3.28 g) is suspended in ether
(30 mL) and n-butyllithium (6.0 mL of a 2.5 M solution in hexane) is added.
After
one hour, this mixture is added dropwise to a solution of
dimethyldichiorosilane
(4.14 g) in ether (20 mL). The mixture is stirred for three hours and
filtered. The
io filtrate is evaporated to give a beige solid (4.68 g). The residue is
dissolved in
ether (60 mL), and a mixture of t-butylamine (1.20 g) and n-butyllithium (6.0
mL
of a 2.5 M solution in hexane) is added dropwise. After 2 h, the mixture is
evaporated and the residue is extracted with pentane. The volume of the
mixture is reduced to 30 mL, and n-butyllithium (12 mL of 2.5 M solution in
1s hexane) is added. After stirring overnight, the yellow solid is collected
by
filtration, washed with pentane, and dried. Yield: 4.49 g. The product is
dissolved in ether (100 mL) and methyllithium (18 mL of a 1.4 M solution in
ether) is added. The mixture is cooled to -30 C and TiCI4(THF)2 (4.15 g) is
then
added. After stirring for 2 hours, the mixture is filtered and the filtrate is
20 evaporated. The residue is extracted with hot heptane (2 x 100 mL).
Evaporation of the combined extracts gives a brown-black solid (2.00 g) having
a'H NMR spectrum consistent with the proposed structure:
H3C
00 O
i. Ti- CH3
_
H CSL.. / \CH3
3
EXAMPLE 7
25 Copolymerization Experiments
Ethylene is copolymerized with 1-hexene using an 8-cell Endeavor
apparatus. Each cell is charged with a toluene solution containing 9.8 x 10-5
mmoles of the open-architecture Ti complex from Example 6, MAO activator
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(1000 equivalents) and varying amounts of 1-hexene comonomer. The
apparatus is pressurized with ethylene (200 psig) and polymerizations proceed
for 30 minutes. The gas is vented and polymer is collected from each of the
cells. Activities are listed in Table 2.
Table 2. Ethylene-Hexene Copolymerizations
1-hexene (ml) 0 0.25 0.50 0.75 1.0 1.25 1.50
toluene (ml-) 4.60 4.35 4.10 3.85 3.60 3.35 3.10
activity (kg polymer 26 22 19 17 13 11 3
per gram Ti per hour)
EXAMPLE 8
Open architecture indeno[1,2-b]indolyl complex 4 is prepared as
described previously.
EXAMPLE 9
The procedure of Example 8 is generally followed except that lithium
1,1,3,3-tetramethylbutylamide is used in place of lithium t-butylamide to
yield
open architecture indeno[1,2-b]indolyl complex 11.
H3C\ N /C H3
H3C--s1 Ti,CH
3
H3C do
Oo N
I
CH3
11
COMPARATIVE EXAMPLE 10
Open Architecture Indeno[2,1-b]indolyl Complex 12
This compound was prepared from 2-indanone substantially according to
the procedure detailed in PCT Int. Appl. WO 01/53360 Example 1 to yield open
architecture indeno[2,1-b]indolyl complex 12.
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H3C\ /N\ /C'H3
H3C-si Ti-CH
NO 0
H3C\
O
r
CH3
12
EXAMPLE 12
Propylene Polymerization
A solution of complex and activator is prepared in an inert atmosphere
dry box by mixing 5 mg of open architecture indeno[1,2-b]indolyl complex 4
from
Example 8 with 3.5 mL of MAO (10% by weight solution of methylalumoxane in
toluene) and 16.5 mL of toluene. This solution is allowed to age for 30
minutes
before adding to the polymerization reactor.
To a 1-L, stainless-steel stirred reactor, at room temperature, is charged
1o 400 mL of dry, oxygen-free propylene. Then 1.6 mL of a 25% by weight
solution
of triisobutylaluminum in heptane is flushed into the reactor with 50 mL of
isobutane. The reactor is brought to 50 C and allowed to equilibrate.
Polymerization begins upon adding 1.0 mL of the solution of complex and
activator and by flushing with 50 mL of isobutane. After 60 minutes of
is polymerization at 50 C, the reactor is vented to remove the remaining
propylene
and isobutane. The polymer is removed from the reactor, soaked overnight in 1
L of methanol, filtered, and dried. Activity: 2467 kg polypropylene per g
titanium
per hour. The weight average molecular weight and polydispersity (by GPC):
M,N = 736,000; MW / Mn = 3.5. The polymer tacticity measured by 13C NMR is 7%
20 mm triads (isotactic triads) and 59% rr triads (syndiotactic triads)
showing that
that the polypropylene is neither highly isotactic nor highly syndiotactic.
The
results indicate that the polypropylene has elastomeric properties.
EXAMPLE 13
The polymerization of Example 12 is repeated to obtain polypropylene
25 with Mw = 683,000. The polypropylene is molded into ASTM type I tensile
bars
and the properties are measured. Tensile strength at break: 4.86 MPa;
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elongation at break: 550%. Tensile set at 200%: 8% (measured by extending
the sample to 200% of the original length and holding the sample for ten
minutes, followed by releasing the sample and then measuring the set after
another ten minutes. A set of 0% indicates complete return to the original
length
while 100% would indicate no return from the elongated position). Stress
recovery: 31 %. (This is the decrease in sample stress at 200% elongation
after
ten minutes.)
These tensile properties demonstrate the good elastomeric properties of
the polypropylene prepared by using indeno[1,2-b]indolyl complexes as catalyst
io components.
EXAMPLES 14 and 15 and COMPARATIVE EXAMPLES 16 and 17
Propylene', Polymerizations
The polymerization procedure of Example 12 is generally followed with
different complexes and polymerization temperatures. The conditions and
results are listed in Table 3.
TABLE 3
Propylene Polymerizations
Example Complex Polym. Activity M,N/1000 MW/Mn mm rr
Temp.
0C
12 4 50 2467 736 3.5 0.07 0.59
14 4 70 2156 582 3.0 0.11 0.49
15 11 50 3392 944 2.9 0.13 0.46
C16 12 50 300 1090 3.5 0.08 0.67
C17 12' 70 197 810 3.2 0.09 0.62
Examples 12, 14 and 15 show that polymerizations performed with open
architecture indeno[1,2-blindolyl complexes give about a tenfold improvement
in
activity versus the polymerizations in Comparative Examples 16 and 17
performed with the open architecture indeno[2,1-b]indolyl complexes. The
polypropylene has high molecular weight and low polydispersity. The tacticity
data shows that the polymers are neither highly isotactic nor highly
syndiotactic.
This level of tacticity is indicative of elastomeric polypropylene.
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Preparation of Silica-Supported Complexes 4 and 12
Grace Davison 955 silica is calcined at 250 C for 12 h. In a glovebox
under nitrogen, a 30 wt.% solution of methylalumoxane (MAO) in toluene (0.8
mL) is slowly added to a sample (1.0 g) of the calcined silica at room
temperature with efficient stirring. After the MAO addition is complete,
stirring
continues for 0.5 h. Volatiles are removed under vacuum (about 28.5 inches
Hg, 1 hour) at room temperature. Yield: 1.30 g of MAO-treated silica.
Also in the glovebox, 30 wt.% MAO/toluene solution (1.18 mL) is diluted
with toluene (3.4 mL), and an amount of open architecture titanium complex (4
to or 12) equal to 0.048 mmol of titanium is then added to the diluted MAO to
form
a solution. This resulting solution is then mixed with the dry, MAO-treated
silica
described above. After stirring for an additional 0.5 h, the supported complex
is
dried under vacuum to give a supported complex (about 1.80 g).
EXAMPLE 18
Copolymerization of Ethylene and 1-Hexene Using
Supported Complex 4
A one-liter, stainless-steel reactor is charged with 1-hexene (15 mL).
Triisobutylaluminum (0.5 mL of 1.0 M solution in heptane, 0.5 mmol) and,Stadis
425 fatty amine (12 mg, product of Akzo Nobel) in heptane solution (3.0 mL)
are
mixed in one sidearm of the injector. This mixture is then flushed into the
reactor with nitrogen pressure and isobutane (about 400 mL). Hydrogen is
added (300 dpsig from a 10-mL stainless-steel cylinder pressurized initially
to
500 psig H2) to the reactor, which is then pressurized with ethylene to 350
psig.
The reactor contents are allowed to equilibrate at 80 C. Supported complex 4
(58 mg) is loaded into the other injector arm and then flushed into the
reactor
with isobutane (85 mL) and nitrogen pressure. The polymerization proceeds for
0.5 h. The reactor is 'vented and the olefin polymer is collected and dried.
Activity: 1,650 kg polyolefin per g titanium per hour.
COMPARATIVE EXAMPLE 19
Copolymerization of Ethylene and 1-Hexene Using
Supported Complex 12
All procedures are repeated, except that supported complex 12 is used.
Activity: 501 kg polyolefin per g titanium per hour.
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Example 18 and Comparative Example 19 demonstrate the advantage of
selecting a supported, open architecture, indeno[1,2-b]indolyl complex for
making ethylene copolymers.
EXAMPLE 20
Propylene Polymerization Using Supported Complex 4
To a 1-L, stainless-steel stirred reactor, at room temperature, 1.0 mL of
1.OM of triisobutylaluminum in heptane is flushed into the reactor with 450 mL
of
dry, oxygen-free propylene. The reactor is brought to 700C and allowed to
equilibrate. Polymerization begins upon adding supported complex 4 (98 mg) by
io flushing with 50 mL of dry, oxygen-free propylene. After 30 minutes of
polymerization at 70 C, the reactor is vented to remove the remaining
propylene.
The polymer is removed from the reactor and dried. Activity: 331 ' kg
polypropylene per g titanium per hour.
COMPARATIVE EXAMPLE 21
Propylene Polymerization Using Supported Complex 12
The polymerization of Example 20 is repeated, except that supported
complex 12 is used. Activity: 79 kg polypropylene per g titanium per hour.
Example 20 and Comparative Example 21 demonstrate the advantage of
selecting a supported, open architecture, indeno[1,2-b]indolyl complex for
making polypropylene.
The preceding examples are meant only as illustrations. The following
claims define the invention.
26
