Bis-phosphinimine catalyst

Details Bis-phosphinimine catalyst Bis-phosphinimine catalyst

2001-01-03

2003-11-18

Choi, Ling-Siu (Department: 1713)

Catalyst, solid sorbent, or support therefor: product or process

Catalyst or precursor therefor

Organic compound containing

C502S117000, C502S103000, C526S161000, C526S172000, C526S169000, C526S901000

Reexamination Certificate

active

06649558

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to an olefin polymerization catalyst component which is an organometallic complex having two phosphinimine ligands and at least one activatable ligand. The catalyst component is further characterized by the absence of any cyclopentadienyl ligand.
BACKGROUND OF THE INVENTION
Certain “metallocenes” (especially bis-cyclopentadienyl complexes of group 4 metals) are highly productive catalysts for olefin polymerization when used in combination with an appropriate activator (see, for example, U.S. Pat. No. (“USP”) 4,542,199 (Sinn et al) and U.S. Pat. No. 5,198,401 (Hlatky and Turner).
Olefin polymerization catalysts having one cyclopentadienyl ligand and one phosphinimine ligand are disclosed in a commonly assigned patent application (Stephan et al).
We have now discovered a family of highly active olefin polymerization catalysts which do not contain a cyclopentadienyl ligand.
SUMMARY OF THE INVENTION
The present invention provides a catalyst component for olefin polymerization which is an unbridged bis-phosphinimine complex defined by the formula:
(Pl)
2
—M—L
n
wherein M is a metal selected from group 3-10 metals; each Pl is independently a phosphinimine ligand defined by the formula:
wherein each R
1
is independently selected from the group consisting of (a) a hydrogen atom, (b) a halogen atom, (c) C
1-20
hydrocarbyl radicals which are unsubstituted by or further substituted by a halogen atom, (d) a C
1-4 8
alkoxy radical, (e) a C
6-10
aryl or aryloxy radical, (f) an amido radical (which may be substituted), (g) 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 (h) a germanyl radical of the formula:
Ge—(R
2
)
3
wherein R
2
is as defined above; L is an activatable ligand; n is 1, 2 or 3 depending upon the valence of M with the proviso that L is not a cyclopentadienyl, indenyl or fluorenyl ligand.
DETAILED DESCRIPTION
1. Description of Catalyst Component
The catalyst component of this invention is unbridged. The term “unbridged” is meant to convey its conventional meaning, namely that there is not a bridging group which connects the phosphinimine ligands with formal bonds. (By contrast, many metallocene catalysts having two cyclopentadienyl-type ligands are “bridged” with, for example, a dimethyl silyl “bridge” in which the silicon atom is formally bonded to both of the cyclopentadienyl ligands). “Unbridged” catalyst components are typically less expensive to synthesize than the corresponding bridged analogues.
1.1 Metals
The catalyst component of this invention is an organometallic complex of a group 3, 4, 5, 6, 7, 8, 9 or 10 metal (where the numbers refer to columns in the Periodic Table of the Elements using IUPAC nomenclature). The preferred metals are selected from groups 4 and 5, especially titanium, hafnium, zirconium or vanadium.
1.2 Phosphinimine Ligand
The catalyst component of this invention must contain a phosphinimine ligand which is covalently bonded to the metal. This ligand is 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.
The preferred phosphinimines are those in which each R
1
is a hydrocarbyl radical. 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” refers to a ligand which may be activated by a cocatalyst (also known as an “activator”) to facilitate olefin polymerization. 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.
The activatable ligands must not be cyclopentadienyl ligands (or related ligands such as indenyl or fluorenyl).
The number of activatable ligands depends upon the valency of the metal and the valency of the activatable ligand. The preferred catalyst metals are group 4 metals in their highest oxidation state (i.e. 4
+
) and the preferred activatable ligands are monoanionic. Thus, the preferred catalyst components contain two phosphinimine ligands and two (monoanionic) activatable ligands bonded to the group 4 metal. In some instances, the metal of the catalyst component may not be in the highest oxidation state. For example, a titanium (III) component would contain only one activatable ligand.
2. Description of Activators (or “Cocatalysts”)
The catalyst components described in part 1 above are used in combination with an “activator” (which may also be referred to by a person skilled in the art as a “cocatalyst”) to form an active catalyst system for olefin polymerization. Simple aluminum alkyls and alkoxides may provide comparatively weak cocatalytic activity under certain mild polymerization conditions. However, the preferred activators are alumoxanes and so-called ionic activators, as described below.
2.1 Alumoxanes
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.
Activation with alumoxane generally requires a molar ratio of aluminum in the activator to (group 4) metal in the catalyst from 20:1 to 1000:1. Preferred ratios are from 50:1 to 250:1.
2.2 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
9
)
3
; wherein each R
9
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 radi

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