Note: Descriptions are shown in the official language in which they were submitted.
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DICATIONIC NON-METALLOCENE GROUP 4 METAL COMPLEXES
BACKGROUND INFORMATION
The present invention relates to compounds that are useful, inter alia, as
catalysts
or catalyst components. More particularly, the present invention relates to
dicationic
compounds comprising a Group 4 metal atom (Ti, Zr, Hf) that are particularly
adapted for
use in the coordination polymerization of unsaturated compounds. Such
compounds are
particularly advantageous for use in a polymerization process wherein at least
one
polymerizable monomer is combined under polymerization conditions with a
catalyst or
catalyst composition to form a polymeric product.
It is previously known in the art to activate Ziegler-Natta polymerization
catalysts,
particularly such catalysts comprising Group 3-10 metal complexes containing
delocalized
~c-bonded ligand groups, using Lewis acids to form catalytically active
derivatives of such
Group 3-10 metal complexes. Examples of suitable Lewis acids include
tris(perfluorophenyl)borane and tris(perfluorobiphenyl)borane. Examples of
such
processes are disclosed in US-A-5,721,185 and J. Am. Chem. Soc., 118, 12451-
12452
(1996), and elsewhere.
According to J. Chem. Soc. Chem. Commun., 1999, 115-116, certain specifically
substituted bis-Cp zirconocenedimethyl complexes may be converted to a
dicationic
derivative at -60°C using multiple equivalents of
trispentafluorophenylborane. The
resulting metallocenes required the presence of either pendant phosphine
moieties or
benzyl groups on the cyclopentadienyl ring system and two equivalents of the
methyltris(pentafluorophenyl)borate anion for charge balance. Upon heating
even to
-40 °C the product decomposed to give the corresponding monocationic
complex and free
tris(pentafluorophenyl)borane, thereby indicating the complexes would be
unsuited for use
as polymerization catalyst components.
In US-A-5,318,935 metal complexes containing two amido groups optionally
linked
by means of a bridging group are disclosed.
Finally, in Or4anometallics, 1998,17, 5908-5912, the reaction of the strongly
Lewis
acidic compound, tris(pentafluorophenyl)aluminum, with
bis(cyclopentadienyl)zirconium
dimethyl was shown to form an unstable (~-methyl) derivative via methide
abstraction,
which rapidly collapsed through a back exchange reaction at temperatures above
0°C to
form bis(cyclopentadienyl)methylpentafluoro-phenyl zirconium. These compounds
also
would find little use as catalyst components for addition polymerizations due
to the lack of
temperature stability.
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All of the foregoing attempts have failed to prepare a metal complex that is
useful
in catalytic applications, especially in the polymerization of one or more
ethylenically
unsaturated monomers under addition polymerization conditions.
SUMMARY OF THE INVENTION
According to the present invention there are now provided dicationic Group 4
metal
compounds corresponding to the formula:
Y'
~ +2
12A- (I)
Y X x'
wherein:
Y' and Y2 independently each occurrence is an anionic ligand group that is
covalently bonded to M by means of a sigma bond through an oxygen, phosphorus
or
nitrogen atom, and containing up to 50 atoms, not counting hydrogen, said Y'
and Y2
optionally being joined through bridging group, J, and further optionally, Y'
and Y2 may
also contain a coordinate/covalent bound to M;
J is an optional divalent bridging group having up to 20 atoms not counting
hydrogen;
jis0orl;
M is a Group 4 metal;
X' independently each occurrence is a Lewis base;
x' is 0, 1 or 2; and
A- independently each occurrence is an anion of up to 50 atoms other than
hydrogen, derived or derivable from a Lewis acid, said A- optionally forming
an adduct with
the metal complex by means of a ~-bridging group, and further optionally two
A' groups
may be joined together thereby forming a single dianion, optionally containing
one or more
w-bridging groups.
The compounds of the invention may be formed by contacting a charge-neutral
Group 4 metal coordination complex having two monovalent, anionic ligand
groups, X (or
optionally the two X groups together form a single divalent, anionic ligand
group), or
precursors) thereof (catalyst) with at least 2 molar equivalents of a charge-
neutral, Lewis
acid compound (activator), A, or a mixture thereof, such that the X groups of
the Group 4
metal coordination complex are abstracted or partially abstracted, thereby
forming a
charge separated cation/anion pair, a zwitterionic metal complex, or a complex
having both
cation/anion and zwitterion functionality. Preferably the molar ratio of
catalyst:activator
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employed in the foregoing process is from 1:2 to 1:10, more preferably the
ratio is from 1:2
to 1:3, and most preferably from 1:2 to 1:2.5.
The foregoing process is illustrated by the following schematic drawing:
Y1 Y1
Ji/ ~M+2 2A_
Y2 Xix, Y2 Xlx,
~ wherein
Y', YZ, M, J, j, X, X', x', A, and A-, are as previously defined.
The present invented compounds are stable at elevated temperatures of at least
0°C, preferably at least 20°C up to as high as 150°C or
higher and are usefully employed
in a process for polymerization of ethylenically unsaturated monomers under
solution,
slurry, high pressure, or gas phase polymerization conditions. Relatively high
molecular
weight polymers may be readily obtained by use of the present metal complexes
in the
foregoing polymerization processes. Additionally, the foregoing metal
complexes are
suitably employed as initiators or catalysts for cationic polymerizations,
such as the
cationic polymerization of styrene or isobutylene, ring opening
polymerizations, such as the
polymerization of oxiranes or epoxides, especially propylene oxide, and the
copolymerization of an olefin, especially ethylene, with a ring openable
monomer.
Accordingly, the present invention additionally provides a process for the
polymerization of one or more ethylenically unsaturated, addition
polymerizable monomers
comprising contacting the same, optionally in the presence of an inert
aliphatic, alicyclic or
aromatic hydrocarbon, under polymerization conditions with the above metal
complex, or
alternatively, forming the above metal complex in situ in the presence of or
prior to addition
to, a reaction mixture comprising one or more ethylenically unsaturated,
polymerizable
compounds.
DETAILED DESCRIPTION OF THE INVENTION
All references herein to elements belonging to a certain Group refer to the
Periodic
Table of the Elements published and copyrighted by CRC Press, Inc., 1995. Also
any
reference to the Group or Groups shall be to the Group or Groups as reflected
in this
Periodic Table of the Elements using the IUPAC system for numbering groups.
Where
any reference is made herein to any publication, patent application or
provisional patent
application, the contents thereof are incorporated herein in its entirety by
reference. By the
term "Lewis acid", in reference to activator compounds herein, is meant
compounds that
are sufficiently electrophilic, such that a fully charge separated
cation/anion pair, a ~-
bridged complex or a zwiterionic complex is formed upon combination of the
respective
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catalyst and activators. Preferred anionic ligand groups, X, are hydrocarbyl,
silyl, N,N-
dialkylamido and alkanediylamido groups of up to 20 atoms not counting
hydrogen, or two
such X groups together are an alkanediyl or alkenediyl group which together
with M form a
metallocycloalkane or metallocycloalkene. By the term "partially dicationic"
is meant that at
least one A- group (or the entity formed from two A- groups collectively) is
not fully charge
separated from the metal center, M, or that at least one A- group (or the
entity formed from
two A- groups collectively) form a zwitterionic complex.
Preferred activators, A, are aluminum compounds containing at least one
halohydrocarbyl ligand, preferably a fluoroaryl ligand. More preferred are
tri(halohydrocarbyl)aluminum compounds having up to 50 atoms other than
hydrogen,
especially tri(fluoroaryl) aluminum compounds, most preferably
tris(perfluoroaryl)aluminum
compounds, and most highly preferably tris(pentafluorophenyl)alumirium. The
activator
compound may be used in pure form or in the form of an adduct with a Lewis
base such as
an ether.
Suitable Lewis acidic activators may be prepared by exchange between
tris(pentafluorophenyl)boron and alkylaluminum- or alkyaluminumoxy- compounds
such as
alumoxanes or diisobutyl(2,6-di-t-butyl-4-methylphenoxy)aluminum, as disclosed
in Biagini
et.al., US-A-5,602,269, and pending application USSN 09/330673 (W000/09515).
The
aluminum containing Lewis acids may be previously prepared and used in a
relatively pure
state or generated in situ by any of the foregoing techniques in the presence
of the metal
complex. Tris(perfluoroaryl)aluminum and exchange products obtained by mixing
tris(perfluoroaryl)borane compounds, especially tris(pentafluoro-phenyl)boron,
with
methylalumoxane (MAO) or trialkylaluminum-, especially, triisobutylaluminum-
modified
methylalumoxane (MMAO) are highly preferred. This reaction product of
tris(perfluoroaryl)boron with an alumoxane comprises a tris(fluoraryl)aluminum
component
of high Lewis acidity and a form of alumoxane which is rendered more Lewis
acidic by the
inherent removal of trimethylaluminum (TMA) via exchange to form
trimethylborane.
Optimized reaction products of these reactions correspond to the empirical
formula:
(AIArf3_W~O'w~)w (AIAr'3_X~(OQ2)X~) x (AIQ'3_y(002)y)r I(-AIQz-O-)Z~]Z, where;
Arf is a fluorinated aromatic hydrocarbyl moiety of from 6 to 30 carbon atoms;
preferably fluoroaryl, more preferably perfluoroaryl, and most preferably
pentafluorophenyl;
Q' is C,_2o alkyl, preferably methyl;
Q2 is C,_2o hydrocarbyl, optionally substituted with one or more groups which
independently each occurrence are hydrocarbyloxy, hydrocarbylsiloxy,
hydrocarbylsilylamino, di(hydrocarbylsilyl)amino, hydrocarbylamino,
di(hydrocarbyl)amino,
di(hydrocarbyl)phosphino, or hydrocarbylsulfido groups having from 1 to 20
atoms other
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than hydrogen, or, optionally, two or more Q2 groups may be covalently linked
with each
other to form one or more fused rings or ring systems;
w' is a number from 0 to 3;
w is a number from 0 to 1.0; preferably from 0.5 to 1.0, more preferably from
0.8 to
1.0;
x' is a number from 0 to 3;
x is a number from 1.0 to 0; preferably from 0.5 to 0, more preferably from
0.2 to 0;
y' is a number from 0 to 3;
y is a number from 1.0 to 0; preferably from 0.5 to 0, more preferably from
0.2 to 0;
z' is a number from 0 to 30; and
z is a number from 0 to 20, preferably from 0 to 5, more preferably from 0 to
0.5.
The moieties, (AIArf3_W~Q'W~), (AIAr'3_x~(OQ2)X~), (AIO'3_y'(OQ2)y~), and [(-
AIQ2-O-)Z~] ,
may exist as discrete entities or as dynamic exchange products. That is, the
foregoing
formula is an idealized representation of the composition, which may actually
exist in
equilibrium with additional exchange products.
An additional suitable Lewis acid activator may be formed in situ by reaction
of
residual or excess Lewis acid activator, prefearbly,
tris(pentaflurophenyl)aluminum, with
the anion resulting from initial abstraction of an X group from the metal
complex.
Accordingly, such anions resulting from the foregoing reaction are of the
formula: [A-~X-A]~
, where, A- is the monovalent ligand derivative of A, preferably -AI(C6F5)3,
and wX is the ~-
bridged derivative of X, preferably a ~-methyl group. An example of such an
anion is
[(C6F5)3AI-~-CH3-AI(C6F5)3]'. However, because the group 4 metal complex and
originally
formed anion form a rather stable coordination pair under normal reaction
conditions, the
formation of the foregoing ~-methyl bridged anion is likely observed only
under reaction
conditions that would favor destabilization of the previously disclosed
coordination pair.
Additional examples of the anion A- are ligands of the formula: [M'Q4] , where
M' is
a Group 13 metal or metalloid, preferably AI, and Q independently each
occurrence is an
anionic ligand group, preferably an alkyl, aryl, aralkyl, or fluorinated
aromatic ligand, that
optionally may form a ~.-bridge to the metal, M. Most preferred examples of
this type of A-
anion are is [CH3AI(C6F5)3]- and [~-CH3AI(C6F5)3] .
Exemplary J groups include O, as well as groups corresponding to the formula:
(ER*2)e, (BNR*2)e, or PR*2BR62, wherein,
E independently each occurrence is C, Si, Sn, or Ge;
e=1,2,3,or4;
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R* independently each occurrence is C,_,o hydrocarbyl, or optionally two R*
groups
are joined together; and
R6 independently each occurrence is halide, or C,_,2 hydrocarbyl.
Suitably, Y'and Y2 are an amido group or phosphido group that is sigma bonded
to
M of the formula =NR', or =PR', where R' is hydrocarbyl,
dihydrocarbylaminohydrocarbyl,
silyl, silylhydrocarbyl, hydrocarbylsilyl, or a cyclic or polycyclic, nitrogen
containing ring
system having up to 20 atoms, not counting hydrogen, and optionally R' may be
covalently
or coordinately covalently bonded to J or M. Preferred sigma bonded ligand
groups of the
formula =NR' or =PR', are those wherein R' is alkyl or cycloalkyl of up to 10
carbons.
Such complexes together with J form divalent bridging structures attached to
the metal M.
Suitable compounds according to the present invention include compounds having
the following structures:
N
+2
O---' M 2A-
M+2 2A_
M+2 2A.
N
R22N
R2
O 2A /
~~ N N R2
/ N~ 1 ~ ~ / M+2 2A
N R2
NR'
~CR3)2S~\ \M+2 2A- R2
NRy
or
where M, R', and A- are as previously defined, and
R2, independently each occurrence is H or a hydrocarbyl, silyl, or
trihydrocarbylsilyl-
substituted hydrocarbyl group, said group having up to 20 atoms not counting
hydrogen.
In the compounds of the invention, some or all of the bonds between M, Y' and
Y2
may possess partial bond characteristics. In addition, when Y' or Y2 is a
nitrogen
containing, sigma bonded group, particularly a group of the formula, =NR',
when R' is a
primary alkyl group, an electronic interaction between the nitrogen and either
one or both
of the anionic moieties, A-, may occur.
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The process for preparing the dicationic complexes of the invention is
conducted at
temperatures from -80 to 220°C, preferably from 25 to 50°C, and
preferably in a
hydrocarbon diluent or solvent, especially C4_,2 aliphatic, cycloaliphatic or
aromatic
hydrocarbons or a mixture thereof.
Suitable addition polymerizable monomers for use with the foregoing novel
catalyst
compositions include ethylenically unsaturated monomers, acetylenic compounds,
conjugated or non-conjugated dienes, and polyenes. Preferred monomers include
olefins,
for example alpha-olefins having from 2 to 20,000, preferably from 2 to 20,
more preferably
from 2 to 8 carbon atoms and combinations of two or more of such alpha-
olefins.
Particularly suitable alpha-olefins include, for example, ethylene, propylene,
1-butene,
isobutylene, 1-pentene, 4-methylpentene-1, 1-hexene, 1-heptene, 1-octene, 1-
nonene, 1-
decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, or
combinations thereof, as well as long chain vinyl terminated oligomeric or
polymeric
reaction products formed during the polymerization, and C,o_3o «-olefins
specifically added
to the reaction mixture in order to produce relatively long chain branches in
the resulting
polymers. Preferably, the alpha-olefins are ethylene, propylene, 1-butene, 1-
pentene, 4-
methyl-pentene-1, 1-hexene, 1-octene, and combinations of ethylene and/or
propene with
one or more other alpha-olefins. Other preferred monomers include styrene,
halo- or alkyl
substituted styrenes, vinylbenzocyclobutene, 1,4-hexadiene, dicyclopentadiene,
ethylidene
norbornene, and 1,7-octadiene. Mixtures of the above-mentioned monomers may
also be
employed.
In general, the polymerization may be accomplished under conditions well known
in
the prior art for Ziegler-Natta or Kaminsky-Sinn type polymerization
reactions.
Suspension, solution, slurry, gas phase or high pressure, whether employed in
batch or
continuous form or other process conditions, may be employed if desired.
Examples of
such well known polymerization processes are depicted in U.S. Patent Nos.
5,084,534,
5,405,922, 4,588,790, 5,032,652, 4,543,399, 4,564,647, 4,522,987, and
elsewhere.
Preferred polymerization temperatures are from 0-250°C. Preferred
polymerization
pressures are from atmospheric to 3000 atmospheres (100 kPa to 300 Pma).
Preferred processing conditions include solution polymerization, more
preferably
continuous solution polymerization processes, conducted in the presence of an
aliphatic or
alicyclic liquid diluent. By the term "continuous polymerization" is meant
that at least the
products of the polymerization are continuously removed from the reaction
mixture.
Preferably one or more reactants are also continuously added to the
polymerization
mixture during the polymerization. Examples of suitable aliphatic or alicyclic
liquid diluents
include straight and branched-chain C4-12 hydrocarbons and mixtures thereof;
alicyclic
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hydrocarbons such as cyclohexane, cycloheptane, methylcyclohexane,
methylcycloheptane, and mixtures thereof; and perfluorinated hydrocarbons such
as
perfluorinated C4_,o alkanes, and the like. Suitable diluents also include
aromatic
hydrocarbons (particularly for use with aromatic a-olefins such as styrene or
ring alkyl-
s substituted styrenes) including toluene, ethylbenzene or xylene, as well as
liquid olefins
(which may act as monomers or comonomers) including ethylene, propylene, 1-
butene,
isobutylene, butadiene, 1-pentene, cyclopentene, 1-hexene, cyclohexene, 3-
methyl-1-
pentene, 4-methyl-1-pentene, 1,4-hexadiene, 1-octene, 1-decene, styrene,
divinylbenzene,
allylbenzene, vinyltoluene (including all isomers alone or in admixture), and
the like.
Mixtures of the foregoing are also suitable. The foregoing diluents may also
be
advantageously employed during the synthesis of the metal complexes and
catalyst
activators of the present invention.
In most polymerization reactions the molar ratio of catalyst:polymerizable
compounds employed is from 10-'2:1 to 10-':1, more preferably from 10'2:1 to
10-5:1.
Molecular weight control agents may be used in combination with the present
cocatalysts. Examples of such molecular weight control agents include
hydrogen, trialkyl
aluminum compounds or other known chain transfer agents. A particular benefit
of the use
of the present cocatalysts is the ability (depending on reaction conditions)
to produce
narrow molecular weight distribution a-olefin homopolymers and copolymers in
greatly
improved catalyst efficiencies. Preferred polymers have Mw/Mn of less than
2.5, more
preferably less than 2.3. Such narrow molecular weight distribution polymer
products are
highly desirable due to improved tensile strength properties.
The catalyst composition of the present invention can also be employed to
advantage in the gas phase polymerization and copolymerization of olefins,
preferably by
supporting the catalyst composition by any suitable technique. Gas phase
processes for
the polymerization of olefins, especially the homopolymerization and
copolymerization of
ethylene and propylene, and the copolymerization of ethylene with higher alpha
olefins
such as, for example, 1-butene, 1-hexene, 4-methyl-1-pentene are well known in
the art.
Such processes are used commercially on a large scale for the manufacture of
high
density polyethylene (HDPE), medium density polyethylene (MDPE), linear low
density
polyethylene (LLDPE) and polypropylene.
The gas phase process employed can be, for example, of the type that employs a
mechanically stirred bed or a gas fluidized bed as the polymerization reaction
zone.
Preferred is the process wherein the polymerization reaction is carried out in
a vertical
cylindrical polymerization reactor containing a fluidized bed of polymer
particles supported
above a perforated plate, the fluidization grid, by a flow of fluidization
gas.
_g_
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The gas employed to fluidize the bed comprises the monomer or monomers to be
polymerized, and also serves as a heat exchange medium to remove the heat of
reaction
from the bed. The hot gases emerge from the top of the reactor, normally via a
tranquilization zone, also known as a velocity reduction zone, having a wider
diameter than
the fluidized bed and wherein fine particles entrained in the gas stream have
an
opportunity to gravitate back into the bed. It can also be advantageous to use
a cyclone to
remove fine particles from the hot gas stream. The gas is then normally
recycled to the
bed by means of a blower or compressor and one or more heat exchangers to
strip the
gas of the heat of polymerization.
A preferred method of cooling of the bed, in addition to the cooling provided
by the
cooled recycle gas, is to feed a volatile liquid to the bed to provide an
evaporative cooling
effect. The volatile liquid employed in this case can be, for example, a
volatile inert liquid,
for example, a saturated hydrocarbon having about 3 to about 8, preferably 4
to 6, carbon
atoms. In the case that the monomer or comonomer itself is a volatile liquid
or can be
condensed to provide such a liquid, this can be suitably be fed to the bed to
provide an
evaporative cooling effect. Examples of olefin monomers which can be employed
in this
manner are olefins containing from about 3 to about eight, preferably from 3
to six carbon
atoms. The volatile liquid evaporates in the hot fluidized bed to form gas
which mixes with
the fluidizing gas. If the volatile liquid is a monomer or comonomer, it may
undergo some
polymerization in the bed. The evaporated liquid then emerges from the reactor
as part of
the hot recycle gas, and enters the compression/heat exchange part of the
recycle loop.
The recycle gas is cooled in the heat exchanger and, if the temperature to
which the gas is
cooled is below the dew point, liquid will precipitate from the gas. This
liquid is desirably
recycled continuously to the fluidized bed. It is possible to recycle the
precipitated liquid to
the bed as liquid droplets carried in the recycle gas stream, as described,
for example, in
EP-A-89691, US-A-4543399, WO 94/25495 and US-A-5352749. A particularly
preferred
method of recycling the liquid to the bed is to separate the liquid from the
recycle gas
stream and to reinject this liquid directly into the bed, preferably using a
method that
generates fine droplets of the liquid within the bed. This type of process is
described in
WO 94/28032.
The polymerization reaction occurring in the gas fluidized bed is catalyzed by
the
continuous or semi-continuous addition of catalyst. Such catalyst can be
supported on an
inorganic or organic support material if desired. The catalyst can also be
subjected to a
prepolymerization step, for example, by polymerizing a small quantity of
olefin monomer in
a liquid inert diluent, to provide a catalyst composite comprising catalyst
particles
embedded in olefin polymer particles.
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The polymer is produced directly in the fluidized bed by catalyzed
(co)polymerization of the monomers) on the fluidized particles of catalyst,
supported
catalyst or prepolymer within the bed. Start-up of the polymerization reaction
is achieved
using a bed of preformed polymer particles, which, preferably, is similar to
the target
polyolefin, and conditioning the bed by drying with a dry inert gas such as
nitrogen prior to
introducing the catalyst, the monomers) and any other gases which it is
desired to have in
the recycle gas stream, such as a diluent gas, hydrogen chain transfer agent,
or an inert
condensable gas when operating in gas phase condensing mode. The produced
polymer
is discharged continuously or discontinuously from the fluidized bed as
desired, optionally
exposed to a catalyst kill and optionally pelletized.
EXAMPLES
It is understood that the present invention is operable in the absence of any
component that has not been specifically disclosed. The following examples are
provided
in order to further illustrate the invention and are not to be construed as
limiting. Unless
stated to the contrary, all parts and percentages are expressed on a weight
basis. The
term "overnight", if used, refers to a time of approximately 16-18 hours,
"room
temperature", if used, refers to a temperature of about 20-25 °C, and
"mixed alkanes"
refers to a mixture of hydrogenated propylene oligomers, mostly C6-C,2
isoalkanes,
available commercially under the trademark Isopar ET~" from Exxon Chemicals
Inc. The'H
(300 MHz) and'3C NMR (75 MHz) spectra were recorded on a Varian XL-300
spectrometer. The'H and'3C NMR spectra are referenced to the residual solvent
peaks
and are reported in ppm relative to tetramethylsilane. All Jvalues are given
in Hz.
Tetrahydrofuran (THF), diethylether, toluene, and hexane were used following
passage
through double columns charged with activated alumina and Q-5~ catalyst
(available from
Englehardt Chemicals, Inc.). The compounds BCI3-SMe2, B(NMe2)3, n-BuLi,
Bis(catecholato)diboron, LiNMe2 and 2,6-diisopropylaniline were all used as
purchased
from Aldrich. All syntheses were performed under dry nitrogen or argon
atmospheres
using a combination of glove box and high vacuum techniques.
Examples 1-2
Preparation of metal complex
A. (N,N'-di(2,6-diisopropylphenyl)-1,3-propanediamido)titanium dimethyl (DIP,
Ex
and Comp. A)
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CH(CH3)2 (CH3)2HC
~ (CH~3\
N\ /N
Ti (C H3)2
CH(CH3)2 (CH3)2HC
This compound was prepared substantially according to the teachings of
US-A-5,318,935.
B. bis(N,N'-di(2,6-diisopropylphenyl)amido)(dimethylamino)boron)titanium
dimethyl
(BAB, Ex. 2)
(HsC)2N N(CH3)2
(CHs)2HC ~ I CH(CH3)2
B-B
/ \
N~ /N
Ti(CH3)2
(CH3)2HC C H(CH3)2
Preparation of Chlorobis(dimethylamido)borane. BC13-SMe2 (62.000 g, 345.78
mmol) and B(NMe2)3 (98.921 g, 691.56 mmol) were stirred together at room
temperature
overnight under a nitrogen bubbler. The mixture was then heated to reflux for
one hour to
drive off any residual SMez. Allowing the pale yellow liquid to stir to room
temperature
followed by filtration resulted in the isolation of the desired product
(139.436 g, 93.3
percent yield).
'H NMR (C6D6): s 2.49 (s, 12 H).'3C NMR (C6D6): b 39.86.
Preparation of Tetrakis(dimethylamido)diborane via CIB(NMe)2.
Chlorobis(dimethylamido)borane (30.000 g, 223.19 mmol) was refluxed in hexane
(200
mL) as Na/K alloy [Na (1.539 g , 66.96 mmol)/8.726 g K (8.726 g, 223.19 mmol)]
was
added dropwise to the solution. After the first several drops the reaction
initiated as
evidenced by a sudden increase in the reflux. The heat was then turned off and
the alloy
added slowly so as to maintain a reflux. After the addition was complete, the
reaction
mixture was heated to reflux for an additional hour and then stirred at room
temperature
for three hours. The mixture was then filtered through a diatomaceous earth
filter pad and
the volatile components removed, resulting in the isolation of a yellow
liquid. Fractional
vacuum distillation resulted in the isolation of the desired compound as a
pale yellow liquid
(7.756 g, 35.1 percent yield).
'H NMR (C6D6): s 2.73 (s, 24 H).'3C NMR (C6D6): 8 41.37.
Preparation of Tetrakis(dimethylamido)diborane via Bis(catecholato)-diboron
Lithium dimethylamide (10.70 g, 210.0 mmol) was added slowly as a solid to a
solution of
bis(catecholato)diboron (10.00 g, 42.00 mmol) in diethylether (200 mL) at
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-20~C. This mixture was then allowed to stir for an additional 40 hours at
room
temperature. After the reaction period, the ether was removed under vacuum and
the
residue extracted and filtered using hexane. Removal of hexane resulted in the
isolation of
a yellow oil: Fractional vacuum distillation resulted in the isolation of the
desired
compound as a pale yellow liquid (5.493 g, 66.0 percent yield).
Preparation of Bis(dimethylamido)diborondichloride
Tetrakis(dimethylamido)diborane (7.756 g, 39.19 mmol) was stirred in
diethylether (100
mL) at -78°C as HCI (156.75 mmol, 156.75 mL of 1.0 M solution in
diethylether) was added
dropwise. This mixture was then allowed to stir for six hours at room
temperature. After
the reaction period the volatiles were removed and the residue extracted and
filtered using
hexane. Removal of the hexane resulted in the isolation of a yellow oil.
Fractional vacuum
distillation resulted in the isolation of the desired compound as a pale
yellow liquid (4.722
g, 66.7 percent yield).
'H NMR (C6D6): 8 2.40 (s, 6 H), 2.50 (s, 6 H).'3C NMR (C6D6): 8 37.62, 41.78.
Preparation of 2,6-Diisopropylaniline, lithium salt n-BuLi (56.40 mmol, 35.25
mL of 1.6 M solution in hexane) was added dropwise to a solution of 2,6-
diisopropylaniline
(10.00 g, 56.40 mmol) in hexane (100 mL). This mixture was allowed to stir for
3 hours
during which time a white precipitate formed. After the reaction period the
mixture was
filtered and the white salt washed with hexane and dried under vacuum and used
without
further purification or analysis (9.988 g, 96.7 percent yield).
Preparation of 1,2-Bis(2,6-diisopropylanilide)-1,2-bis(dimethylamido)-
diborane Bis(dimethylamido)diborondichloride (2.350 g, 13.00 mmol) in
diethylether (10
mL) was added dropwise to a solution of 2,6-diisopropylaniline, lithium salt
(4.765 g, 26.01
mmol) in diethylether (50 mL) at 0°C. This mixture was then allowed to
stir overnight at
room temperature. After the reaction period the volatiles were removed and the
residue
extracted and filtered using hexane. Removal of the hexane resulted in the
isolation of a
the desired product as a white solid (5.322 g, 88.9 percent yield).
'H NMR (toluene-de): 8 0.9-1.4 (br m, 24 H), 2.3 (s, 6 H), 2.8 (s, 6 H), 3.7
(s, 2 H),
7.0 (br s, 6 H).
'3C NMR (toluene-d8): 8 22.51, 24.03 (br), 28.17, 36.82, 42.67, 123.19,
124.78,
140.71, 145.02 (br).
MS(EI): m/z 460.4025 (M-H)+, calcd. (M-H)+ 460.4026.
Preparation of 1,2-Bis(2,6-diisopropylanilide)-1,2-
bis(dimethylamido)diborane, dilithium salt. 1,2-Bis(2,6-diisopropylanilide)-
1,2-
bis(dimethylamido)diborane (1.820 g, 3.950 mmol) was stirred in hexane (75 mL)
as n-
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BuLi (7.91 mmol, 4.94 mL of 1.6 M solution in hexane) was added dropwise. This
mixture
was then allowed to stir overnight. After the reaction period the mixture was
filtered and
the salt washed well with hexane and dried under vacuum resulting in the
isolation of the
desired product as a white powder (1.6878 g, 90.4 percent yield).
'H NMR (THF-da): 8 1.04 (d, 6 H), 1.18 (d, 6 H), 2.45 (s, 12 H), 3.66 (septet,
4 H),
6.29(t,2H),6.73(d,4H).
'3C NMR (THF-d8): 8 24.88, 25.34, 28.00, 40.91, 114.40, 121.95, 137.21,
158.76.
Anal. Calcd. For C28H46NaB2Li2: C, 70.92; H, 9.78; N, 11.81. Found: C, 70.90;
H,
11.12; N, 9.66.
Preparation of Dichloro-[1,2-Bis(2,6-diisopropylanilide)-1,2-
bis(dimethylamido)diborane]titanium. 1,2-Bis(2,6-diisopropylanilide)-1,2-
bis(dimethylamido)diborane, dilithium salt (0.600 g, 1.27 mmol) in THF (20 mL)
was added
dropwise to a slurry of TiCl3(THF)3 (0.471 g, 1.27 mmol) in THF (50 mL) at
0°C. This
mixture was then allowed to stir at room temperature for 45 minutes. PbCl2
(0.177 g,
0.640 mmol) was then added as a solid and the mixture allowed to stir for an
additional 30
minutes. After the reaction period the volatiles were removed and the residue
extracted
and filtered using hexane. Concentration of the hexane and cooling to -
10°C overnight
resulted in the formation of orange X-ray quality crystals (0.156 g, 21.3
percent yield).
'H NMR (toluene-d8): 8 1.23 (d, 6 H), 1.45 (d, 6 H), 2.17 (s, 6 H), 2.76 (s, 6
H), 3.53
(septet, 4 H), 7.11 (s, 6 H).
'3C NMR (toluene-de): s 24.94, 24.67, 29.48, 39.33, 42.93, 124.08 (br), 17.23,
150.64.
MS(EI): mlz 578.2789 (M)+, calcd. (M)+ 578.2781.
Anal. Calcd. For C28H4sB2N2TiCl2: C, 58.07; H, 8.01; N, 9.67. Found: C, 58.28;
H,
8.20; N, 9.42.
Preparation of Dimethyl-[1,2-Bis(2,6-diisopropylanilide)-1,2-
bis(dimethylamido)diborane]titanium Dichloro-[1,2-Bis(2,6-diisopropylanilide)-
1,2-
bis(dimethylamido)diborane]titanium (0.272 g, 0.470 mmol) was stirred in
diethylether (40
mL) as MeMgBr (0.940 mmol, 0.313 mL of 3.0 M solution in diethylether) was
added
dropwise. This mixture was allowed to stir for one hour. After the reaction
period the
volatiles were removed and the residue extracted and filtered using hexane.
Removal of
the hexane resulted in the isolation of the desired product as a dark yellow
oil (0.209 g,
82.5 percent yield).
'H NMR (C6D6): 8 1.05 (s, 6 H), 1.21 (d, 3JHH = 6.9 Hz, 16 H), 1.32 (d, 3JHH =
6.3 Hz,
16 H), 2.19 (s, 6 H), 2.69 (s, 6 H), 3.58 (br, 2 H), 7.0-7.2 (m, 6 H).
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'3C NMR (C6D6): 8 24.06, 24.83, 29.31, 39.58, 42.93, 57.38, 123.97, 125.18,
139.5
(br), 149.45.
MS(EI): m/z 538.3858 (M)+, calcd. (M)+ 538.3793.
Solution Polyethylene Polymerization
Mixed hexanes and 1-octene were purified by sparging with purified nitrogen
followed by passage through columns containing alumina (A-2, available from
LaRoche
Inc.) and Q5 reactant (available from Englehard Chemicals Inc.) at 50 psig
(340 kPa) using
a purified nitrogen pad. All transfers of solvents and solutions described
below were
accomplished using a gaseous pad of dry, purified nitrogen or argon. Gaseous
feeds to
the reactor were purified by passage through columns of A-204 alumina
(available from
LaRoche Inc.) and Q5 reactant. The aluminas were previously activated by
treatment at
375°C with nitrogen and Q5 reactant was activated by treatment at
200°C with 5 percent
hydrogen in nitrogen.
Batch reactor polymerizations were conducted in a two liter Parr reactor
equipped
with an electrical heating jacket, internal serpentine coil for cooling, and a
bottom drain
valve. Pressures, temperatures and block valves were computer monitored and
controlled.
Mixed alkanes solvent (about 740 g) and 1-octene (118 g) were measured in a
solvent
shot tank fitted with a differential pressure transducer or weigh cell. These
liquids were
then added to the reactor from the solvent shot tank. The contents of the
reactor were
stirred at 1200 rpm. Hydrogen was added by differential expansion (0 25 psi,
170 kPa)
from a 75 ml shot tank initially at 300 psig (2.1 Mpa). The contents of the
reactor was then
heated to the desired run temperature under 500 psig (3.4 Mpa) of ethylene
pressure. The
catalyst composition (as a 0.0050 M solution in toluene) and cocatalyst
(tris(pentafluorophenyl)aluminum, FAAL) were combined in the desired ratio in
the glove
box and transferred from the glove box to the catalyst shot tank through 1/16
in (0.16 cm)
tubing using toluene to aid in the transfer. The catalyst tank was then
pressurized to 700
psig (4.8 Mpa) using nitrogen. After the contents of the reactor had
stabilized at the
desired run temperature of 140°C, the catalyst was injected into the
reactor via a dip tube.
The temperature was maintained by allowing cold ethylene glycol to pass
through the
internal cooling coils. The reaction was allowed to proceed for 15 minutes
with ethylene
provided on demand. The contents of the reactor were expelled into a 4 liter
nitrogen
purged vessel and quenched with isopropyl alcohol. Approximately 10 ml of a
toluene
solution containing approximately 67 mg of a hindered phenol antioxidant
(IrganoxT"" 1010
from Ciba Geigy Corporation) and 133 mg of a phosphorus stabilizer (IrgafosTM
168 from
Ciba Geigy Corporation) were added. Volatile materials were removed from the
polymers
in a vacuum oven that gradually heated the polymer to 140°C overnight
and cooled to at
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least 50°C prior to removal from the oven. After completion of the
polymerization, the
reactor was washed with 1200 ml of mixed hexanes solvent at 150°C
before reuse.
Results are contained in Table 1.
Table 1
Catalyst/ melt
cocatalyst Efficiency Densityindex**
Ex. Catalyst cocatalyst (.motes) (g/mg g/ml (dg/min)
Ti)
A* DIP FAAL 5/5 1 - -
1 " " 5/20 34 0.915 2.0
2 BAB " 5/20 40 0.896 >500
* Comparative, no bimetallic anion formed
due to 1:1 molar ratio of catalyst and
cocatalyst
** determined by micromelt index technique
As may be seen by reference to Table 1, a complex formed by use of at least 2
equivalents of cocatalyst gave a catalyst species having substantially greater
activity as
evidenced by catalyst efficiency than the catalyst species formed from use of
only a 1:1
molar ratio of catalyst and cocatalyst.
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