Heterogeneous catalyst components for olefins...

Details Heterogeneous catalyst components for olefins... Heterogeneous catalyst components for olefins...

1998-01-30

2001-08-21

Gupta, Yogendra (Department: 1751)

Organic compounds -- part of the class 532-570 series

Organic compounds

Heavy metal containing

C556S051000, C556S057000, C556S042000, C556S081000, C556S400000, C556S465000, C502S104000, C502S129000, C502S227000, C502S236000, C502S242000

Reexamination Certificate

active

06278009

ABSTRACT:

STATE OF THE ART PRIOR TO THE INVENTION
It is well known that metallocene compounds such as bis(cyclopentadienyl)titanium dialkyl or bis(cyclopentadienyl)zirconium dialkyl in combination with alkyl aluminiums act as catalysts for olefin polymerization in homogeneous phase. Thus, German patent DE-2,608,863 describes the use of bis(cyclopentadienyl)titanium dialkyl in combination with trialkylaluminium and a controlled quantity of water in olefins polymerization.
The controlled hydrolysis of alkyl aluminiums gives rise to the formation of species containing an Al—O bond (aluminoxane) which are real co-catalysts in the polymerization of olefins with metallocenes. Kaminsky (Adv. Organomet. Chem. 1980, 18, 99) shows that aluminoxanes in combination with dichlorometallocenes produce catalyst systems which are very active in ethylene polymerization.
It is also possible (Turner, EP 277004 and Ewen et al. EP 426637) to use co-catalysts formed by bulky boron compounds which, acting as non-coordinative anions, stabilize the cationic form of the metallocene without preventing the incorporation of the olefin in the polymerization process.
The polymerization processes that use homogeneous catalyst systems produce high polymerization activities. However, most industrial processes require heterogenous catalyst systems which on the one hand produce polymers with a controlled morphology, but on the other hand have an activity of the order of the homogeneous systems.
In European patent EP 206794 it is described heterogeneous catalysts obtained through simultaneous or subsequent (in any order) addition of aluminoxane and metallocene onto an inorganic support.
This process, according to patent EP 260130, can also be applied to multicomponent systems. These catalysts are those which contain various metallocenes or one metallocene and one non-metallocene compound of a transition element. In this way, polyolefins with a multimodal molecular weight distribution are obtained.
In patents EP 361866, EP 323716, EP 367503, EP 368644 and U.S. Pat. No. 5,057,475 it is described the preparation of a heterogeneous catalyst system composed by one aluminoxane and one metallocene characterized in that the aluminoxane is generated “in situ” through reaction of a trialkylaluminium with undehydrated silica. The use of this catalyst system in &agr;-olefins polymerization gives rise to high activities.
Another well known technique used in the preparation of heterogeneous catalyst is the chemical modification of the inorganic support. In patents EP 474391 and EP 314797 it is described a process wherein the support, before the addition of the metallocene, is treated with an organoaluminium compound which reacts with hydroxyl groups present in the silica surface.
The above described catalyst systems present the drawback that the catalyst is not tightly enough bonded to the support so that the separation of the metallocene from the support can occur, producing polymerization in solution, which prejudices the emorphology of the obtained polymer.
As a consequence of that, methods for obtaining the formation of a chemical bond between the support and the metallocene are looked for. A possible solution is the formation of a chemical bond by reacting a functionalized metallocene and a partly dehydrated silica. In patents EP 293815 and DE 3718888 it is described a method for the preparation of a supported catalyst wherein the chemical bond between the support and the metallocene is obtained by reacting an alkoxysilane group united to the metallocene and an hydroxy group of the support. The synthesis of this catalyst is difficult and very low yields are obtained. Furthermore, the activity in the polymerization of the olefins of the resulting catalysts is rather low.
Patent DE 3840772 describes the use of metallocenes functionalized with vinyl groups united to the cyclopentadienyl ring. Heterogeneous systems are obtained by reacting the double bond with polysiloxanes in the presence of a fit catalyst. This method presents the drawback of needing an additional purification process for removing this catalyst.
According to patent EP 628566, it is possible to prepare heterogeneous catalysts by reacting ligands already chemically bonded to the support first with alkyllithium and then with metal halides MX
r
(wherein M is a transition metal and X is a halide). This process produces catalysts with the metallocene tightly bonded to the support. They are used in olefins polymerization in combination with alumoxanes. Also in this case it is necessary a purification of the catalyst system to eliminate the residues of the reagents used in its formation.
EP-A-757053 discloses new metallocenes characterized by the following general formula:
X
m
M(L—M
2
(R
1
R
2
)—A—ZR
3
o
Hal
p
)
n
, wherein M is a metal of group 4, 5 or 6 of the periodic table, each X is independently selected from hydrogen, halogen or a C
1
-C
40
carbon-containing rest; me is equal to 1, 2 or 3; n is equal to 1 or 2; each L is independently a Π ligand, which coordinates to the central atom M; each M
2
is independently selected from silicon, germanium or tin; R
1
is a C
1
-C
20
carbon-containing group; R
2
is a C
1
-C
20
carbon-containing group of a Π ligand, which coordinates to the central atom M; each A is independently a divalent C
1
-C
40
carbon-containing rest; each Z is independently selected from boron, silicon, germanium or tin; each R
3
is independently selected from hydrogen or a C
1
-C
20
carbon -containing rest; o is equal to 0, 1 or 2; each Hal is independently selected from a halogen atom; p is equal to 1, 2 or 3.
These compounds are characterized by the presence of a hydrocarbon bridge connecting two silicon, germanium or tin atoms to whom the halogen atom is connected. This characteristic makes them especially suitable in the preparation of supported catalysts.
An object of the present invention is to provide new catalyst component comprising a bridged metallocene having a Si—Cl functional group bonded to bridge. The compounds can be supported on silica.
DESCRIPTION OF THE INVENTION
In this invention it is described organo metallic compounds of transition of groups 3, 4, 5 or 6 of the periodic table of the metallocene-type. Besides, the compounds of the present invention are characterized in that they have at least one link or bridge between the cyclopentadienyl type unities. The bridge is characterized in that it shows at least one functionality, either include in the bridge or bonded to it, this being a Si—Y, Ge—Y or Sn—Y-type unity, preferably Si—Y, Y being halogen; preferably Y is chlorine or bromine.
In the present invention it is described the synthesis of these metallocenes as well as methods for supporting these compounds onto solids. The invention refers in general to metallocenes represented by the following formula (Formula 1)
Wherein:
Y is halogen;
M is a transition metal of groups 3-6 of the periodic table;
each L is selected from a cyclopentadienyl-type unity, including indenyl or fluorenyl, substituted or not and the substituents being equal or different, united to M through a &pgr; bond; Z is a group that forms a union bridge between the two unities L, which can have between 0 and 20 carbon atoms and between 0 and 5 oxygen, sulfur, nitrogen, phosphorus, silicon, germanium, tin or boron atoms;
E is a spacer group that unites Z and Y and can have between 0 and 20 carbon atoms and between 0 and 5 oxygen; sulfur, nitrogen, phosphorus, silicon, germanium, tin or boron atoms. It is characterized for having in its skeleton at least one silicon, germanium or tin atom, which the substituent Y is united to;
o is a number of value 0 or 1;
k is a number of value 1,2 or 3;
m is a number equal to or higher than 2 and coinciding with the oxidation state of the transition metal;
j is a number of value 0 or 1 with the condition that its value is 1 at least once; when j is 1 and o is 0, Z is characterized by having at least one silicon, germanium or tin atom which Y is directly united to;
with the proviso that the compound does not have genera

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