Organic compounds -- part of the class 532-570 series – Organic compounds – Heavy metal containing
Reexamination Certificate
2001-08-07
2002-11-19
Nazario-Gonzalez, Porfirio (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heavy metal containing
C556S043000, C556S058000, C502S103000, C502S108000, C502S111000, C502S117000, C526S160000, C526S352000, C526S943000
Reexamination Certificate
active
06482967
ABSTRACT:
This invention relates to certain metallocenes. In another aspect this invention relates to the polymerization of olefins. In another aspect this invention relates to metallocene based catalyst systems for the polymerization of olefins.
BACKGROUND OF THE INVENTION
The discovery that metallocenes of transition metals can be used as catalysts for the polymerization of olefins has led to significant amounts of research since it was found that different metallocenes could produce different types of polymers. One of the earliest references to the use of metallocenes in the polymerization of olefins is U.S. Pat. No. 2,827,446 which discloses a homogeneous, i.e. liquid, catalyst system of bis(cyclopentadienyl) titanium dichloride and an alkyl aluminum compound. The activity of such systems was not, however, as high as would be desired. It was latter discovered that more active catalyst systems would result if the metallocene was employed with an alkylaluminoxane cocatalyst, such as that disclosed in U.S. Pat. No. 3,242,099.
U.S. Pat. Nos. 5,498,581 and 5,565,592 revealed a particularly interesting class of new metallocenes that are suitable for use in the polymerization of olefins, namely bridged metallocenes having a terminally unsaturated group extending from the bridge. One particularly preferred metallocene of that type was the metallocene which can be called 1-(9-fluorenyl)-1-(cyclopentadienyl)-1-(methyl)-1-(but-3-enyl)methane zirconium dichloride. The metallocenes of that type were found to be particularly desirable in that they allowed for the production of solid catalyst systems that could be employed effectively in slurry polymerization processes.
The present invention is based on the subsequent discovery that fluorenyl containing metallocenes which have a bridge with a terminally unsaturated group and also a hydrocarbyl substituent on the 4 position of the fluorenyl group produce unexpected benefits.
SUMMARY OF THE INVENTION
In accordance with the present invention there is provided a bridged metallocene in which two cyclodienyl-type groups are connected by a single carbon bridge which contains a terminally unsaturated substituent, one of the cyclodienyl groups being a 9-fluorenyl radical having hydrocarbyl substitution at the 4 position. In accordance with another aspect of the present invention there is provided olefin catalyst compositions comprising such metallocenes and a suitable cocatalyst. In accordance with yet another aspect of the present invention there is provided a process for polymerizing olefins using such catalyst systems.
DETAILED DESCRIPTION OF THE INVENTION
The metallocenes of the present invention include those represented by the formula R(Z)(Z)MQ
k
wherein each Z bound to M and is the same or different and is a cyclodienyl-type ligand selected from substituted or unsubstituted cyclopentadienyl, indenyl, tetrahydroindenyl, octahydrofluorenyl, and fluorenyl ligands; with the further proviso that at least one Z is a 9-fluorenyl having a hydrocarbyl substituent at the 4 position, R is a structural bridge linking the Z's which is a single carbon atom connecting the Z's and which has its other valences satisfied by a terminally unsaturated hydrocarbyl substituent, preferably having 2 to 20 carbon atoms, and by hydrogen or a hydrocarbyl group, preferably having 1 to 10 carbon atoms, and M is a metal selected from the group consisting of IVB, VB, and VIB metals of the periodic table, each Q is the same or different and is selected from the group consisting of hydrogen, halogens, and organo radicals; k is a number sufficient to fill out the remaining valances of M.
A particularly preferred type of bridged metallocene includes those in which the olefinically unsaturated substituent has the formula
wherein R″ is a hydrocarbyl diradical having 1 to 20 carbon atoms; more preferably 2 to 10; n is 1 or 0, and each R′ is individually selected from the group consisting of organo radicals, most preferably alkyl radicals, having 1 to 10 carbon atoms and hydrogen. Most preferably R″ has at least two carbons in its main alkylene chain, i.e. it is a divalent ethylene radical or a higher homolog thereof.
The present invention thus envisions bridged metallocenes prepared from vinyl terminated branched bridged ligands of the formula
wherein n is a number typically in the range of about 0 to 20; more preferably 2-10; wherein R′ is selected from hydrogen, or organo groups having 1 to 10 carbons and R′″ is selected from hydrogen or hydrocarbyl radicals having 1 to 20 carbon atoms. Currently preferred R′ components are hydrogen or alkyl groups typically having 1 to 10 carbon atoms, or aryl groups typically having 6 to 10 carbon atoms. Each Z is a cyclodienyl-type radical as described earlier.
The metallocenes of such olefinically unsaturated branched-bridged ligands can be prepared by reacting the olefinically branched-bridged bis(cyclopentadienyl-type) ligand with an alkali metal alkyl to produce a divalent ligand salt that is then reacted with the transition metal compound to yield the metallocene, using the techniques generally known in the art for forming such metallocenes. See, for example, the technique disclosed in U.S. Pat. No. 5,436,305, the disclosure of which is incorporated herein by reference.
The necessary olefinically branched-bridged organic compounds suitable for use as ligands for such metallocenes can be made by reacting a suitable alkenyl ketone with an alkali metal salt of a cyclopentadiene-type compound such as cyclopentadiene or indene to form a 6-terminal alkenyl fulvene then reacting the fulvene with an alkali metal salt of fluorene.
Some typical examples of metallocenes containing a substituent having olefinic unsaturation include 1-(cyclopentadienyl)-1-(4- methyl-9-fluorenyl)-1-(but-3-enyl)-1-(methyl)methane zirconium dichloride; 1-(cyclopentadienyl)-1-(4-methyl-9-fluorenyl)-1-(but-3-enyl)-1-(methyl) methane zirconium dimethyl; 1-(3-methyl-cyclopentadienyl)-1-(4-methyl-9-fluorenyl)-1-(but-3-enyl)-1-(methyl)methane zirconium dichloride; 1-(indenyl)-1-(4-methyl-9-fluorenyl)-1-(but-3-enyl)-1-(phenyl)methane zirconium dichloride; 1-(cyclopentadienyl)-1-(4,7-dimethyl-9-fluorenyl)-1-(pent-4-enyl)-1-(methyl)methane zirconium dichloride; 1-(cyclopentadienyl)-1-(4-methyl-9-fluorenyl)-1-(but-3-enyl)-1-(phenyl)methane zirconium dichloride; and the like.
The inventive metallocenes are suitable for preparing catalysts for the polymerization of olefins. Such catalyst systems are prepared by combining at least one inventive metallocene with a suitable cocatalyst. It is also within the scope of the present invention to use two or more of the inventive metallocenes or an inventive metallocene in combination with one or more other metallocenes.
Examples of suitable cocatalysts include generally any of those organometallic compounds which have been found suitable as cocatalysts for metallocenes in the past. Some typical examples include organometallic compounds of the metals of Groups IA, IIA, and IIIB of the Periodic Table. Examples of compounds that have been used in the past as cocatalysts for metallocenes include organometallic halide compounds, organometallic hydrides, and even metal hydrides. Some specific examples include organoaluminum alkyl compounds such as triethylaluminum, triisobutyl aluminum, diethylaluminum chloride, ethyl aluminum dichloride, ethyl aluminum sesquichloride, diethylaluminum hydride, and the like. Other examples of known cocatalysts include compounds capable of forming stable non-coordinating counter anion such as those disclosed in U.S. Pat. No. 5,155,080. Examples of such is triphenyl carbenium tetrakis (pentafluorophenyl) boronate and tris(pentafluorophenyl) borane. Still another example of a cocatalyst would be a mixture of trimethylaluminum and dimethylfluoroaluminum such as disclosed in Zambelli et al, Macromolecules, 22, 2186 (1989).
There are three types of currently preferred catalyst systems. The first, referred to hereinafter as Catalyst System I, is prepared by prepolymerizing
Alt Helmut G.
Köppl Alexander
Welch M. Bruce
Nazario-Gonzalez Porfirio
Phillips Petroleum Company
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