Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2001-01-29
2002-04-23
Wu, David W. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S160000, C526S943000, C556S043000, C556S047000, C556S053000, C556S058000, C556S112000, C556S121000, C556S143000
Reexamination Certificate
active
06376629
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to catalysts useful for olefin polymerization. In particular, the invention relates to “single-site” catalysts that incorporate at least one indenoindolyl ligand.
BACKGROUND OF THE INVENTION
Interest in single-site (metallocene and non-metallocene) catalysts continues to grow rapidly in the polyolefin industry. These catalysts are 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 &agr;-olefin comonomers, lower polymer density, controlled content and distribution of long-chain branching, and modified melt rheology and relaxation characteristics.
While traditional metallocenes commonly include one or more cyclopentadienyl groups, many other ligands have been used. Putting substituents on the cyclopentadienyl, ring, for example, changes the geometry and electronic character of the active site. Thus, a catalyst structure can be fine-tuned to give polymers with desirable properties. “Constrained geometry” or “open architecture” catalysts have been described (see, e.g., U.S. Pat. No. 5,624,878). Bridging ligands in these catalysts lock in a single, well-defined active site for olefin complexation and chain growth. Other bridged complexes are stereospecific catalysts for &agr;-olefin polymerizations, providing a route to isotactic or syndiotactic polypropylene (see, for example, Herzog et al.,
J. Am. Chem. Soc
. 118 (1996) 11988 and Mansel et al.,
J. Organometal. Chem
. 512 (1996) 225).
Other known single-site catalysts replace cyclopentadienyl groups with one or more heteroatomic ring ligands such as boraaryl (see, e.g., U.S. Pat. No. 5,554,775), pyrrolyl, indolyl, (U.S. Pat. No. 5,539,124), or azaborolinyl groups (U.S. Pat. No. 5,902,866).
Substituted metallocenes, constrained-geometry catalysts, bridged complexes, and many heterometallocenes offer interesting advantages, including higher activity, control over. polyolefin properties, and stereoregular polymers. Variety, however, comes at a price: ligands used to make many of these catalysts require costly multi-step syntheses from expensive and often hard-to-handle starting materials and reagents.
In sum, there is a continuing need for single-site catalysts that can be prepared inexpensively and in short order. In particular, there is a need for catalysts that can be tailored to have good activities and to give polyolefins with desirable physical properties.
SUMMARY OF THE INVENTION
The invention is a single-site olefin polymerization catalyst. The catalyst comprises an activator and an organometallic complex. The organometallic complex comprises a Group 3 to 10 transition or lanthanide metal, M, and at least one indenoindolyl ligand that is &pgr;-bonded to M.
The invention includes a three-step method for making the organometallic complex. First, an indanone reacts with an aryl hydrazine in the presence of a basic, or acidic catalyst to produce an aryl hydrazone. Next, the aryl hydrazone is cyclized in the presence of an acidic catalyst to produce an indenoindole ligand precursor. Finally, the precursor is deprotonated, and the resulting anion reacts with a Group 3 to 10 transition or lanthanide metal source to produce the desired organometallic complex.
The invention provides a remarkably simple synthetic route to single-site olefin polymerization catalysts. Because many indanones and aryl hydrazines are commerically available or easily made, a wide variety of organometallic complexes that contain &pgr;-bonded indenoindolyl ligands can be expeditiously prepared. The ease and inherent flexibility of the synthesis puts polyolefin makers in charge of a new family of single-site catalysts.
DETAILED DESCRIPTION OF THE INVENTION
Catalysts of the invention comprise an activator and an organometallic complex. The catalysts are “single site” in nature, i.e., they are distinct chemical species rather than mixtures of different species. They typically give polyolefins with, characteristically narrow molecular weight distributions (Mw/Mn<3) and good, uniform comonomer incorporation.
The organometallic complex includes a Group 3 to 10 transition or lanthanide metal, M. More preferred complexes include a Group 4 to 6 transition metal; most preferably the complex contains a Group 4 metal such as titanium or zirconium.
The organometallic complex also comprises at least one indenoindolyl ligand that is &pgr;-bonded to M. By “indenoindole,” 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 or more carbon atoms. Preferably, the rings are fused such that the indole nitrogen and the only sp
3
-hybridized carbon on the indenyl ring are “trans” to each other. Such is the case in an indeno[3,2-b]indole ring system such as:
To identify how the rings are fused, the indene ring is numbered beginning with the —CH
2
— group. The “b” side of the indole ring matches the “3,2” side of the indene. In accord with IUPAC Rule A-21.5, the order of the numbers (3,2) conforms to the direction of the base (indolyl) component (i.e., from a to b). Suitable ring systems include those in which the indole nitrogen and the sp
3
-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[2,3-b]indole ring system:
Any of 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. For example, a benzo ring can be fused in the “e,” “f,” or “g” positions of either or both of the indene and indole rings, as in a benzo[f]indeno[3,2-b]indole system:
Numbering of indenoindoles follows IUPAC Rule A-22. The molecule is oriented as shown above, and numbering is done clockwise beginning with the ring at, the uppermost right of the structure. Thus, 10-methyl-5H-indeno[3,2-b]indole is numbered as follows:
Suitable indenoindole ligand precursors include, for example, 5,10-dihydroindeno[3,2-b]indole, 4,8,10-trimethyl-5H-indeno[3,2-b]indole, 4-tert-butyl-8-methyl-5,10-dihydroindeno[3,2b]indole, 4,8-dichloro-5,10-dihydroindeno[3,2-b]indole, 10-methylbenzo[f]-5H-indeno[3,2-b]indole, benzo[g]-5,10-dihydroindeno[3,2-b]indole, 5,10-dihydroindeno[3,2-b]benzo[e]indole, benzo[g]-5,10-dihydroindeno[3,2-b]benzo[e]indole, and the like.
The indenoindolyl ligand is generated by deprotonating a ligand precursor with a base to give an anionic ring system with a high degree of aromaticity (highly delocalized). Reaction of the anion with, e.g., a transition metal halide gives the desired organometallic complex. The indenoindolyl ligand is &pgr;-bonded to M in the complex.
The organometallic complex optionally includes one or more additional polymerization-stable, anionic ligands. Examples include substituted and unsubstituted cyclopentadienyl, fluorenyl, and indenyl, or the like, 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. A preferred group of polymerization-stable ligands are heteroatomic ligands such as boraaryl, pyrrolyl, indolyl, quinolinyl, pyridinyl, and azaborolinyl as described in U.S. Pat. Nos. 5,554,775, 5,539,124, 5,637,660, and 5,902,866, the teachings of which are incorporated herein by reference. The organometallic complex also usually includes one or more labile ligands such as halides, alkyls, alkaryls, aryls, dialkylaminos, or the like. Particularly. preferred are halides, alkyls, and alkaryls (e.g., chloride, methyl, benzyl).
The indenoindolyl and/or polymerization-stable ligands can be bridged. For instance, a —CH
2
—, —CH
2
Etherton Bradley P.
Krishnamurti Ramesh
Nagy Sandor
Tyrell John A.
Equistar Chemicals LP
Lu Caixia
Schuchardt Johnathan L.
Wu David W.
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