Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2001-04-11
2003-06-17
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...
C526S134000, C526S172000, C526S943000, C526S170000, C502S103000, C502S117000, C502S155000, C549S003000, C549S013000, C556S052000
Reexamination Certificate
active
06579957
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to catalysts useful for polymerizing olefins. In particular, the invention relates to catalysts that contain at least one anionic ligand derived from a thiopyran dioxide.
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.
Traditional metallocenes commonly include one or more cyclopentadienyl groups, but 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. 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).
Isolobal equivalents to the cyclopentadienide anion (i.e., other types of cyclic, anionic, 6&pgr;-electron donor ligands) provide an opportunity to expand the capabilities of single-site catalysts. There is a continuing need for catalysts with higher activities and/or the ability to produce polyolefins with better physical properties or improved processability. Of particular interest are catalysts that can be made from readily available starting materials.
SUMMARY OF THE INVENTION
The invention is catalyst system useful for polymerizing olefins. The catalyst system comprises an organometallic complex and an optional activator. The complex includes a Group 3 to 10 transition, lanthanide, or actinide metal and at least one anionic thiopyran dioxide ligand. Because a wide variety of thiopyran dioxides are easy to prepare from commercially available starting materials, the invention enables the preparation of a new family of single-site catalysts.
DETAILED DESCRIPTION OF THE INVENTION
Catalyst systems of the invention comprise an organometallic complex and an optional activator. The complex is “single site” in nature, i.e., it is a distinct chemical species rather than a mixture of different species. Single-site catalysts, which include metallocenes, 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, lanthanide, or actinide metal, M. More preferred complexes include a Group 4 to 10 transition metal. Group 4 complexes are particularly preferred.
The complex includes at least one anionic thiopyran dioxide ligand. These ligands are prepared by deprotonating a thiopyran dioxide using a potent base.
The simplest thiopyran dioxide is 2H-thiopyran-1,1-dioxide, which has the structure:
Deprotonation removes a methylene proton and generates an anionic species that is an isolobal equivalent of the cyclopentadienide anion:
The anion is incorporated into an organometallic complex as described later below.
Suitable thiopyran dioxides can include subsituent groups such as alkyl, aryl, alkoxy, aryloxy, halide, dialkylamino, nitro, or the like, provided that one methylene proton (on the sp
3
-hybridized carbon next to the SO
2
group) is present. The thiopyran dioxide can be prepared by any suitable method. In one preferred method, the procedure of Y. Gaoni (
J. Org. Chem.
46 (1981) 4502) is used. This method makes the thiopyran dioxide in three steps from a 3-sulfolene, which is available commercially or from the reaction of a diene (e.g., butadiene or isoprene) with sulfur dioxide. The route provides access to a wide variety of substituted thiopyran dioxides because substituted dienes are readily converted to the corresponding 3-sulfolenes.
In the three-step method, a 3-sulfolene is first reacted with dichlorocarbene. The resulting adduct is partially dehalogenated with lithium aluminum hydride. Base-catalyzed ring expansion with lithium diisopropylamide gives the desired thiopyran dioxide (Scheme 1):
Other suitable methods for making thiopyran dioxides have been described. See, for example, E. Molenaar and J. Strating,
Rec. Trav. Chim. Pays-Bas
86 (1967) 1047 or J. Kuthan, “Pyrans, Thiopyrans, and Selenopyrans,” in
Adv. Heterocycl. Chem.
34 (1983) 145 and J. Kuthan et al., “Developments in the Chemistry of Thiopyrans, Selenopyrans, and Teluropyrans,” in
Adv. Heterocycl. Chem.
59 (1994) 179, and references cited therein.
In addition to an anionic thiopyran dioxide ligand, the organometallic complex may include additional labile or polymerization-stable, anionic ligands. Polymerization-stable ligands include, for example, 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. Suitable polymerization-stable ligands include heteroatomic ligands such as boraaryl, pyrrolyl, indolyl, quinolinoxy, pyridinoxy, 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. Suitable polymerization-stable ligands include indenoindolyl anions such as those described in PCT publication WO 99/24446 and copending appl. Ser. No. 09/417,510, filed Oct. 14, 1999, now U.S. Pat. No. 6,232,260. The organometallic complex 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). A variety of other kinds of ligands are particularly useful with late transition metals, including, for example, N,N′-diaryl-substituted diazabutanes and other imines as described in U.S. Pat. Nos. 5,714,556 and 5,866,663, the teachings of which are incorporated herein by reference.
The catalyst system optionally includes an activator. Activators help to ionize the organometallic complex and activate the catalyst. Suitable activators are well known in the art. Examples include alumoxanes (methyl alumoxane (MAO), PMAO, ethyl alumoxane, diisobutyl alumoxane), alkylaluminum compounds (triethylaluminum, diethyl aluminum chloride, trimethylaluminum, triisobutyl aluminum), and the like. Suitable activators include acid salts that contain non-nucleophilic anions. These compounds generally consist of bulky ligands attached to boron or aluminum. Examples include lithium tetrakis(pentafluorophenyl)borate, lithium tetrakis(pentafluorophenyl)aluminate, anilinium tetrakis(pentafluorophenyl)borate, and the like. Suitable activators also include organoboranes, which include boron and one or more alkyl, aryl, or aralkyl groups. Suitable activators include substituted and unsubstituted trialkyl and triarylboranes such as tris(pentafluorophenyl)borane, triphenylborane, tri-n-octylborane, and the like. These and other suitable boron-containing activators are described in U.S. Pat. Nos. 5,153,157, 5,198,401, and 5,241,025, the teachings of which are incorporated herein by reference.
The optimum amount of activator needed relative to the amount of organometallic complex depends on many factors, including the nature of the complex and activator, whether a supported catalyst is used, the desired reaction rate, the kind of polyolefin product, the reaction conditions, and other factors. Generally, however, when the activator is an alumoxane or an alkyl aluminum compound, the amount used will be within the range of about 0.01 to about 5000 moles, preferably from about 0.1 to about 500 moles, of aluminum per mole of transition, lanthanid
Hlatky Gregory G.
Nagy Sandor
Equistar Chemicals LP
Rabago R.
Schuchardt Jonathan L.
Wu David W.
LandOfFree
Single-site catalysts based on anionic thiopyran dioxide... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Single-site catalysts based on anionic thiopyran dioxide..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Single-site catalysts based on anionic thiopyran dioxide... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3128810