Aryl substituted metallocene catalysts and their use

Details Aryl substituted metallocene catalysts and their use Aryl substituted metallocene catalysts and their use

1999-06-17

2001-07-17

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...

C526S160000, C526S943000, C556S011000, C556S053000, C502S152000

Reexamination Certificate

active

06262201

ABSTRACT:

BACKGROUND OF THE INVENTION
U.S. Pat. No. 5,324,800 discloses that certain substituted metallocenes when used in catalyst systems for producing olefin polymers produce higher activity than when one uses an unsubstituted metallocene such as bis(cyclopentadienyl)zirconium dichloride. The patent contains the broad statement that included among the possible substituents are various hydrocarbyl radicals having 1 to 20 carbon atoms. Arylalkyl radicals are recited as one example of such hydrocarbyl radicals. There is, however, only one arylalkyl substituted metallocene actually named, i.e. bis(beta-phenylpropyl cyclopentadienyl) zirconium dimethyl. See column 5, lines 23 and 24. Example 4 of the patent might conceivably have used bis(beta-phenylpropylcyclopentadienyl) zirconium dichloride; however, even that is just an assumption based on the fact that the symbols used in Example 4 were the same as those used in connection with the naming of the dimethyl metallocene in column 5, lines 23 and 24. From the nomenclature used in the patent it is assumed that in both of those metallocenes the substituted cyclopentadienyl group was 1-cyclopentadienyl-2-phenyl-2-methyl-ethane, that is to say that there were only two carbons separating tie cyclopentadienyl group and the phenyl group. Example 4 of that patent provides some evidence that that particular metallocene was slightly more than twice as active as the unsubstituted metallocene bis(cyclopentadienyl)zirconium dichloride.
The present inventors have since prepared the metallocenes bis(phenylmethylidene cyclopentadienyl) zirconium dichloride, bis(phenylethylidene cyclopentadienyl) zirconium dichloride, and bis (phenyl-n-propylidene cyclopentadienyl) zirconium dichloride, which could also be called bis(1-phenyl-3-cyclopentadienyl-n-propane) zirconium dichloride, and have used those metallocenes with an aluminoxane cocatalyst in the polymerization of olefins. It was observed that the activity increased as the length of the alkylidene group was increased. The first two named metallocenes gave activities that were much less than half of the activity of the later. It would therefor be logical to assume that the metallocene having the n-propylidene alkylene group connecting the phenyl and the cyclopentadienyl was more active than the metallocene of Example 4 of the above mentioned patent, said metallocene having only two carbons between the phenyl and the cyclopentadienyl rather than 3.
The applicants also prepared bis(phenyl-isopropylidene-cyclopentadienyl) zirconium dichloride, i.e. a metallocene in which the alkylene radical connecting the phenyl and the cyclopentadienyl was 1,1-dimethyl methylene. That metallocene was of very low activity as compared to that of even bis(phenylmethylidene cyclopentadienyl) zirconium dichloride and bis(phenylethylidene cyclopentadienyl) zirconium dichloride. The metallocene had an activity of only about 5.8 kg of polyethylene per hour which is even lower than that reported for the unsubstituted cyclopentadienyl metallocene bis(cyclopentadienyl) zirconium dichloride. See U.S. Pat. No. 5,780,659 which shows that under substantially the same polymerization conditions bis(cyclopentadienyl) zirconium dichloride had an activity of about 136 kg of polyethylene per hour.
The present invention is based in part upon the discovery that different aryl alkyl, aryl alkyl silyl, or aryl silyl substituted metallocenes produce unexpected effects when used with a cocatalyst in the polymerization of olefins.
Thus an object of the present invention is to provide certain metallocenes having unexpected properties. Another object is to provide processes for the polymerization of olefins using such metallocenes.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided new substituted metallocenes which have a substituent selected from the group consisting of aryl alkyl, aryl alkyl silyl, and aryl silyl groups.
In accordance with another aspect of the present invention there are provided catalyst systems resulting from the combination of such metallocenes with a suitable cocatalyst.
In accordance with yet another aspect of the present invention there is provided methods for producing olefins using such catalyst systems.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the present invention there is provided unbridged bis metallocenes in which each ligand has the formula
Cp-Si(R)
2
—(C(R′)
2
)
n
-A
wherein Cp is selected from cyclopentadienyl, 3-methylcyclopentadienyl, and 1-indenyl, each R can be the same or different and is an alkyl radical having 1 to 6 carbon atoms, each R′ can be the same or different and is selected from hydrogen and alkyl radicals having 1 to 6 carbon atom, A is an aryl radical, i.e. a cyclic compound having conjugated unsaturation, and is n is 0 to 5 or
Cp—(C(R′)
2
)
n
-A
wherein Cp is selected from cyclopentadienyl, 3-methylcyclopentadienyl, 1-indenyl, A is an aryl radical as defined above, and n is 1 to 5, except when Cp is cyclopentadienyl and A is phenyl then R′ is not methylene, dimethyl methylene, or 2-methyl ethylene which is connected such that the phenyl is also bonded to the 2 carbon of the 2-methyl ethylene. Some examples of A include phenyl, 4-methylphenyl, 1-indenyl, 9-fluorenyl, naphthyl, 4-fluorophenyl, 3,5-dimethylphenyl, and the like.
The inventive metallocenes are produced by reacting the necessary ligands using techniques known in the art. Unbridged mixed metallocenes can be prepared by reacting unsubstituted half sandwich cyclodienyl ZrCl
3
with the lithium salt of a selected aryl substituted cyclodienyl compound. For example cyclopentadienyl ZrCl
3
can be reacted with the lithium salt of cyclopentadienyl methylidene phenyl to yield the metallocene (phenyl methylidene cyclopentadienyl) (cyclopentadienyl) ZrCl
2
.
Aryl substituted cyclodienyl compounds needed to produce the inventive metallocenes can be produced by reacting an omega bromo alkyl aryl compound or an omega bromo alkyl silyl aryl compound or an omega bromo silyl aryl compound with cyclopentadienyl sodium. A similar technique can yield aryl substituted fluorenyl compounds. 1-Aryl substituted indenyl compounds can be produced by reacting indenyl lithium with aryl 1-haloalkanes or aryl dialkyl chloro silanes. Aryl indenyl compounds with the aryl group attached at the 2 position can be produced by reacting 2-indanone with omega phenylalkyl magnesium bromide in diethyl ether, then hydrolyzing, and finally dehydrogenating using p-toluenesufonic acid.
The aryl substituted metallocenes can be used for the polymerization. The inventive catalyst systems are particularly useful for the polymerization of alpha-olefins having 2 to 10 carbon atoms. Examples of such olefins include ethylene, propylene, butene-1, pentane-1, 3-methylbutene-1, hexene-1, 4-methylpentene-1, 3-methylpentene-1, heptene-1, octene-1, decene-1, 4,4-dimethyl-1-pentane, 4,4-diethyl-1-hexene, 3,4-dimethyl-1-hexene, and the like and mixtures thereof. The catalysts are also useful for preparing copolymers of ethylene and propylene and copolymers of ethylene or propylene and a higher molecular weight olefin. Monomers such as styrene and butadiene are also useful.
Polymerizations with the inventive catalyst can be carried out under a wide range of conditions depending upon the particular metallocene employed and the particular results desired. The inventive catalyst systems are considered useful for polymerization conducted under solution, slurry, or gas phase reaction conditions. Typically the inventive metallocene would be used with a suitable cocatalyst.
Examples of suitable cocatalysts include generally any of those organometallic cocatalysts which have in the past been employed in conjunction with transition metal containing olefin polymerization catalysts. Some typical examples include organometallic compounds of metals of Groups IA, IIA, and IIIB of the Periodic Table. Examples of such compounds have included organometallic halide compounds, organometallic hydrides and even metal hydrides. Some specific exa

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