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
1999-03-16
2003-09-09
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...
C502S111000, C502S121000, C502S125000, C502S129000, C502S126000
Reexamination Certificate
active
06617278
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a catalyst system and a process of preparing the same and uses of the same in ethylene polymerization and copolymerization processes.
Great efforts have been made in increasing the activity of ethylene polymerization catalysts and improving the properties of the product polymer and the production. Since 1970's, Mitsui Petrochemical Industries, Ltd. and others have successfully developed varieties of magnesium chloride-supported Ti-Mg high active catalyst and led to a great development in the slurry polymerization technical field in world-wide. For example, JP 49-51378 discloses representative processes for ethylene polymerization and copolymerization. The catalyst used in these processes was prepared by the steps comprising mixing a grinded magnesium dichloride with ethanol in a lamp oil medium to form a MgCl
2
.6C
2
H
5
OH slurry and then adding diethyl aluminum chloride to consume most of ethanol through an esterification followed by the addition of titanium tetrachloride to obtain an Ti-Mg high active catalyst. The preparation technique of the catalyst was uncomplicated. The reaction conditions were not severe. And the operations were facilitated. However, several obvious disadvantages of this catalyst gradually appeared in the later practice. First, due to a large polarity difference between the solvents alcohols and alkanes used therein, it is difficult for the solvents to dissolve magnesium halide. In such a case, magnesium halide can not be dissolved completely to form homogeneous solution, even heated to higher temperature (e.g. above 100° C.), but only a fine-grained colloidal suspension or a swelled magnesium halide slurry was formed. So the Catalyst thus prepared appeared some defects imparted by the characteristics of magnesium halide lamellar crystal, for example, the resultant polymer particles exhibit relatively low apparent density, poor particle morphology and poor particle size distribution.
CN 8510097.2 disclosed a catalyst system for olefine polymerization and copolymerization, and the catalyst system comprises (A) titanium-containing solid catalyst component, (B) alkyl aluminum compounds, and (C) organic silicon, wherein component (A) as a solid substance is obtained by dissolving magnesium halide into organic epoxy compounds and organic phosphorus compounds to form a homogeneous solution, then mixing with titanium tetrahalide or its derivatives, and in the presence of copreciptator such as organic anhydrides, organic acids, ethers, ketones and the like to precipitate a solid followed by treating with polycarboxylic ester to cause it to be supported onto the solid, and finally treating with titanium tetrachloride and inert diluent. The mixed solvent system used in the catalyst consisting of chlorine-containing epoxy compounds, organic phosphorus compounds and toluene was used to dissolve magnesium halide in place of alcohol and alkane solvent system. Owing to the similar polarity of those components discribed above, magnesium halide can be completely dissolved at a lower temperature (e.g. 50° C.) and a homogeneous solution was formed. The defects related to the characteristics of magnesium halide lamellar crystal can be overcome, especially the apparent density, regularity and particle morphology etc. are remarkaly improved. When the catalyst system is used in propene polymerization, the catalyst system exhibits higher activity, and the resultant polymer exhibits high regularity and its particles has larger apparent denisity. However, when used in ethylene polymerization, the catalyst appears a disadvantage of low activity yet. For example, as desclosed in example 24, under the conditions of the temperature 85° C., hydrogen pressure 0.25 MPa, ethylene pressure 0.75 MPa and ethylene polymerization for 2 hours, the polymerization activity of said catalyst is 537 kg PE/g Ti (10.7 kgPE/g Cat.), and the catalyst is not sufficiently sensitive to the molecular wight modification by using hydrogen as regulator (hydrogen modification). Owing to the defects described above, it is difficult to use the catalyst in industrial-scale.
SUMMARY OF THE INVENTION
The present invention provides a catalyst system suitable for use in ethylene polymerization and copolymerization and the process of preparing the same so as to overcome the disadvantages in the prior art. The present catalyst system for use in ethylene polymerization and copolymerization is prepared by dissolving an electron-donor activator in a solution of magnesium halide in a solvent system consisting essentially of organic epoxy compounds and organic phosphorus compounds to form a homogeneous solution, and then mixing with at least one coprecipitator and a transition metal titanium halide or its derivative to form a solid component, followed by incorporating in combination with an organic aluminum component prior to use in polymerizations. The preparation procedure of the catalyst system is uncomplicated. The catalyst exhibits high activity as being used in ethylene polymerization and the resultant polymer has better particle morphology and high apparent density, and with only small amount of low molecular weight byproduct being formed.
The catalyst system of the present invention for use in ethylene polymerization or copolymerization comprises components A and B. Said component A is a titanium-containing solid catalyst component obtained by dissolving an electron-donor activator into a solution of magnesium halide in a solvent system consisting essentially of organic epoxy compounds and organic phosphorus compounds to form a homogeneous solution and then mixing with at least one coprecipitator and transition metal titanium halide or its derivative. The electron-donor activator is at least one of organic alcohols, organic ethers and/or mixtures thereof; and the coprecipitator is selected from organic anhydrides, organic acids, ethers, and/or ketones. Said component B is an organic aluminum compound. The molar ratio of Al of component B to Ti of component A is from 5 to 1000.
The present invention further provides a process for preparing the catalyst system, particularly a process for preparing component (A) of the catalyst system.
The present invention also provides a method of using the catalyst system in ethylene polymerization.
The catalyst system of the present invention for use in ethylene polymerization comprises components (A) and (B) and optionally a metal halide adjusting agent.
Component (A) is a solid prepared by the following method:
Magnesium halide is first dissolved in a solvent system consisting essentially of organic epoxy compounds and organic phosphorus compounds, followed by mixing with an electron-donor activator to form a homogeneous clear solution. Then a coprecipitator such as organic anhydrides, organic acids, ethers, ketones and the like is added into the resultant solution, followed by mixing with trasition metal titanium halide or its derivative to from precipitate. Then the precipitate solids are filtered out, followed by washing with toluene and hexane to obtain a titanium-containing solid catalyst component (A).
Component (B) is an organic aluminum compound.
A metal halide adjusting agent is optionally used during the period of preparing component (A). Said metal halide adjusting agent is selected from a halide of Bi, Zn, Pb, Ca, Hg, V, Fe, Co and Sr or a mixture thereof.
DETAILED DESCRIPTION OF THE INVENTION
1. Preparation of the magnesium halide solution
The magnesium halide solution is a homogeneous solution obtained by dissolving a magnesium halide in a solvent system consisting essentially of organic epoxy compounds and organic phosphorus compounds with or without other inert diluents, then adding an electron-donor activator to the solvent system.
Said magnesium halide of component (A) according to the present invention includes magnesium dihalide, complexes of magnesium dihalide with water or alcohol and the like, and derivatives of magnesium dihalide wherein a halogen atom is substituted by a hydrocarboxyl g
Jin Maozhu
Ma Zhaowen
Peng Rengi
Sun Yijing
Wang Yi
Bell Mark L.
China Petro-Chemical Corporation
Pasterczyk J.
LandOfFree
Catalyst system for use in ethylene polymerization and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Catalyst system for use in ethylene polymerization and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Catalyst system for use in ethylene polymerization and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3083365