Metal organic catalysts for polymerizing unsaturated compounds

Details Metal organic catalysts for polymerizing unsaturated compounds Metal organic catalysts for polymerizing unsaturated compounds

2001-10-24

2003-07-15

Wu, David W. (Department: 1713)

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

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S161000, C526S171000, C526S172000, C526S169100, C526S134000, C556S137000, C556S140000, C556S142000, C556S143000

Reexamination Certificate

active

06593437

ABSTRACT:

The present invention relates to a process for preparing 1,2-diimine compounds, metallocenyl-substituted 1,2-diimine compounds, catalysts having metallocenyl-substituted 1,2-diimine ligands, a process for preparing them and also their use in the polymerization of unsaturated compounds.
The use of metallocene catalysts in the polymerization of unsaturated compounds has a great influence on the preparation of polyolefins since it opens up a route to novel polyolefinic materials or to materials having improved properties. There is therefore great interest in the development of new families of catalysts for the polymerization of unsaturated compounds in order to obtain better control over the properties of polyolefins or further novel products.
The use of transition metal catalysts containing late transition metals (in particular transition metals of transition group VIII of the Periodic Table of the Elements) is of particular interest because of their ability to tolerate heteroatom functions. However, a disadvantage is that the transition metal catalysts containing late transition metals frequently tend, in contrast to transition metal catalysts containing early transition metals (in particular transition metals of transition groups III to V of the Period Table of the Elements), to result in dimerization or oligomerization of unsaturated compounds because of competing &bgr;-hydride elimination.
The prior art discloses transition metal catalysts derived from late transition metals which are suitable for the polymerization of unsaturated compounds.
V. C. Gibson et al., Chem. Commun. 1998, 849-850, and M. Brookhart et al., J. Am. Chem. Soc. 1998, 120, 4049-4050, disclose new olefin polymerization catalysts based on Fe(II) and Co(II). These catalysts bear 2,6-bis(imino)pyridyl ligands which are aryl-substituted on the imino nitrogens and display high activities in the polymerization of ethlyene. The polyethylene obtained is essentially linear and the molecular weight is strongly dependent on the substituents on the aryl radical. H. tom Dieck, Z. Naturforsch. 1981, 36b, 823-832,relates to bis(diazadiene)nickel(0) complexes having aromatic substituents on the nitrogen atom and also their conformations as a function of the substituents on the aromatic radical.
M. Brookhart et al., J. Am. Chem. Soc. 1995, 117, 6415-6415, describe catalysts based on Pd(II) and Ni(II) for the polymerization of ethylene and &agr;-olefins. These catalysts bear 1,2-diimine ligands. In the polymerization of ethylene and &agr;-olefins, they give polymers having a high molecular weight. The branching of polyethylene prepared using these catalysts can be adjusted from strongly branched to only slightly branched as a function of the ligand system, metal, temperature and the pressure. According to M. Brookhart et al., J. Am. Chem. Soc. 1996, 118, 267-268, the copolymerization of ethylene and propylene with functionalized vinyl monomers is also possible using these catalysts with Pd(II) as metal.
WO 96/23010 relates to processes for the polymerization and copolymerization of olefins such as ethylene, acrylic olefins and others. Catalysts used are transition metal compounds containing metals selected from the group consisting of Ti, Zr, Sc, V, Cr, rare earth metals, Se, Co, Ni and Pd. Ligand systems disclosed are diimine ligand systems, in particular 1,2-diimine ligand systems.
It is an object of the present invention to provide a novel catalyst containing a transition metal of transition group VIII of the Periodic Table of the Elements (late transition metal) as central metal for the polymerization of unsaturated compounds. This object can be divided into the provision of a ligand system for this catalyst and a process for preparing this ligand system and provision of a process for preparing the corresponding catalyst.
We have found that this object is achieved by a process for preparing 1,2-diimine compounds of the formula I,
where the symbols have the following meanings
R
1
and R
2
are, independently of one another, alkyl, aryl or metallocenyl radicals, and
R
3
, R
4
are, independently of one another, H, alkyl or aryl radicals, or
R
3
and R
4
are joined so as to form, with inclusion of the two imine carbon atoms, a 5- to 8-membered ring which may be saturated or unsaturated and may be unsubstituted or substituted by any hydrocarbon radicals,
by reacting 1,2-dicarbonyl compounds with primary amines.
In the process of the present invention, the amines are activated with trialkylaluminum compounds prior to the reaction with the 1,2-dicarbonyl compounds.
The process of the present invention is particularly useful for preparing 1,2-diimine compounds having bulky radicals R
1
to R
4
which cannot be obtained without addition of trialkylaluminum compounds. Thus, the process of the present invention makes it possible to obtain new groups of 1,2-diimine compounds which can be used as ligand systems for novel catalysts.
For the purposes of the present invention, alkyl radicals R
1
, R
2
, R
3
and R
4
are linear, branched or cyclic alkyl radicals, preferably C
1
-C
20
-alkyl radicals, particularly preferably C
1
-C
8
-alkyl radicals.
Aryl radicals are, for the purposes of the present invention, unsubstituted and substituted aryl radicals, preferably C
6
-C
20
-aryl radicals, particularly preferably substituted C
6
-C
14
-aryl radicals, which may be monosubstituted or polysubstituted, very particularly preferably C
1
-C
6
-alkyl-substituted C
6
-C
10
-aryl radicals such as 4-methylphenyl, 2,6-dimethylphenyl, 2,6-diethylphenyl, 2,6-diisopropylphenyl, 2-tert-butylphenyl, 2,6-di(tert-butyl)phenyl or 2-i-propyl-6-methylphenyl.
According to the present invention, R
3
and R
4
in the formula I may be joined so as to form, with inclusion of the two imine carbon atoms, a 5- to 8-membered ring which may be saturated or unsaturated and may be unsubstituted or substituted by any hydrocarbon radicals.
For the purposes of the present invention, hydrocarbon radicals are linear, branched or cyclic hydrocarbon radicals which may be saturated or monounsaturated or polyunsaturated. The cyclic hydrocarbon radicals may together with the 5- to 8-membered ring system form a fused system which may be ortho-fused or ortho- and peri-fused. The hydrocarbon radicals preferably have from 1 to 20 carbon atoms. Particular preference is given to a fused-on naphtho group which may be unsubstituted or monosubstituted or polysusbstituted by alkyl radicals or aryl radicals, so that, with inclusion of the 5- to 8-membered ring system formed from R
3
and R
4
, an ortho- and peri-fused system is formed.
In a fused system (at least two rings each having at least five ring atoms including the shared atoms), if two rings have two atoms in common or the system contains a plurality of rings each having two atoms in common, the system is said to be ortho-fused. The number of shared atoms is then double the number of shared sides. If a ring of a fused system shares two atoms with each of two or more rings of a series of adjacent rings, the system is said to be ortho- and peri-fused and the number of atoms is less than twice the number of the shared sides.
For the purposes of the present invention, metallocenyl radicals are bis(&eegr;
5
-cyclopentadienyl)metal radicals in which the metal is preferably Fe, Co
+
, Ni, Ru, Os, Rh
+
or Ir
+
. The metal is particularly preferably Fe, i.e. the metallocenyl radical is a bis(&eegr;
5
-cyclopentadienyl)iron radical (ferrocenyl radical). The cyclopentadienyl radicals may be substituted or unsubstituted, with the radical being bound to the imine nitrogen in the formula I via one of the two cyclopentadienyl radicals. Preferred substituents on the cyclopentadienyl radical are —Me, —SiMe
3
or —SicHexMe
2
.
The process of the present invention is preferably used for preparing compounds of the formula I in which the radicals R
1
and R
2
are, independently of one another, substituted aryl radicals or metallocenyl radicals. R
1
and R
2
are particularly preferably ferrocenyl radicals. Very particular prefer

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