Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Plural component system comprising a - group i to iv metal...
Reexamination Certificate
1999-11-05
2001-05-15
Wu, David W. (Department: 1713)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Plural component system comprising a - group i to iv metal...
C502S104000, C502S117000, C502S154000, C502S155000, C526S161000, C526S943000
Reexamination Certificate
active
06232256
ABSTRACT:
The present invention relates to a catalyst composition useful for the polymerization of olefins, which is prepared by contacting a cycloalkadienyl compound, a transition metal amide of the formula M(NMe
2
)
m
X
n
, an aluminoxane, and optionally a solid support at a temperature of 0 to 100° C.
BACKGROUND OF THE INVENTION
Transition metal metallocene compounds are useful as olefin polymerization catalysts in conjunction with cocatalysts such as aluminoxanes. These catalysts can advantageously produce olefin polymers with narrow molecular weight distributions, homogeneous comonomer distributions, and good processability.
However, the cost of such catalysts is higher than traditional Ziegler-Natta catalysts, due in part to the complex synthesis methods required to make them. Metallocene precursors are usually synthesized through transmetallation reactions, as illustrated in Scheme I (using the compound bis(indenyl)dimethylsilane as an example).
Scheme I
Since this process involves several organic/organometallic reaction steps, often at low temperatures, it becomes very costly on a large scale. Furthermore, the yields from this process can be fairly low. For example, it has been shown that in the process of converting dimethylsilyl bridged-bis(indenyl) type compounds to their corresponding zirconium complexes, the yield is typically between 10% to 60% (
Organometallics
1994, 13, 964). This is highly undesirable since a large portion of expensive ligand is lost.
One way to reduce the overall cost of making this type of catalyst system is to avoid isolation of the metallocene precursor by simply combining the ingredients of the catalyst composition. For example, U.S. Pat. Nos. 5,378,567 and 5,451,555 relate to catalyst compositions for the homopolymerization or copolymerization of olefins. The catalyst compositions comprise a first compound of the formula Me
1
(OR
1
)
p
R
2
q
X
1
4-p-q
, wherein Me
1
is Ti, Zr, or Hf, a second compound of the formula Me
2
(OR
3
)
m
R
4
n
X
2
z-m-n
, wherein Me
2
is a Group I-III metal, and a third compound that is an organocyclic compound having two or more conjugated double bonds.
Similarly, U.S. Pat. No. 5,331,071 describes a process for the polymerization of olefinic hydrocarbons carried out in the presence of a catalyst component derived from reacting a compound of the formula Me
1
R
1
n
X
1
4-n
, wherein Me
1
is Ti, Zr, or Hf, a compound of the formula Me
2
R
2
m
X
2
z-m
, wherein Me
2
is a Group I-III metal, an organocyclic compound having two or more conjugated double bonds, and an inert carrier, along with a modified organoaluminum compound having Al—O—Al bonds.
Another way to reduce the overall cost of these catalyst compositions is to increase the yield of metallocene precursor through the use of Group 4 metal amides. For example, U.S. Pat. Nos. 5,495,035, and 5,597,935 describe the reaction of Group 4 metal amides with rac-bis-cyclopentadiene compounds to form metallocene amide precursors. However, these precursors must be isolated, chlorinated, and then activated separately with cocatalyst to form an active catalyst composition. Moreover, synthesis of the precursor by this process typically requires high temperatures (100° C. or above) and long reaction times. As a result, this method has been applied primarily to make compounds with ligands that are less sterically hindered. A constant nitrogen purge or dynamic vacuum to remove the co-product amine also has to be applied to drive the reaction to completion. These further add to the overall catalyst manufacturing cost.
SUMMARY OF THE INVENTION
Applicants have discovered a one-step process for directly preparing an activated metallocene catalyst composition using transition metal amide compounds, which requires mild reaction conditions and shorter reaction times compared to known processes. The process comprises contacting a cycloalkadienyl compound, a transition metal amide of the formula (MNMe
2
)
m
X
n
, an aluminoxane, and optionally a solid support at a temperature of 0 to 100° C. Neither isolation nor chlorination of the metallocene precursor is required. Advantageously, interaction between the transition metal amide and the aluminoxane generates highly unsaturated and reactive intermediates that combine with the ligand to form the active catalyst composition. As a result, this process works extremely well even with more sterically hindered ligands.
The invention provides a process for producing a catalyst composition, which comprises contacting:
a) a cycloalkadienyl compound;
b) a metal compound having the formula:
M(NMe
2
)
m
X
n
wherein M is a Group 3, 4, or 5 metal;
Me is a methyl group;
each X is a halide, a hydrocarbyl group containing 1 to 20 carbons, an alkoxy group containing 1 to 20 carbons, or an amide group containing 1 to 20 carbons; and
the sum of m and n equals the valence of M, but m≠0;
c) an aluminoxane; and
d) optionally, a solid support;
at a temperature in the range of 0 to 100° C.
The invention also provides a catalyst composition produced by the above process, along with a process for the polymerization of olefins using this catalyst composition.
DETAILED DESCRIPTION OF THE INVENTION
The catalyst composition is prepared by contacting a cycloalkadienyl compound, a transition metal amide, an aluminoxane, and optionally a solid support at a temperature of 0 to 100° C. Preferably, contacting takes place at a temperature of less than 100° C., more preferably in the range of 20 to 85° C.
Contacting is typically performed under atmospheric pressure. The time of contacting ranges from 0.01 to 24 hours, preferably from 0.1 to 6 hours, more preferably from 0.5 to 3 hours.
The cycloalkadienyl compound, transition metal amide, aluminoxane, and optionally the solid support, may be admixed in any order. Preferably, the order of mixing is as follows: cycloalkadienyl compound, aluminoxane, transition metal amide, and (if used) the solid support. A diluent such as isobutane, butane, pentane, hexane, heptane, toluene, and the like, or mixtures thereof, may by used if desired to dissolve one of more of the ingredients of the catalyst composition.
The cycloalkadienyl compound is an organic compound capable of interacting with a transition metal through pi-bonding. The cycloalkadienyl compound preferably has one of the formulas:
C
5
H
x
R
5-x
or
Y(C
5
H
z
R
4-z
)(C
5
H
y
R
4-y
),
wherein each R is independently a hydride, a substituted or unsubstituted alkyl group containing 1 to 20 carbons, or a substituted or unsubstituted aryl group containing 1 to 20 carbons. Two adjacent R groups may be joined to form a ring, such that the cycloalkadienyl compound comprises for example an indenyl or fluorenyl structure. Y is a bridging group, preferably containing 1 to 5 carbons, 1 to 3 heteroatoms such as silicon, germanium, boron, phosphorous, and nitrogen, or mixtures thereof. The letter x is 1 to 5; y is 1 to 4; and z is 1 to 4.
Examples of cycloalkadienyl compounds include but are not limited to dicyclopentadiene, methyldicyclopentadiene, 1,2-dimethylcyclpentadiene, 1,3-dimetylcyclopentadiene, iso-propylcyclopentadiene, methylpropylcyclopentadiene, n-butylcyclopentadiene, methyl-n-butylcyclopentadiene, bis(dicyclopentadienyl)dimethylsilane, bis(methylcyclopentadienyl)dimethylsilane, bis(1,3-dimethylcyclopentadienyl)dimethylsilane, indene, 1-methylindene, 2-methylindene, 1,3-dimethylindene, 1-propylindene, 2-propylindene, 1-phenylindene, 2-phenylindene, fluorene, 1,2-bis(indenyl)ethane, 1,2-bis(3-methylindenyl)ethane, 1-indenyl-2-(3-methylindenyl)ethane, 1,2-bis(2-methyindenyl)ethane, 1-indenyl-2-(2-methylindenyl)ethane, 1,2-bis(2-phenylindenyl)ethane, 1-indenyl-2-(2-phenylindenyl)ethane, bis(indenyl)dimethylsilane, bis(3-methylindenyl)dimethylsilane, indenyl(3-methylindenyl)dimethylsilane, bis(2-methylindenyl)-dimethylsilane, indenyl(2-methylindenyl)dimethylsilane, and bis(2-phenylindenyl)dimethylsilane.
Preferably, the cycloalkadienyl compound is selected from the group consisting of 1,2-bis(indenyl)ethane, 1,2-bis(2-methylindenyl)ethane, bis(indenyl)dimethylsilane, and bis(
Karol Frederick John
Reichle Walter Thomas
Yang Xinmin
Leuzzi P. W.
Rabago R.
Union Carbide Chemicals & Plastics Technology Corporation
Wu David W.
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