Ethylene Polymerization Catalyst Preparation via Mixed Solvent Control

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Solution Overview

Problem

Existing catalysts for ethylene (co)polymerization lack high catalytic activity and uniform polymer bulk density due to irregular particle morphology and size distribution.

Innovation Solution

A method involving the preparation of a magnesium compound solution by reacting a halogenated magnesium compound with a mixed solvent of cyclic ether and alcohol, followed by reaction with a silicon compound and a titanium compound, and optionally a monoester, to produce a catalyst with regulated particle shape and size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If existing catalyst preparation methods are used, then catalyst can be obtained, but particle morphology is irregular and size distribution is poor

Engineering Contradiction:
Improveparticle morphology and size distributionVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by preparing a magnesium compound solution with controlled properties before catalyst formation. The magnesium compound is dissolved in a mixed solvent of cyclic ether and alcohol to create a solution with specific concentration and composition, which then serves as the basis for forming uniform catalyst particles. This preliminary preparation ensures that the subsequent catalyst formation yields particles with regulated shape and uniform size distribution.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent employs parameter changes by systematically adjusting the composition of the mixed solvent (cyclic ether and alcohol ratios), the concentration of magnesium compound solution, the type and amount of silicon compound, and the titanium compound addition conditions. These parameter optimizations enable precise control over catalyst particle morphology and size distribution while maintaining manufacturing feasibility.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If catalyst with high activity is pursued, then polymerization yield increases, but bulk density of polymer decreases

Engineering Contradiction:
Improvepolymerization yieldVSAvoidbulk density of polymer
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent applies local quality by creating catalysts with uniform particle size distribution and regulated shape. This uniformity ensures that active sites are evenly distributed throughout the catalyst particles, leading to consistent polymerization rates and uniform polymer particle formation. The result is high polymerization yield combined with high bulk density, as the uniform catalyst structure prevents localized aggregation that would reduce polymer density.

Inventive Principle:
Principle #3Local quality

3Quantity of substance

If catalyst particle size is not controlled, then manufacturing is simpler, but polymer bulk density and uniformity suffer

Engineering Contradiction:
Improvebulk density and uniformity of polymerVSAvoidcatalyst preparation process
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent uses an intermediary approach by introducing a silicon compound as a mediating agent in the catalyst formation process. The silicon compound interacts with the magnesium compound solution and titanium compound to control particle nucleation and growth, resulting in catalysts with regulated particle size and shape. This intermediary mechanism enables precise control over catalyst morphology without requiring complex equipment or multi-step processes.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 results in a catalyst with high catalytic activity and polymers of high bulk density and uniform particle size distribution, enhancing polymerization efficiency.

Implementation Method 1

preparing a magnesium compound solution by contact-reacting a halogenated magnesium compound with a mixed solvent of cyclic ether and at least one alcohol

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

reacting the resulted magnesium compound solution from the above step (1) with a silicon compound having at least one alkoxy group

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 3

preparing a support by adding a titanium compound to the resulted product from the step (2)

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 4

reacting thus obtained support with a titanium compound and optionally a monoester compound, resulting in a catalyst

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentUS7759272B2Preparation method of catalyst for ethylene polymerization and copolymerization
Publication Date: 2010.07.20 HANWHA TOTALENERGIES PETROCHEMICAL CO LTD

AI summary

Provided is a preparation method of a catalyst for ethylene (co)polymerization, comprising the following steps: (1) preparing a magnesium compound solution by contact-reacting a halogenated magnesium compound with a mixed solvent of cyclic ether and at least one alcohol; (2) reacting the resulted magnesium compound solution from the above step (1) with a silicon compound having at least one alkoxy group; (3) preparing a support by adding a titanium compound to the resulted product from the step (2); and (4) reacting thus obtained support with a titanium compound and optionally a monoester compound, resulting in a catalyst. Catalysts prepared according to the present invention have a regulated particle shape, and their particle size can be easily adjusted. Therefore, with such catalyst, it is possible to produce polymers having high bulk density at high production yield.