Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Organic compound containing
Reexamination Certificate
2000-02-23
2002-07-09
Bell, Mark L. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Organic compound containing
C502S172000, C502S103000, C502S226000, C568S851000
Reexamination Certificate
active
06417132
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a process for preparing a carrier used in olefin polymerization catalysts, and more particularly, to a process for preparing a carrier used in Ziegler-Natta high-efficiency solid catalyst component.
BACKGROUND OF THE INVENTION
It is well known that high-efficiency supported catalysts for polymerizing olefins are prepared by using inorganic materials such as magnesium chloride and the like as the carrier and supporting a transition metal compound onto it, and that the properties of the carrier are very important. In early stages, magnesium chloride carriers were mainly prepared by employing a grinding method, which is disadvantageous in that the resultant catalysts have a poor particle morphology and thus the polymers produced by employing such catalysts also have a poor particle morphology, more fine powders and a low apparent density.
Later on, it is proposed to prepare a carrier by employing a chemical method wherein a magnesium compound is dissolved certain solvents and is then precipitated to obtain the carrier having a uniform particle size distribution. For example, Chinese Patent Application Publication No. CN1085569A discloses a process for preparing a titanium catalyst, wherein a magnesium halide is contacted with an alcohol having at least 6 carbon atoms in a hydrocarbon solvent to form a magnesium solution, and is then reacted with an organoaluminium compound to form a solid magnesium-aluminium complex. The solid magnesium-aluminium compolex is suspended in a hydrocarbon solvent and then to the resulting suspension is added a tetravalent titanium compound to form a solid titanium catalyst suitable for polymerizing ethylene.
Now many attempts have been made to further develop supported catalysts having a controllable morphology. By employing such catalysts, it is possible to prepare polymers having a particle morphology similar to that of the catalysts and having high flowability, thus simplifying the procedures involving the preparation and/or post-treatment of the resulting polymers.
U.S. Pat. No. 4,399,054 discloses solid catalyst components for the polymerization of propylene, having a particle size of 1 to 100 microns. The carrier used for the components is an adduct having the formula MgX
2
.nED, wherein X is a halogen, n is a number from 1 to 3 and ED is an electron-donor compound containing active hydrogen atoms such as ethanol and the like. Said carrier is prepared by passing a homogeneous emulsion of the molten adduct through a pipe under turbulent conditions and quenching the emulsion to partially dealcoholize.
Chinese Patent Application Publication Nos. CN1089622A and CN1047302A also empoly an adduct of a magnesium halide with an alcohol as the carrier for solid catalyst components. The adduct is prepared by adding an alcohol to a magnesium halide in the presence of an inert hydrocarbon solvent to form a solution and has a higher content of alcohol, for example larger than 3 moles, and then the carrier for catalyst components is obtained by removing some of the alcohol from the adduct. The alcohol is removed usually by heating or chemical treatment, and the removal of alcohol by chemical treatment is conducted by adding sufficient amounts of a dealcoholizing agent to react with OH groups contained in the adduct. The dealcoholizing agent is usually selected from consisting of the group of alkyl aluminium such as triethyl aluminium and triisobutyl aluminium, silicon halides and tin halides.
The object of the present invention is to provide a process for preparing a carrier used in olefin polymerization catalysts, which is simple and by which the resultant carrier has a narrow particle size distribution, while the solid catalyst components prepared from the carrier have high catalytic activity.
SUMMARY OF THE INVENTION
The present invention in its one aspect provides a process for preparing a carrier used in olefin polymerization catalysts, comprising suspending anhydrous magnesium chloride in an inert hydrocarbon solvent and then under stirring, activating the magnesium chloride with a C
2
-C
8
alcohol at a temperature of 30° C. to 200° C., preferably 60° C. to 150° C., for 0.3 to 5.0 hours, with the molar ratio of said alcohol to said magnesium chloride being in the range of 0.05 to 2.5, preferably 0.1 to 1.0.
The present invention in its another aspect provides a process for preparing a carrier used in olefin polymerization catalysts, comprising suspending anhydrous magnesium chloride in an inert hydrocarbon solvent, pre-dispersing the magnesium chloride with a dispersing agent, with the molar ratio of said dispersing agent to said magnesium chloride is 0.01 to 2.0, and then under stirring, activating the magnesium chloride with a C
2
-C
8
alcohol at a temperature of 30° C. to 200° C., preferably 60° C. to 150° C., for 0.3 to 5.0 hours, with the molar ratio of said alcohol to said magnesium chloride being in the range of 0.05 to 2.5, preferably 0.1 to 1.0.
DETAILED DESCRIPTION OF THE INVENTION
The C
2
-C
8
alcohol used in the processes of the present invention can be ethanol, propanol, isopropanol, butanol, hexanol, octanol or the mixtures thereof, more preferably ethanol, isopropanol or butanol.
The inert hydrocarbon solvent used in the processes of the present invention can be C
5
-C
15
alkanes or C
6
-C
8
aromatic hydrocarbons, preferably C
5
-C
12
alkanes, more preferably hexane, decane, heptane or octane. The weight ratio of the inert hydrocarbon solvent to anhydrous magnesium chloride is from 5 to 200, preferably from 20 to 100.
Upon activation, the stirring rate is controlled to be 30 to 3000 rpm, preferably 30 to 1000 rpm, most preferably 30 to 600 rpm.
The amount of C
2
-C
8
alcohol used for activating the magnesium chloride in the processes of the present invention should be strictly controlled so that the molar ratio of alcohol/magnesium is in the range of 0.05 to 2.5. When the molar ratio of alcohol/magnesium is larger than 2.5, the magnesium chloride suspension will become too viscous and thus the carrier having a good particle morphology and a uniform particle size distribution can not be obtained; and when the molar ratio of alcohol/magnesium is less than 0.05, the resultant solid catalyst component will have very low activity.
In addition, the particle morphology and particle size distribution of the carrier produced by the processes of the present invention are closely related to the types and amounts of the alcohol used for activating. When ethanol is used for activating, the magnesium chloride suspension will become too viscous in the case of the molar ratio of alcohol/magnesium larger than 2.0 and thus a carrier having a uniform particle size distribution can not be obtained; and when butanol is used for activating, the magnesium chloride suspension will become too viscous in the case of the molar ratio of alcohol/magnesium larger than 1.0 and thus a carrier having a uniform particle size distribution can not be obtained.
Prior to activation by C
2
-C
8
alcohol, anhydrous magnesium chloride may be preferably pre-dispersed by a dispersing agent, so as to avoid the adherence of the carrier during the preparation (which influences the particle morphology and the particle size distribution of the resultant carrier) and to obtain solid catalyst components having higher catalytic activity from the carrier. The conditions for pre-dispersing, such as temperature and the stirring rate, can be same as those in the activation step, and the molar ratio of the dispersing agent to anhydrous magnesium chloride is controlled to be in the range of 0.01 to 2.0. When the molar ratio of the dispersing agent to the magnesium chloride is larger than 2.0, the magnesium chloride will become dissolved or a colloid will be formed, which influences the particle morphology and the particle size distribution of the resultant carrier. The dispersing agent used for pre-dispersing can be selected from the group consisting of alkoxides of titanium having the formula Ti(OR)
4
, wherein R is C
2
-C
6
alky
Hong Xiaoyu
Jing Zhenhua
Rong Junfeng
Zhang Wei
Bell Mark L.
China Peirochemical Corporation
Ladas & Parry
Pasterczyk J.
LandOfFree
Process for preparing a carrier used in olefin... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for preparing a carrier used in olefin..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for preparing a carrier used in olefin... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2908893