Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1998-12-30
2001-02-06
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...
C526S160000, C526S943000, C526S131000, C526S352000, C526S348600, C502S152000, C556S053000, C556S007000, C556S020000
Reexamination Certificate
active
06184320
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to metallocene compounds in which a transition metal is complexed by two anionic cyclopentadienyl ligands (carbanions) and the two carbanions are connected to one another by at least one bridge comprising a donor and an acceptor. The coordinative bond formed between the donor atom and the acceptor atom generates a positive (partial) charge on the donor group and a negative (partial) charge on the acceptor group:
The invention further relates to a process for preparing such new metallocene compounds and to their use as polymerization catalysts.
BACKGROUND OF THE INVENTION
Metallocenes and their use as catalysts in the polymerization of olefins have been known for a long time (EP-A 129 368 and the literature cited therein). Furthermore, EP-A '368 discloses that metallocenes in combination with aluminum alkyl/water as cocatalysts are effective systems for the polymerization of ethylene. (Thus, for example, 1 mol of trimethylaluminum and 1 mol of water form methylaluminoxane=MAO. Other stoichiometric ratios have also been successfully employed (WO 94/20506).) Metallocenes whose cyclopentadienyl frameworks are covalently linked to one another by a bridge are also already known. As an example of the numerous patents and applications in this field, mention may be made of EP-A 704 461 in which the linking group mentioned is a (substituted) methylene or ethylene group, a silylene group, a substituted silylene group, a substituted germylene group or a substituted phosphine group. In EP '461 too, the bridged metallocenes are envisaged as polymerization catalysts for olefins. Despite the numerous patents and applications in this field, there is still a desire for improved catalysts which have a high activity so that the amount of catalyst remaining in the polymer can be made small and which are equally suitable for the polymerization and copolymerization of olefins to give thermoplastics and to give elastomeric products and for the polymerization and copolymerization of diolefins, if desired together with olefins.
SUMMARY OF THE INVENTION
It has now been found that particularly advantageous catalysts can be prepared from bridged metallocene compounds in which the bridge between the two cyclopentadienyl-containing ligands is produced by one, two or three donor-acceptor bonds in each of which a coordinative or dative bond which is, at least formally, superimposed on an ionic bond is formed between the donor atom and the acceptor atom. The reversibility of the donor-acceptor bond permits not only the bridged state denoted by the arrow between D and A but also the unbridged state in which the two x systems can rotate relative to one another, for example by 360°, as a result of their intrinsic rotational energy without the integrity of the metal complex being surrendered. After rotation has occurred, the donor-acceptor bond “snaps” back into place. If a plurality of donors and/or acceptors are present, such “snapping into place” can take place after rotation through less than 360°. Metallocenes of the invention can therefore only be represented by a double arrow and the subformulae (Ia) and (lb) to encompass both states.
DETAILED DESCRIPTION OF THE INVENTION
The invention accordingly provides metallocene compounds of the formula
wherein
CpI and CpII are two identical or different carbanions having a cyclopentadienyl-containing structure in which from one to all H atoms can be replaced by identical or different radicals selected from the group consisting of linear or branched C
1
-C
20
-alkyl which may be monosubstituted to fully substituted by halogen, monosubstituted to trisubstituted by phenyl or monosubstituted to trisubstituted by vinyl; C
6
-C
12
-aryl; halogenoaryl having from 6 to 12 carbon atoms and organometallic substituents such as silyl, trimethylsilyl and ferrocenyl; and which may be monosubstituted or disubstituted by D and A,
D is a donor atom which can additionally bear substituents and which, in its respective bonding state, has at least one free electron pair,
A is an acceptor atom which can additionally bear substituents and which, in its respective bonding state, has at least one electron pair vacancy,
where D and A are linked by a reversible coordinative bond in such a way that the donor group takes on a positive (partial) charge and the acceptor group takes on a negative (partial) charge,
M represents a transition metal of transition group III, IV, V or VI of the Periodic Table of the Elements (Mendeleev) including the lanthanides and actinides,
X is one anion equivalent and
n is, depending on the charge of M, zero, one, two, three or four.
The invention further provides a process for preparing metallocene compounds of the formula (I), which comprises reacting with one another either one compound each of the formulae (II) and (III)
or one compound each of the formulae (IV) and (V)
or one compound each of the formulae (VI) and (VII)
with elimination of M′X in the presence of an aprotic solvent or one compound each of the formulae (VIII) and (III)
or one compound each of the formulae (IV) and (IX)
or one compound each of the formulae (X) and (VII)
with elimination of E(R
1
R
2
R
3
)X and F(R
4
R
5
R
6
)X in the absence or in the presence of an aprotic solvent, where
CpI, CpII, D, A, M, X and n are as defined above, CpIII, CpIV are two identical or different uncharged molecule parts having a cyclopentadiene-containing structure, but otherwise the same as CpI and CpII,
M′ is one cation equivalent of an alkali or alkaline earth metal or Tl,
E and F are, independently of one another, one of the elements Si, Ge or Sn and
R
1
, R
2
R
3
, R
4
, R
5
and R
6
are, independently of one another, straight-chain or branched C
1
-C
20
-alkyl, C
6
-C
12
-aryl, C
1
-C
6
-alkyl-C
6
-C
12
-aryl, C
6
-C
12
-aryl-C
1
-C
6
-alkyl, vinyl, allyl or halogen,
where, furthermore, in the formulae (VIII), (IX) and (X) hydrogen can be present in place of E(R
1
R
2
R
3
) and F(R
4
R
5
R
6
) and in this case X can also represent an amide anion of the type R
2
N
⊖
or a carbanion of the type R
3
C
⊖
or an alkoxide anion of the type RO
⊖
, and where it is furthermore possible to react compounds of the formula (II) or (VIII) in the presence of compounds of the formula (V) or (IX) directly with a transition metal compound of the formula (VII). Furthermore, two anions can be connected, with or without insertion of a monoatomic or polyatomic bridge, to form a dianion.
In the reaction of (VIII) with (III) or of (IV) with (IX) or of (X) with (VII) the structure (I) is formed in the last-named variant with elimination of amine R
2
NH or R
2
NE(R
1
R
2
R
3
) or R
2
NF(R
4
R
5
R
6
) or a hydrocarbon compound of the formula R
3
CH or R
3
CE(R
1
R
2
R
3
) or R
3
CF(R
4
R
5
R
6
) or an ether ROE(R
1
R
2
R
3
) or ROF(R
4
R
5
R
6
), where the organic radicals R are identical or different and are, independently of one another, C
1
-C
20
-alkyl, C
6
-C
12
-aryl, substituted or unsubstituted allyl, benzyl or hydrogen. Examples of eliminated amine or hydrocarbon, ether, silane, stannane or germane are dimethylamine, diethylamine, di-(n-propyl)-amine, di-(isopropyl)-amine, di-(tert-butyl)-amine, tertiary butylamine, cyclohexylamine, aniline, methyl-phenylamine, di-(allyl)-amine or methane, toluene, trimethylsilylamine, trimethylsilyl ether, tetramethylsilane and the like.
It is also possible to react compounds of the formula (II) or (VIII) directly with a transition metal compound of the formula (VII) in the presence of compounds of the formula (V) or (IX).
The invention further provides for the use of the metallocene compounds described in a process for the homopolymerization or copolymerization of one or more olefins, i-olefins, alkines or diolefins as monomers or for ring-opening polyaddition in the gas, solution, high-pressure or slurry phase at from −60 to +250° C., preferably up to +200° C., and from 0.5 to 5000 bar, preferably from 1 to 3000 bar, and in the presence or absence of saturated
Kelly Warren Mark
Ostoja Starzewski Karl-Heinz Aleksander
Bayer Aktiengesellschaft
Cheung Noland J.
Gil Joseph C.
Harlan R.
Wu David W.
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