Aluminum-phosphinimine complexes as catalysts for the...

Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Organic compound containing

Reexamination Certificate

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C502S167000, C526S139000, C526S141000, C556S013000, C556S014000, C556S027000, C556S170000, C556S174000, C556S176000

Reexamination Certificate

active

06239061

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to the catalytic polymerization of ethylene using an aluminum-phosphinimine catalyst component.
BACKGROUND OF THE INVENTION
The use of transition metals, especially chromium or Group 4/5 metals such as titanium, zirconium and hafnium as catalysts in the polymerization of ethylene is well known. These polymerization reactions may use simple aluminum alkyls of the general formula ALR
3
as cocatalysts.
U.S. Pat. No. 5,777,120 (Jordan et al) discloses aluminum-amidinate complexes which catalyzes the polymerization of ethylene in the absence of transition metals.
We have now discovered an aluminum-phosphinimine complex which may be used to catalyze the polymerization of ethylene in the absence of transition metals.
SUMMARY OF THE INVENTION
In one embodiment, this invention provides a catalyst component for ethylene polymerization comprising an aluminum complex which is characterized by containing a phosphinimine ligand.
In another embodiment, this invention provides a process for the (co)polymerization of ethylene and at least one additional alpha olefin having from 3 to 20 carbon atoms wherein said process comprises the catalytic (co)polymerization of said ethylene and said at least one additional alpha olefin in the presence of a catalyst system comprising:
1) an aluminum complex which is characterized by containing a phosphinimine ligand; and
2) an activator.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
1.1 Description of Catalyst Components
Aluminum is a member of the Group 13 (also known as Group IIIA) elements. The group 13 elements are trivalent and are, by convention, described by the general formula “ML
3
” wherein M is the metal and L is a ligand. However, as will be appreciated by those skilled in the art, such ML
3
compounds may “behave as Lewis acids and can accept either neutral donor molecules or anions to give tetrahedral species”; and “react with themselves to form dimeric molecules” (see, for example, Advanced Inorganic Chemistry, fifth edition, edited by Cotton and Wilkinson, ISBN 0-471-84997-9, p. 209). Thus, even though aluminum compounds form dimers and adducts with neutral donors, these compounds are conventionally referred to by the “ML
3
” formula.
We have used the ML
3
convention in this specification to describe the catalyst components of this invention. As noted above, this convention is intended to be inclusive of dimers and oligomers and/or adducts with neutral donor molecules.
Thus, the present catalyst components may be conveniently described by the formula:
Al(Pl)X
2
wherein Pl is a phosphinimine ligand (as described in section 1.2 below) and each X is an activatable ligand (as described in section 1.3 below).
1.2 Phosphinimine Ligand
The catalyst component must contain a phosphinimine ligand which is covalently bonded to the metal. These phosphinimine ligands are characterized by containing a nitrogen which is bonded to the aluminum by a single covalent bond and a phosphorus (V) atom which is doubly bonded to this nitrogen atom. Preferred phosphinimine ligands are defined by the formula:
wherein each R
1
is independently selected from the group consisting of a hydrogen atom, a halogen atom, C
1-20
hydrocarbyl radicals which are unsubstituted by or further substituted by a halogen atom, a C
1-8
alkoxy radical, a C
6-10
aryl or aryloxy radical, an amido radical, a silyl radical of the formula:
—Si—(R
2
)
3
wherein each R
2
is independently selected from the group consisting of hydrogen, a C
1-8
alkyl or alkoxy radical, C
6-10
aryl or aryloxy radicals, and a germanyl radical of the formula:
Ge—(R
2
)
3
wherein R
2
is as defined above.
Preferred phosphinimines are those in which each R
1
is a hydrocarbyl radical (especially a hydrocarbyl radical having from 1 to 20 carbon atoms). A particularly preferred phosphinimine is tri-(tertiary butyl)phosphinimine (i.e. where each R
1
is a tertiary butyl group).
1.3 Activatable Ligand
The term “activatable ligand”, X, refers to a ligand which reacts with an “activator” to facilitate olefin polymerization. Activators are described in section 2 below.
Exemplary activatable ligands are independently selected from the group consisting of a hydrogen atom, a halogen atom, a C
1-10
hydrocarbyl radical, a C
1-10
alkoxy radical, a C
5-10
aryl oxide radical; each of which said hydrocarbyl, alkoxy, and aryl oxide radicals may be unsubstituted by or further substituted by a halogen atom, a C
1-8
alkyl radical, a C
1-8
alkoxy radical, a C
6-10
aryl or aryl oxy radical, an amido radical which is unsubstituted or substituted by up to two C
1-8
alkyl radicals; a phosphido radical which is unsubstituted or substituted by up to two C
1-8
alkyl radicals. Preferred activatable ligands are C
1-10
hydrocarbyls, especially methyl.
1.4 Preparation of Al(Pl)X
2
The preferred preparation of Al(Pl)X
2
is by the reaction of a trialkyl aluminum (especially trimethyl aluminum) with a hydrido-phosphinimine (i.e. HN═PR
3
). The reaction is assisted by heating. The reaction is convenient and facile, as illustrated in the Examples. Moreover, the reaction may be undertaken in-situ (i.e. in the polymerization reactor). The in-situ reaction may employ a trivalent aluminum precursor (such as a trialkyl aluminum—especially TMA, as shown in example 2) or an alumoxane (as shown in example 1) and a hydrido-phosphinimine.
2.0 Activators
Alumoxanes and so-called “ionic activators” are preferred, as described below.
The alumoxane activator may be of the formula:
(R
4
)
2
AlO(R
4
AlO)
m
Al(R
4
)
2
wherein each R
4
is independently selected from the group consisting of C
1-20
hydrocarbyl radicals and m is from 0 to 50, preferably R
4
is a C
1-4
alkyl radical and m is from 5 to 30. Methylalumoxane (or “MAO”) is the preferred alumoxane.
Alumoxanes are well known as activators for metallocene-type catalysts and are widely described in the academic and patent literature.
Activation with alumoxane generally requires a molar ratio of aluminum in the activator to aluminum in the catalyst component Al(Pl)X
2
from 20:1 to 1000:1. Preferred ratios are from 50:1 to 250:1.
2.1 Ionic Activators
Ionic activators are also well known for metallocene catalysts. See, for example, U.S. Pat. No. 5,198,401 (Hlatky and Turner). These compounds may be selected from the group consisting of:
(i) compounds of the formula [R
5
]
+
[B(R
7
)
4
]

wherein B is a boron atom, R
5
is a cyclic C
5-7
aromatic cation or a triphenyl methyl cation and each R
7
is independently selected from the group consisting of phenyl radicals which are unsubstituted or substituted with from 3 to 5 substituents selected from the group consisting of a fluorine atom, a C
1-4
alkyl or alkoxy radical which is unsubstituted or substituted by a fluorine atom; and a silyl radical of the formula —Si—(R
2
)
3
; wherein each R
2
is independently selected from the group consisting of a hydrogen atom and a C
1-4
alkyl radical; and
(ii) compounds of the formula [(R
8
)
t
ZH]
+
[B(R
7
)
4]

wherein B is a boron atom, H is a hydrogen atom, Z is a nitrogen atom or phosphorus atom, t is 2 or 3 and R
8
is selected from the group consisting of C
1-8
alkyl radicals, a phenyl radical which is unsubstituted or substituted by up to three C
1-4
alkyl radicals, or one R
8
taken together with the nitrogen atom may form an anilinium radical and R
7
is as defined above; and
(iii) compounds of the formula B(R
7
)
3
wherein R
7
is as defined above.
In the above compounds preferably R
7
is a pentafluorophenyl radical, and R
5
is a triphenylmethyl cation, Z is a nitrogen atom and R
8
is a C
1-4
alkyl radical or R
8
taken together with the nitrogen atom forms an anilium radical which is substituted by two C
1-4
alkyl radicals.
The “ionic activator” may abstract one or more activatable ligands so as to ionize the catalyst center into a cation but not to covalently bond with the catalyst and to provide sufficient distance between the catalyst and the ionizing activator to permit

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