Solid Catalyst for Propylene Polymerization via Diester Donor
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Solution Overview
Problem
Existing methods for propylene polymerization fail to produce polypropylene with high melt flow rate, wide molecular weight distribution, and excellent stereoregularity while maintaining a high production yield, as they often result in low catalyst activity and insufficient physical properties.
Innovation Solution
A method involving the reaction of dialkoxymagnesium and titanium halide in the presence of an organic solvent, followed by the addition of specific internal electron donors, and subsequent reaction with titanium halide, to form a solid catalyst comprising magnesium, titanium, halogen, and an internal electron donor, which is then used for propylene polymerization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional solid catalyst systems comprising magnesium, titanium, electron donor and halogen are used for propylene polymerization, then polymerization can proceed, but the stereoregularity and production yield are insufficient
Solution Approach 1:
The patent changes the chemical parameters of the electron donor from conventional options to specifically diester of aromatic dicarboxylic acid, and optimizes the molar ratios of components (Ti: Mg: electron donor: halogen within 1:10:2-5:2-5). This parameter optimization resolves the contradiction by achieving both high stereoregularity (95-99% isotactic) and high production yield (50-200 kg polypropylene per gram of catalyst).
Solution Approach 2:
The patent creates a composite catalyst system integrating magnesium compound, titanium compound, diester of aromatic dicarboxylic acid as internal electron donor, and halogen in specific proportions. This composite structure synergistically enhances both stereoregularity control and catalytic activity, simultaneously resolving the contradiction between manufacturing precision and productivity.
2Productivity
If aromatic dialkyldiesters or aromatic monoalkylmonoesters are used as internal electron donor to improve catalyst activity, then production cost is reduced, but high stereoregular polymers with high yield cannot be provided to satisfying degree
Solution Approach 1:
The patent specifically selects diester of aromatic dicarboxylic acid (such as dimethyl terephthalate, diethyl phthalate) with optimized molar ratios (Ti: electron donor = 1:2-5) to achieve both high catalyst activity and high stereoregularity. This resolves the contradiction by finding the optimal parameter range where both productivity and manufacturing precision are maximized simultaneously.
3Adaptability or versatility
If methods using solid catalyst with organoaluminum compound and isoquinoline silicon compound are employed to broaden molecular weight distribution, then molecular weight distribution increases, but catalyst activity and flowability need improvement
Solution Approach 1:
The patent optimizes the component ratios (particularly Ti: Mg: electron donor: halogen within 1:10:2-5:2-5) and selects specific diester of aromatic dicarboxylic acid to achieve wide molecular weight distribution while maintaining high catalyst activity (50-200 kg polypropylene per gram of catalyst), resolving the contradiction between adaptability and productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves high catalyst activity, excellent stereoregularity, and wide molecular weight distribution, resulting in polypropylene with improved melt flow rate and production yield.
Implementation Method 1
reacting dialkoxymagnesium and a titanium halide, in the presence of an organic solvent
Implementation Method 2
adding an internal electron donor selected from the compounds represented by the following formula (II) together with another internal electron donor selected from the compounds represented by the following formula (III) or (IV) to the resulted product from the above step (1), and mixing them together, while elevating the temperature to the range of 80-130° C.
Implementation Method 3
a solid catalyst comprising magnesium, titanium, an electron donor and halogen as essential elements is known in this field of art, and methods for polymerizing or copolymerizing olefins which use a catalyst system comprised of said solid catalyst
Data Source
AI summary
Disclosed is a method for preparing a solid catalyst for propylene polymerization, specifically to a method for preparing a solid catalyst for propylene polymerization which can produce a polypropylene having high melt flow rate, a wide molecular distribution and excellent stereoregularity with a high production yield.