Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Organic compound containing
Reexamination Certificate
2000-10-12
2003-05-27
Harlan, Robert D. (Department: 1713)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Organic compound containing
C556S053000, C526S124200, C526S127000, C526S160000, C526S164000
Reexamination Certificate
active
06569799
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a catalytic system which can be used for copolymerization of ethylene and a conjugated diene monomer, a method for preparation of this catalytic system, and a method for preparation of a copolymer of ethylene and a conjugated diene monomer, using the catalytic system.
It is known that ethylene may be polymerized using certain complex compounds based on lanthanides. These catalysts can be used over a wide range of pressures and temperatures, advantageously at a reduced pressure and a temperature which is close to ambient temperature, for the polymerization of ethylene.
The first complex compounds based on lanthanides described in the literature were alkylated complex compounds. In particular, in J. Chem. Soc., Chem. Comm. pp 994-995 (1978), Ballard et al. described the polymerization of ethylene by means of a complex compound corresponding to the formula [(C
5
H
5
)
2
ErMe]
2
(in which Me is a methyl group).
These alkylated complex compounds can achieve instantaneous levels of activity which are very high, as described in U.S. Pat. No. 4,716,257, with reference to a similar complex compound corresponding to the formula [(C
5
Me
5
)
2
LnH]
2
(in which Ln represents a lanthanide).
However, a major disadvantage of these alkylated complex compounds is that they are deactivated very quickly. Another disadvantage consists in the relative complexity of their synthesis.
In order to eliminate these disadvantages, there have been attempts to develop non-alkylated complex compounds which are based on lanthanides. These complex compounds have a metal-halogen bond and are alkylated in the polymerization medium. U.S. Pat. No. 5,109,085 describes the polymerization of ethylene with complex compounds having the formula C
pn
LnX
4-n
M′Lx (in which L is a complexing molecule, and x is a whole number equivalent to, or higher than 1), which have one or more co-catalysts added to them. The patent also refers to the possible use of the complex for copolymerizing ethylene and butadiene.
This type of non-alkylated complex compound has in its environment one or more complexing molecules L, which for example can consist of tetrahydrofurane or diethylic ether, and are added for reasons of organometallic synthesis.
However, it is found that these complexing molecules can compete with the ethylenic monomer during complexing on the lanthanide, with the undesirable consequence of limiting catalytic activity and, thus, the polymerization output.
In addition, Cui, Li Qiang et al: “Preliminary investigations on polymerization catalysts composed of lanthanocene and methyl aluminoxane”, Polymer Bulletin (Berlin), 1998, 40(6), pp 729-734, describe a catalytic system which is designed for homopolymerization of isoprene, butadiene, or styrene. This catalytic system comprises:
a rare earth organometallic complex compound in accordance with one or another of the following formula:
(C
5
H
9
Cp)
2
NdCl (I);
(C
5
H
9
Cp)
2
SmCl (II);
(MeCp)
2
SmOAr′ (III);
(Ind)
2
NdCl (IV);
Me
2
Si(Ind)
2
NdCl (V);
(Flu)
2
NdCl (VI);
in which Cp, Ind and Flu are respectively cyclopentadienyl, indenyl and fluorenyl groups, and OAr′ is a phenoxy group; and
a co-catalyst consisting of methylaluminoxane, tested in comparison with a co-catalyst consisting of an aluminium alkyl.
The present invention provides an improved catalytic system for preparing copolymers of ethylene and a conjugated diene which do not have the aforementioned disadvantages of the art.
SUMMARY OF THE INVENTION
The present invention provides a catalytic system for copolymerizing ethylene and a conjugated diene comprising an organometallic complex compound represented by one of the following generic formula A′ or B′:
in which Ln represents a metal of a lanthanide, the atomic number of which is between 57 and 71;
X represents a halogen, selected from among chlorine, fluorine, bromine and iodine; wherein
in formula A′, two ligand molecules Cp
1
and Cp
2
, which may be identical or different, selected from a substituted or unsubstituted cyclopentadienyl and fluorenyl group are bonded to metal Ln; and
in formula B′, a ligand comprising Cp
1
and Cp
2
bonded to each other by a bridge P is bonded to metal Ln, wherein Cp
1
and Cp
2
comprise a substituted or unsubstituted cyclopentadienyl or fluorenyl group, bridge P corresponds to the formula MR
2
, in which M is silicon or another element of column IVA of Mendeleev's periodic classification and R is an alkyl group having 1 to 20 atoms of carbon;
and a co-catalyst selected from the group consisting of a magnesium alkyl, a lithium alkyl, an aluminum alkyl, a Grignard's reagent and mixtures thereof.
In a preferred embodiment metal, Ln is neodymium. Cp
1
and Cp
2
are preferably identical, each being a cyclopentadienyl group. More preferably, Cp
1
and Cp
2
are each a cyclopentadienyl group, substituted by an alkyl radical or a silyl alkyl radical.
The invention also provides for methods for preparing the catalytic system and its use thereof in preparing copolymers of ethylene and a conjugated diene.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides an improved catalytic system for preparing copolymers of ethylene and a conjugated diene which do not have the aforementioned disadvantages of the art. The present invention provides a catalytic system for copolymerizing ethylene and a conjugated diene comprising an organometallic complex compound represented by one of the following generic formula A′ or B′:
in which Ln represents a metal of a lanthanide, the atomic number of which can be between 57 and 71;
X represents a halogen, selected from among chlorine, fluorine, bromine and iodine; wherein
in formula A′, two ligand molecules Cp
1
and Cp
2
, which may be identical or different, selected from a substituted or unsubstituted cyclopentadienyl and fluorenyl group are bonded to metal Ln; and
in formula B′, a ligand comprising Cp
1
and Cp
2
bonded to each other by a bridge P, is bonded to metal Ln, wherein Cp
1
and Cp
2
comprise a substituted or unsubstituted cyclopentadienyl or fluorenyl group, bridge P corresponds to the formula MR
2
, in which M is silicon or another element of column IVA of Mendeleev's periodic classification and R is an alkyl group having 1 to 20 atoms of carbon;
and a co-catalyst selected from the group consisting of a magnesium alkyl, a lithium alkyl, an aluminum alkyl, a Grignard's reagent and mixtures thereof.
In a preferred embodiment, Ln is neodymium Cp
1
and Cp
2
are preferably identical, each being a cyclopentadienyl group. More preferably, Cp
1
and Cp
2
are each a cyclopentadienyl group, substituted by an alkyl radical or a silyl alkyl radical.
Thus, in one aspect, the catalytic system of the invention comprises an organometallic complex compound, which is represented by one of formula A′ or B′:
in which Ln represents a metal of a lanthanide, the atomic number of which is between 57 and 71;
X represents a halogen selected from among chlorine, fluorine, bromine and iodine; wherein
in formula A, two ligand molecules CP
A
, each a substituted cyclopentadienyl group, are bonded to metal Ln;
and in formula B, a ligand, comprising two Cp
B
, bonded to one another by a bridge P are bonded to metal Ln, wherein Cp
B
is a substituted or unsubstituted cyclopentadienyl or fluorenyl group and P corresponds to formula MR
2
, in which M is an element in column IVA of Mendeleev's periodic classification, and R is an alkyl group having 1 to 20 carbon atoms; and
a co-catalyst selected from the group consisting of a magnesium alkyl, a lithium alkyl, an aluminium alkyl, a Grignard's reagent, and mixtures thereof.
In the case of substitution by a silyl alkyl radical, Cp
1
and Cp
2
each correspond to formula Cp
A
=(C
5
H
4
)(SiMe
3
) in generic formula A′, or to formula Cp
B
=(C
5
H
3
)(SiMe
3
) in generic for
Barbotin Fanny
Boisson Cristophe
Spitz Roger
Baker & Botts L.L.P.
Harlan Robert D.
Michelin & Recherche et Technique S.A.
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