Catalytic complexes and their use for polymerizing...

Details Catalytic complexes and their use for polymerizing... Catalytic complexes and their use for polymerizing...

2002-05-20

2003-12-30

Harlan, Robert (Department: 1713)

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

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S172000, C502S155000, C502S167000

Reexamination Certificate

active

06670434

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to complexes of 2,6-pyridinebis(imines) with transition metals and their use for polymerizing alpha-olefins.
DISCUSSION OF THE BACKGROUND
It is known that alpha-olefins can be polymerized by means of complexes comprising a transition metal and a tridentate ligand, and an aluminoxane. Patent application WO 99/62967 describes the copolymerization of ethylene with the aid of complexes of iron with 2,6-pyridinebis(imines). However, the catalytic complexes described in that application do not efficiently incorporate propylene during the manufacture of copolymers of ethylene. Patent application WO 99/12981, Britovsek et al. (Chem. Eur., 2000, 6(12), 2221) and Qiu et al. (Polym. Int., 2000, 49(1), 5) report the syntheses of {2,6-bis[1-(1-naphthylimino)methyl]-pyridine-&kgr;
3
: N,N′,N″}FeCl
2
and of {2,6-bis[1-(1-naphthylimino)ethyl]pyridine-&kgr;
3
: N,N′,N″}FeCl
2
and their use for polymerizing ethylene in the presence of methylaluminoxane (MAO). However, the catalytic activity of these complexes and the molecular weights of the polyethylenes obtained are low.
We have now found complexes of a transition metal with 2,6-pyridinebis(imines) for polymerizing alpha-olefins where these do not have the abovementioned disadvantages.
SUMMARY OF THE INVENTION
The present invention therefore provides complexes of a transition metal complying with the general formula (I) in which
M is a transition metal of groups 6 to 12,
T is the oxidation state of M,
each A, which may be identical with or differ from each other, is an atom or an atomic grouping bonded covalently or ionically to the transition metal M,
b is the valency of A,
each R
1
, R
2
, R
3
, R
4
and R
5
is independently a hydrogen atom, an unsubstituted or substituted hydrocarbon group, an unsubstituted or substituted heterohydrocarbon group, or an inert functional group,
R
6
and R
7
are, independently of one another, a polynuclear aromatic hydrocarbon group containing at least two condensed benzene nuclei, substituted with at least one hydrocarbon group.
DETAILED DESCRIPTION OF THE INVENTION
All the references to the Periodic Table of the Elements refer to the version published in CRC Handbook of Chemistry and Physics, 77th Edition, 1996/97; the notation utilized is the new IUPAC notation for the groups.
An “inert functional group” is understood to be an atomic grouping which is not an unsubstituted or substituted (hetero) hydrocarbon group, this group being inert under the conditions of the process using the complex of the present invention, and not coordinating with the transition metal M. Examples which may be mentioned of inert functional groups are halogen atoms and ethers of formula OR in which R is an unsubstituted or substituted hydrocarbon group.
Preferred complexes are those complying with the general formula (I) in which M is Fe, Cr, Co, Ru or Mn. Particular preference is given to Fe. Suitable complexes are those complying with the general formula (I) in which T is 2.
Each A is generally selected from halogen atoms, sulphates, nitrates, thiolates, thiocarboxylates, BF
4
—, PF
6
—, hydrogen atoms, hydrocarbon oxides, carboxylates, unsubstituted or substituted hydrocarbon groups, and heterohydrocarbon groups. Preferred complexes are those complying with the general formula (I) in which A is a halogen atom or a linear or branched alkyl group containing from 1 to 8 carbon atoms. Preference is very particularly given to complexes of the formula (I) in which A is a halogen atom.
Suitable complexes of the invention are those complying with the general formula (I) in which R
1
, R
2
, R
3
, R
4
and R
5
are independently a hydrogen atom or a linear or branched alkyl group containing from 1 to 6 carbon atoms. The complexes in which R
1
and R
5
are independently a linear or branched alkyl group containing from 1 to 6 carbon atoms are particularly preferred, since they have high activity.
R
6
and R
7
are preferably selected independently of each other from groups complying with the formulae (II) or (III) below: in which R
8
to R
21
are independently hydrogen atoms or hydrocarbon groups, such
that at least two thereof can form a ring, with the proviso that at least one of the groups selected from R
8
to R
14
is not a hydrogen atom.
The groups (II) in which R
11
and R
12
, R
12
and R
13
, or R
13
and R
14
together form an unsubstituted or substituted benzene nucleus advantageously give alpha-olefin polymers having high molecular weight. The groups (II) in which R
12
and R
13
together form an unsubstituted or substituted benzene nucleus are particularly suitable. The groups (II) in which at least one of the groups selected from R
12
, R
8
and R
9
represents a linear or branched alkyl group containing from 1 to 8 carbon atoms are preferred because they generally give high catalytic activity. The groups (II) in which R
8
is a linear or branched alkyl group containing from 1 to 8 carbon atoms are particularly preferred. The groups (II) in which R
12
and R
13
together form an unsubstituted or substituted benzene nucleus and R
8
is a linear or branched alkyl group containing from 1 to 8 carbon atoms are particularly preferred because they usually permit alpha-olefin polymers having high molecular weight to be obtained with high activity.
The groups (III) in which R
18
and R
19
, R
19
and R
20
, or R
20
and R
21
together form an unsubstituted or substituted benzene nucleus usually give alpha-olefin polymers having high molecular weight. The groups (III) in which at least one of the groups selected from R
15
and R
16
is a linear or branched alkyl group containing from 1 to 8 carbon atoms are preferred because they generally give complexes having high catalytic activity. The groups (III) in which R
19
and R
20
together form an unsubstituted or substituted benzene nucleus and R
15
or R
16
is a linear or branched alkyl group containing from 1 to 8 carbon atoms advantageously permit alpha-olefin polymers having high molecular weight to be obtained with high activity.
It is preferable to use complexes in which R
6
and R
7
comply with formula (II). The complexes in which R
1
and R
5
are a linear or branched alkyl group containing from 1 to 6 carbon atoms, and R
6
and R
7
comply with the formula (II) in which R
8
is a linear or branched alkyl group containing from 1 to 8 carbon atoms are very particularly preferred. Examples which may be mentioned of abovementioned complexes are {2,6-bis[1-(2-methyl-1-naphthylimino)methyl]pyridine-&kgr;
3
: N,N′,N″}FeCl
2
, {2,6-bis[1-(1-anthracenylimino)methyl]pyridine-&kgr;
3
: N,N′,N″}—FeCl
2
, {2,6-bis[1-(1-anthracenylimino)ethyl]pyridine-&kgr;
3
: N,N′,N″}FeCl
2
and {2,6-bis[1-(2-methyl-1-naphthyl-imino)ethyl]pyridine-&kgr;
3
: N,N′,N″}FeCl
2
.
The complexes of the invention are generally prepared by a first condensation step of Schiff-base type, using amine and unsubstituted or substituted 2,6-bis(carbonyl)pyridine, as described by Britovsek et al. in J. Am. Chem. Soc., 1999, 121, 8728 and Small et al. in J. Am. Chem. Soc., 1998, 120, 4049. This reaction is then followed by addition of the di(imino)pyridine thus obtained to a salt of the transition metal (M) in order to obtain a complex complying with the general formula (I). The condensation reaction is usually carried out by using 2 equivalents of amine to 1 equivalent of 2,6-bis(carbonyl)pyridine. The di(imino)pyridine obtained is preferably added to a halide of the transition metal (M). This complexation reaction may be followed by reaction of the complex obtained with a Grignard reagent of formula AMgBr, in which A is a linear or branched alkyl group containing from 1 to 8 carbon atoms.
The complexes of the invention may be used as catalysts for polymerizing alpha-olefins. The invention therefore also provides a process for polymerizing alpha-olefins by bringing at

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