Polmerization catalysts

Details Polmerization catalysts Polmerization catalysts

1999-12-23

2002-03-26

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, C526S161000, C526S943000, C502S117000, C502S152000, C502S155000, C502S104000, C556S011000, C556S012000, C556S053000

Reexamination Certificate

active

06362292

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to catalysts suitable for the polymerisation of olefins in particular to catalysts comprising supported transition metal complexes suitable for use for the polymerisation of ethylene or the copolymerisation of ethylene with alpha-olefins.
The use of transition metal complexes as components of catalyst compositions suitable for the polymerisation of olefins is well known. For example olefin polymerisation catalysts based on metallocene complexes are known. Such catalysts typically comprise bis(cyclopentadienyl)zirconium complexes together with activators such as aluminoxanes and are disclosed in detail in EP 129368 and EP 206794. When used for polymerisation in the gas phase such complexes are typically supported for example on silica.
There have however been many attempts at fixing or tethering such metallocene complexes in order to enable them to be utilised as heterogeneous catalysts for the polymerisation of olefins in particular for use in the slurry or gas phase.
EP 586 167-A1 discloses the functionalisation of metal complexes with polymerisable groups which allow the formation of metallocene containing polymers, usually low yield polyolefins, providing a method for fixing metal complexes to supports, for example silica.
U.S. Pat. No. 5,498,581 discloses the production of solid metallocene-containing catalyst systems by incorporating an olefinic group attached to a metallocene (eg (methyl-1-butenyl)methylene-bridged (cyclopentadienyl)(fluorenyl)ZrCl
2
) into a solid prepolymer.
U.S. Pat. Nos. 5,492,973, 5,492,974, 5,492,975, 5,492,978, and 5,492,985 disclose the formation of polymer-bound ligands by the reaction of a metallated polymer (eg polystyrene) with a chlorinated cyclopentadienyl (Cp)-containing moiety, followed by reaction with a metal compound (eg CpMCl
3
) to give a polymer-bound catalyst precursor. This method however suffers from the possible disadvantage that the ligand modification necessary to effect the polymer binding may interfere with the chemistry of the active site.
U.S. Pat. No. 5,466,766 discloses a process for preparing supported metallocene complexes by using a ligand possessing an active halogen, and reacting it with a hydroxylated support to give an immobilised complex (eg silica-O-Cp-fluorenylmethylsilane ZrCl
2
). This method also suffers from the possible disadvantage that the ligand modification necessary to effect the polymer binding may interfere with the chemistry of the active site, and the release of polar compounds as by-products on interaction of the active halogen with the support hydroxyl functionality (eg HCl), which could act as a poison for olefin polymerisation catalyst systems.
EP 670 336-A1 discloses bridged bis-Cp complexes, eg silyl-bridged bis-indenyl zirconium chlorides, which possess alkylamino-substituents attached to the ligand, eg to the indenyl moiety. These are then reacted with a hydroxylated oxide support (eg silica) treated with halogenated silanes (eg (RO)
3
Si(4-CH
2
Cl-Ph) and Me
3
SiCl) in a solvent (eg toluene) to effect immobilisation via quaternisation of the amine N (eg [indenyl-N
+
(Me)
2
-CH
2
-Ph-Si-support][Cl]
−
).
WO 96/04319 discloses immobilisation of a borate activator to the surface of a support to form a supported borate (eg [support-O-B(C
6
F
5
)
3
]
−
[H]
+
) with subsequent treatment with metallocene dialkyl (eg Cp
2
M(Me)
2
) to give an immobilised catalyst (eg [support-O—B(C
6
F
5
)
3
]
−
[Cp
2
M(Me)]
+
).
JP 1-259005 and 1-259004 disclose the preparation of complexes with ligands containing silane functionality (eg ((MeO)
3
Si—CH
2
—CH
2
-indenyl)ZrCl
3
) and their use in supported catalyst formulations using hydroxylated oxide supports. One possible problem with this approach may be the release of polar compounds as by-products on interacting the silane with the support hydroxyl functionality (eg MeOH), and their role as poisons for olefin polymerisation catalyst systems.
Other complexes have been disclosed with similar functionality but which do not teach their use specifically to tether or bind the metallocene complex onto a support.
For example EP 670 325-A2 discloses bridged bis-Cp complexes, eg silyl-bridged bis-indenyl zirconium chlorides, which possess alkylamino-substituents attached to the ligand, eg to the indenyl moiety. No indication of use of the alkylamino-substituents for tethering purposes is however disclosed.
U.S. Pat. No. 5,486,585 discloses the preparation of metal complexes which possess ligands containing silyl-bridges which are amido-functionalised (eg((Me
2
N)
2
Si)(2-Me-indenyl)
2
ZrCl
2
. The complexes may be used with an activator to make a catalyst system which may be supported but few details of the preferred supporting method are disclosed.
It would be most desirable therefore to have an immobilisation method for such metallocene complexes which does not rely on chemical modification of the ligand system which remains attached to the active metal site during use as a polymerisation catalyst.
It would also be desirable to have an immobilisation method for metal complexes which does not involve the release or formation of reactive materials during the immobilisation process.
It would also be very desirable to have an immobilisation method which may be used for a wide range of metal complexes.
In recent years there have been a number of patents describing polymerisation catalyst systems based on transition metal complexes which also comprise an unsaturated moiety eg neutral conjugated or non-conjugated diene ligands which form complexes with the metal of the complex. Such catalyst systems are disclosed in WO 95/00526 and WO 96/04290 incorporated herein by reference.
SUMMARY OF THE INVENTION
We have now discovered that such complexes may be suitably supported by use of the unsaturated moiety when containing a Lewis base functionality.
Thus according to the present invention there is provided a transition metal complex suitable for use in the polymerisation of olefins comprising a transition metal complex of formula:
L
x
Q
y
M-D
wherein
M is titanium, zirconium or hafnium in the +2 or +4 oxidation state,
L is a group containing a cyclic delocalised anionic &pgr; system through which the group is bound to M,
Q is a moiety bound to M via a &sgr;-bond comprising boron or a member of Group 14 of the Periodic Table and also comprising nitrogen, phosphorus, sulphur or oxygen, said moiety having up to 60 non-hydrogen atoms,
x=1 or 2
y=0 or 1
such that when x=1, y=1 and when x=2, y=0, and
D is a neutral, conjugated or non-conjugated unsaturated moiety optionally substituted with one or more hydrocarbyl groups, said D having up to 40 carbon atoms and forming a &pgr; complex with M when M is in the +2 oxidation state and a &sgr; complex with M when M is in the +4 oxidation state and having at least one Lewis Base group B.
The L group is preferably a C
5
H
4
group bound to Q and bound in an &eegr;
5
bonding mode to M or is such an &eegr;
5
bound group substituted with from one to four substituents independently selected from hydrocarbyl, silyl, germyl, halo, cyano, and combinations thereof, said substituent having up to 20 non hydrogen atoms, and optionally, two such substituents (except cyano or halo) together cause L to have a fused ring structure.
The L group is preferably cyclopentadienyl or substituted cyclopentadienyl eg indenyl.
When the Q group is present (when y=1) it may be suitably represented as Z—Y wherein
Y is —O—, —S—, —NR*—, —PR*—, and
Z is SiR*
2
, CR*
2
, SiR*
2
SiR*
2
, CR*
2
CR*
2
, CR*═CR*, CR*
2
SiR*
2
, or GeR*
2
, wherein:
R* each occurence is independently hydrogen, or a member selected from hydrocarbyl, silyl, halogenated alkyl, halogenated aryl, and combinations thereof, said R* having up to 10 non-hydrogen atoms, and optionally, two R* group from Z (when R* is not hydrogen), or an R* group from Z and an R* group from Y fo

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