Olefin polymerization catalysts

Details Olefin polymerization catalysts Olefin polymerization catalysts

2002-01-18

2004-06-22

Nazario-Gonzalez, Porfirio (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Heavy metal containing

C502S103000, C502S117000, C526S160000, C526S943000, C534S011000, C534S015000, C556S012000, C556S043000, C556S046000, C556S052000, C556S054000, C556S058000, C556S136000, C556S137000

Reexamination Certificate

active

06753436

ABSTRACT:

The present invention concerns new organometallic compounds and polymerization catalysts comprising the organometallic compounds.
During the last 20 years a lot of research has been carried out in order to establish the relation structure-reactivity in single site olefin polymerization catalysis. As a result, several information concerning the influence of the catalyst structure on molecular weight, tacticity and comonomer insertion are available today.
One of the first methods used for achieving a better control of the catalyst properties is the use of a bridge which renders two cyclopentadienyl ligands stereorigid. In this way, it has been possible to obtain highly isotactic and highly syndiotactic propylene polymers.
EP 416 815 discloses monocyclopentadienyl catalysts wherein a cyclopentadienyl ligand and an amido ligand are connected through a covalent bridge. The resulting catalyst can incorporate very efficiently long chain alpha-olefins.
In the last decade, a lot of effort have been dedicated to the development of these complexes and to the study of the influence of the ligand structure on catalyst activity.
SUMMARY OF THE INVENTION
It has been surprisingly found that it is possible to prepare organometallic compounds wherein a transition metal is bonded to three ligands which are rigidly connected through structural bridges, wherein at least one ligand is of the cyclopentadienyl type or is isolobal to cyclopentadienyl and the remainder(s) are monovalent anionic ligands. These complexes are effective catalysts for olefin polymerization. By varying the type of ligands and the structure of the two (or three) covalent bridges it is possible to modify the characteristics of the resulting catalyst in terms of molecular weight, comonomer incorporation and tacticity of the obtained polymer.
DESCRIPTION OF THE INVENTION
The organometallic catalysts of the invention are represented by general formula (I):
wherein:
M is a transition metal of groups 3, 4-10, lanthanide or actinide of the periodic table of the elements, preferably titanium, zirconium or hafnium;
each R is independently a structural bridge rigidly connecting two ligands L
1
, L
2
and L
3
and is constituted by 1 to 4 chain atoms selected from carbon, silicon, germanium, oxygen, boron; these atoms can be part of fused rings, aromatic rings, aliphatic rings or spiro rings; preferred examples of groups R are: CR
1
2
, SiR
1
2
, CR
1
2
—CR
1
2
, CR
1
2
—SiR
1
2
, SiR
1
2
—SiR
1
2
;
wherein each R
1
is independently selected from hydrogen, C
1
-C
20
alkyl, C
3
-C
20
cycloalkyl, C
6
-C
20
aryl, C
3
-C
20
alkenyl, optionally comprising 1 to 5 heteroatoms such as Si, N, P, O, F, Cl, Br, preferably R
1
is selected from C
1
-C
6
linear or branched alkyls; most preferably is methyl, ethyl, isopropyl, tertbutyl;
m, n and o are 0 or 1, with the proviso that m+n+o is 2 or 3;
L
1
is a ligand of the cyclopentadienyl type or is isolobal to cyclopentadienyl, preferably a cyclopentadienyl, indenyl or fluorenyl ring, cyclopenteno[b]tiophenyl cyclopenteno[b:b′]-dithiophenyl cyclopenteno[b]pyrrolyl, boratabenzene, phospholyl, dihydroindeno[b]indolyl, optionally substituted by one or more R
1
groups; most preferably a cyclopentadienyl, indenyl or fluorenyl ring, optionally substituted by one or more R
1
groups;
L
2
is a ligand defined as L
1
, or a monovalent anionic ligand selected from the group consisting of N, P, B when m+n=2, from the group consisting of NR
1
, PR
1
, BR
1
, O and S when m+n=1;
L
3
is a monovalent anionic ligand selected from the group consisting of N, P, B when n+o=2, from the group consisting of NR
1
, PR
1
, BR
1
, O and S when n+o=1;
each X is independently selected from the group consisting of hydrogen, halogen, NR
2
2
, R
2
with R
2
equal to C
1
-C
20
alkyl, C
3
-C
20
cycloalkyl, C
6
-C
20
aryl, C
3
-C
20
alkenyl, optionally comprising 1 to 5 heteroatoms such as Si, N, P, O, F, Cl, Br.
q is a number whose value is: 0, 1, 2 or 3, depending on the valence of the metal M, so that q+3 is the valence of M;
D is a neutral Lewis base, preferably it is selected from the group consisting of linear or cyclic ethers, amines and phosphines; most preferably it is selected from the group consisting of diethyl ether, tetrahydrofurane, aniline, dimethylaniline, triphenylphosphine, n-butylamine;
p is a number whose value is: 0, 1, 2 or 3.
When m is 1, n is 0 and o is 1, the formula I becomes the following formula Ia:
When m is 1, n is 1 and o is 0, the formula I becomes the following formula Ib:
When m is 1, n is 1, o is 0 and L
2
is a ligand defied as L
1
the formula I becomes the following formula Ic
When m, n and o are 1 the formula (I) becomes the following formula Id
It has been calculated using molecular modeling methods that compounds according to general formula (I) having three ligands rigidly interconnected can have a geometry wherein the bond angles of the metal M are more constrained than the catalyst disclosed in EP 416815. By varying the type of R and the ligands L
1
, L
2
and L
3
it is possible to vary the bond angle as well as the steric hindrance on the metal center, influencing in this way Mw, MWD, long chain branching, short chain branching and, in case of C
3
-C
20
alpha olefins, the tacticity of the polymer.
A preferred class of compounds belonging to formula Ia is defined by the following formula II:
wherein Cp is a cyclopentadienyl or indenyl ring, optionally substituted by one or more R
1
groups, M is selected from Ti, Zr and Hf
each R is independently selected from CR
1
2
, SiR
1
2
, CR
1
2
—CR
1
2
, CR
1
2
—SiR
1
2
, SiR
1
2
—SiR
1
2
, wherein R
1
is hydrogen, C
1
-C
20
alkyl, C
3
-C
20
cycloalkyl, C
6
-C
20
aryl, C
3
-C
20
alkenyl, optionally comprising 1 to 5 heteroatoms such as Si, N, P, O, F, Cl, Br. Two groups R
1
bonded to the same or to adjacent atoms can unite to form a ring.
L
2
and L
3
are independently selected from the group consisting of NR
1
, PR
1
, BR
1
, O and S;
X is independently selected from the group consisting of hydrogen, halogen, NR
2
, R
2
with R
2
equal to C
1
-C
20
alkyl, C
3
-C
20
cycloalkyl, C
6
-C
20
aryl, C
3
-C
20
alkenyl, optionally comprising 1 to 5 heteroatoms such as Si, N, P, O, F, Cl, Br.
D is a neutral Lewis base; preferably it is selected from the group consisting of linear or cyclic ethers, amines and phosphines; most preferably it is selected from the group consisting of diethyl ether, tetrahydrofurane, aniline, dimethylaniline, triphenylphosphine, n-butylamine;
p is a number whose value is: 0, 1, 2 or 3.
In one embodiment of the invention, the compounds of formula I are preferably obtained by reacting a compound of formula MX
q+3
wherein M is a transition metal of groups 3, 4-10, lanthanide or actinide of the periodic table of the elements, X is a monovalent anionic ligand, preferably selected from the group consisting of N(CH
3
)
2
, benzyl, and q is 0, 1, 2, 3 depending on the valence of M, with a compound of formula III
wherein L
1
is a group of the cyclopentadienyl type or is isolobal to cyclopentadienyl, preferably a cyclopentadienyl, indenyl or fluorenyl ring, cyclopenteno[b]tiophenyl cyclopenteno[b:b′]-dithiophenyl cyclopenteno[b]pyrrolyl, boratabenzene, phospholyl, dihydroindeno[b]indolyl, optionally substituted by one or more R
1
groups; most preferably a cyclopentadienyl, indenyl or fluorenyl ring, optionally substituted by one or more R
1
groups;
m, n and o are 0 or 1, with the proviso that m+n+o is 2 or 3.
L
2
is a ligand of the cyclopentadienyl type or is isolobal to cyclopentadienyl, preferably a cyclopentadienyl, indenyl or fluorenyl ring, cyclopenteno[b]tiophenyl cyclopenteno[b:b′]-dithiophenyl cyclopenteno[b]pyrrolyl, boratabenzene, phospholyl, dihydroindeno[b]indolyl, optionally substituted by one or more R
1
groups; most preferably a cyclopentadienyl, indenyl or fluorenyl ring

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