Solid Organomagnesium Precursor for Ziegler-Natta Catalyst Synthesis
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Solution Overview
Problem
Existing Ziegler-Natta catalyst systems for olefin polymerization require multiple steps, expensive raw materials, and high alcohol content, making them inefficient and costly to produce, with issues related to handling hazardous substances like hydrogen halides and expensive magnesium alkyls.
Innovation Solution
A solid organomagnesium precursor with the formula {Mg(OR′)X}.a{MgX2}.b{Mg(OR′)2}.c{R′OH} is synthesized through a single-step process using a magnesium source, solvating agent, and organohalide, followed by contact with a transition metal compound and internal donor to produce a highly active Ziegler-Natta catalyst system with reduced alcohol content and simplified purification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple steps and expensive raw materials are used for catalyst synthesis, then catalyst activity can be improved, but production cost increases and process complexity increases
Solution Approach 1:
The invention changes the chemical composition parameters of the magnesium carrier by incorporating specific ratios of MgCl2, Mg(OR)2, and MgX2, along with controlled amounts of alcohol and water. This compositional parameter optimization achieves high catalyst activity while using cost-effective raw materials and simplifying the synthesis process to fewer steps.
Solution Approach 2:
The invention creates a composite magnesium carrier material containing multiple magnesium compounds (MgCl2, Mg(OR)2, MgX2) in specific ratios, along with controlled alcohol and water content. This composite structure combines the advantages of different magnesium compounds to achieve high catalyst activity while reducing production cost and complexity.
2Ease of manufacture
If hydrogen halides are used for chlorination, then MgCl2 carrier can be produced, but handling difficulty and safety hazards increase
Solution Approach 1:
The invention uses alcohol as an intermediary substance to facilitate the conversion of magnesium alkyl or alkoxy compounds to MgCl2 carrier. Instead of directly using hazardous hydrogen halides, the alcohol mediates the reaction to produce the desired MgCl2 carrier while avoiding the handling difficulties and safety hazards of hydrogen halides.
Solution Approach 2:
The invention employs alcohol, a relatively safe and inexpensive reagent, as a disposable intermediate in the carrier synthesis process. The alcohol is consumed in the reaction to produce the MgCl2 carrier and can be easily removed, replacing the need for hazardous hydrogen halides that require special handling and safety precautions.
3Ease of operation
If high alcohol content is used in catalyst system, then solubility and handling are improved, but purification complexity and cost increase
Solution Approach 1:
The invention optimizes the alcohol content parameter in the magnesium carrier to a specific controlled range (0.1-5.0 wt%). This parameter optimization maintains sufficient solubility and ease of handling for the catalyst system while minimizing the alcohol content to reduce purification complexity and associated costs.
Solution Approach 2:
The invention applies local quality control by maintaining different alcohol content levels in different parts of the catalyst system. The magnesium carrier contains controlled alcohol (0.1-5.0 wt%) for adequate solubility, while the final catalyst system uses minimal additional alcohol, creating a gradient of alcohol concentration that balances solubility needs with purification simplicity.
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 process results in a highly active, stereospecific, and efficient Ziegler-Natta catalyst system for olefin polymerization with low xylene solubility and excellent hydrogen response, reducing production costs and simplifying the synthesis process.
Implementation Method 1
contacting a solution of transition metal compound with the solid organomagnesium precursor to obtain a resulting solution
Implementation Method 2
contacting a magnesium source with a solvating agent, an organohalide and an alcohol
Data Source
AI summary
The present invention provides a solid organomagnesium precursor having formula {Mg(OR′)X}.a{MgX2}.b{Mg(OR′)2}.c{R′OH}, wherein R′ is selected from a hydrocarbon group, X is selected from a halide group, and a:b:c is in range of 0.01-0.5:0.01-0.5:0.01-5 and process for preparing the same, said process comprising contacting a magnesium source with a solvating agent, an organohalide and an alcohol to obtain the solid organomagnesium precursor. The present invention also provides a process for preparing a catalyst system using the organomagnesium precursor and its use thereof for polymerization of olefins.