Bridged zirconocene compounds, process for their preparation...

Details Bridged zirconocene compounds, process for their preparation... Bridged zirconocene compounds, process for their preparation...

2001-10-05

2004-01-06

Nazario-Gonzalez, Porfirio (Department: 1621)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S065000, C526S082000, C526S084000, C526S124200, C526S160000, C526S943000, C502S103000, C502S117000, C556S011000, C556S012000, C556S053000, C585S027000, C560S076000

Reexamination Certificate

active

06673880

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to bridged zirconocene compounds, to the corresponding ligands, to a new process for their preparation and to the use of said zirconocenes as catalytic components in the polymerization of olefins.
PRIOR ART DISCLOSURE
Stereorigid chiral metallocene compounds possessing two bridged indenyl groups are well known in the state of the art and are mainly used as catalytic components in olefin polymerization processes, and in particular in the preparation of stereoregular polyolefins. The numbering of the substituents on the indenyl group, to which reference is made in the present application, in accordance with the IUPAC nomenclature, is the following:
In the bridged indenyl metallocene compounds known in the state of the art, the indenyl groups are linked together by divalent radicals containing one or more carbon atoms and/or heteroatoms; the divalent bridging groups are generally linked to the 1 position of said indenyl groups, and therefore, the common indenyl metallocenes are 1-indenyl compounds. For example, the European patent application EP 0 485 823 describes a class of bridged bis(1-indenyl) metallocenes, wherein the indenyl groups have a substituent other than hydrogen in the 2 position and are bridged in the 1 position by means of a bridge containing 1 or more carbon atoms (e.g. an ethylene or isopropylidene group) or containing heteroatoms (e.g. a dimethyl-silyl or a diphenyl-silyl group).
The European patent application EP 0 372 414 describes a very broad class of bridged or unbridged metallocenes; among the many metallocenes exemplified, are reported two specific bis-indenyl metallocene compounds, wherein the divalent group bridging the indenyl groups is linked to the 1 position of one indenyl group and to the 2 position of the other indenyl group (formulae II-1 and II-2, on page 5 of said patent application).
The International patent application WO 94/11406 describes a very broad class of metallocene compounds of formula R′Ind-M-(CP)Q
k
, wherein: Ind is an indenyl group; R′ is a substituent, other than hydrogen, linked in the 2 position of said indenyl group; Cp is a cyclopentadienyl group; M is a transition metal belonging to group 3, 4, 5 or 6 of the Periodic Table of Elements; and Q is a &sgr;-ligand of the metal M, k being an integer linked to the valence of said metal M. Among the huge plethora of embodiments envisaged in the reported general formula, R′ can form a bridge between the 2 position of the Ind group and the Cp group of the above formula; therefore, the class of bis(2-indenyl) compounds is generically described. The definition of the bridging group R′ is very broad too, the preferred bridges linking the two indenyl residues being —S—, (CH
3
)
2
Si< and —CH
2
— groups; in fact, in the working examples only bis-indenyl zirconocenes with a one-atom-bridge have actually been synthesized and tested in ethylene (co)polymerization, giving ethylene homopolymers in very low yield and ethylene/propylene copolymers having very low molecular weights and in low yields too.
SUMMARY OF THE INVENTION
The Applicant has now unexpectedly found a new class of bridged bis(2-indenyl)zirconocenes, particularly active as catalyst components for the polymerization of olefins. Said zirconocene compounds are characterized by the presence of two indenyl ligands, bridged in the 2 position by means of a two-carbon-atoms divalent group.
Therefore, an object of the present invention is a bridged zirconocene compound of formula (I):
wherein R
1
, R
2
, R
3
and R
4
, the same or different from each other, are selected from the group consisting of hydrogen, 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 one or more Si or Ge atoms, or wherein two substituents of R
1
, R
2
, R
3
and R
4
form a ring having from 4 to 8 carbon atoms;
R
5
and R
6
, the same or different from each other, are selected from the group consisting of 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 one or more Si or Ge atoms, or two vicinal R
6
substituents on the same indenyl group form a ring having from 4 to 8 carbon atoms;
m is an integer ranging from 0 to 2; n is an integer ranging from 0 to 4;
the groups X, the same or different from each other, are hydrogen, halogen, —R, —OR, —SR, —NR
2
or —PR
2
, wherein R is selected from the group consisting of 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 one or more Si or Ge atoms.
Another object of the present invention is a catalyst for the polymerization of olefins comprising the product obtainable by contacting:
(A) one or more bridged zirconocene compounds of formula (I), as described above, and
(B) a suitable activating cocatalyst.
Furthermore, 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 as described above.
Another object of the present invention is a ligand of formula (II):
wherein R
1
, R
2
, R
3
, R
4
, R
5
and R
6
, m and n have the meaning reported above, with the proviso that:
when R
1
, R
2
, R
3
and R
4
are hydrogen and n is 0, then m is different from 0; and
when R
1
, R
2
, R
3
and R
4
are hydrogen, n is 0 and m is 1, then R
5
is different from —CH
3
, —CH
2
Ph and —Si(CH
3
)
3
.
The present invention further concerns a process for the preparation of the above ligands of formula (II), comprising the following steps:
(1) reacting an adipic ester of formula (III) with at least 2 equivalents of a benzyl compound of formula (IV) and at least 2 equivalents of an alkali metal or alkaline earth metal base, in the presence of an organic solvent, to obtain an intermediate compound of formula (V); said step may be represented by the following reaction scheme:
 wherein R
1
, R
2
, R
3
, R
4
, R
6
and n have the meaning reported above, R
7
is selected from the group consisting of 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, and Y is a suitable leaving group;
(2) cycling said compound of formula (V) to obtain a compound of formula (VII); said step may be represented by the following reaction scheme:
 wherein R
1
, R
2
, R
3
, R
4
, R
6
and n have the meaning reported above and Y′ is a suitable leaving group;
(3) reducing the ketonic functions of the indanyl moieties of the compound of formula (VII) to obtain the diol (VIII) and finally dehydrating the hydroxy functions of the indanyl moieties of said diol (VIII) to give the ligand (II); said step may be represented by the following reaction scheme:
 wherein R
1
, R
2
, R
3
, R
4
, R
6
and n have the meaning reported above.
When in the ligand of formula (II) m is ≠ 0, then the substituents R
5
can be introduced on the cyclopentadienyl ring by reacting a compound of formula (VII) or the same ligand of formula (II) with a suitable amount of an alkylating agent R
5
MgBr, R
5
MgCl or R
5
j
B, wherein B is an alkaline or alkaline-earth metal, and j is 1 or 2.
Finally, the present invention concerns intermediate compounds of formula (V), as reported above, useful in the synthesis of the ligands (II), according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The bridged zirconocene compounds of formula (I), the corresponding ligands, the process for their preparation and the catalysts for the polymerization of olefins containing them, according to the present invention, will be better described in the following detailed description.
It is an object of the present invention a bridged zirconocene compound of formula (I), wherein R
1
, R
2
, R
3

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