Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Plural component system comprising a - group i to iv metal...
Reexamination Certificate
2001-02-05
2003-11-04
Bell, Mark L. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Plural component system comprising a - group i to iv metal...
C502S128000, C526S132000, C526S133000, C526S134000
Reexamination Certificate
active
06642169
ABSTRACT:
The present invention relates to a catalyst system for use in the preparation of substantially terminally unsaturated polyolefins.
Substantially terminally unsaturated polyolefins where the terminal group in the polymer is a vinylidene group have been used as starting materials for the preparation of a variety of compounds for example oil additives, sealants, dispersants, cleaning agents, etc. Such terminally unsaturated polyolefins, especially poly(iso)butenes, have been prepared using various catalysts such as boron trifluoride as claimed and described in our EP-A-0145235 and EP-A-0671419. Other processes have been used to produce conventional polymers of 1-olefins using catalysts such as metallocenes alone or in combination with an activator/cocatalyst such as methylaluminoxane. Polyolefins which can be produced by the latter method include homopolymers of propylene, 1-butene, 1-pentene, 1-hexene and 1-octene as well as copolymers of such olefins with one another, in particular copolymers of propylene e.g. with ethylene. Such polyolefins are characterised by a low molecular weight typically in the range 300-5000.
A particular advantage of such terminally unsaturated polymers is their high degree of reactivity especially towards enophiles such as unsaturated dicarboxylic acid anhydrides which make them particularly suitable for the ene/enophile reactions which enable functionalisation of such polymers into useful products such as lubricating oil additives.
For example EP-A-353935 describes ethylene/alpha-olefin copolymer substituted mono- and dicarboxylic acid lubricant dispersant additives in which the ethylene copolymer is prepared by use of bis(n-butylcyclopentadienyl)zirconium dichloride catalyst and methylaluminoxane (MAO) cocatalyst.
EP-A-490454 describes alkenyl succinimides as lube oil additives comprising an alkenyl substituent group derived from a propylene oligomer which is conveniently prepared using as a catalyst a bis(cyclopentadienyl)zirconium compound and cocatalyst MAO.
Similarly, EP-A-268214 describes the use of an alkyl substituted cyclopentadienyl compound of zirconium or hafnium for the oligomerisation of propylene. A vast number of compounds are listed which include inter alia [(CH3)
5
C
5
]
2
ZrCl
2
. However, all the compounds listed are bis(penta-alkyl substituted cyclopentadiene) derivatives of zirconium or hafnium and these tend to give rise to polymers in which the terminal unsaturated linkage is predominantly a vinyl linkage.
EP 427697 describes a catalyst system based on a neutral metallocene, an aluminium alkyl and a Lewis acid e.g. tris(pentafluorophenyl)boron. In such a system the Lewis acid is utilised to ionize the neutral metallocene to form an ionic metallocene catalyst system. EP 570982 describes the use of a catalyst system comprising a metallocene, an organoaluminium compound and an ionic compound e.g. a trialkylammnonium borate. The catalyst system described may also comprise a boron compound e.g. tris(pentafluorophenyl) borane. Again in this system an ionic metallocene is prepared by interaction between the complex and the ionic compound.
We have now found that certain metallocene complexes when used in the presence of Group III metal alkyl compounds and Lewis acids comprising aryl boron compounds may be suitable for the preparation of substantially terminally unsaturated polyolefins having molecular weights in the range 300-500,000.
Thus according to the present invention there is provided a catalyst system suitable for use for the preparation of substantially terminally unsaturated atactic polymers or copolymers of &agr;-olefins having a number average molecular weight in the range 300-500,000 said catalyst system comprising (A) a metallocene of formula:
[R
m
CpH
(5−m)
][R
n
CpH
(5−n)
]M(Z)Y
wherein
CpH is a cyclopentadienyl ligand,
Each R represents an alkyl or an aryl substituent on the CpH ligand or two R groups may be joined together to form a ring, or the R groups in each CpH group when taken together represents an Si or C bridging group linking two CpH groups wherein
said Si or C group may itself be substituted by hydrogen atoms or C1-C3 alkyl groups,
M is a metal selected from hafnium, zirconium and titanium,
Z and Y are anionic ligands and may be the same or different, and
(B) a cocatalyst comprising (i) a Group III metal alkyl compound and (ii) a triarylboron compound.
Unless otherwise specified, the terms (co) polymers and (co) polymerisation are used herein and throughout the specification to cover the homopolymerisation and copolymerisation of &agr;-olefins as well as including oligomerisation.
By substantially terminally unsaturated polymers or copolymers is meant polymers or copolymers having ≧60% polymer chains which contain terminal unsaturation.
More specifically, catalysts that may be used to (co)polymerise &agr;-olefins include bis(alkyl cyclopentadienyl)metallocenes wherein R is a suitably a methyl group. Thus, the alkyl substituent on the cyclopentadienyl ligands in the metallocene may be a methyl-; 1,3-dimethyl-; 1,2,4-trimethyl-; or tetramethyl-group. Where R represents a substituted or unsubstituted silicon or carbon bridging group linking two CpH ligands, such metallocenes are suitably dimethylsilyl dicyclopentadienyl-zirconium, -hafnium or -titanium compound.
When two R groups are joined together the cyclopentadienyl ligand may be represented by indenyl or hydrogenated indenyl.
The metal M in the metallocene may be zirconium, hafnium or titanium. Of these zirconium is preferred.
The group Z or Y in the metallocene is preferably hydrocarbyl and most preferably alkyl. The most preferred metallocene complexes are those wherein Z and Y is methyl.
The preferred metallocenes for use in the present invention are bis(1,3-dimethylcyclopentadienyl)zirconium dimethyl and bis(cyclopentadienyl)zirconium dimethyl.
The Z and Y ligands may also be selected from a 1,3-diketone group, a &bgr;-ketoester and a triflate. The diketonate comprises an anion of the formula
[R
1
—C(O)—C(R
2
)—C(O)—R
3
]
−
where R
1
, R
2
and R
3
may be the same or different alkyl or aryl groups or halogenated alkyl groups and in addition R
2
may be a hydrogen atom. The keto-ester anion comprises anions of the formula
[R
1
—C(O)—C(R
2
)—C(O)—OR
3
]
−
where R
1
, R
2
and R
3
may be the same or different alkyl or aryl groups or halogenated all groups and in addition R
2
may be a hydrogen atom.
Of these, preferred metallocene catalysts which carry a methyl or a 1,3-dimethyl or a 1,2,4-trimethyl cyclopentadienyl ligands (ie when n is 1-3) give rise to (co)polymers in which the terminal unsaturation is predominantly a vinylidene group e.g. suitably >97%, preferably >99% vinylidene. However, where the value of each of m and n in these catalysts is 4 or 5, the product may comprise a significant proportion of vinyl terminated chains.
The cocatalyst comprises a Group III metal alkyl and a triarylboron compound.
Preferred Group III metal alkyl compounds are trialkylaluminium compounds in particular triisobutylalurninium. Other suitable Group III metal compounds include tri(sec-butyl)boron and triethyl boron.
A preferred triaryl boron compound is tris(pentatluorophenyl)boron.
In the catalyst system of the present invention the mole ratio of the triaryl boron to metallocene is suitably in the range 0.1 to 100, preferably in the range 0.5 to 50 and most preferably in the range 1 to 5.
The concentration of the Group III metal alkyl may be most beneficial between at a minimum that is required to neutralise any harmful impurities present in the feedstock and a maximum governed level by its potential to degrade the activating effect of the aryl boron compound.
Within the above range the mole ratio of the Group III metal alkyl to the aryl boron compound is in the range from 0.01 to 300, preferably in the range 0.5 to 100 and most preferably in the range 1 to 40.
The metallocene catalyst and the cocatalyst may suitably be supported on supports which include organic and ino
Bell Mark L.
BP Chemicals Limited
Nixon & Vanderhye
Pasterczyk J.
LandOfFree
Polymerisation catalysts does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Polymerisation catalysts, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Polymerisation catalysts will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3154732