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
2000-06-29
2002-04-23
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...
C502S125000, C502S126000, C502S127000, C502S132000, C502S134000
Reexamination Certificate
active
06376417
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a catalyst for the polymerization of propylene and a method of using the same in the polymerization of propylene.
It is known that particle size, particle shape and particle size distribution of a catalyst have an important influence on the properties of the polymer manufactured using the catalyst. A balance of an adjustable particle size, desirable particle shape and a narrow particle size distribution of a catalyst is an attribute that all catalyst manufacturers look for. However, it is difficult to keep a good particle shape and a narrow particle size distribution of a catalyst as the size particle of the catalyst increases.
The various polymerization processes in commercial scale require corresponding size particle of the catalyst. Therefore, there is a need in the art to adjust the size of the catalyst particle.
U.S. Pat. No. 4,784,983 discloses a catalyst system for olefinic polymerization comprising components (A), (B) and (C). Component (A) is prepared by dissolving a halide of magnesium in a solvent mixture of an organic epoxy compound and an organic phosphorus compound to form a homogeneous solution; mixing the homogeneous solution with a liquid halide of titanium; adding an auxiliary precipitant such as organic carboxylic acid anhydrides, organic carboxylic acids, ethers and ketones to form a precipitate; adding at least one polycarboxylic acid ester when the precipitate appears; and separating the precipitate from the mixture and treating the separated precipitate with the halide of titanium or a mixture of the halide of titanium in an inert diluent. The activity of the catalyst system of the patent is a very high. The resultant polymer using the catalyst system has very high stereospecificity and a narrow particle size distribution.
However, the main problem with the catalyst system is that it is difficult to adjust the size particle of the catalyst. The particles with irregular shape such as needle or date core-like are formed when the catalyst particles with a large size are prepared using the method of U.S. Pat. No. 4,784,983, especially in the industrial production scale plant. The presence of the catalyst particles with irregular shape deteriorates the properties of the resultant polymer, and may block the catalyst feed or the resultant polymer discharge system.
The above U.S. patent describes that, based on per mole of the magnesium halide, the amount of epoxy compounds added in the magnesium halide solution is about 0.1-10.0 moles and the amount of organic phosphorus compounds added is about 0.1-3.0 moles, which corresponds to the molar ratio of epoxy compounds to organic phosphorus compounds being about 0.033-100 (see column 2; lines 63~68). But, in all the Examples of the specification of the patent, 0.05 mol anhydrous magnesium chloride, 75 ml toluene, 0.1 mol epoxy chloropropane and 0.03 mol tributyl phosphate are used, which corresponds to the molar ratio of epoxy chloropropane to tributyl phosphate being 3.3.
The inventors have found that the use of the large amount of the organic epoxy compounds is the main cause for the formation of the catalyst particles with irregular shape, and the size particle of the catalyst can be adjusted by changing the amount of the inert diluent added to the solvent mixture or system for dissolving the halide of magnesium at a low ratio of the organic epoxy compound to the organic phosphorus compound.
Therefore, the particle shape, particle size and particle size distribution of the catalyst for the polymerization of propylene can be controlled by adjusting the ratio of the organic epoxy compounds to the organic phosphorus compounds and the amount of the inert diluent used. Based on such recognition, the invention has been completed.
SUMMARY OF THE INVENTION
The present invention provides a catalyst for the polymerization of propylene comprising the following components:
(A) A solid catalyst component prepared by dissolving a halide of magnesium in a solvent system consisting of an organic epoxy compound, an organic phosphorus compound and an inert diluent to form a homogeneous solution; mixing the homogeneous solution with a halide of titanium to form a mixture; precipitating a solid from the mixture in the presence of an auxiliary precipitant; treating the solid with a polycarboxylic acid ester to load the ester on the solid; and treating the ester loaded solid with the halide of titanium and the inert diluent,
Wherein said auxiliary precipitant is selected from organic anhydrides, organic acids, ethers and ketones, and wherein based on per mole of the halide of magnesium, the amount of the organic epoxy compound is from 0.2 to 5 moles, and the molar ratio of the organic compound to the organic phosphorus compound is from 0.5 to 1.6;
(B) An organic aluminium compound having the formula AlR
n
X
3-n
wherein each R is independently hydrogen or a hydrocarbyl group having 1-20 carbon atoms, X is a halogen, and n is a number of from 1 to 3;
(C) An organic silicon compound having the formula R
n
Si(OR′)
4-n
wherein R and R′ each is independently selected from alkyl, cycloalkyl, aryl and haloalkyl and n is an integer of from 0 to 3;
Wherein the ratio of component (B) to component (A) is, measured as the molar ratio of aluminium to titanium, from 5 to 1000, and the ratio of component (C) to component (A) is, measured as the molar ratio of silicon to titanium, from 2 to 100
The present invention also provides a method of using the catalyst in the polymerization of propylene.
DETAILED DESCRIPTION OF THE INVENTION
In a preferred embodiment, solid catalyst component (A) is prepared by the following method. A halide of magnesium is first dissolved in a solvent system consisting of an organic epoxy compound, an organic phosphorus compound and an inert diluent at a temperature of from 0 to 100° C., preferably from 30 to 70° C. with stirring to form a homogenous solution. The homogenous solution is then mixed with a halide of titanium at a temperature of from −35 to 60° C., preferably from −30 to 5° C. in the presence of an auxiliary precipitant to form a mixture. A polycarboxylic acid ester is added to the mixture after or before a solid is precipitated to load at least part of the ester on the solid. The temperature of the resultant mixture is raised to 60~110° C. to form a suspension, the suspension is stirred at that temperature for from 10 minutes to 10 hours, then a solid is precipitated from the suspension. After separation, the separated solid is treated with the halide of titanium and the inert diluent, is then washed with toluene and hexane to obtain a solid catalyst component (A).
Suitable halide of magnesium includes magnesium halide such as magnesium chloride, magnesium bromide and magnesium iodide; a complex of magnesium halide with water or alcohol; a derivative of magnesium halide wherein a halogen atom is substituted by a hydrocarboxyl or halohydrocarboxyl group; and like.
Suitable organic epoxy compound includes oxides of aliphatic olefins, aliphatic diolefins, halogenated aliphatic olefins, and halogenated aliphatic diolefins, glycidyl ethers, cyclic ethers and the like having 2-8 carbon atoms. Examples of suitable organic epoxy compounds are ethylene oxide, propylene oxide, butylene oxide, butadiene dioxide, epoxy chloropropane, methylglycidyl ether, diglycidyl ether, tetrahydrofuran, and the like.
Suitable organic phosphorus compound includes hydrocarbyl esters of phosphoric acid or phosphorus acid, e.g. trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, trimethyl phosphite, triethyl phosphite, tributyl phosphite, triphenyl phosphite and the like.
Suitable insert diluent includes hexane, hepane, octane, benzene, toluene, xylene, 1,2-dichloroethane, chlorobenzene and other hydrocarbons or halohydrocarbons.
The amounts of the components of the halide of magnesium solution are as follow: based on per mole of the halide of magnesium, the amount of the organic epoxy compound is from 0.2 to 5 moles, prefe
Li Zhulan
Mao Bingquan
Song Wenbo
Yang Aichun
Yang Huiru
Bell Mark L.
China Petro Chemical Corp.
Pasterczyk J.
Shanks & Herbert
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