Spherical Magnesium Catalyst Support for Olefin Polymerization
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Solution Overview
Problem
Existing Ziegler-Natta catalyst systems for olefin polymerization often produce polyolefins with varying properties and morphologies, and the replacement of organic magnesium with magnesium halides results in catalysts with divergent and aspherical morphology, making polymer transport and removal challenging in reactors.
Innovation Solution
A solid titanium catalyst system is developed using a magnesium-based support with a substantially spherical shape, formed by reacting magnesium halide, alkylepoxide, and phosphate acid ester in an organic solvent, combined with an organoaluminum compound to create a competent Ziegler-Natta catalyst system for olefin polymerization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnesium halide is used instead of organic magnesium to reduce cost, then catalyst cost is reduced, but catalyst morphology becomes divergent and aspherical
Solution Approach 1:
The patent introduces an organic magnesium compound as an intermediary substance that mediates between the inexpensive magnesium halide and the desired spherical morphology. The organic magnesium compound serves as a precursor that directs the formation of spherical particles during the precipitation process, while the magnesium halide provides the magnesium source at lower cost. This intermediary approach allows achieving both cost reduction and morphology control.
2Productivity
If conventional Ziegler-Natta catalysts are used, then polymerization activity is achieved, but polymer transport and removal in reactors is difficult due to irregular morphology
Solution Approach 1:
The patent explicitly applies spheroidality by designing the catalyst support particles to have a spherical shape with a diameter of 10-50 μm. This spherical morphology is achieved through controlled precipitation from emulsion droplets. The spherical shape improves polymer transport and removal in reactors by reducing particle aggregation and improving flow characteristics, while maintaining high polymerization activity through the preserved Ziegler-Natta catalytic system.
3Ease of operation
If spherical catalyst support is formed using emulsion process, then polymer transport is improved, but manufacturing process complexity increases
Solution Approach 1:
The patent controls particle morphology by adjusting process parameters including temperature (0-50°C), pH (2-10), and composition ratios of magnesium halide, organic magnesium compound, and water. By optimizing these parameters, the process achieves spherical particle formation through a relatively simple precipitation method from emulsion droplets, avoiding the need for complex equipment while maintaining good polymer transport properties.
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 spherical catalyst support facilitates easy movement and removal of polymer particles within reactors, leading to improved polymerization efficiency and product morphology, with a narrow particle size distribution and high isotacticity.
Implementation Method 1
The spherical magnesium-based catalyst supports are made by reacting a magnesium halide, an alkylepoxide, and a phosphate acid ester in an organic solvent
Data Source
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AI summary
Disclosed are spherical magnesium-based catalyst supports and methods of using the same in a Ziegler-Natta catalyst system for the polymerization of an olefin. The spherical magnesium-based catalyst supports are made by reacting a magnesium halide, a haloalkylepoxide, and a phosphate acid ester in an organic solvent that does not have to contain substantial amounts of toluene.