Organic compounds -- part of the class 532-570 series – Organic compounds – Heavy metal containing
Reexamination Certificate
1998-03-30
2001-07-31
Nazario-Gonzalez, Porfirio (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heavy metal containing
C556S047000, C556S053000, C556S058000, C526S160000, C526S943000, C526S351000, C502S103000, C502S117000, C585S360000, C585S361000
Reexamination Certificate
active
06268518
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a new class of bridged metallocene compounds, to the process for their preparation and to a catalyst for the polymerization of olefins containing them. The invention also relates to a novel class of ligands useful as intermediates in the synthesis of said metallocenes.
PRIOR ART DISCLOSURE
Metallocene compounds with two bridged cyclopentadienyl groups are known as catalyst components for the polymerization of olefins.
For example, the European Patent Application EP 0 129 368 describes a catalyst system for the polymerization of olefins which comprises a bis-cyclopentadienyl coordination complex with a transition metal, wherein the two cyclopentadienyl groups can be joined by a bridging group. In this type of metallocene compounds the two cyclopentadienyl groups are generally bridged by divalent radicals having two or more carbon atoms, such as an ethylene group, or with atoms other than carbon, such as a dimethyl-silanediyl group.
Metallocene compounds having two cyclopentadienyl groups bridged by a single carbon atom are also known. In particular, metallocene compounds of this type having two different cyclopentadienyl groups are known.
For example, the European Patent Application EP 0 351 392 describes a catalyst which can be used for the preparation of syndiotactic polyolefins and contains a metallocene compound with two cyclopentadienyl groups linked by a bridge between them, in which one of the two cyclopentadienyl groups is substituted in a different manner from the other. The compound indicated as being preferred is isopropylidene(fluorenyl)(cyclopentadienyl) hafnium dichloride.
As regards metallocene compounds having two equally substituted cyclopentadienyl groups bridged by a single carbon atom, the European Patent Application EP 0 416 566 describes a process for the polymerization of &agr;-olefins, carried out in liquid monomer, in the presence of a catalyst consisting of an alumoxane and a metallocene compound wherein the two cyclopentadienyl rings, the same or different from each other, are bridged by a —CR
2
— divalent group, R being broadly defined, and preferably being an alkyl or an aryl group. The two compounds indicated as being preferred are Ph
2
C-bis(indenyl)ZrCl
2
and (CH
3
)
2
C-bis(indenyl)ZrCl
2
, the latter compound being the only metallocene actually synthesized said application and used in the polymerization of propylene, in order to produce low molecular weight polypropylene waxes.
In the International Application WO 96/22995 a class of metallocene compounds having two equally substituted cyclopentadienyl groups bridged by a —CR
2
— divalent group is disclosed. The definitions given for the R substituents do not encompass the case in which both the R substituents are hydrogen atoms. By polymerizing propylene in the presence of a catalyst based on these metallocenes, highly isotactic polypropylenes with high molecular weights are obtained. However, the molecular weights that can be obtained at polymerization temperatures of industrial interest are still too low for many utilizations, for example for the preparation by extrusion of thick articles, such as pipes.
Therefore, it would be desirable to improve the class of one-carbon-bridged metallocenes by providing novel compounds which, when used in catalysts for the polymerization of olefins, could allow to widen the range of obtainable molecular weights.
J. A. Ewen et al. (
Macromol. Chem.; Macromol. Symp
. 48/49, 253-295, 1991) characterized a series of Group IV metallocenes possessing chiral ligand environments in order to evaluate the relationship existing between their structure and their stereospecificity, and in particular their isotacticity in propylene polymerization. Among the metallocenes used there is methylene-bis(indenyl)hafnium dichloride, which gives polypropylene with low isotacticity.
The European patent application EP 0 751 143 describes a process for the preparation of carbon-bridged bis-cyclopentadienyl compounds by reacting, in a two- or more-phases system, one or two cyclopentadienyl compounds with a carbonyl compound in the presence of a base and of a phase-transfer catalyst. Among the large number of bridged metallocenes obtainable with said process, methylene-bis(4-phenyl-1-indenyl)zirconium dichloride, methylene-bis(4-isopropyl-1-indenyl)zirconium dichloride and methylene-bis(4,5-benzo-1-indenyl)zirconium dichloride are mentioned as illustrative examples; nevertheless, neither their synthesis nor their use in olefin polymerization is reported.
SUMMARY OF THE INVENTION
The Applicant has now unexpectedly found a novel class of metallocenes having two identical cyclopentadienyl groups linked to one another by a methylene group; said metallocenes can advantageously be used as catalyst components for the polymerization of olefins.
Therefore, according to a first aspect, the present invention provides a bridged metallocene compound of formula (I):
wherein:
the substituents R
1
and R
2
, the same or different from each other, are selected from the group consisting of hydrogen atoms, linear or branched, saturated or unsaturated C
1
-C
20
-alkyl, C
3
-C
20
-cycloalkyl, C
6
-C
20
-aryl, C
7
-C
20
-alkylaryl and C
7
-C
20
-arylalkyl radicals, optionally containing Si or Ge atoms;
the substituents R
3
and R
4
form a condensed, 5- to 8-membered, aliphatic, aromatic or heterocyclic ring, optionally substituted, with the proviso that, when R
1
and R
2
are hydrogen atoms and said condensed ring is a benzene ring, the benzene ring is substituted in the position ortho or meta with respect to the carbon atom of the cyclopentadienyl group linked to R
4
;
M is a transition metal belonging to groups 3, 4 or 5, or to the lanthanide or actinide groups of the Periodic Table of the Elements (new IUPAC notation);
the groups X, the same or different from each other, are monoanionic sigma ligands selected from the group consisting of hydrogen, halogen, —R, —OR, —OSO
2
CF
3
, —OCOR, —SR, —NR
2
and PR
2
groups, wherein the R substituents are C
1
-C
20
-alkyl, C
3
-C
20
-cycloalkyl, C
2
-C
20
-alkenyl, C
6
-C
20
-aryl, C
7
-C
20
-alkylaryl or C
7
-C
20
-arylalkyl radicals, optionally containing Si or Ge atoms; and
p is an integer ranging from 0 to 3, being equal to the oxidation state of the metal M minus two.
It is another object according to the present invention a ligand of formula (II):
and its double bond isomers, wherein R
1
, R
2
, R
3
and R
4
have the meaning reported above, with the exclusion of bis(3-t-butyl-indenyl)methane, said ligand being useful in the preparation of said bridged metallocene compounds of formula (I).
Furthermore, the present invention concerns a process for the preparation of the metallocene compounds of formula (I), as well as a catalyst system for the polymerization of olefins comprising the product obtainable by contacting:
(A) one or more bridged metallocene compounds of formula (d), as described above, and
(B) a suitable activating cocatalyst.
Finally, the present invention provides a process for the polymerization of olefins comprising the polymerization reaction of one or more olefinic monomers in the presence of a catalyst system as described above.
REFERENCES:
patent: 5670681 (1997-09-01), Kuber et al.
patent: 5698645 (1997-12-01), Weller et al.
patent: 5786433 (1998-07-01), Tomotsu et al.
patent: 5945553 (1999-08-01), Kuber et al.
patent: 196 37 669 A1 (1998-03-01), None
patent: 0 416 566 A2 (1991-03-01), None
patent: 0 751 143 A2 (1997-01-01), None
patent: WO 96/22995 (1996-08-01), None
Derwent English language abstract of EP 0 416 566 A2 (1997).
Luttikhedde, et al., Synthesis and molecular structure of rac-methylenebis (4,5,6,7-tetrahydro-1-indenyl) titanium dichloride,Journal of Organometallic Chemistry,vol. 547, pp. 129-132 (1997).
Ewen, et al., Chemical Abstracts, vol. 116, No. 16, abstract No. 152458 (1992).
Balboni Davide
Dang Vu Anh
Resconi Luigi
Yu Lin-Chen
Bryan Cave LLP
Montell Technology Company B.V.
Nazario-Gonzalez Porfirio
Stiefel Maurice B.
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