Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1998-07-15
2002-05-07
Bell, Mark L. (Department: 1755)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S125300, C526S128000
Reexamination Certificate
active
06384160
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a catalyst, a method of making said catalyst and a process for polymerizing &agr;-olefins with said catalyst. The catalyst precursor is synthesized using metal alkoxides or metal dialkyls, a halogenating agent, an electron donor compound and a titanating agent. The catalyst precursor is activated with an aluminum alkyl and is used, optionally with a stereoselectivity control agent, to polymerize &agr;-olefins, particularly propylene.
2. Description of the Related Art
Ziegler-Natta catalysts, their general methods of making, and subsequent use for polymerization of olefins, are well known in the art. However, while much is known about Ziegler-Natta catalysts, improvements in catalyst performance and in their ability to produce polyolefins having certain properties are desirable.
U.S. Pat. No. 4,472,521, issued Sep. 18, 1984 to Band, discloses a polyolefin catalyst made by contacting a Mg(OR)
2
and/or Mn(OR)
2
with titanium tetrachloride, then with a titanium tetrachloride halogenating agent, and then with an electron donor.
U.S. Pat. No. 4,673,661, issued Jun. 16, 1987, and U.S. Pat. No. 4,724,255, issued Feb. 9, 1988, both to Lofgren et al. disclose a polyolefin catalyst component made by chlorinating a magnesium alkyl which is then contacted with titanium tetrachloride, a Lewis base, and then at least once with titanium tetrachloride in the absence of a Lewis base. Lofgren et al. teach the criticality of an electron donor at the first titanium tetrachloride treatment step and further teach that away from the presence of an electron donor at subsequent titanation steps.
U.S. Pat. No. 4,855,271, issued Aug. 8, 1989, and U.S. Pat. No. 4,937,300, both to McDaniel et al. disclose a polyolefin catalyst derived from alumina impregnated with magnesium alkoxide, which is subsequently contacted with a lower order alcohol, chlorinated with silicon tetrachloride, and subsequently etched with a titanium tetrachloride.
U.S. Pat. No. 5,075,270, issued Dec. 24, 1991 to Brun et al. discloses a polyolefin catalyst made by reacting a magnesium alkoxide with an aluminosiloxane derivative, which product is then chlorinated with silicone tetrachloride, followed by transition metal treatment with titanium tetrachloride, with an electron donor optionally associated with the transition metal.
Even with these prior art methods there is another need for polyolefin catalysts having improved performance. These and other needs in the art will become apparent to those of skill in the art upon review of this patent specification.
SUMMARY OF THE INVENTION
It is one object of the present invention to provide for improved polyolefin catalysts, methods of their making, and methods of polymerizing olefins, particularly propylene.
It is another object of the present invention to provide for polyolefin catalysts having improved performance.
These and other objects of the present invention will become apparent to those of skill in the art upon review of this patent specification.
According to one embodiment of the present invention there is provided a process for preparing a polyolefin catalyst precursor. The method first includes contacting a metal alkoxide, such as magnesium ethoxide, or a metal dialkyl with a halogenating agent, such as titanium tetrachloride, to form (A) an alkoxy metal halide (or an alkyl metal halide), metal dihalide and complexes thereof. These compounds and complexes are formed in a slurry with a hydrocarbon solvent. An electron donor, such as an alkyl phthalate compound, was added and the mixture was heated. The slurry was cooled and the solid separated and washed. The solid was again treated with titanium tetrachloride in a slurry and heated. The solid was separated, washed and dried.
DETAILED DESCRIPTION OF THE INVENTION
The method of the present invention for making a catalyst component generally includes the steps of halogenating a metal alkoxide, metal dialkyl or metal alkoxyhalide, introducing an electron donor which is then followed by at least one subsequent titanation treatment.
Metal alkoxides, metal dialkyls or metal alkoxyhalides suitable for use in the present invention include any that which when utilized in the present invention will yield a suitable polyolefin catalyst. Preferred metal alkoxides, metal dialkyls and metal alkoxyhalides include those with metal from Group IIA and VIIB. Metal alkoxide, metal dialkyls and metal alkoxyhalides are preferred in that order. Most preferred is a magnesium alkoxide.
The general formula of the metal alkoxide, metal dialkyl or metal alkoxyhalide is M(OR)
2
, MR
2
M(OR)X, wherein M is any suitable metal, and R is a hydrocarbyl or substituted hydrocarbyl moiety having from 1 to 20 carbon atoms and X is a halogen. M is preferably a Group IIA and VIIB metal, most preferably magnesium; R is preferably a hydrocarbyl or substituted hydrocarbyl moiety having from 2 to 10 carbon atoms, and more preferably R is a hydrocarbyl or substituted hydrocarbyl moiety having from 2 to 6 carbon atoms, and most preferably, R has from 2 to 4 carbon atoms. X is preferably chlorine.
Examples of preferred species of metal alkoxides include magnesium ethoxide, magnesium butoxide, manganese ethoxide, and manganese butoxide. The most preferred metal alkoxide species is magnesium ethoxide. While not required, it is preferred that the magnesium alkyls be soluble in a hydrocarbon solvent. Examples of suitable magnesium dialkyls include dibutyl magnesium and butylethyl magnesium.
Halogenating agents are those compounds which can cause replacement of the alkoxide group(s) or the alkyl groups with a halogen. Halogenating agents useful in the halogenating step for halogenating the metal alkoxide, metal dialkyl or metal alkoxyhalide include any halogenating agent which when utilized in the present invention will yield a suitable polyolefin catalyst. Chlorides are the preferred halogenating agents.
Group III, Group IV and Group V halides may be employed, as may hydrogen halides, or the halogens themselves. Specific examples of preferred halogenating agents are BCl
3
, AlCl
3
, CCl
4
, SiCl
4
, TiCl
4
, ZrCl
4
, VOCl
4
, VO
2
Cl, CrO
2
Cl, SbCl
5
, POCl
2
, PCl
5
, and HfCl
4
. More preferred halogenating agents are SiCl
4
and TiCl
4
, with the most preferred halogenating agent being TiCl
4
. Other halogenating agents include alkyl halo silanes of the formula R
x
SiX
(4−x)
, wherein X is a halogen, R is a substituted or unsubstituted hydrocarbyl having 1 to 20 carbon atoms, and X is a halogen.
This initial halogenating of the metal alkoxide or metal dialkyl compound is generally conducted in a hydrocarbon solvent under an inert atmosphere. Non-limiting examples of suitable solvents include toluene, heptane, hexane, octane and the like. The preferred solvents are toluene and heptane.
In this halogenating step, the mole ratio of metal alkoxide or metal dialkyl to halogenating agent is generally in the range of about 6:1 to about 1:3, preferably in the range of about 3:1 to about 1:2, and more preferably in the range of about 2:1 to about 1:2.
This initial halogenating step is generally carried out at a temperature in the range of about 0° C. to about 100° C., a pressure in the range of about 15 psi to about 50 psi, and for a reaction time in the range of about 0.5 to about 4 hours. Preferably, the halogenating step is carried out at a temperature in the range of about 20° C. to about 90° C., a pressure in the range of about 15 psi to about 30 psi, and for a reaction time in the range of about 1 hour to about 2 hours.
Once the halogenating step is carried out and the metal alkoxide, metal dialkyl or metal alkoxyhalide is halogenated,the precipitated solid halide product is recovered by any suitable method, and washed with a hydrocarbon solvent to remove any reactants from the halogenating step.
An internal electron donor is then added to the metal halide. Internal electron donors for use in the preparation of polyolefin catalysts are well known, and any suitable internal electron d
Bauch Christopher Garland
Rauscher David John
Shamshoum Edwar Shoukri
Bell Mark L.
Fina Technology, Inc.
Jackson William D.
Pasterczyk J.
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