Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1999-06-10
2001-07-17
Bell, Mark L. (Department: 1755)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S160000, C526S943000, C526S319000, C526S346000, C502S102000, C502S103000, C502S117000, C502S153000, 53, 53, C556S027000, C556S028000, C556S043000, C556S053000, C556S058000, C556S187000
Reexamination Certificate
active
06262200
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates, inter alia, to novel compositions of matter useful, inter alia, as cocatalysts, to novel catalyst compositions made using such cocatalysts, to methods for preparing these catalysts, and to methods for polymerization utilizing such catalysts.
The use of soluble Ziegler-Natta type catalysts in the polymerization of olefins is well known in the prior art. In general, such systems include a Group 4 metal compound and a metal or metalloid alkyl cocatalyst, such as aluminum alkyl cocatalyst. More broadly, it may be said to include a mixture of a Group 1, 2 or 13 metal alkyl and a transition metal complex from Group 4-5 metals, particularly titanium, zirconium, or hafnium with aluminum alkyl cocatalysts.
First generation cocatalyst systems for homogeneous metallocene Ziegler-Natta olefin polymerization, alkylaluminum chlorides (AlR
2
Cl), exhibit low ethylene polymerization activity levels and no propylene polymerization activity. Second generation cocatalyst systems, utilizing methyl aluminoxane (MAO), raise activities by several orders of magnitude. In practice however, a large stoichiometric excess of MAO over catalyst ranging from several hundred to ten thousand must be employed to have good activities and stereoselectivities. Moreover, it has not been possible to isolate characterizable metallocene active species using MAO. The third generation of cocatalyst, B(C
6
F
5
)
3
, proves to be far more efficient while utilizing a 1:1 catalyst-cocatalyst ratio. Although active catalyst species generated with B(C
6
F
5
)
3
, are isolable and characterizable, the anion MeB(C
6
F
5
)
3
⊖
, formed after Me
⊖
abstraction from metallocene dimethyl complexes, is weakly coordinated to the electron-deficient metal center, thus resulting in a drop of certain catalytic activities. The recently developed B(C
6
F
5
)
4
⊖
type of non-coordinating anion exhibits some of the highest reported catalytic activities, but such catalysts have proven difficult to obtain in the pure state due to poor thermal stability and poor crystallizability, which is crucial for long-lived catalysts and for understanding the role of true catalytic species in the catalysis for the future catalyst design. Synthetically, it also takes two more steps to prepare such an anion than for the neutral organo-Lewis acid.
In our prior applications referred to hereinabove, and in publications appearing in
J. Am. Chem. Soc
. 1997, 119, 2582-2583, and
J. Am. Chem. Soc
. 1998, 120, 6287-6305 new, sterically encumbered (polyfluoroaryl)fluoroanions of aluminum, such as tris(perfluorobiphenyl)fluoroaluminate (PBA)
⊖
, and the preparation and use of such anions as highly efficient cocatalysts for metallocene-mediated olefin polymerization are described. The catalytically active species generated from Ph
3
C
⊕
PBA
⊖
are isolable and X-ray crystallographically characterizable instead of the unstable, oily residues which often result in the case of B(C
6
F
5
)
4
⊖
.
This invention provides, inter alia, technology described in the above-referred-to prior applications, and additionally, improvements in the technology described in the above-referred-to prior applications.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the subject invention to provide, prepare and utilize new types of weakly coordinating anions which form organo-Lewis acid salts that are useful in forming novel, highly-effective olefin polymerization catalysts.
A further object of the subject invention is to provide a catalyst which permits better control over molecular weight, molecular distribution, stereoselectivity, and/or comonomer incorporation.
Another object of the subject invention is to provide a Ziegler-Natta type catalyst system which reduces the use of excess cocatalyst and activates previously unresponsive metallocenes.
In accordance with one of its embodiments, this invention provides novel (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium which may be represented by the formula
[ER′R″R′″F]
⊖
(I)
wherein E is aluminum, gallium, or indium, wherein F is fluorine, wherein R′ is a fluoroaryl group having at least one additional substituent other than fluorine, wherein R″ and R′″ each is, independently, (i) a fluoroaryl group having at least one additional substituent other than fluorine, or (ii) a fluorinated aryl group devoid of additional substitution. Preferably, E is aluminum. In these compounds, R″ and R′″ are preferably the same as each other and, preferably, are fluoroaryl groups having at least one additional substituent other than fluorine. Most preferably, R′ of formula (I) is the same as R″ and R′″. The substituent(s) other than fluorine present in the (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of formula (I) can be (i) one or more substituents which increase the solubility of the compound in an organic solvent as compared to the corresponding compound in which each such substituent other than fluorine is replaced by a fluorine atom, (ii) one or more electron withdrawing substituents other than fluorine, or (iii) a combination of at least one substituent from (i) and at least one substituent from (ii).
A second embodiment provides (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium which may be referred to by the formula
[ER′R″R′″F]
⊖
(II)
wherein E is aluminum, gallium, or indium, wherein F is fluorine, where at least one of R′, R″, and R′″ is a fluorinated biphenyl or fluorinated polycyclic fused ring group such as naphthyl, anthracenyl or fluorenyl. E is preferably aluminum. Preferably two, and more preferably all three, of R′, R″, and R′″ are fluorinated biphenyl or fluorinated polycyclic fused ring groups such as naphthyl, anthracenyl or fluorenyl. Two of the biphenyl groups may be replaced by a phenyl group. That is, R′ is a biphenyl group and R″ and R′″ each is a phenyl group. The biphenyl groups and the phenyl groups plus any polycyclic fused ring group or groups of the compounds of formula (II) should be highly fluorinated, preferably with only one or two hydrogen atoms on a group, and most preferably, as in PBA
⊖
, with no hydrogen atoms and all fluorine substituents. Thus in one subgroup of these (polyfluoroaryl)fluoroanions, R′ of formula (II) is a fluorobiphenyl group having 0 to 2 hydrogen atoms and 7 to 9 fluorine atoms on the rings thereof, the sum of the foregoing integers being 9, and R″ and R′″ of formula (II) each is a phenyl group having 0 to 2 hydrogen atoms and 3 to 5 fluorine atoms on the ring, the sum of the foregoing integers being 5. In this subgroup, most preferably R′ is nonafluorobiphenyl and R″ and R′″ each is a pentafluorophenyl group, i.e., the compound is nonafluorobiphenylbis(pentafluorophenyl)fluoroaluminate. In another subgroup of these (polyfluoroaryl)fluoroanions, R′ of formula (II) is a fluorobiphenyl group having 0 to 2 hydrogen atoms and 7 to 9 fluorine atoms on the rings thereof, the sum of the foregoing integers being 9, and R″ and R′″ of formula (II) each is a fluorinated polycyclic fused ring group such as naphthyl, anthracenyl or fluorenyl. Preferably the polycyclic fused ring group is perfluorinated. However, the fused rings may have one or two hydrogen atoms on the ring with the other available positions occupied by fluorine. A third subgroup of (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of this second embodiment are tris(fluorobiphenyl)fluoroaluminates wherein R′ of formula (II) and R″ and R′″ of formula (II) each is a fluorobiphenyl group having 0 to 2 hydrogen atoms and 7 to 9 fluorine atoms on the rings thereof, the sum of the foregoing integers being 9, especially where such fluorobiphenyl grou
Chen You-Xian
Marks Tobin J.
Bell Mark L.
Northwestern University
Pasterozyk J.
Sieberth & Patty L.L.C.
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