Amidinato catalyst systems for the polymerization of olefins

Details Amidinato catalyst systems for the polymerization of olefins Amidinato catalyst systems for the polymerization of olefins

1997-06-06

2001-07-17

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, C526S172000, C526S164000

Reexamination Certificate

active

06262198

ABSTRACT:

The present invention relates to catalyst systems which are suitable for the polymerization of olefinically unsaturated hydrocarbons and contain, as active components,
A) an amidinato metal complex of the general formula A
 where
M is a metal from subgroup III, IV, V or VI of the Periodic Table of Elements or a metal from the lanthanide group,
X is a negative leaving atom or a negative leaving group, and the radicals X may be identical or different if (n−m)>1,
R
1
, R
2
and R
3
are each a C-organic or Si-organic radical,
n is the valency of M in the metal complex A and
m is from 1 to 5, with the proviso that
n−m≧0,
and, if required,
B) an acceptor compound for the substituent X of the component A as an activator.
The present invention furthermore relates to the use of the catalyst systems for the preparation of polymers from olefinically unsaturated hydrocarbons, and the polymers obtainable thereby.
The polymerization of olefins with the aid of Ziegler-Natta catalysts has in general long been known. These are in general complex systems comprising an organoaluminum compound on the one hand and at least one organometallic compound of a transition metal, in particular a titanium compound, on the other hand, which can be formed in situ from the components. Many systems of this type have been described to date and some are also known to have been used on a large industrial scale, especially for the production of polyethylene.
However, none of these systems is free from one disadvantage or another; either their components are very difficult to prepare, the systems or their components are extremely sensitive to oxygen and water or their solubility in organic solvents is only low so that they are difficult to meter.
Teuben et al., J. Am. Chem. Soc. (1993), 115, 4931-4932, describe the dimerization of alkynes with a bisbenzamidinatoyttrium complex. They mention in passing the polymerization of ethylene with this complex, but in the absence of organoaluminum compounds.
Furthermore, Green et al., J. Chem. Soc., Chem. Commun. (1993), 1415-1417, disclose specific benzamidinato complexes of the formula
where
M′ is Ti, Zr or Hf,
X and Y are each Cl or benzyl, and
Cp is cyclopenadienyl,
which were used together with methylaluminoxane for the polymerization of ethylene. However, owing to the cyclopentadienyl group being bonded by a coordinate bond, these complexes are difficult to obtain and are furthermore highly sensitive, so that they are virtually unsuitable for industrial purposes.
It is an object of the present invention to provide novel catalyst systems for the polymerization of olefinically unsaturated hydrocarbons, which systems have the stated disadvantages only to a small extent, if at all, and are universally applicable.
We have found that this object is achieved by the catalyst systems defined at the outset. We have also found the use of the catalyst systems for the preparation of polymers of unsaturated hydrocarbons, processes for the preparation of polymers of unsaturated hydrocarbons with the aid of these catalyst systems and the polymers obtainable thereby.
The central atom M in A is primarily a metal of subgroup IV of the Periodic Table of Elements, ie. titanium, hafnium or very particularly zirconium. Metals of subgroup V of the Periodic Table of Elements, such as vanadium, niobium and tantalum, and those of subgroup VI of the Periodic Table, such as chromium, molybdenum and tungsten, may also act as the central atom, chromium being particularly preferred. Examples of lanthanoid metals are the metals having atomic numbers 57 to 71, for example lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, thulium and lutetium. The metals of subgroup III of the Periodic Table, such as scandium and yttrium, are also suitable.
As is generally known with regard to the function of Ziegler-Natta catalysts, a substituent is detached from the metal of one component and is taken up by the other component with formation of a coordinate unsaturated transition metal alkyl or transition metal hydride compound. Olefinic monomers are then inserted by the insertion polymerization mechanism into the transition metal-C or transition metal-H bond activated in this manner. Accordingly, in the present case the substituents X generally perform the function of being readily abstracted from the central metal M and taken up by the component B). The radicals X are therefore atoms or groups of atoms which can be transferred as anionic leaving groups to the component B). However, X may also permit binding of the metal complex A to the surface of an oxide carrier, for example by substitution of X for surface OH groups. The nature of these radicals in other respects is therefore unimportant or only of minor importance.
Examples of radicals X are:
hydrogen, halogen, such as fluorine, bromine, iodine and preferably chlorine, and anions of inorganic acids, such as nitrate, sulfate, perchlorate, phosphate, carbonate, dihydrogen sulfate and bicarbonate. Anions of organic acids, such as acetate, trifluoroacetate, trichloroacetate, benzoate, trifluoromethylsulfonate, methylsulfonate and p-toluenesulfonate, are also suitable. Other examples are alcoholates and thiolates such as methanolate, ethanolate, n-propanolate, isopropanolate, phenolate, thiophenolate, trifluoromethylphenolate, naphtholate and silanolate. X is furthermore particularly preferably an aliphatic C
1
-C
10
-alkyl radical, in particular methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl or hexyl, or vinyl, allyl or pentadienyl, or an alicyclic C
3
-C
12
-hydrocarbon radical, such as cyclopropyl, cyclobutyl, cyclopentyl or in particular cyclopentadienyl, cyclohexyl or C
5
-C
20
-bicycloalkyl, such as bicyclopentyl, or in particular bicycloheptyl or bicyclooctyl. Examples of substituents X having aromatic structural units are C
6
-C
15
-aryl, preferably phenyl, or naphthyl or indenyl, fluorenyl or benzindenyl, alkylaryl or arylalkyl, each having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, for example tolyl or benzyl.
R
1
to R
3
are each C- or Si-organic groups, such as C
1
-C
10
-alkyl, preferably methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl or tert-butyl. R
1
to R
3
may furthermore be a 3-membered to 12-membered cycloalkyl radical, which in turn may carry C
1
-C
10
-alkyl as substituents. Preferred cycloalkyl radicals are cyclopropyl, cyclobutyl, cyclopentyl and in particular cyclohexyl. Bicyclic C
5
-C
20
radicals, such as norbornyl, are also used. R
1
to R
3
may each furthermore be a group of atoms having aromatic structural units, such as C
6
-C
20
-aryl, preferably phenyl, tolyl, naphthyl or biphenyl, or alkylaryl or arylalkyl, each having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, for example tolyl or benzyl. R
1
to R
3
may each furthermore be an Si-organic radical, such as Si(R
4
)
3
, where R
4
is C
1
-C
10
-alkyl, preferably methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, or C
3
-C
12
-cycloalkyl, preferably cyclopropyl, cyclobutyl, cyclopentyl or in particular cyclohexyl. R
4
may also be C
5
-C
20
-bicycloalkyl, preferably bicycloheptyl or bicyclooctyl. Moreover, R
1
to R
3
may each be a group of atoms having aromatic structural units, such as C
6
-C
20
-aryl, preferably phenyl or naphthyl, or alkylaryl or arylalkyl, each having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, for example tolyl or benzyl.
If the central atom M carries two amidinato ligands, these ligands may furthermore be linked to one another by the radicals R
1
to R
3
. Suitable bridge members are C
1
-C
6
-alkylene bridges or diorganosilyl bridges, for example dimethylsilyl, diethylsilyl or diphenylsilyl, or mixed C
1
-C
6
-alkylene/diorganosilyl bridges, for example —CH
2
—Si(CH
3
)
2
—CH
2
— or —Si(CH
3
)
2
—CH
2
—Si(CH
3
)
2
—.
Particularly suitable compounds of the general formula A are those in which R
1

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