Organic compounds -- part of the class 532-570 series – Organic compounds – Heavy metal containing
Reexamination Certificate
2000-01-11
2002-03-26
Nazario-Gonzalez, Porfirio (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heavy metal containing
C556S011000, C556S012000, C556S043000, C526S160000, C526S943000, C502S103000, C502S117000
Reexamination Certificate
active
06362356
ABSTRACT:
The present invention relates to novel metallocene compounds based on a transition metal (Groups 3-10 of the Periodic Table (IUPAC 1990)). The invention also relates to polymerization catalyst compositions comprising a metallocene compound selected from said metallocene compounds and an aluminoxane. Further, the invention relates to a process for polymerizing at least one ethylenically unsaturated monomer such as an olefin in the presence of a metallocene compound, selected from said metallocene compounds, and an aluminoxane.
Metallocene stands for metal complexes having at least one isocyclic or heterocyclic &eegr;-cyclopentadiene ligand or at least one ligand structurally including isocyclic or heterocyclic &eegr;-cyclopentadiene. Such an &eegr;-cyclopentadiene ligand or ligand structurally including &eegr;-cyclopentadiene is below called an &eegr;
5
ligand, because all 5 cyclopentadienyl ring carbons are, without limiting the scope of protection, assumed to be essentially equally bound to the transition metal. Transition metals are elements with an incomplete d-shell in their atoms. They are metals of Groups 3-10 of the Periodic Table (IUPAC 1990). Aluminoxane stands for compounds having units of organometallic aluminium bound to oxygen.
Chiral bis(indenyl) ansa-metallocenes are well known catalyst components for polymerizations of alpha olefins. The performance of these metallocenes are different, depending on the metal used and the size and structure of the ligands, above all its &eegr;
5
ligands. For the production of isotactic polypropene, C
2
-symmetric ethylene-bridged bisindenyl zirconocene dichloride can be regarded as a key structure. It was first reported by Brinzinger et al. in 1982 (Wild, F. R. W. P., Zsolnai, I., Huttner, G., Brintzinger, H. H., J. Organomet. Chem. (1982) 232:233). Syndiotactic polypropene was prepared in 1988 using C
S
-symmetric methylene-bridged fluorenyl cyclopentadienyl zirconocene dichloride. See Ewen, J. A., Jones, R. L., Razavi, A., Ferrara, J. D., J. Am. Chem. Soc. (1988) 110:6255.
Metallocenes having bulkier &eegr;
5
ligands have also been prepared and investigated. Unsymmetric ethylene-bridged 7,9-diphenylcyclopent[a]acenaphthadienyl cyclo-pentadienyl zirconocene dichloride was used together with methylaluminoxane (MAO) for propene polymerization. It produces atactic polypropene with high activity. See Rieger, B., Repo, T., Jany, G., Polymer Bulletin 35 (1995) 78-94.
The above mentioned metallocenes are primarily suitable for the polymerization of polypropene. The successful production of polyethene, and in particular high molecular weight polyethene (molecular weight of the magnitude up to one million), using metallocenes of the above type, has not been reported. Thus, the purpose of the invention is to find a suitable metallocene for the production of high molecular polyethylene in good yields.
The above mentioned prior metallocenes are primarily suitable for the polymerization of linear or short chain branched polypropene. The successful production of long chain branched polypropene, using metallocenes of the above type, has not been reported. Thus, an additional purpose of the invention is to find a metallocene for the production of long chain branched polypropene in good yields.
The above purposes of the invention has now been achieved with a metallocene compound based on a transition metal (of Groups 3-10 of the Periodic Table (IUPAC 1990)), which metallocene compound is essentially characterized in that at least one of its &eegr;
5
ligands comprises at least four fused rings including the &eegr;
5
bound cyclopentadiene ring and that the sum of fused rings in all of its &eegr;
5
ligands is at least 6.
Thus, it has been realized that a metallocene compound having more than a certain number fused rings in one and all of its &eegr;
5
ligands give high molecular weight polyethene in good yields. It has also been found that such a metallocene gives vinyl terminated polypropene, which via its reactive vinyl group forms, or is able to form, a polypropene having long chain branches. These two technically relevant functional properties distinguish the metallocene compounds of the invention from e.g. the metallocene compounds of above mentioned Rieger, B., Repo, T., lany, G., Polymer Bulletin 35 (1995) 78-94.
In its widest scope, the present document claims metallocenes of transition metals (metals of Group 3-10 of the Periodic Table) having a certain minimum number of fused rings including the cyclopentadiene ring in one and all of its &eegr;
5
ligands. However, according to a preferred embodiment of the invention, the metallocenes are based on transition metals of Groups 4-6, preferably Groups 4 and 5 of the Periodic Table (IUPAC 1990). Especially preferred transition metals are the Group 4 metals titanium, zirconium and hafnium, even more preferred zirconium and hafnium. Generally, the most preferred transition metal is zirconium.
According to the invention, the number of fused rings in at least one of the metallocene's &eegr;
5
ligands is at least four. The fused rings may be 5- and 6-membered rings, which are isocyclic or heterocyclic, for example containing up to 4 ring heteroatoms selected from O, N, S and P. By the terms “isocyclic” and “heterocyclic” is meant cyclic having only carbon ring members and cyclic having ring members of carbon and at least another element, respectively. The fused rings are preferably aromatic, but they can also be hydroaromatic, i.e. partially or completely hydrogenated (alicyclic). Typically, such &eegr;
5
ligands are four ring &eegr;
5
ligands, e.g. cyclopent[a]-as-indacenadienyl, cyclopent[a]-s-indacenadienyl, cyclopent[a]acenaphthadienyl, and five ring &eegr;
5
ligands, e.g. cyclopent[d]-acephenathradienyl, cyclopent[a]aceanthradienyl.
According to a preferred embodiment of the invention, the &eegr;
5
ligand of the metallocene comprising at least four fused rings is a ligand having the formula (I)
wherein each same or different of groups R
1
-R
9
is one of hydrogen, a halogen and an organic group having from 1 to 20 carbon atoms, or at least one pair of adjacent groups from R
1
-R
9
form together an organic ring structure having from 5 to 20 carbon atoms, one of R
7
-R
9
being optionally replaced by a bridge to another &eegr;
5
ligand, and a indicates the &eegr;
5
bound cyclopentadienyl ring of said &eegr;
5
ligand comprising at least four fused rings; or is a hydroaromatic derivative ligand thereof.
Organic group or organic ring structure mean a group or ring structure, which is organic, i.e. is a carbon compound radical with the exception of radicals of non-hydrogen chalcogenides and their derivatives, salt-like and metallic carbides and metal carbonyls. A hydroaromatic derivative means a compound of similar ring structure but with the benzene rings partially or completely hydrogenated.
In the &eegr;
5
ligand according to formula (I), R
1
-R
6
are preferably hydrogen and, independently, one or two of R
7
-R
9
are each independently a C
1
-C
20
hydrocarbyl, preferably a C
5
-C
20
hydrocarbyl, most preferably phenyl. Said ligand having the formula (I) is preferably a substituted or unsubstituted cyclopent[a]acenaphthtadienyl ligand or a hydroaromatic derivative thereof, preferably a 7,9-diphenylcyclopent[a]acenaphthtadienyl ligand.
It is advantageous, if in the metallocene compound, the number of said &eegr;
5
ligands comprising at least four fused rings is 1 or 2.
The metallocene compound according to the invention can in addition to said &eegr;
5
ligands comprising at least four fused rings have other ligands, as well. These other ligands can be &eegr;
5
ligands comprising less than four fused rings, &sgr; (-bound) ligands, ligands of ionic nature and bridge ligands. A bridge is a bivalent atom or group which is bound to two moieties selected from the transition metall central atom and the ligands of the metallocene compound.
According to one embodiment of the invention, all &eegr;
5
Leskelä Markku
Repo Timo
Borealis A/S
Nazario-Gonzalez Porfirio
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