Organic compounds -- part of the class 532-570 series – Organic compounds – Heavy metal containing
Reexamination Certificate
1999-02-17
2001-05-29
Nazario-Gonzalez, Porfirio (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heavy metal containing
C585S354000, C987S002000, C502S103000, C502S117000, C526S160000, C526S943000
Reexamination Certificate
active
06239300
ABSTRACT:
The invention relates to metallocenes and in particular to a process for producing a bridged cyclopentadienyl-fluorenyl metallocene.
A bridged cyclopentadienyl-fluorenyl metallocene has a cyclopentadienyl group and a fluorenyl group bound together by a structural bridge. In its most preferred form, the structural bridge has a branch characterized by olefinic unsaturation. These types of metallocenes have been found to be very effective in catalyst systems for the polymerization of olefins. Heretofore, however, processes for producing such metallocenes have been relatively rudimentary and impractical for commercial implementation. It is one thing to prepare bench scale quantities of such metallocenes. It is another to design a process capable of using readily available materials to produce large commercial scale quantities of such metallocenes in a safe and effective manner.
It is, therefore, an object of the invention to provide an improved process for producing a bridged cyclopentadienyl-fluorenyl metallocene which lends itself to commercial implementation.
Another object of the present invention is provide processes for preparing commercial scale quantities of the various intermediates needed to prepare such metallocenes.
In a particularly preferred embodiment, an object of this invention is to provide a process for producing a commercially viable process for producing metallocenes of the type covered by claim 3 of U.S. Pat. No. 5,565,592 as well as metallocenes of the type described in claim 13 of U.S. Pat. No. 5,498,581. The disclosures of those patents is hereby incorporated by reference.
SUMMARY OF THE INVENTION
In accordance with one embodiment of the present invention a bridged cyclopentadienyl fluorenyl metallocene is produced by (1) reacting a fluorene compound with an alkyl lithium in a liquid consisting essentially of a non-cyclic ether, alkane, or mixtures thereof to form the fluorenyl lithium salt, (2) adding an unsubstituted or hydrocarbyl substituted fulvene to the reaction mixture of step (1) to produce a lithium salt of an organic compound in which fluorenyl and cyclopentadienyl radicals are connected by a single carbon atom, (3) adding additional alkyl lithium to produce the dilithium salt of the organic compound, (4) forming a liquid mixture of a transition metal compound selected from the group consisting of the tetrahalides of Ti, Zr, and Hf by combining the transition metal compound with an liquid alkane and non-cyclic ether, (5) combining the liquid mixture with the product of step (3) to form the metallocene, and (6) separating the metallocene from the reaction product.
In accordance with another embodiment of the present invention there is provided a process for producing a bridged cyclopentadienyl fluorenyl metallocene by
(1) passing dicyclopentadiene into a wiped film evaporator under conditions suitable for effecting cracking of the dicyclopentadiene to cyclopentadiene vapor,
(2) distilling the reaction product and recovering cyclopentadiene,
(3) reacting the recovered cyclopentadiene with a carbonyl compound selected from hydrocarbyl substituted ketones and hydrocarbyl substituted aldehydes in the presence of methanol and an organic base to produce a 6-hydrocarbyl substituted fulvene, preferably a 6-omega alkenyl fulvene,
(4) adding a liquid alkane to the product of step (3) and subjecting the resulting mixture to separation in a liquid/liquid extraction column using water as the continuous phase,
(5) recovering the 6-hydrocarbyl substituted fulvene from the alkane phase,
(6) reacting a fluorene compound with an alkyl lithium in a liquid consisting essentially of non-cyclic ether, alkane, or mixtures thereof to form the fluorenyl lithium salt,
(7) adding the 6-hydrocarbyl substituted fulvene to the reaction mixture of step (6) to produce a lithium salt of an organic compound in which fluorenyl and cyclopentadienyl radicals are connected by a single carbon atom,
(8) adding additional alkyl lithium to produce the dilithium salt of the organic compound,
(9) forming a liquid mixture of a transition metal compound selected from the group consisting of the tetrahalides of Ti, Zr, and Hf by combining the transition metal compound with an liquid alkane and non-cyclic ether,
(10) combining the liquid mixture with the product of step (8) to form the metallocene, and
(11) separating the metallocene from the reaction product.
In accordance with another aspect of the invention there is provided a method for producing cyclopentadiene from dicyclopentadiene comprising cracking the dicyclopentadiene in a wiped film evaporator.
In accordance with another aspect of the invention a fulvene is reacted with the lithium salt of a fluorene compound to produce a an organic compound in which a cyclopentadienyl radical and a fluorenyl radical are connected to each other by a single carbon atom, adding and acid and a hydrocarbon to the reaction mixture, and passing the resulting mixture to a liquid/liquid extraction column containing water, and withdrawing the organic phase from the top of the extraction column and then separating the organic compound from the solvent by evaporation.
In accordance with yet another aspect of the invention there is provided a process for recovering metallocene from a raw product comprising metallocene and alkali metal halide comprising mixing the raw product with a halogenated organic solvent in which the metallocene is soluble and the alkali metal halide is insoluble and then subjecting the mixture to centrifuging to separate the solid alkali metal halide as a solid and then recovering the metallocene from the solvent.
DETAILED DESCRIPTION OF THE INVENTION
The alkyl lithium employed in the present invention can be selected from any suitable alkyl lithium. Generally one would employ an alkyl lithium having 1 to 10 carbon atoms. In a particularly preferred embodiment one employs n-hexyl lithium, which has advantages over lower molecular weight alkyl lithium compounds such as methyl lithium and butyl lithium in that n-hexyl lithium is less flammable. By using hexyllithium, the resulting by-product is hexane, which can simply be left in the third mixture as the above-mentioned second hydrocarbon. According to conventional practice, the use of butyllithium gives off butane gas, which must be vented. Moreover, butyllithium is highly pyrophoric and therefore hazardous. Hexyllithium is less pyrophoric than butyllithium to thereby enhance safety.
The term hydrocarbyl substituted fulvene is used herein to refer to a compound having the structure of fulvene but having at least one hydrocarbyl group on either the cyclic structure or on the terminal carbon of the olefin double bond of the fulvene structure. Typically the hydrocarbyl substituent on the fulvene would be an alkyl group have 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms. In a particularly preferred embodiment the hydrocarbyl substituted filvenes are substituted at the 6 position with a terminal alkenyl group. An example would be 6-(3-butenyl)-6-methylfulvene. The organic base used in producing the fulvene can be selected from any suitable organic secondary amine. Pyrrolidine is currently preferred.
In the embodiment wherein a carbonyl compound is reacted with cyclopentadiene to form a 6-hydrocarbyl fulvene, the carbonyl compound is selected from hydrocarbyl substituted ketones and hydrocarbyl substituted aldehydes. Typically the hydrocarbyl groups of the carbonyl compound would have 1 to 10 carbon atoms. In a particularly preferred embodiment the hydrocarbyl group substituent of the carbonyl compound has terminal olefinic unsaturation. An example would be 5-hexene-one.
The term fluorene compound as used herein refers to unsubstituted fluorene as well a compounds in which one or more of the hydrogens of fluorene has been replaced by a hydrocarbyl group, preferably containing 1 to 10 carbon atoms. Examples include fluorene, 1-methylfluorene, 4-methylfluorene, 9-butylfluorene, 5-(4-butenyl)fluorene), 1,2-benzofluorene, 2,3:6,7-dibenzofluorene, 4,5 benzofluorene,and the l
Glass Gary L.
Hottovy John D.
Jensen Michael D.
Palackal Syriac J.
Stouffer Carleton E.
Bowman Edward L.
Nazario-Gonzalez Porfirio
Phillips Petroleum Company
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