U.S. patent application number 09/761134 was filed with the patent office on 2001-08-30 for olefin polymerization catalysts containing amine derivatives.
This patent application is currently assigned to EQUISTAR CHEMICALS, L.P.. Invention is credited to Etherton, Bradley P., Krishnamurti, Ramesh, Nagy, Sandor, Tyrell, John A..
Application Number | 20010018502 09/761134 |
Document ID | / |
Family ID | 23124376 |
Filed Date | 2001-08-30 |
United States Patent
Application |
20010018502 |
Kind Code |
A1 |
Nagy, Sandor ; et
al. |
August 30, 2001 |
Olefin polymerization catalysts containing amine derivatives
Abstract
A single-site olefin polymerization catalyst is described. The
catalyst comprises an activator and an organometallic compound that
includes an amine derivative ligand. The catalyst is highly
productive, incorporates comonomers well, and gives polymers with
narrow molecular weight distributions.
Inventors: |
Nagy, Sandor; (Grand Island,
NY) ; Etherton, Bradley P.; (Cincinnati, OH) ;
Krishnamurti, Ramesh; (Williamsville, NY) ; Tyrell,
John A.; (Williamsville, NY) |
Correspondence
Address: |
Kevin M. Carroll
LYONDELL CHEMICAL COMPANY
3801 West Chester Pike
Newtown Square
PA
19073
US
|
Assignee: |
EQUISTAR CHEMICALS, L.P.
|
Family ID: |
23124376 |
Appl. No.: |
09/761134 |
Filed: |
January 16, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09761134 |
Jan 16, 2001 |
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09292369 |
Apr 15, 1999 |
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6204216 |
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Current U.S.
Class: |
526/147 ;
526/145; 526/146; 526/161; 526/172 |
Current CPC
Class: |
Y10S 526/943 20130101;
C08F 10/00 20130101; B01J 2231/12 20130101; C08F 210/08 20130101;
C08F 2500/03 20130101; B01J 31/1805 20130101; C08F 2500/12
20130101; C08F 210/16 20130101; C08F 4/65916 20130101; C08F 210/16
20130101; C08F 110/02 20130101; C08F 4/60 20130101; C08F 2500/03
20130101; C08F 2500/12 20130101; C08F 4/6592 20130101; C08F 4/6592
20130101; C08F 4/64048 20130101; C08F 4/65912 20130101; C08F 10/00
20130101; C08F 110/02 20130101; C08F 10/02 20130101; B01J 31/2295
20130101; B01J 31/2243 20130101; B01J 31/143 20130101; B01J 2531/46
20130101; B01J 2531/48 20130101; C08F 4/65908 20130101; C08F 10/00
20130101; C08F 10/00 20130101; C08F 10/02 20130101 |
Class at
Publication: |
526/147 ;
526/145; 526/146; 526/161; 526/172 |
International
Class: |
B01J 021/06; B01J
023/20; B01J 023/24; B01J 023/38 |
Claims
We claim:
1. A catalyst which comprises: (a) an organometallic compound of
the formula: 6wherein M is a Group 3-10 transition metal; A is O,
S, N--R", or P--R"; L is a polymerization-stable anionic ligand; X
is hydride, halide, C.sub.1--C.sub.20 alkoxy, siloxy, hydrocarbyl,
or dialkylamido; R, R', and R", which can be same or different, are
selected from hydrogen and C.sub.1--C.sub.20 hydrocarbyl; and m+ n
equals the valency of M minus 1; and (b) an activator.
2. The catalyst of claim 1 wherein L is a cyclopentadienyl.
boraaryl, pyrrolyl, azaborolinyl, quinolinyl, or pyridinyl group,
or is another amine derivative of the formula: RR'N--A.sup.- or
RR'C.dbd.N--A.sup.-.
3. The catalyst of claim 1 wherein M is a transition metal of
Groups 4 to 6.
4. The catalyst of claim 3 wherein M is a Group 4 transition
metal.
5. The catalyst of claim 4 wherein X is a chlorine, methyl or
benzyl.
6. The catalyst of claim 1 wherein the activator is an
alumoxane.
7. The catalyst of claim 6 wherein the activator further comprises
a trialkyl or triaryl aluminum compound.
8. The catalyst of claim I wherein the activator is a trialkyl or
triaryl boron compound or an ionic borate.
9. A supported catalyst of claim 1.
10. A catalyst which comprises: (a) an organometallic compound of
the formula: 7wherein M is a Group 4-6 transition metal; L is a
polymerization-stable anionic ligand; X is hydride, halide, methyl,
phenyl, benzyl, neopentyl, or a C.sub.1--C.sub.20 alkoxy, siloxy,
or dialkylamido; R, R', and R", which can be same or different, are
selected from hydrogen and C.sub.1--C.sub.20 hydrocarbyl and m+ n
equals the valency of M minus 1; and (b) an activator.
11. The catalyst of claim 10 wherein L is a cyclopentadienyl,
boraaryl, pyrrolyl, azaborolinyl, quinolinyl, or pyridinyl group,
or is another amine derivative of the formula: RR'N--A.sup.- or
RR'C.dbd.N--A.sup.-.
12. The catalyst of claim 11 wherein M is a Group 4 transition
metal.
13. The catalyst of claim 12 wherein X is a chlorine, methyl, or
benzyl.
14. The catalyst of claim 10 wherein the activator is an
alumoxane.
15. The catalyst of claim 14 wherein the activator further
comprises a trialkyl or triaryl aluminum compound.
16. The catalyst of claim 10 wherein the activator is a trialkyl or
triaryl boron compound or an ionic borate.
17. A supported catalyst of claim 10.
18. The catalyst of claim 10 wherein the organometallic compound
has the structure: 8wherein Cp is a cyclopentadienyl ligand.
19. A catalyst which comprises: (a) an organometallic compound of
the formula: 9wherein M is a Group 3-10 transition metal; A is O,
S, N--R", or P--R"; L is a polymerization-stable anionic ligand; X
is hydride, halide, C.sub.1--C.sub.20 alkoxy, siloxy, hydrocarbyl,
or dialkylamido; R, R', and R", which can be same or different, are
selected from hydrogen and C.sub.1--C.sub.20 hydrocarbyl, and m+ n
equals the valency of M minus 1; and (b) an activator.
20. The catalyst of claim 19 wherein L is a cyclopentadienyt,
boraaryl, pyrrolyl, azaborolinyl, quinolinyl, pyridinyl group or
another amine derivative of the formula: RR'C.dbd.N--A.sup.-.
21. A method which comprises polymerizing an olefin in the presence
of the catalyst of claim 1.
22. The method of claim 21 wherein the olefin is ethylene or a
mixture of ethylene and another olefin.
23. A method which comprises polymerizing an olefin in the presence
of the catalyst of claim 10.
24. The method of claim 23 wherein the olefin is ethylene or a
mixture of ethylene and another olefin.
25. A method which comprises polymerizing an olefin in the presence
of the catalyst of claim 19.
26. The method of claim 25 wherein the olefin is ethylene or a
mixture of ethylene and another olefin.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a catalyst for polymerizing
olefins. The catalyst contains two polymerization-stable anionic
ligands, at least one of which is an amine derivative.
BACKGROUND OF THE INVENTION
[0002] Many olefin polymerization catalysts are known, including
conventional Ziegler-Natta catalysts. While these catalysts are
inexpensive, they exhibit low activity and must be used at high
concentrations. As a result, it is sometimes necessary to remove
catalyst residues from the polymer, which adds to production costs.
Furthermore, Zeigler-Natta catalysts typically produce polymers
having high densities and broad molecular weight distributions,
properties that are undesirable for some applications such as
injection molding. They are also generally poor at controlling
polymer density through incorporation of .alpha.-olefin comonomers.
Unfortunately, when comonomers are used, they are distributed in a
non-uniform fashion among the different molecular weights that
comprise the molecular weight distribution. Most of the comonomer
is incorporated into the low molecular weight polymer molecules; a
more uniform incorporation would be desirable.
[0003] To improve polymer properties, highly active single-site
catalysts, in particular metallocenes, are beginning to replace
Zeigler-Natta catalysts. Although more expensive, the new catalysts
give polymers with narrow molecular weight distributions, low
densities, and good comonomer incorporation.
[0004] A metallocene catalyst consists of one or more
cyclopentadienyl ring ligands bound to a transition metal in an
.eta..sup.5 fashion. The cyclopentadienyl ring ligands are
polymerization-stable; that is, they remain bound to the metal
during the course of the polymerization. One disadvantage of
metallocene catalysts is that they tend to produce lower molecular
weight polymers at higher temperatures.
[0005] Recent attention has focused on developing improved
single-site catalysts in which a cyclopentadienyl ring ligand of
the metallocene is replaced by a heteroatomic ring ligand. These
catalysts may be referred to generally as heterometallocenes.
[0006] In particular, U.S. Pat. No. 5,554,775 discloses catalysts
containing a boraaryl moiety such as boranaphthalene or
boraphenanthrene. Further, U.S. Pat. No. 5,539,124 discloses
catalysts containing a pyrrolyl ring, i.e., an "azametallocene." In
addition, PCT Int. Appl. WO 96/34021 discloses azaborotinyl
heterometallocenes wherein at least one aromatic ring includes both
a boron atom and a nitrogen atom.
[0007] Metallocenes and heterometallocenes are much more expensive
to produce than the Zeigler-Natta catalysts. Therefore, further
research has focused on developing less expensive single-site
catalysts that give advantageous polymer properties. One approach
is to use readily available organic compounds that can act as
polymerization-stable, anionic ligands for transition metals. For
example, U.S. Pat. No 5,637,660 discloses catalysts in which a
cyclopentadienyl moiety of a metallocene is replaced by a readily
available quinolinyl or pyridinyl ligand. Other inexpensive organic
ligands capable of binding a transition metal may also be
available. One example is hydroxylamine derivatives Hughes, et al.,
J. Chem. Soc., Dalton Trans. (1989) 2389, for example describe the
crystal structure of organometallic compounds containing
hydroxylamine or hydrazine derivatives bound to a titanium complex
in an .eta..sup.2 fashion, but they do not describe olefin
polymerization catalysts
[0008] In sum, new single-site catalysts are needed. Particularly
valuable catalysts would be easily synthesized from readily
available starting materials. These catalysts would combine the
cost advantages of Zeigler-Natta catalysts with the polymer
property advantages of single-site catalysts.
SUMMARY OF THE INVENTION
[0009] The invention is a catalyst for polymerizing olefins. The
catalyst comprises: (a) an organometallic compound of a Group 3-10
transition metal containing an amine derivative ligand; and (b) an
activator such as alumoxane. The amine derivative ligand has the
formula RR'N--A.sup.- or RR'C.dbd.N--A-- where A is O, S, N--R", or
P--R". Substituents R, R' and R" are hydrogen or C.sub.1--C.sub.20
hydrocarbyl. The Group 3-10 metal also contains other ligands to
fill the vacancy of the metal. The additional ligands include
polymerization-stable anionic ligands and a ligand X where X is
hydride, halide, C.sub.1--C.sub.20 alkoxy, siloxy, hydrocarbyl, or
dialkylamido.
[0010] We surprisingly found that catalysts based on amine
derivative ligands are true "single-site" catalysts for olefin
polymerization: they are highly productive, they incorporate
comonomers well, and they give polymers with narrow molecular
weight distributions.
DETAILED DESCRIPTION OF THE INVENTION
[0011] Catalysts of the invention comprise an activator and an
organometallic compound of the formula: 1
[0012] where
[0013] M is a Group 3-10 transition metal;
[0014] A is O, S, N--R", or P--R";
[0015] L is a polymerization-stable anionic ligand;
[0016] X is hydride, halide, C.sub.1--C.sub.20 alkoxy, siloxy,
hydrocarbyl, or dialkylamido;
[0017] R, R', and R", which can be same or different, are selected
from hydrogen and C.sub.1--C.sub.20 hydrocarbyl;
[0018] and m+ n equals the valency of M minus 1.
[0019] The transition metal, M, may be any Group 3 to 10 metal or a
metal from the lanthanide or actinide series. Preferably, the
catalyst contains a Group 4 to 6 transition metal; more preferably,
the catalyst contains a Group 4 metal such as titanium or
zirconium.
[0020] When X is a C.sub.1--C.sub.20 hydrocarbyl group, it is
preferably a group that lacks a hydrogen atom on a carbon that is
beta to M. Thus, preferred hydrocarbyl groups include methyl,
benzyl, phenyl, neopentyl, or the like.
[0021] Catalysts of the invention include a polymerization-stable
anionic ligand, L. Suitable L ligands include cyclopentadienyl or
substituted cyclopentadienyl anions such as those described in U.S.
Pat. Nos 4,791,180 and 4,752,597, the teachings of which are
incorporated herein by reference. Suitable L ligands also include
substituted or unsubstituted boraaryl, pyrrolyl, quinolinyl, and
pyridinyl groups as described in U.S. Pat. Nos. 5,554,775,
5,539,124, and 5,637,660, the teachings of which are also
incorporated herein by reference. L can also be a substituted or
unsubstituted azaborolinyl ligand, such as those described in PCT
Int AppI. WO 96/34021. When multiple L ligands are present, they
may be the same or different.
[0022] Suitable polymerization-stable anionic ligands include amine
derivatives of the formula RR'N--A.sup.- or RR'C.dbd.N--A.sup.-
wherein R, R' and A are as described above. Thus, catalysts of the
invention include ones having more than one amine derivative
ligand.
[0023] The polymerization-stable anionic ligand L and the amine
derivative ligand can be bridged. Groups that can be used to bridge
the polymerization-stable anionic ligand and the amine derivative
include, for example, methylene, ethylene, 1,2-phenylene, and
dialkyl silyls. Normally, only a single bridge is used in the
organometallic compound. Bridging the ligand changes the geometry
around the transtion metal and can improve catalyst activity and
other properties, such as comonomer incorporation and thermal
stability.
[0024] A preferred catalyst comprises an activator and an
organometallic compound of the formula: 2
[0025] where
[0026] M is a Group 4-6 transition metal, preferably a Group 4
metal;
[0027] and L, X, R, R', m, and n are as described above.
[0028] Preferably, X is chlorine, methyl, or benzyl.
[0029] Another catalyst of the invention comprises an activator and
an organometallic compound of the formula: 3
[0030] where
[0031] M is a Group 3-10 transition metal, preferably Groups 4-6
and more preferably Group 4; and
[0032] A, L, X, R, R', m, and n are as described above.
[0033] Preferably, X is chlorine, methyl, or benzyl.
[0034] A particularly preferred catalyst comprises an activator and
an organometallic compound of the formula: 4
[0035] where
[0036] Cp is a cyclopentadienyl ligand.
[0037] Suitable activators include alumoxanes. Preferred alumoxanes
are polymeric aluminum compounds represented by the cyclic formula
(R.sup.4--Al--O), or the linear formula
R.sup.4(R.sup.4--Al--O).sub.sAIR.- sup.4 wherein R.sup.4 is a
C.sub.1--C.sub.20 alkyl group and s is an integer from 1 to about
20. Preferably, R.sup.4 is methyl and s is from about 4 to about
10. Exemplary alumoxane activators are (poly)methylalumoxane (MAO),
ethylalumoxane, and diisobutylalumoxane. Optionally, the alumoxane
activator is used with a trialkyl or triaryl aluminum compound,
which preferably has the formula AIR.sup.5.sub.3 where R.sup.5
denotes a C.sub.1--C.sub.20 hydrocarbyl. MAO and mixtures of MAO
with other aluminum alkyls are preferred activators because they
give high catalyst activity, good comonomer incorporation, and
polymers with narrow molecular weight distributions.
[0038] Suitable activators also include substituted or
unsubstituted trialkyl or triaryl boron derivatives, such as
tris(perfluorophenyl)boron- , and ionic borates such as
tri(n-butyl)ammonium tetrakis(pentafluoropheny- l) boron or trityl
tetrakis(pentafluorophenyl) boron. The ionic borates ionize the
neutral organometallic compound to produce an active catalyst for
olefin polymerization. See, for instance, U.S. Pat. Nos. 5,153,157,
5,198,401, and 5,241,025, all of which are incorporated herein by
reference.
[0039] The organometallic compound is prepared by any suitable
method. Usually, the amine derivative is deprotonated with a strong
base, and the resulting anion is reacted with a transition metal
complex to give the organometallic compound.
[0040] In one convenient method, the amine derivative reacts with
n-butyl lithium in an inert organic solvent (THF, toluene, diethyl
ether, e g ) to give an amine derivative anion. Preferably, the
solution is concentrated The amine derivative anion is then
preferably added to a slurry of the starting transition metal
complex (e.g., cyclopentadienyl zirconium trichloride) in an
organic solvent as described above. Stoichiometric quantities are
typically used. The reaction can occur at room temperature, but a
lower temperature of -100.degree. C. to 0.degree. C. is preferred
By-products are removed by filtration, the solvent is evaporated,
and the organometallic compound is collected.
[0041] Preferably, the organometallic compound is used promptly
after preparation because it may lose activity during storage.
Storage of the organometallic compound should be at a low
temperature, such as -100.degree. C to 20.degree. C.
[0042] It is preferable not to premix the organometallic compound
and the activator, as this may result in lower catalyst activity.
Rather, the organometallic compound and activator are preferably
injected separately into a reactor containing the monomer to be
polymerized. Preferably, the activator is injected first. The molar
ratio of activator to organometallic compound is preferably from
about 1:1 to about 15,000:1.
[0043] The organometallic compound and the activator may be used
with a support such as silica, alumina, magnesia, or titania. A
support may be required for some processes. For example, a support
is generally needed in gas phase and slurry polymerization
processes to control polymer particle size and to prevent fouling
of the reactor walls. In one method, the organometallic compound is
dissolved in a solvent and is deposited onto the support by
evaporating the solvent. An incipient wetness method can also be
used. The activator can also be deposited on the support or it can
be introduced into the reactor separately from the supported
organometallic compound.
[0044] The catalyst is particularly valuable for polymerizing
olefins. preferably .alpha.-olefins. Suitable olefins include, for
example, propylene. 1-butene, 1-hexene, 1-octene, ethylene and the
like, and mixtures thereof The catalyst is valuable for
copolymerizing ethylene with .alpha.-olefins or di-olefins (e.g.,
1,3-butadiene, 1,4-hexadiene, 1,5-hexadiene).
[0045] The catalysts can be used in a variety of polymerization
processes They can be used in a liquid phase (slurry, solution,
suspension bulk) high-pressure fluid phase, or gas phase
polymerization processes, or a combination of these. The pressure
in the polymerization reaction zones typically ranges from about 15
psia to about 15,000 psia, and the temperature usually ranges from
about -100.degree. C. to about 300.degree. C.
[0046] Catalysts of the invention are highly productive. Typical
activities range from 40 to 200 kilograms polymer per gram
transition metal per hour, or higher (see Table 2 below). The
catalysts incorporate comonomers such as 1-butene well (see Example
5) and also produce polymers with narrow molecular weight
distributions. Typical melt flow ratios (MFR= MI.sub.20/MI.sub.2)
range from about 10 to about 25. A MFR below 25 indicates narrow
molecular weight distribution and suggests improved properties
characteristic of polymers made using a single-site catalyst.
Typically, Zeigler-Natta catalysts yield polymers with MFRs of
about 35.
[0047] 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.
EXAMPLE 1
[0048] This example describes the synthesis of diethyl
hydroxylamine cyclopentadienyl zirconium dichloride of the
structural formula: 5
[0049] 1.6 M n-butyllithium in hexane (1.7 mL, 2.72 mmol) is added
to diethylhydroxylamine (0.238 g, 2.67 mmol) dissolved in 10 mL of
tetrahydrofuran at -78.degree. C. After warming to room
temperature, this mixture is added via cannula to a stirred slurry
of cyclopentadienyl zirconium trichloride (0.7 g, 2.67 mmol) and 30
mL of dry tetrahydrofuran at -78.degree. C. The reaction mixture is
stirred an additional 15 hours as the mixture warms to room
temperature. The volatiles are removed with vacuum and the
resultant solid is isolated.
EXAMPLES 2-7
[0050] In these examples, ethylene is polymerized using the
catalyst of Example 1. The polymerization is conducted in a stirred
1.7-liter stainless steel autoclave at 80.degree. C. and
110.degree. C. Dry, oxygen-free toluene (840 mL) is charged to the
dry, oxygen-free reactor. MAO (10% in toluene, from Ethyl
Corporation) is added by syringe without further purification. The
reactor is then heated to the desired temperature and sufficient
ethylene is added to bring the reactor pressure to 150 psig. The
reactor is allowed to equilibrate at the desired temperature and
pressure. A solution of catalyst is prepared by dissolving 0.100 g
of the catalyst of Example 1 in 100 mL of toluene, and the desired
amount is added to the reactor.
[0051] After one hour, the ethylene flow is stopped and the reactor
is rapidly cooled to room temperature. The polymer is filtered,
dried in a vacuum oven, and weighed. Table 1 lists polymerization
conditions, and Table 2 gives the results of the
polymerizations.
[0052] The melt index of the polymer is measured according to ASTM
D-1238, Condition E and Condition F. MI is the melt index measured
with a 2.16 kg weight (Condition E). HLMI is the melt index
measured with a 21.6 kg weight (Condition F). The melt flow ratio
(MFR) is defined as the ratio of HLMI (or MI.sub.20) to MI (or
MI.sub.2) and is a measure of molecular weight distribution. A MFR
below 25 indicates narrow molecular weight distribution and
suggests improved properties characteristic of polymers made using
a single-site catalyst. Typically, a Zeigler catalyst yields
polymer with a MFR of about 35.
1TABLE 1 Polymerization Conditions Temp Time Hydrogen Catalyst AI/M
Example (.degree. C.) (min) (mmoles) Comonomer (mmoles) Activator
(atomic) 2 80 60 0 None 0.018 MAO 494 3 80 60 0 None 0.0073 MAO
1240 4 80 60 0 None 0.0018 MAO 4950 5 110 60 30 Butene, 0.0018 MAO
4950 20 mL 6 110 60 30 None 0.0018 MAO 4950 7 110 60 0 None 0.0018
MAO 4950
[0053]
2TABLE 2 Polymerization Results Wt. Catalyst PE Activity MI HLMI
Density Example (g) (kg/g Zr/hr) (dg/min) (dg/min) MFR (g/ml) 2
68.8 41.4 0.0430 0.736 17.3 -- 3 69.6 105 0.0263 0.605 23.0 0.950 4
34.7 209 0.0452 0.729 16.1 0.958 5 10.8 65.1 -- -- -- >0.970 6
10.6 63.9 -- -- -- >0.970 7 34.7 209 1.58 6.08 10.5 0.962
* * * * *