Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Organic compound containing
Reexamination Certificate
1999-09-02
2001-05-29
Bell, Mark L. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Organic compound containing
C502S103000, C502S123000, C502S152000, C502S155000, C502S169000, C502S200000, C526S128000, C526S141000, C526S160000, C526S943000
Reexamination Certificate
active
06239062
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a catalyst for polymerizing olefins. The catalyst comprises an activator and an organometallic compound that incorporates a multidentate indolyl-amido ligand. The catalyst is easily formed from readily available organic compounds.
BACKGROUND OF THE INVENTION
Many olefin polymerization catalysts are known, including conventional Ziegler-Natta catalysts. While these catalysts are inexpensive, they exhibit low activity, produce polymers having medium to broad molecular weight distributions (M
w
/M
n
>4), and are generally poor at incorporating &agr;-olefin comonomers. To improve polymer properties, highly active single-site catalysts, in particular metallocenes, are beginning to replace Ziegler-Natta catalysts. Although more expensive, the new catalysts give polymers with narrow molecular weight distributions, and good comonomer incorporation, which allows easier production of low-density polymers. One disadvantage of metallocene catalysts is that they tend to produce lower molecular weight polymers at higher temperatures.
Recent attention has focused on developing “constrained geometry” or “open architecture” single-site catalysts. These catalysts, which contain a transition metal bound to a multidentate ligand, are believed to have exposed active sites that impart unique properties to the catalyst. U.S. Pat. Nos. 5,703,257, 5,347,024, 5,096,867, and 5,064,802 disclose constrained geometry catalysts having ligands comprising a substituted or unsubstituted cyclopentadienyl ring that is covalently linked to a divalent ligand group comprising nitrogen, phosphorus, oxygen, or sulfur. The cyclopentadienyl group is &pgr;-bonded to the metal and the divalent ligand group is &sgr;-bonded to the transition metal. U.S. Pat. Nos. 5,541,349 and 5,495,036 disclose similar constrained geometry catalysts in which the cyclopentadienyl ring is replaced by non-aromatic dienyl ligands. Further, U.S. Pat. No. 5,688,880 discloses constrained geometry catalysts in which the cyclopentadienyl ring is replaced by a delocalized, &pgr;-bonded group.
However, heteroatom-containing &pgr;-bonded groups are not disclosed and, in particular, indolyl systems are not disclosed. Indolyl catalyst systems for olefin polymerization are disclosed in U.S. Pat. No. 5,539,124, but the indolyl group is not covalently linked to a divalent ligand group. PCT Intl. Appl. WO 96/13529 discloses monoanionic multidentate ligands having a heteroatom-containing cyclopentadienyl ring substituent and a trivalent amine or phosphine substituent, but dianionic ligands are not disclosed.
Constrained geometry catalysts are believed to have unique properties. U.S. Pat. No. 5,278,272 discloses that ethylene/1-octene copolymers produced by a constrained geometry catalyst have much better processability and higher melt elasticity than similar polymers produced by metallocene catalysts. One significant problem with constrained geometry catalyst systems is that they are difficult to prepare, requiring complicated multi-step synthetic pathways. For example, see Examples 1-3 in U.S. Pat. No. 5,688,880.
A cost-effective route to single-site catalysts starts with readily available organic compounds that can act as stable ligands for transition metals. For example, U.S. Pat. No. 5,637,660 discloses single-site catalysts in which a cyclopentadienyl moiety of a metallocene is replaced by a quinolinyl or pyridinyl ligand. Such a route has not been attempted for constrained geometry single-site catalysts.
In sum, new constrained geometry 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 constrained geometry catalysts.
SUMMARY OF THE INVENTION
The invention is a catalyst for polymerizing olefins. The catalyst comprises: (a) an activator; and (b) an organometallic compound comprising a Group 3 to 10 transition or lanthanide metal, M, and a multidentate ligand characterized by an indolyl group that is covalently linked to an amido group, wherein the indolyl group is &pgr;-bonded to M and the amido group is &sgr;-bonded to M. The catalyst is easily formed from readily available organic compounds.
DETAILED DESCRIPTION OF THE INVENTION
Catalysts of the invention comprise an activator and an organometallic compound comprising a Group 3 to 10 transition or lanthanide metal, M, and a multidentate ligand characterized by an indolyl group that is covalently linked to an amido group, wherein the indolyl group is &pgr;-bonded to M and the amido group is &sgr;-bonded to M.
The metal, M, may be any Group 3 to 10 transition or lanthanide metal. 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.
The indolyl group can be any substituted or unsubstituted indolyl. Examples of substituted indolyls include 2-tert-butylindolyl, 7-methylindolyl, 3-phenylindolyl, and 4,7-dimethylindolyl. The indolyl group is &pgr;-bonded to M such that the pyrrolyl substituent of the indolyl group is bound to M in an &eegr;
5
fashion.
The amido group can be any substituted or unsubstituted amido group that is covalently linked to the indolyl group. Preferred amido groups have hydrogen or a C
1
-C
20
hydrocarbyl bound to the nitrogen atom of the amido group. The amido group is &sgr;-bonded to M.
The indolyl group is covalently linked to the amido group. The indolyl and amido groups can be bonded directly to each other, but there is preferably a bridging group. Bridging groups contain at least one nonhydrogen atom. Preferred groups that can be used to bridge the two ligands include methylene, ethylene, 1,2-phenylene, dimethyl silyl, diphenyl silyl, and methyl phenyl silyl. Particularly preferred groups include methylene and ethylene. The amido group is covalently linked to the indolyl group at any position on the indolyl ring. Preferably, the amido group is covalently linked through the pyrrolyl ring of the indolyl group.
The transition or lanthanide metal may also have other ligands. Preferred ligands include halides and C
1
-C
20
alkoxy, siloxy, hydrocarbyl, or dialkylamido ligands. Particularly preferred ligands are halides and C
1
-C
20
hydrocarbyl or dialkylamido ligands. If the ligand is a C
1
-C
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.
A preferred catalyst comprises an activator and an organometallic compound of the formula:
where
M is a Group 4-6 transition metal;
X is hydride, halide, C
1
-C
20
alkoxy, siloxy, hydrocarbyl, or dialkylamido, or mixtures thereof;
R is hydrogen or C
1
-C
20
hydrocarbyl;
a=1-4; and
b=1-4.
A particularly preferred catalyst comprises an activator and an organometallic compound of the formula:
where
M is a Group 4 transition metal;
X is hydride, halide, C
1
-C
20
alkoxy, siloxy, hydrocarbyl, or dialkylamido, or mixtures thereof;
R is hydrogen or C
1
-C
20
hydrocarbyl; and
b=1-2.
The organometallic compound is prepared by any suitable method. In one convenient method, the indole-amine compound is reacted directly with a Group 3-10 transition metal or lanthanide metal, M, hydrocarbyl complex or a Group 3-10 transition metal or lanthanide metal, M, dialkylamido complex in an inert organic solvent. Stoichiometric quantities are typically used. The reactions can occur at room temperature, but a higher temperature of 30° C. to 150° C. is preferred. By-products and solvent are removed by evaporation and the organometallic compound is collected.
The metal hydrocarbyl complex includes any Group 3-10 transition or lanthanide metal that is covalently bound to at least two hydrocarbyl groups. Preferred hydrocarbyl groups include C
1
-C
20
hydrocarbyls. Particularly preferred hydrocarbyl groups lack a hydrogen atom on a carbon that is be
Bell Mark L.
Carroll Kevin M.
DiVerdi Michael J.
Equistar Chemicals L.P.
LandOfFree
Olefin polymerization catalysts containing indolyl-amido... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Olefin polymerization catalysts containing indolyl-amido..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Olefin polymerization catalysts containing indolyl-amido... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2496981