Olefin Polymerization Catalyst with Diether Donor Ratio
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Solution Overview
Problem
Existing catalysts for olefin polymerization face challenges in achieving high hydrogen response and stereospecificity, leading to low melt flow rates and isotacticity in polypropylene production, while also potentially using harmful phthalate compounds.
Innovation Solution
A catalyst component comprising magnesium, titanium, a halogen, and an internal electron donor with a specific molar ratio of monocarboxylic ester to diether compounds (0.0035-0.7:1) is used, which enhances hydrogen response and stereospecificity without phthalate compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a large amount of hydrogen is added during polymerization to achieve high melt flow rate, then the polymer has low molecular weight and high fluidity, but the productivity decreases due to lower olefin partial pressure and the isotacticity of polypropylene becomes low
Solution Approach 1:
The patent changes the chemical parameters of the catalyst system by introducing specific electron donor compounds (diester, triester, or polyol ester) to modify the catalyst's hydrogen response. This allows the system to achieve high melt flow rate with low hydrogen addition, maintaining both productivity and stereosspecificity through parameter optimization rather than brute-force hydrogen addition
Solution Approach 2:
The electron donor compounds act as intermediaries between hydrogen and the titanium catalyst center. These compounds modulate the catalyst's interaction with hydrogen, enhancing the hydrogen response and enabling efficient molecular weight control without requiring high hydrogen partial pressures that would reduce productivity
2Speed
If a large amount of hydrogen is added during polymerization to achieve high melt flow rate, then the polymer has low molecular weight, but the isotacticity of polypropylene becomes low
Solution Approach 1:
The patent optimizes the chemical composition parameters of the catalyst system by incorporating electron donor compounds with specific molecular structures (diester, triester, or polyol ester). This parameter change enhances the catalyst's stereosspecificity, allowing high isotacticity to be maintained even under high hydrogen response conditions
Solution Approach 2:
The patent creates a composite catalyst system combining magnesium halide carrier, titanium compound, and electron donor compounds. This composite structure provides both high stereosspecificity for isotactic polypropylene formation and high hydrogen response for melt flow rate control, resolving the contradiction between manufacturing precision and speed
3Manufacturing precision
If phthalate compounds are used as electron donors to improve stereosspecificity, then the catalyst achieves high isotacticity, but harmful effects on animal and human health occur
Solution Approach 1:
The patent extracts and eliminates the harmful phthalate compounds from the electron donor system while retaining the beneficial stereosspecificity enhancement function. By selecting alternative electron donors (diester, triester, or polyol ester compounds), the harmful effects on health and environment are removed while maintaining high isotacticity
Solution Approach 2:
The patent replaces persistent harmful phthalate plasticizers with safer, biodegradable electron donor compounds. These alternative compounds fulfill the catalytic function temporarily during polymerization without causing long-term environmental or health damage, effectively substituting harmful substances with safe alternatives
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 catalyst achieves high isotacticity and melt flow rates in polypropylene production while avoiding the use of harmful phthalate compounds, demonstrating improved performance and safety.
Implementation Method 1
a catalyst component for olefin polymerization, a catalyst comprising the catalyst component, and use thereof
Data Source
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AI summary
Disclosed are a catalyst component and a catalyst for olefin polymerization, and an olefin polymerization method. The catalyst component comprises magnesium, titanium, a halogen and an internal electron donor, wherein the internal electron donor comprises a monocarboxylic acid ester compound and a diether compound, and the molar ratio of the monocarboxylic acid ester compound to the diether compound is (0.0035-0.7): 1. By using the catalyst, a polymer having both a high isotactic index and a high melt flow index can be prepared.