Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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METALLOCENES, LIGANDS AND OLEFIN POLYMEP~iZATION
FIELD OF THE INVENTION
The present invention relates to a new class of metallocene compounds, to a
catalyst for the
polymerization of olefins containing them and to a polymerization process
carried out in the
presence of said catalyst. The invention also relates to the corresponding
ligands useful as
intermediates in the synthesis of said metallocene compounds, as well as to
processes for
preparing said ligands and said metallocene compounds.
DESCRIPTION OF THE PRIOR ART
Metallocene compounds with two cyclopendadienyl groups are known as catalyst
components
for the polymerization of olefins.
European Patent 0 I29 368, for instance, describes a catalyst system for the
polymerization of
olefins comprising (a) a bis-cyclopentadienyl coordination complex with a
transition metal and
(b) an alumoxane. The two cyclopentadienyl groups can be linked by a bridging
group, which
is generally a divalent radical containing one or more carbon atoms or
heteroatoms.
Also known are bridged metallocene compounds wherein the cyclopentadienyl
moiety is
condensed to one aromatic or non aromatic ring.
For example, European Patent Application EP 0 185 9I8 describes the use of
ethylenbis(4,5,6,7-tetrahydro-1-indenyl)zirconium dichloride together with a
suitable
cocatalyst for the preparation of isotactic polyolefins.
Metallocenes compounds in which the cyclopentadienyl groups have heteroatom
containing
substituents and catalysts containing them are also known.
CONFIRMATION COPY
_.._..~__....~.~..~. __ . _._..._... r . . . ~_~~......~_..__
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From the European Patent Application EP-A2- 0 743 317 are known metallocene
compounds
possessing a cyclopentadienyl group containing a heteroatom as part of a
substituted or
condensed ring system. Illustrative examples are indenyl moieties substituted
with a chinoline
or pyridine radical. These catalysts containing said metallocenes are useful
for the
polymerization of olefins.
US Patent 5 489 659 relates to a class of silicon-containing metallocene
compounds for the
polymerization of alpha-olefins wherein the silicon atom is part of a non
aromatic ring
condensed to the cyclopentadienyl ring, such as, for example, ethylenbis(4,4-
dimethyl-4,5,6,7-
tetrahydro-4-silaindenyl) zirconium dichloride.
European Patent Application EP 0 590 486 describes metallocene compounds
containing a
cyclopentadienyl group having a heteroatom in the ring system for use in the
preparation of
polyolefins. The only illustrative examples are bis(1-phospha-2,3,4,5-
tetramethylcyclopentadienyl) zirconium dichloride and tetrakis(2,5-
dimethylpyrrol)zirconium.
International patent application PCT/EP97/6297, in the name of the same
Applicant, discloses
a class of bridged and unbridged heterocyclic metallocene compounds containing
a
cyclopentadienyl group to which a heteroatom containing ring is fused. The
catalytic system
containing said metallocenes are useful for the polymerization of olefins.
It would be desirable to provide a novel class of metallocenes which, when
used in catalysts for
the polymerization of olefins, are suitable for the preparation of
polyolefins.
SUMMARY OF THE INVENTION
A novel class of metallocene compounds having a particular cyclopentadienyl
ligand system
has now unexpectedly been found, which can advantageously be used as catalyst
components
for the polymerization of olefins.
2
._ ..._.._.,-.."~".~......_.._,.....~.. _. T . _._.._"... _.......
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According to a first aspect, the present invention provides a metallocene
compound of formula
(I):
Rn(Cp)(A)MLp
wherein Rn is a structural bridge;
Cp is a heterocyclic cyclopentadienyl group of formula (II):
R2 X
~Z
O y (II)
R1
wherein substituents R' and RZ, same or different, are hydrogen atoms, C,-Czo
alkyl, C3-Czo
cycloalkyl, CZ-Czo alkenyl, C6-CZO aryl, C; CZO alkylaryl, or C,-CZO arylalkyl
radicals, optionally
two adjacent substituents R' and RZ can form a cycle comprising from 5 to $
carbon atoms and,
furthermore, substituents R' and R2 can contain silicon or germanium atoms;
Z is NR3 or O, R' being defined as substituents R' and R2;
X and Y, same or different, are selected from (CR42)n BR°v PR4, SiR4z
or GeR°Z; and
substituents R4, same or different, are hydrogen atoms, C,-CZO alkyl, C3-CZO
cycloalkyl, Cz-CZO f
alkenyl, C6-CZO aryl, C; CZO alkylaryl or C,-CZO arylalkyl radicals; and,
furthermore, substituents
R4 can contain hetero atoms such as nitrogen, phosphor, oxygen, silicon or
germanium atoms,
with the proviso that both X and Y can not be carbon atoms at the same time;
A is a group selected from substituted or unsubstituted cyclopentadienyls,
which may carry one
or more condensed cycles, =NRS, -O-, -S- and =PRS groups, RS being defined as
substituents R'
and R'-, and groups corresponding to formula (II);
3
_.~ . .. ...._~,_~."~"~."m,~.~...,. . T .. . _ . ._~ . ~. ,..-. _.....-.._._-
.._....
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M is a transition metal selected from those belonging to group 3, 4, 5 or 6 or
to the lanthanides
or the actinides of the Periodic Table of the Elements (new IUPAC version);
the substituent L, same or different, is a monoanionic ligand, selected from
the group
consisting of hydrogen, halogen, -SR6, R6, -OR6, -NRG,, OCOR6, OSOzCF3 and
PR62, wherein
the substituents R6, same or different, are linear or branched, saturated or
unsaturated C,-CZo
alkyl, C3 CZO cycloalkyl, Cz-CZO alkenyl, C6-Czo aryl, C,-CZO alkylaryl, or C;
CZO arylalkyl
radicals, optionally containing silicon or germanium atoms;
p is an integer from 0 to 3, p being equal to the oxidation state of the metal
M minus two;
n is an integer ranging from 0 to 4; and
r is an integer ranging from 1 to 4.
According to another aspect of the present invention there is provided a new
class of ligands of
formula (III):
~,(CP)(A)q
wherein R, n, Cp, A, have the meanings as reported above and q is 0 when n is
0 and is 1 when
n is 1 to 4, particularly useful as intermediates in the preparation of the
metallocene compounds
of formula (I).
A further aspect of the present invention is a process for the preparation of
ligands Rn(Cp)(A)q
of formula (III), wherein R", Cp, A and q have the meanings as reported above.
A still further aspect of the present invention is a process for the
preparation of the metallocene
compounds of formula {I), obtainable by contacting the ligand of formula (III)
R"{Cp)(A)q with
a compound of formula ML~.z, wherein M, L and p are defined as above, in the
presence of a
compound capable of forming the corresponding dianionic compound of the ligand
of formula
(III).
4
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Another aspect of the present invention is a catalyst for the polymerization
of olefins
comprising said heterocyclic metallocene and the use thereof in the
polymerization of olefins.
DETAILED DESCRIPTION OF THE INVENTION
The numbering of the substituents on the cyclopentadienyl group of formula
(II), to which
reference is made in the present invention, is the following:
1
R2
2
Y (I1)
Rl
4 3
In the metallocene compounds of the aforementioned type, the cyclopentadienyl
group of
formula (II) may be linked to an identical cyclopentadienyl group, to a
cyclopentadienyl
derivate or to a heteroatom containing group, such as an amino group, by
divalent radicals
containing one or more carbon atoms, such as CHz groups, or atoms other than
carbon atoms,
such as dimethylsilanediyl groups, linking the cyclopentadienyl group in the 4
position of the
above ring system to either an identical cyclopentadienyl group, to a
cyclopentadienyl derivate
or to a heteroatom containing group.
An advantageous class of heterocyclic metallocenes according to the present
invention
corresponds to formula (I) wherein A is a group selected from substituted or
unsubstituted
cyclopentadienyls, which may carry one or more aromatic or non-aromatic
condensed cycles,
such as indenyl, fluorenyl, benzoindenyl, hydrogenated or partially
hydrogenated cycles, and n
is different from 0, i.e. the two cyclopentadienyl groups are linked to each
other by a bridging
divalent group. Preferably, the divalent group (QR'm)~ is selected from the
group consisting of
CR'2, SiR',, GeR',, NR', PR' and (CR'2)~ and the R' groups, equal or
different, are linear or
. _._..._~..~_._._ ... ..._.__.._w..~~.....~....._... . ~
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branched, saturated or unsaturated C'-CZO alkyl, C3-CZO cycloalkyl, C2-Czo
alkenyl, C6 C,a aryl,
C,-Czo alkylaryl, or C,-Czo arylalkyl radicals optionally, when Q is C, Si or
Ge, both
substituents R' can form a cycle comprising from 3 to 8 atoms. More
preferably, said divalent
bridge is Si(CH3)2, SiPhz, CHZ, (CHz)2 or C(CH3)2.
m is 1 or 2, being 1 when Q is N or P, and being 2 when Q is C, Si or Ge; n
ranges from 0 to b
and, when n > 1, the atoms Q can be the same or different, such as, for
example, in the bridges
-CHz-Si(CH3)2-, -CHz NRz- and CHZ-PRZ-.
The transition metal is preferably titanium, zirconium and hafnium, more
preferably it is
zirconium.
The substituents R' and RZ are preferably hydrogen atoms.
The substituents L are preferably halogen atoms or R6 groups, R6 being defined
as reported
above. More preferably they are chlorine atoms or methyl groups.
A more advantageous class of heterocyclic metallocenes according to the
present invention
corresponds to formula (I) wherein A is represented by the above formula (II),
i.e., the two
cyclopentadienyl moieties of the metallocene compound of the invention are
identical.
Non limitative examples of said metallocenes are:
isopropylidenebis{2-(methyl)-1,1,3,3-tetramethyl-1,2,3,3a-
tetrahydrocyclopenta[c][1,2,5]
azadisilole}zirconium dichloride or dimethyl;
isopropylidenebis{2-(ethyl)-1,1,3,3-tetramethyl-1,2,3,3a-
tetrahydrocyclopenta(c] [1,2,5]
azadisilole}zirconium dichloride or dimethyl;
isopropylidenebis { 2-(iso-propyl)-1,1,3,3-tetramethyl-1,2,3,3 a-
tetrahydrocyclopenta[c] [ 1,2, 5 ]
azadisilole}zirconium dichloride or dimethyl;
6
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isopropylidenebis {2-(tent-butyl)-1,1,3,3,5-pentamethyl-1,2,3,3a-
tetrahydrocyclopenta[c] [ 1,2,5]
azadisiloie}zirconium dichloride or dimethyl;
isopropylidenebis { 2-(ethyl)-1,1,3,3, 5-pentamethyl-1,2,3,3 a-
tetrahydrocyclopenta[c] [ 1,2, 5 ]
azadisilole}zirconium dichloride or dimethyl;
isopropylidenebis { 2-(iso-propyl)-1,1,3,3,5-pentamethyl-1,2,3,3a-
tetrahydrocyclopenta[c][1,2,5] azadisilole}zirconium dichloride or dimethyl;
isopropylidenebis{2-(tert-butyl)-1,1,3-trimethyl-1,2,3,3a-
tetrahydrocyclopenta[c][1,2,5]
azaborasilole}zirconium dichloride or dimethyl;
isopropylidenebis { 2-(tent-butyl)-1,1,3-trimethyl-1,2,3, 3 a-
tetrahydrocyclopenta[c] [ 1,2,5]
azaphosphasilole}zirconium dichloride or dimethyl;
isopropylidenebis{2-(tert-butyl)-1,3-dimethyl-1,2,3,3a-
tetrahydrocyclopenta[c][1,2,5]
azadiborole}zirconium dichloride or dimethyl;
isopropylidenebis{2-(tert-butyl)-1,3-dimethyl-1,2,3,3a-
tetrahydrocyclopenta[c][1,2,5]
azadiphosphole}zirconium dichloride or dimethyl;
isopropylidenebis{2-(tert-butyl)-1,1,3,5-tetramethyl-1,2,3,3a-
tetrahydrocyclopenta[c][1,2,5]
azaborasilole}zirconium dichloride or dimethyl;
isopropylidenebis { 2-(tert-butyl)-1,1,3, 5-tetramethyl-1,2,3,3 a-
tetrahydrocyclopenta(c] ( 1,2,5]
azaphosphasiloie}zirconium dichloride or dimethyl;
isopropylidenebis { 2-(tert-butyl)-1,3, 5-trimethyl-1,2,3,3 a-
tetrahydrocyclopenta[c] [ 1,2, 5]
azadiborole}zirconium dichloride or dimethyl;
isopropylidenebis {2-(tert-butyl)-1,3,5-trimethyl-1,2,3,3 a-
tetrahydrocyclopenta[c] [ 1,2,5]
azadiphosphole}zirconium dichloride or dimethyl;
7
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dimethylsilanediylbis { 2-(tert-butyl)-1,1,3-trimethyl-1,2,3,3a-
tetrahydrocyclopenta[c] [ 1,2,5]
azaborasilole}zirconium dichloride or dimethyl;
dimethylsilanediylbis { 2-(tert-butyl)-1,1,3-trimethyl-1,2,3,3 a-
tetrahydrocyclopenta[c] [ 1,2,5]
azaphosphasilole}zirconium dichloride or dimethyl;
dimethylsilanediylbis {2-(tert-butyl)-1,3-dimethyl-1,2,3,3a-
tetrahydrocyclopenta[c] [ 1,2,5]
azadiborole}zirconium dichloride or dimethyl;
dimethylsilanediylbis{2-(tert-butyl)-1,3-dimethyl-I,2,3,3a-
tetrahydrocyclopenta[c] [ 1,2,5]
azadiphosphole}zirconium dichloride or dimethyl;
dimethylsilanediylbis { 2-(tent-butyl)-1,3,5-trimethyl-1,2,3,3 a-
tetrahydrocyclopenta[c] [ 1,2, 5 ]
azadiborole}zirconium dichloride or dimethyl;
dimethylsilanediylbis { 2-(tert-butyl)-1,3,5-trimethyl-1,2,3,3 a-
tetrahydrocyclopenta[c] [ 1,2, 5 ]
azadiphosphole}zirconium dichloride or dimethyl;
ispropylidene{2-(tert-butyl)-1,1-dimethyl-2,3,4,7a-tetrahydro-1 H-
cyclopenta[c] [ 1,2]
azasiline}zirconium dichloride or dimethyl;
dimethylsilanediylbis { 2-(tert-butyl)-1,1-dimethyl-2,3,4,7a-tetrahydro-1 H-
cyclopenta[c] [ 1,2]
azasiline}zirconium dichloride or dimethyl;
Another interesting class of heterocyclic metallocenes according to the
present invention
corresponds to formula (I), wherein A corresponds to formula (II) and n = 0,
i.e., the two
identical cyclopentadienyl groups are not linked to each other by a bridging
divalent group.
Non limiting examples of said class are:
{2-(tent-butyl)-1,1,3,3-tetramethyl-1,2,3,3a-tetrahydrocyclopenta[c] [ 1,2,5]
azadisilole}zirconium dichloride or dimethyl;
8
.._._~-...-.-.._ _. . _..~.....r..._...-...,~,.~.....~._ ._ _ ~ .. .
,......,~...-...~.~.___
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{2-(tert-butyl)-1,1,3,3,5-pentamethyl-1,2,3,3a-tetrahydrocyclopenta[c]
[1,2,5]azadisilole}
zirconium dichloride or dimethyl;
{2-(methyl)-1,1,3,3-tetramethyl-1,2,3,3a-tetrahydrocyclopenta [c][1,2,5]
azadisilole}zirconium
dichloride or dimethyl;
{2-{methyl)-1,1,3,3,5-pentamethyl-1,2,3,3a-tetrahydrocyclopenta[c] [ 1,2,5]
azadisilole}zirconium dichloride or dimethyl;
{2-(ethyl)-1,1,3,3-tetramethyl-1,2,3,3a-
tetrahydrocyclopenta[c][1,2,5]azadisilole}zirconium
dichloride or dimethyl;
{2-(ethylrl,1,3,3,5-pentamethyl-1,2,3,3a-tetrahydrocyclopenta [c] [1,2,5]
azadisilole}zirconium dichloride or dimethyl;
{ 2-(iso-propyl)-1,1,3,3-tetramethyl-1,2,3,3 a-tetrahydrocyclopenta[c] [
1,2,5]azadisilole }
zirconium dichloride or dimethyl;
{2-(iso-propyl)-1,1,3,3,5-pentamethyl-1,2,3,3a-
tetrahydrocyclopenta[c][1,2,5]azadisilole}
zirconium dichloride or dimethyl;
{2-(tert-butyl)-1,1,3-trimethyl-1,2,3,3a-tetrahydrocyclopenta [c] [1,2,5]
azaborasilole}zirconium dichloride or dimethyl;
{2-(tert-butyl)-1,1,3-trimethyl-1,2,3,3a-tetrahydrocyclopenta[c]
[1,2,5]azaphosphasilole}
zirconium dichloride or dimethyl;
{2-(tert-butyl)-1,3-dimethyl-1,2,3,3 a-tetrahydrocyclopenta[c] [
1,2,5]azadiborol } zirconium
dichloride or dimethyl;
{2-(tert-butyl)-1,3-dimethyl-1,2,3,3a-tetrahydrocyclopenta [c][1,2,5]
azadiphosphole}zirconium dichloride or dimethyl;
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{2-(tert-butyl)-1,1,3,5-tetramethyl-1,2,3,3a-tetrahydrocyclopenta[c] [
I,2,5]azaborasilole}
zirconium dichloride or dimethyl;
{2-(tent-butyl)-1,1,3,5-tetramethyl-1,2,3,3a-
tetrahydrocyclopenta[c][1,2,5]azaphosphasilole}
zirconium dichloride or dimethyl;
{2-(tert-butyl)-1,3,5-trimethyl-1,2,3,3a-
tetrahydrocyclopenta[c][1,2,5]azadiborol}zirconium
dichloride or dimethyl;
{2-(tert-butyl)-1,3,5-trimethyl-1,2,3,3a-
tetrahydrocyclopenta[c][1,2,5]azadiphosphole}zirconium dichloride or dimethyl;
{ 2-(tert-butyl)-1,1-dimethyl-2,3,4,7a-tetrahydro-1 H-cyclopenta[c] [
1,2]azasiline } zirconium
dichloride or dimethyl;
{2-(tert-butyl)-1,I-dimethyl-2,3,4,7a-tetrahydro-1H-
cyclopenta[c][1,2]azasiline}zirconium
dichloride or dimethyl;
According to another aspect of the present invention there is provided a class
of ligands of
formula (III):
R"(Cp)(A)q (III)
wherein R" is a structural bridge;
Cp is a heterocyclic cyclopentadienyl group of formula (IV):
R2 X
~Z HIV)
1
R
wherein R, R', R2, X, Y and Z, n and q have the meaning as reported, A is a
group selected
from substituted or unsubstituted cyclopentadienyls, which may carry one or
more condensed
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cycles, =NRj, -O-, -S- and =PRS groups, RS being defined as substituents R'
and R'-, and groups
corresponding to formula (IV).
The two double bonds of the cyclopentadienyl ring of the ligands of formula
(IV) can be in any
of the allowed positions.
The aforementioned compounds of formula (IV) are particularly useful as
intermediate ligands
for the preparation of the heterocyclic metallocene compounds of formula (I).
An advantageous class of heterocyclic ligands according to the present
invention corresponds
to formula (III) wherein A is a group selected from substituted or
unsubstituted
cyclopentadienyls, which may carry one or more aromatic or non-aromatic
condensed cycles,
such as indenyl, fluorenyi, benzoindenyl, hydrogenated or partially
hydrogenated cycles, and n
is different from 0, i.e. the two cyclopentadienyi moieties are linked to each
other by a bridging
divalent radical. As to the divalent group R", reference is made to the above
said.
A more advantageous class of heterocyclic ligands according to the present
invention
corresponds to formula (III) wherein n is different from 0 and A corresponds
to formula (IV).
Non-limiting examples of this class of ligands according to the invention are:
isopropylidenebis { 2-(tert-butyl)-1,1,3,3-tetramethyl-1,2,3,3 a-
tetrahydrocyclopenta[c] [ 1,2, 5]
azadisilole};
isopropylidenebis {2-(methyl)-1,1,3,3-tetramethyl-1,2,3,3a-
tetrahydrocyciopenta[cJ [ 1,2,5]
a~adisilole};
isopropylidenebis { 2-(ethyl)-1,1,3,3-tetramethyl-1,2,3,3 a-
tetrahydrocyclopenta[c] [ 1,2,5]
azadisilole};
isopropylidenebis { 2-(iso-propyl)-1,1,3,3-tetramethyl-1,2,3,3 a-
tetrahydrocyclopenta[c] [ 1,2, 5
azadisilole};
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isopropylidene {2-(tert-butyl)-1,1,3,3,5-pentamethyl-1,2,3,3a-
tetrahydrocyclopenta[cJ[ 1,2,5]
azadisilole};
isopropylidene {2-(ethyl)-1,1,3,3,5-pentamethyl-1,2,3,3a-
tetrahydrocyclopenta[c] [1,2,5]
azadisilole};
isopropylidene { 2-(iso-propyl)-1,1,3,3,5-pentamethyl-1,2,3,3 a-
tetrahydrocyclopenta[c] [ 1,2, 5]
azadisilole};
isopropylidenebis {2-(tert-butyl)-1,1,3-trimethyl-1,2,3,3a-
tetrahydrocyclopenta[c] [ 1,2,5]
azaborasilole } ;
isopropylidenebis {2-{tent-butyl)-1,1,3-trimethyl-1,2,3,3a-
tetrahydrocyclopenta[c] [ 1,2,5]
azaphosphasilole};
isopropylidenebis { 2-(tert-butyl}-1,3-dimethyl-1,2,3,3a-
tetrahydrocyclopenta[cJ [ 1,2,5]
azadiborol};
isopropylidenebis { 2-(tert-butyl)-1, 3-dimethyl-1,2,3,3 a-
tetrahydrocyclopenta[c] [ 1,2, 5
azadiphosphole};
isopropylidenebis { 2-(tent-butyl)-1,1,3, 5-tetramethyl-1,2,3,3 a-
tetrahydrocyclopenta[c] [ 1,2, 5
azaborasilole};
isopropylidenebis {2-(tert-butyl)-1,1,3,5-tetramethyl-1,2,3,3a-
tetrahydrocyclopenta[c] [1,2,5]
azaphosphasilole};
isopropylidenebis { 2-(tert-butyl)-1,3,5-trimethyl-1,2,3,3a-
tetrahydrocyclopenta[c] [ 1,2,5]
azadiborol};
isopropylidenebis {2-(tent-butyl)-1,3,5-trimethyl-1,2,3,3a-
tetrahydrocyclopenta[c] [ 1,2,5]
azadiphosphole};
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dimethylsilanediylbis {2-(tert-butyl)-1,1,3-trimethyl-1,2,3,3a-
tetrahydrocyclopenta[c] [ 1,2,5]
azaborasilole};
dimethylsilanediylbis{2-(tert-butyl)-1,1,3-trimethyl-1,2,3,3a-
tetrahydrocyclopenta[c][1,2,5]
azaphosphasilole};
dimethylsilanediylbis { 2-(tert-butyl)-1,3-dimethyl-1,2,3,3 a-
tetrahydrocyclopenta[c] [ 1,2,5 ]
azadiborol};
dimethylsilanediylbis{2-(tert-butyl)-1,3-dimethyl-1,2,3,3a-
tetrahydrocyclopenta[c][1,2,5]
azadiphosphole};
dimethylsilanediylbis{2-(tert-butyl)-1,1,3,5-tetramethyl-1,2,3,3a-
tetrahydrocyclopenta[c][1,2,5] azaborasilole};
dimethylsilanediylbis{2-(tert-butyl)-1,1,3,5-tetramethyl-
1,2,3,3atetrahydrocyclopenta[c] [1,2,5]
azaphosphasilole};
dimethylsilanediylbis{2-(tert-butyl)-1,3,5-trimethyl-1,2,3,3a-
tetrahydrocyclopenta[c][1,2,5]
azadiborol};
dimethylsilanediylbis { 2-(tert-butyl)-1,3,5-trimethyl-1,2,3,3a-
tetrahydrocyclopenta[c] [ 1,2,5]
azadiphosphole};
isopropylidenebis { 2-(tert-butyl)-1,1-dimethyl-2,3,4,7a-tetrahydro-1 H-
cyclopenta[c] [ 1,2]
azasiline};
dimethylsilanediylbis{2-(tert-butyl)-1,1-dimethyl-2,3,4,7a-tetrahydro-1 H-
cyclopenta[c] [ 1,2]
azasiline}.
A further interesting class of ligands according to the present invention
corresponds to formula
(III), wherein A corresponds to formula (IV) and n = 0, i.e., the two
identical cyclopentadienyl
groups are not linked to each other by a bridging divalent residue.
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Non limiting examples of said ligands are:
bis{2-(tent-butyl)-1,1,3,3-tetramethyl-1,2,3,3a-tetrahydrocyclopenta[c]
[1,2,5] azadisilole};
bis{2-(tent-butyl)-1,1,3,3,5-pentamethyl-1,2,3,3a- tetrahydrocyclopenta[c]
[1,2,5] azadisilole};
bis{2-(methyl)-1,1,3,3-tetramethyl-1,2,3,3a-tetrahydrocyclopenta [c] [1,2,5]
azadisilole};
bis{2-(methyl)-1,1,3,3,5-pentamethyl-1,2,3,3a-tetrahydrocyclopenta [c] [1,2,5]
azadisilole};
bis{2-(ethyl)-1,1,3,3-tetramethyl-1,2,3,3a-tetrahydrocyclopenta [c] [1,2,5]
azadisilole};
bis{2-(ethyl)-1,1,3,3,5-pentamethyl-1,2,3,3a-tetrahydrocyclopenta [c] [1,2,5]
azadisilole};
bis{2-(iso-propyl)-1,1,3,3-tetramethyl-1,2,3,3a- tetrahydrocyclopenta[c]
[1,2,5] azadisilole};
bis{2-(iso-propyl)-1,I,3,3,5-pentamethyl-1,2,3,3a-
tetrahydrocyclopenta[c][1,2,5] azadisilole};
bis{2-(tent-butyl)-1,1,3-trimethyl-1,2,3,3a-tetrahydrocyclopenta [c] [1,2,5]
azaborasilole};
bis{2-(tent-butyl)-1,1,3-trimethyl-1,2,3,3a-tetrahydrocyclopenta [c] [1,2,5]
azaphosphasilole};
bis{2-{tent-butyl)-1,3-dimethyl-1,2,3,3a-tetrahydrocyclopenta [c] [1,2,5]
azadiborol};
bis{2-(tert-butyl)-1,3-dimethyl-1,2,3,3a-tetrahydrocyclopenta [c] [1,2,5]
azadiphosphole};
bis{2-(tert-butyl)-1,1,3,5-tetramethyl-1,2,3,3a-tetrahydrocyclopenta[c]
[1,2,5] azaborasilole}
bis {2-(tent-butyl)-1,1,3,5-tetramethyl-1,2,3,3 a-tetrahydrocyclopenta[c] [
1,2,5]
azaphosphasilole};
bis{2-(tent-butyl)-1,3,5-trimethyl-1,2,3,3a-tetrahydrocyclopenta [c] [1,2,5]
azadiborol};
bis{2-(tert-butyl~1,3,5-trimethyl-1,2,3,3a-tetrahydrocyclopenta [c] [1,2,5]
azadiphosphole}.
According to a further aspect of the present invention there is provided a
process for the
preparation of ligands R"(Cp)(A)q of formula (III), wherein R has the meaning
as described
above, Cp corresponds to formula (IV), A has the meaning as reported above and
both n and q
are 0, comprising the step of contacting a compound of formula (V):
14
_...w~........~,_..........~~...~...m~....._..._.-._.~.~..-~..~~"..~,.-
.w.._.~.___.. _~.. ~.....,r_._.......-.~,~..~....._.__._._. _.._~....~.
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R2 X
M
R
and its double bond isomers, wherein X, R' and R2 are defined as above and Z
is nitrogen, with
a compound of general formula YZ'2, wherein Y is defined as above and Z' is a
halogen atom,
in the presence of a base, to form a compound of formula (VI)
X~
(VI)
RI
and its double bond isomers.
The aforementioned cyclopentadienyl derivate of formula (V) can be prepared by
means of
known methods such as those as described in International Patent Application
PCT/US92/08730.
According to a still further aspect of the present invention there is provided
a process for the
preparation of a ligand R"(Cp)(A')q of formula (IIIa), wherein R has the
meaning as reported
above, n is an integer from 1 to 4 and q is 1, i.e. the two groups Cp and A'
are linked by a
divalent bridge, A' is a group selected from substituted or unsubstituted
cyclopentadienyls,
which may carry one or more condensed cycles, NRS, -O-, -S- and =PRS groups,
RS being
defined as substituents R' and R2, Cp corresponds to formula (IV) and Z' is a
halogen atom,
comprising the following steps:
( a ) contacting a compound of formula (V):
R2 X
~Z
/ ~ (~
Rl
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WO 99/58539 PCTlEP99/03247
and its double bond isomers, wherein X, R' and RZ have the meaning as reported
above
and Z is nitrogen, with a compound of general formula YZ'Z, wherein Y and Z'
are
defined above, in the presence of a base, to form a compound of formula (VI)
R2 X ~
(VI)
RI
and its double bond isomers, and
( b ) contacting with a compound able to form an anion of formula (VII)
R2 X
2 (VII)
RI ~ Y
and thereafter with a compound of general formula (VIII)
RnZ'z (VIIII)
in a molar ratio (VII)/(VIII) equal to or higher than 2, or with a compound of
general
formula (IX)
Z'R"A'HRS (IX)
in a molar ratio (VII)/(iX) equal to or greater than 1.
As to the structural bridge R" in the above ligands, reference is made to the
above said.
Non-limiting examples of bases used to form the above compounds of formula
(VI) are
hydroxides and hydrides of alkali or earth-alkali metals, metallic sodium or
potassium and
organometallic lithium compounds. Preferably, methyllithium or n-butyllithium
is used.
Non-limiting examples of compounds able to form the anionic compounds of
formula (VII) are
hydroxides and hydrides of alkali or earth-alkali metals, metallic sodium or
potassium and
organometallic lithium compounds. Preferably, methyllithium or n-butyllithium
is used.
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WO 99/58539 PCT/EP99/03247
Non-limiting examples of compounds of general formula R"Z'z (VIII) are
dimethyldichlorosilane, diphenyldichlorosilane, dimethyldichlorogermanium, 2,2-
dichloropropane and 1,2-dibromoethane.
The synthesis of the above bridged ligands is preferably carned out by adding
a solution of an
organic lithium compound in an apolar solvent to a solution of the compound
(VI) in an aprotic
polar solvent. The thus obtained solution containing the compound (VII) in the
anionic form is
then added to a solution of the compound of formula R"Z'z in an aprotic polar
solvent. The
bridged ligand can be finally separated by conventional general known
procedures.
Not limitative examples of aprotic polar solvents which can be used in the
above process are
tetrahydrofurane, dimethoxyethane, diethylether, toluene and dichloromethane.
Not limitative
examples of apolar solvents suitable for the above process are pentane, hexane
and benzene.
During the whole process, the temperature is preferably kept between -
180°C and 80°C, and
more preferably between -20°C and 40°C.
A still further aspect of the present invention is a process for the
preparation of the metallocene
compounds of formula (I), obtainable by contacting the ligand R"(Cp)(A)q of
formula (III) as
described above, with a compound capable of forming a corresponding dianionic
compound
thereof and thereafter with a compound of formula ML~2, wherein M, L and p
have the
meanings as defined above.
The compound able to form said dianion is selected from the group consisting
of hydroxides
and hydrides of alkali- and earth-alkali metals, metallic sodium and
potassium, and
organometallic lithium salts, and preferably said anion is n-butyllithium.
Non-limiting examples of compounds of formula ML'~z are titanium
tetrachloride, zirconium
tetrachloride and hafnium tetrachloride.
17
._.....~....~.~..~. ~ ._.. . . ._. .....ww.~_...-.-~.w 1 .. ..~.. .._....-
...~.,. -. .. ... . _.._....~. ..
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The metallocene compounds of formula (I), when n is different from 0 and A is
a
cyclopentadienyl derivate, can be prepared by first reacting the bridged
Iigands of formula (III),
prepared as described above, with a compound able to form a delocalized anion
on the
cyclopentadienyl rings, and thereafter with a compound of formula ML~2,
wherein M and the
substituents L are defined as above. Non limitative examples of compounds of
formula ML~2
are titanium tetrachloride, zirconium tetrachloride and hafnium tetrachloride.
More specifically, said bridged ligands are dissolved in an aprotic polar
solvent and to the
obtained solution is added a solution of an organic lithium compound in an
apolar solvent. The
thus obtained anionic form is separated, dissolved in an aprotic polar solvent
and thereafter
added to a suspension of the compound ML~2 in an aprotic polar solvent. At the
end of the
reaction, the solid product obtained is separated from the reaction mixture by
techniques
commonly used in the state of the art. Non limitating examples of aprotic
polar solvents
suitable for the above reported processes are tetrahydrofi>rane,
dimethoxyethane, diethylether,
toluene and dichloromethane. Non limitating examples of apolar solvents
suitable for the above
process are pentane, hexane and benzene.
During the whole process, the temperature is preferably kept between -
180°C and 80°C, and
more preferably between -20°C and 40°C.
The unbridged metallocene compounds of formula (I), wherein n = 0 and A
corresponds to
formula (II), can be prepared by reacting the anions of the formula (VII) with
a tetrahalide of
the transition metal M (i.e. ML4), M and L having the above described
meanings, said reaction
being carried out in a suitable solvent.
When at least one L substituent in the metallocene compound of formula (I) is
different from
halogen, it is necessary to substitute at least one substituent L in the
obtained metallocene with
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WO 99/58539 PCTlEP99/03247
at least another substituent different from halogen. Such a substitution
reaction is carried out by
methods known in the state of the art. For example, when the substituents L
are alkyl groups,
the metallocenes can be reacted with alkylmagnesium halides (Grignard
reagents) or with
lithiumalkyl compounds.
During the whole process, the temperature is preferably kept between -
180°C and 80°C, and
more preferably between -20°C and 40°C.
The heterocyclic metallocene compounds of the present invention can
conveniently be used as
catalyst components for the polymerization of olefins.
Thus, according to a still further aspect of the present invention there is
provided a catalyst for
the polymerization of olefins, obtainable by contacting:
( A ) a metallocene compound of formula (I), and
( B ) an alumoxane and/or a compound capable of forming an alkyl metallocene
cation.
The alumoxane used as component (B) can be obtained by reacting water with an
organo-
aluminium compound of formula A1R8, or A12R86, where at least one R8 is not
halogen. In this
reaction the molar ratio of Al/water is comprised between 1: l and 100:1.
The molar ratio between aluminium and the metal of the metallocene is
comprised between
about 10:1 and about 20000:1, and preferably between about 100:1 and about
5000:1.
The alumoxanes used in the catalyst according to the invention are considered
to be linear,
branched or cyclic compounds containing at least one group of the type:
R9\ ~R9
Al-O-Al
R~ \ R9
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WO 99!58539 PCTlEP99l03247
wherein the R9 substituents, same or different, are hydrogen atoms, C,-Czo
alkyl, C3 CZO-
cyclalkyl, C6-Czo-aryl, C,-CZO alkylaryl or C,-Czo-arylalkyl, optionally
containing silicon or
germanium atoms, or are a -O-Al(R9)2 group and, if appropriate, some R9
substituents can be
halogen atoms.
In particular, alumoxanes of the formula:
R9 R9
\Al-O--(A1-O)n-Aly
R9~ R9
can be used in the case of linear compounds, wherein n is 0 or an integer from
1 to 40 and the
R9 substituents are defined as above, or alumoxanes of the formula:
R9
(Al-O)n
can be used in the case of cyclic compounds, wherein n is an integer from 2 to
40 and the R9
substituents are defined as above.
Examples of alumoxanes suitable for use according to the present invention are
methylalumoxane (MAO), isobutylalumoxane (TIBAO) and 2,4,4-trimethyl-
pentylalumoxane
(TIOAO).
In the catalyst used in the process according to the invention for the
preparation of polyolefins,
both the heterocyclic metallocene compound of the formula (I) and the
alumoxane can be
present as the product of the reaction with an organometallic aluminium
compound of the
formula A1R83 or AlZR86,in which the R8 substituents, same or different, are
hydrogen atoms,
halogen atoms, C,-CZO-alkyl, C3-CZO-cyclalkyl, C6-Czo-aryl, C~ CZO alkylaryl
or C,-Czo-arylalkyl,
optionally containing silicon or germanium atoms.
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Non-limiting examples of aluminium compounds of the formula A1R83 or A1,R86
are: Al(Me)3,
Al(Et)3, AIH(Et)~, Al{iBu)3, Al(iHex)3, Al(iOct);, Al(C6H5)~, AI(CH,C6H5)3,
Al(CH,CMe3)3,
Al(CH,SiMe3)3, Al(Me)ZiBu, Al(Me)ZEt, AIMe(Et)z, AIMe(iBu)2, Al(Me)ZiBu,
Al(Me)zCl,
Al{Et)2C1, AlEtCl2, A12(Et)3C13, wherein Me=methyl, Et=ethyl, iBu=isobutyl,
iHex=isohexyl,
iOct=2,4,4-trimethyl-pentyl.
Among the aforementioned aluminium compounds, trimethylaluminium (TMA),
triisobutylaluminium (TIBAL) and tris(2,4,4-trimethyl-pentyl)aluminium (TIOA)
are preferred.
Non limitative examples of compounds able to form a metallocene alkyl canon
are compounds
of formula T'D', wherein T+ is a Broensted acid, able to give a proton and to
react irreversibly
with a substituent L of the metallocene of formula (I), and D' is a compatible
anion, which does
not coordinate, which is able to stabilize the active catalytic species which
originates from the
reaction of the two compounds and which is sufficiently labile to be able to
be removed from
an olefinic substrate. Preferably, the anion D' comprises one or more boron
atoms. More
preferably, the anion D' is an anion of the formula BAr~'~q, wherein
substituents Ar, the same or
different from each other, are aryl radicals such as phenyl,
pentafluorophenyl,
bis(trifluoromethyl)phenyl. Particularly preferred is the tetrakis-
pentafluorophenyl borate.
Furthermore, compounds of formula BAr3 can be suitably used.
The catalysts used in the process of the present invention can be also used on
inert supports.
This is obtained by depositing the metallocene (A), or the product of the
reaction of the same
with the component (B), or the component (B) and thereafter the metallocene
(A), on supports
such as for example silica, alumina, styrene-divinylbenzene copolymers,
polyethylene or
polypropylene.
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WO 99/58539 PCT/EP99/03247
The solid compound so obtained, in combination with further addition of the
alkyl aluminium
compound as such or pre-reacted with water, is usefully employed in gas phase
polymerisation.
Catalysts of the present invention are useful in the homo- and
copolymerization reaction of
olefins.
Therefore, a still further object of the present invention is a process for
the polymerization of
olefins comprising the polymerization reaction of at least an olefinic monomer
in the presence
of a catalyst as above described.
The catalysts of the present invention can be used in the homo-polymerisation
reaction of
olefins, preferably of ethylene for the preparation of HDPE, or of a-olefins,
such as propylene
and 1-butene. In ethylene polymerisation, the heterocyclic metallocenes of the
invention show
good activities even when used in very low Al/Zr ratios.
Another interesting use of the catalysts according to the present invention is
in the
copolymerization of ethylene with higher olefins. In particular, the catalysts
of the invention
can be used for the preparation of LLDPE.
Suitable olefins to be used as comonomers comprise a-olefins of the formula
CHI=CHR'°,
wherein R'° is an alkyl radical having from 1 to 10 carbon atoms, and
cycloolefins. Examples
of these olefins are propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-
hexene, 1-octene, 1-
decene, 1-dodecene, 1-tetradecene, 1-esadecene, 1-octadecene, 1-eicosene,
allylcyclohexene,
cyclopentene, cyclohexene, norbornene and 4,6-dimethyl-i-heptene.
The copolymers may also contain small proportions of units deriving from
polyenes, in
particular from straight or cyclic, conjugated or non conjugated dienes, such
as 1,4-hexadiene,
isoprene, 1,3-butadiene, 1,5-hexadiene and 1,6-heptadiene.
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The units deriving from a-olefins of formula CHz CHR'°, from
cycloolefins and/or from
polienes are present in the copolymers preferably in amounts ranging from 1 %
to 20% by
mole.
The saturated elastomeric copolymers can contain ethylene units and a-olefins
and/or non
conjugated diolefins able to cyclopolymerise. The unsaturated elastomeric
copolymers can
contain, together with the units deriving from the polymerisation of ethylene
and a-olefins,
also small proportions of unsaturated units deriving from the copolymerization
of one or more
polyenes. The content of unsaturated units is preferably comprised between 0
and 5% by
weight.
Non limitative examples of suitable a-olefins comprise propylene, 1-butene and
4-methyl-1-
pentene. Suitable non conjugated diolefins able to cyclopolymerise comprise
1,5-hexadiene,
1,6-heptadiene and 2-methyl-1,5-hexadiene.
Non limitative examples of suitable polyenes are:
(i) polyenes able to give unsaturated units, such as:
- linear, non-conjugated dienes, such as 1,4-hexadiene traps, 1,4-hexadiene
cis, 6
methyl-1,5-heptadiene, 3,7-dimethyl-1,6-octadiene and 11-methyl-1,10-
dodecadiene;
- bicyclic diolefins, such as 4,5,8,9-tetrahydroindene and 6 and 7-methyl-
4,5,8,9
tetrahydroindene;
- alkenyl or alkyliden norbornenes, such as 5-ethyliden-2-norbornene, 5-
isopropyliden-
2-norbomene and exo-5-isopropenyl-2-norbornene;
- polycyclic diolefins, such as dicyclopentadiene, tricyclo-[6.2.1.02']4,9-
undecadiene
and the 4-methyl derivative thereof;
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WO 99/58539 PCT/EP99/03247
(ii) non-conjugated diolefms able to cyclopolymerise, such as 1.5-hexadiene,
1,6-
heptadiene and 2-methyl-1,5-hexadiene;
(iii) conjugated dienes, such as butadiene and isoprene.
Another object of the present invention is a process for the polymerisation of
propylene carned
out in the presence of the above described catalyst.
A further interesting use of the catalysts according to the present invention
is for the
preparation of cycloolefin polymers. Monocyclic and polycyclic olefin monomers
can be either
homopolymerised or copolymerised, also with linear olefin monomers.
Polymerisation processes according to the present invention can be carried out
in gaseous
phase or in liquid phase, optionally in the presence of an inert hydrocarbon
solvent either
aromatic (such as toluene), or aliphatic (such as propane, hexane, heptane,
isobutane and
cyclohexane).
The polymerisation temperature is preferably ranging from about 0°C to
about 250°C. In
particular, in the processes for the preparation of HDPE and LLDPE, it is
preferably comprised
between 20°C and 150°C and, more preferably between 40°C
and 90°C, whereas for the
preparation of the elastomeric copolymers it is preferably comprised between
0°C and 200°C
and, more preferably between 20°C and 100°C.
The polymerization pressure is ranging from 0,5 to 100 bar, preferably from 2
to 50 bar, and
more preferably from 4 to 30 bar.
The molecular weight of the polymers can be also varied merely by varying the
polymerization
temperature, the type or the concentration of the catalytic components or by
using molecular
weight regulators such as, for example, hydrogen.
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WO 99/58539 PCT/EP99/03247
The molecular weight distribution can be varied by using mixtures of different
metallocenes, or
carrying out the polymerization in several steps at different polymerization
temperatures and/or
different concentrations of the molecular weight regulator.
The polymerization yields depend on the purity of the metallocene component of
the catalyst.
Therefore, in order to increase the yields of polymerization, metallocenes are
generally used
after a purification treatment.
The components of the catalyst can be brought into contact before the
polymerization. The pre-
contact concentrations are generally between 1 and 10-g mol/1 for the
metallocene component
(A), while they are generally between 10 and 10-8 mol/1 for the component (B).
The pre-contact
is generally effected in the presence of a hydrocarbon solvent and, if
appropriate, of small
quantities of monomer. The pre-contact time is generally comprised between 1
minute and 24
hours.
The following examples are given to illustrate and not to limit the invention.
GENERAL PROCEDURES CHARACTERIZATIONS
All operations were performed under nitrogen by using conventional Schlenk-
line techniques.
Solvents were distilled from blue Na-benzophenone ketyl (EtzO), CaH2 (CHZCIz)
or AliBu3
(hydrocarbons), and stored under nitrogen. BuLi (Aldrich) was used as
received.
The'H-NMR analyses of the metallocenes were carried out on an AC200 Broker
spectrometer
(CD,CIz, referenced against the middle peak of the triplet of the residual
CHDC12 at 5.35 ppm).
All NMR solvents were dried over Pz05 and distilled before use. Preparation of
the samples
were carried out under nitrogen using standard inert atmosphere techniques.
The 'H-NMR and "C-NMR analyses of the polymers were carned out on a Broker 400
MHz
instrument. The samples were analysed as solutions in
tetrachlorodideuteroethane at 130°C.
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The intrinsic viscosity [rl] (dl/g) was measured in tetralin at 135°C.
The melting point Tm (°C) and DH (3/g) of the polymers were measured by
Differential
Scanning Calorimetry (DSC) on a Mettler apparatus, according to the following
procedure:
about 10 mg of sample obtained from the polymerisation were heated to
180°C with a scanning
speed equal to 20°C/minute; the sample was kept at 180°C for S
minutes and thereafter was
cooled with a scanning speed equal to 20°C/minute. A second scanning
was then carried out
according to the same modalities as the first one. The reported values are the
ones obtained in
the second scanning.
The density (g/ml) was determined by immersion of a sample of extruded
copolymer in a
column with a density gradient according to the ASTM D-1505 method.
In the copolymers according to the present invention, the product of the
reactivity ratios r,~rz,
wherein r, is the relative reactivity of the alpha-comonomer versus ethylene
and r, that of
ethylene versus the alpha-comonomer.
PREPARATION OF THE LIGANDS
(N-t-butylamino)(dimethyl)(cyclopentadienyl)silane and (N-t-butylamino)
(dimethyl)
(methylcyclopentadienyl) silane were prepared as described in International
Patent
Application PTC/US92/08730, 1992, in the name of Nickias, P.N., Devore, D.D.
Bis(1,3-bistrimethylsilylcyclopentadienyl)zirconium dichloride was purchased
from Boulder
Scientific Co., Mead Co, USA. Bis(cyclopentadienyl)zirconium dichloride was
purchased
from Strem Chemicals, Inc., Newburyport, MA, USA.
Example 1
Preparation of 1,1,3,3-tetramethyl-1,2,3,3a- tetrahydrocyclopenta[c] [1,2,5]
azadisilole
26
.. ~. _..... ~~........~..__ ~__. . ~r.._~ .y..~..~._.__._.
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WO 99/58539 PCT/EP99/03247
(N-t-butylamino)(dimethyl)(cyclopentadienyl)silane (0.071 mol, 13.9 g) was
dissolved in
THF (100 mL) and treated with BuLi (144 mmol of a 2.5 M solution in hexanes)
at 0 °C.
After stirring for 16 h at room temperature, the dianion solution and a THF
solution (75 mL)
of dichlorodimethylsilane (0.071 mol) were added dropwise simultaneously to a
flask
containing 25 mL of THF stirring at -10 °C. The mixture was warmed to
room temperature
and stirred overnight. Solvents were removed in vacuo, and the residue was
extracted with
pentane. After filtration and evaporation of pentane, the extract was
distilled giving 1.2 g of a
colorless liquid identified to be 1,1,3,3-tetramethyl-1,2,3,3a-
tetrahydrocyclopenta[c] [1,2,5]
azadisilole and isomers. 'H-NMR 8 (CDC13) (major isomer): 6.7 (m, 3H), 5.7
(broad s, 2H),
1.3 (s, 9H), 0.2 (s, 12H). ms (m/e) (rel intensity): 251 ([PM], 12), 236
(100), 179 (4), 114
(4), 73 (7).
Example 2
Preparation of 1,1,3,3,5-pentamethyl-1,2,3,3a- tetrahydrocyclopenta[c] [1,2,5]
azadisilole
(N-t-butylamino)(dimethyl)(methylcyclopentadienyl)silane (0.070 mol, 14.7 g)
was
dissolved in THF (199 mL) and treated with butyllithium (0.14 mol of a 2.5 M
sol. in
hexanes) at -78 °C. After stirring for 16 h at room temperature, the
dianion solution was
added dropwise to a solution of dichlorodimethylsilane (0.070 mol, 9.03 g) in
THF (100 mL)
at -78 °C. The mixture was slowly warmed to room temperature while
stirring overnight.
After evaporating the solvent, the residue was extracted with pentane,
filtered, and
evaporated to an oil. The oil was distilled giving 5.0 g of a colorless liquid
identified as
1,1,3,3,5-pentamethyl-1,2,3,3a- tetrahydrocyclopenta[c] [1,2,5] azadisilole
and isomers. 'H-
NMR 8 (CDCl3) (major isomer): 6.3 (m, 1 H), 5.8 (broad s, 1 H), 4.9 (broad s,
1 H), 2.1 (s,
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WO 99/58539 PCT/EP99/03247
3H), 1.3 (s, 9H), 0.3 (broad s, 6H), 0.1 S (broad s, 6H). ms (m/e) {rel
intensity): 265 ([PM],
14), 250 (100), 193 (3), 135 (4), 73 (16).
Example 3
Preparation of 1,1,5-trimethyl-3-phenyl-1,2,3,3a-
tetrahydrocyclopenta[c][1,2,5]
azaborasilole
(N-t-butylamino){dimethyl)(methylcyclopentadienyl)silane (95.7 rnmol, 20 g)
was dissolved
in THF (120 mL) cooled at -78 °C and treated with butyllithium (2,1
eq., 201 mmol of a 2.5
M sol. in hexanes). The solution was stirred for 4 h at room temperature. At -
78 °C 95.1
mmol (15.7 g) of PhBCl2 in 20 ml of pentane were added dropwise. The mixture
was slowly
warmed to room temperature and stirred overnight. After filtration and
evaporating the
solvent an orange-oil was obtained. The oil was distilled giving 7.0 g of a
colorless liquid
identified as the title compound. ms (m/e) (rel intensity): 295 ([PM], 80),
280 (70), 239 (30),
224 (70), 160 ( 100).
Example 4
Preparation of 1,1,5-trimethyl-3-phenyl-1,2,3,3a-tetrahydrocyclopenta[c)
[1,2,5]
azaphosphasilole
(N-t-butylamino)(dimethyl)(methylcyclopentadienyl)silane {20 mmol, 4.17 g) was
dissolved
in THF (25 mL) cooled at -78 °C and treated with butyllithium (40 mmol,
16 ml of a 2.5 M
sol. in hexanes). After the reaction was completed the solution was stirred
for 1.5 h at room
temperature. In a separate 250 ml flask 2.7 ml (20 mmol) of
dichlorophenylphosphine and 25
ml THF were added. At -78 °C the above dianion was added dropwise,
warmed to room
temperature and stirred for 2 h. After filtration and evaporating the solvent
6.61 g of an
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orange-oil was obtained. After washing with hexane 3.68 g of a pentane soluble
oil was
obtained identified as the title compound. ms (m/e) (rel intensity): 315
([PM], 100), 300 (40),
244 (50), 135 (30), 57 (60).
PREPARATION OF THE METALLOCENES
Example 5
Preparation of Bis(1,1,3,3-tetramethyl-1,2,3-
trihydrocyclopentadienyl[c][1,2,5]
azadisilole)ZrCh
Butyllithium (4.0 mmol of a 2.5 M sol. in hexanes) was added slowly to a
solution of 1,1,3,3-
tetramethyl-1,2,3,3a- tetrahydrocyclopenta[c] [1,2,5] azadisilole (3.8 mmol,
0.95 g) in ether
{30 mL) at -78 °C. The reaction mixture was warmed to room temperature
and stirred for an
additional 3 h. Solvents were removed in vacuo and the residue was mixed with
ZrCl4 ( 1.9
mmol, 0.443 g) in a glove box. The mixture was slurried in pentane (40
mL)/ether ( 1 mL)
and stirred for 16 h. After evaporating the solvents, the residue was
extracted with
dichloromethane and filtered. Evaporation of the filtrate gave 1.0 g of
bis(1,1,3,3-
tetramethyl-1,2,3,trihydrocyclopentadienyl[c][1,2,5]azadisilole)ZrCl2,
{1,2(tBuN=(SiMe2)2)Cp)zZrCl2. as a tan powder. 'H-NMR S (CDZCIz): 6.85 (s,
2H), 6.5 (t,
1H), 1.4 (s, 9H), 0.6 (s, 6H), 0.3 (s, 6H).
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POLYMERIZATION OF ETHYLENE
Methylalumoxane (MAO)
A commercial product commercialised by Schering was used in solution of 10% by
weight in
toluene.
EXAMPLES 6 TO 9
A dry 200 mL glass autoclave equipped with magnetic stirrer, temperature
probe, and feed
line for ethylene was sparged with ethylene at 35 °C. At room
temperature, 90 mL of hexane
were introduced. The catalyst system was prepared separately in 10 mL of
hexane by
consecutively introducing the methylalumoxane, or triisooctylaluminum/water
(Al/H20 =
2.1 ) mixture, and after 5 minutes stirring, the metallocene compound
(1,2(tBuN=(SiMe2)2)Cp)zZrCl2 dissolved in minimum amount of toluene. After
stirring for 5
minutes, the solution was introduced into the autoclave under ethylene flow,
the reactor was
closed, the temperature was raised to 80 °C and pressurized with
ethylene to 4.6 bang. The
total pressure was kept constant by feeding ethylene on demand. The
polymerization was
stopped by cooling, degassing the reactor, and introducing 1 mL of methanol.
The resulting
polymer was washed with acidic methanol, methanol, and dried in an oven at 60
°C under
vacuum. The results are listed in Table 1. The polymerization conditions are
reported in
table 1.
Examples 10 to 11 (Comparison)
The examples were repeated according to the procedure described in the
examples 6-9, but
using bis[1,3-bis(trimethylsilyl) cyclopentadienylJ zirconium dichloride
instead of
Bis(1,1,3,3-tetramethyl-1,2,3, trihydrocyclopentadienyl[c][1,2,5]
azadisilole)ZrCI,. The
polymerization conditions are reported in table 1.
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Examples 12 to 13 (Comparison)
The examples were repeated according to the procedure described in the
examples 6-9, but
using bis(cyclopentadienyl)zirconium dichloride instead of Bis(1,1,3,3-
tetramethyl-1,2,3,
trihydrocyclopentadienyl[c][1,2,5] azadisilole)ZrCh. The polymerization
conditions are
reported in table 1.
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Table 1.
Ethylene polymerization results
Ex. metallocene, cocatalyst, AUZr time, Pol. Activity [ri],
mg (~mo!) (mmol) mol. ratio min g Kg/gZr/h dL/g
6 1.00 ( MAO ( 1.51 1000 10 2.43 1 O5. n.
1. S ) 83 d.
1 )
7 0.50 (0.76)MAO (0.76) 1000 10 2.65 230.83 1.48*
8 0.16 (0.24)MAO (0.25) 1026 10 0.84 228.65 1.26
9 0.50 (0.76)TIOA-HZO 1013 8 0.42 45.73 3.58
(0.765)
0.13 (0.22)MAO (0.23) 1028 15 1.34 262.68 2.05
comp.
11 0.13 (0.22)TIOA-H20 1073 20 0.20 29.40 n.d.
comp. (0.24)
12 0.10 (0.34)MAO (0.35) 1023 10 1.07 205.76 2.99
comp.
13 0.30 (1.03)TIOA-H20 997 20 traces
comp. ( 1.02)
n.d =not determined
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COPOLYMERISATION OF ETHYLENE WITH 1-HEXENE
Example 14
A dry 200 mL glass autoclave equipped with magnetic stirrer, temperature
probe, and feed
line for ethylene was sparged with ethylene at 35 °C. Heptane (80 mL)
and 1-hexene (10 ml)
were introduced at room temperature. The catalyst system was prepared
separately in 10 mL
of heptane by consecutively introducing methylalumoxane (0.33 mmol) and the
metallocene
(0.2 mg) dissolved in 3 mL of toluene. After stirring for 5 minutes, the
solution was
introduced into the autoclave under ethylene flow, the reactor was closed, the
temperature
was raised to 70 °C and pressurized with ethylene to 4.5 barg. The
total pressure was kept
constant by feeding ethylene on demand. After 10 minutes, the polymerization
was stopped
by cooling, degassing the reactor, and introducing 1 mL of methanol. The
resulting polymer
was washed with acidic methanol, methanol, and dried in an oven at 60
°C under vacuum.
1.2 g of polymer were recovered (activity of 261 Kg/g-Zr/h) and a value of
[rl] = 1.0 dL/g
was obtained, and 7.7 wt.% of 1-hexene was incorporated.
DSC analysis (2° melt); Tm=114°C; DH=142 J/g.
The '3C NMR analysis showed the presence of 2.72 mol% 1-hexene content, a nE
(average
ethylene sequence lenght) of 37 and value of r,=62.1, r2 0.034, and r,xr2
2.11.
33
