MgCl2-ROH Adduct Flowability via Inorganic Spacers
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Solution Overview
Problem
Ziegler-Natta catalyst component precursors face cohesiveness issues that worsen flowability and hinder homogeneous distribution during catalyst preparation, with existing solutions like slip agents and nanoparticle coatings either ineffective or burdensome.
Innovation Solution
A dry mechanical mixture of MgCl2-ROH adduct particles and low amounts of separated inorganic particles with specific SiO2 content, where the ratio of average particle sizes of the two components ranges from 0.4 to 1.5, improves flowability without compromising performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If slip agents such as stearates or erucamide are used to improve flowability, then the precursor particles show some improvement in flowability features, but the flowability is not sufficiently improved and the additives do not resolve the cohesiveness issues
Solution Approach 1:
The patent introduces inorganic particles (such as silica, alumina, or titania) as intermediary substances that mediate between the cohesive precursor particles. These inorganic particles act as spacers or ball bearings that reduce inter-particle adhesion and improve flowability without chemically interacting with the precursor components, thereby resolving the cohesiveness issue effectively.
Solution Approach 2:
The patent changes the physical parameters of the precursor system by adding inorganic particles with specific size ranges (0.1-10 μm) and surface properties. This parameter change transforms the powder mixture from a cohesive state to a free-flowing state by modifying the inter-particle force balance through the introduction of inorganic particle size, shape, and surface area parameters.
2Ease of operation
If catalyst or carrier particles are coated with a layer of nanoparticles made of conductive material, then flowability may be improved, but an additional separate step for preparation of gel comprising nanoparticles must be performed and the additional layer may prevent necessary interaction between catalytically active metal(s) and carriers
Solution Approach 1:
The patent merges the flowability improvement function with the existing precursor particles by directly incorporating inorganic particles into the precursor composition during the same preparation process. This eliminates the need for separate coating steps and additional gel preparation, as the inorganic particles are mixed with the precursor components in a single homogeneous mixture that maintains catalytic activity.
Solution Approach 2:
The patent extracts the problematic additional coating layer from the process and replaces it with inorganic particles that are integrated into the precursor structure. This removes the unnecessary intermediate step of preparing nanoparticle gels and applying coatings, while still achieving the desired flowability improvement through the inorganic particle addition.
3Ease of operation
If a water-based nanoparticles gel is used to coat particles, then flowability may be improved, but the procedure can subsequently inactivate the Ti based catalyst
Solution Approach 1:
The patent uses inorganic particles that are chemically inert and do not contain water or other substances that could inactivate the Ti-based catalyst. These inorganic particles provide flowability improvement without creating a reactive environment, thereby maintaining catalyst activity while achieving the desired operational improvement.
Solution Approach 2:
The patent employs simple inorganic particles (such as silica or alumina) that are stable, non-reactive, and do not require complex preparation or maintenance. These particles provide a permanent flowability solution without the need for water-based gels that could compromise catalyst integrity, offering a reliable and catalyst-compatible approach.
Data Source
AI summary
A solid mixture comprising a mechanical mixture of (a) distinct particles of adducts of formula MgCl2(R1OH)n where R is a C1-C8 alkyl group, preferably ethyl, and n is from 0.2 to 6 having average particle size (P50a) ranging from 5 to 100 μm (b) from 0.2 to 5.0% by weight of distinct particles of a solid compound containing more than 50% by weight of SiO2 units and having average particle size (P50b) such that the ratio P50b/P50a ranges from 0.4 to 1.5.