Spherical Magnesium Halide Adduct for Olefin Polymerization Catalyst
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Solution Overview
Problem
Existing catalysts for olefin polymerization, particularly in propylene polymerization, face issues with uniform distribution of catalytic active sites, leading to cracking of catalyst and polymer particles, resulting in low stereospecificity and isotacticity indices, especially at higher hydrogen concentrations.
Innovation Solution
Incorporating an o-alkoxybenzoate compound into a magnesium halide/alcohol adduct support to form a spherical magnesium halide adduct, which reacts with a titanium compound and optional internal electron donors to create a catalyst component with enhanced stereospecificity and polymerization activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a magnesium dichloride/alcohol adduct is used as support, then the catalyst exhibits high polymerization activity, but catalytic active sites are not uniformly distributed leading to particle cracking
Solution Approach 1:
The patent introduces electron donor compounds at specific locations within the support structure - both during support preparation (incorporated into the matrix) and during catalyst component preparation (incorporated into the catalyst component). This creates localized zones of electron donation that promote uniform active site distribution while maintaining high activity centers, resolving the contradiction between high productivity and uniform distribution.
2Manufacturing precision
If electron donor compound is introduced during support preparation, then active site distribution improves, but the support becomes viscous and difficult to form spherical particles
Solution Approach 1:
The patent segments the electron donor compound introduction into two distinct stages: (1) during support preparation where a first electron donor is incorporated into the support matrix, and (2) during catalyst component preparation where a second electron donor is incorporated into the catalyst component. This segmentation allows each stage to be optimized independently - the support remains formable while still incorporating electron donors, and the catalyst component receives additional electron donors for uniform active site distribution.
Solution Approach 2:
The patent performs preliminary action by incorporating the first electron donor compound during support preparation, before the catalyst component is formed. This preliminary incorporation establishes a baseline level of electron donation in the support structure, which then facilitates subsequent uniform active site distribution without compromising the support's formability during the preliminary support synthesis stage.
3Productivity
If higher hydrogen concentration is used in propylene polymerization, then polymerization activity increases, but stereospecificity and isotacticity index decrease
Solution Approach 1:
The patent changes the chemical parameter of the support and catalyst component by incorporating electron donor compounds, which modifies the electronic environment of the catalytic active sites. This parameter change makes the active sites more resistant to deactivation by hydrogen, allowing the system to maintain high stereospecificity even at higher hydrogen concentrations that boost polymerization activity. The electron donors alter the electronic properties to achieve both high productivity and high stereospecificity simultaneously.
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 catalysts exhibit higher stereospecificity and isotacticity indices, producing polymers with improved mechanical properties and processability, and reduced polymer fines, making them suitable for industrial-scale polypropylene production.
Implementation Method 1
An adduct of a magnesium halide and an alcohol is often used as the active magnesium halide support
Implementation Method 2
reacts with a titanium compound and optionally an internal electron donor compound
Data Source
AI summary
A magnesium halide adduct represented by the formula (I): MgX2.mROH.nE.pH2O, in which X is chlorine, bromine, a C1-C12 alkoxy, a C3-C10 cycloalkoxy or a C6-C10 aryloxy, with the proviso that at least one X is chlorine or bromine; R is a C1-C12 alkyl, a C3-C10 cycloalkyl or a C6-C10 aryl; E is an o-alkoxybenzoate compound represented by the formula (II): in which R1 and R2 groups are independently a C1-C12 linear or branched alkyl, a C3-C10 cycloalkyl, a C6-C10 aryl, a C7-C10 alkaryl or an C7-C10 aralkyl, the R1 and R2 groups are identical to or different from the R group; m is in a range of from 1.0 to 5.0; n is in a range of from 0.001 to 0.5; and p is in a range of from 0 to 0.8, is disclosed. A catalyst component useful in olefin polymerization, which comprises a reaction product of (1) the magnesium halide adduct, (2) a titanium compound, and optionally (3) an electron donor compound, is also disclosed.