Procatalyst Solubility in Aliphatic Hydrocarbons
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Solution Overview
Problem
Current catalyst systems for polyethylene and polypropylene polymerization lack improved solubility in aliphatic hydrocarbons, limiting process flexibility and polymer properties.
Innovation Solution
A procatalyst with a specific metal-ligand complex structure, comprising titanium, zirconium, or hafnium, and specific ligands that enhance solubility in aliphatic hydrocarbons, allowing for improved polymerization processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional catalyst systems are used for polyethylene polymerization, then the polymerization process can proceed, but the solubility in aliphatic hydrocarbons is insufficient, limiting process flexibility
Solution Approach 1:
The patent modifies the catalyst system by changing the ligand structure from conventional phosphine ligands to carbenes (N-heterocyclic carbenes or fluorinated carbenes). This parameter change in the chemical structure fundamentally improves solubility in aliphatic hydrocarbons while maintaining catalytic activity, directly resolving the contradiction between solubility and process flexibility
Solution Approach 2:
The invention creates a composite catalyst system combining metal centers (Ti, Zr, or Hf) with specifically designed carbene ligands featuring fluorinated alkyl groups. This composite structure integrates the solubility-enhancing fluorinated hydrocarbon chains with the catalytically active metal-carbene core, achieving both improved solubility and maintained catalytic function
2Adaptability or versatility
If the catalyst structure is modified to improve solubility, then process flexibility increases, but the catalyst complexity increases
Solution Approach 1:
The catalyst molecule is segmented into distinct functional domains: the metal center for catalysis, the carbene ligand for structural stability, and the fluorinated alkyl chains for solubility. This segmentation allows each component to perform its specific function independently, managing overall complexity through functional modularity
Solution Approach 2:
The carbene ligand acts as an intermediary between the metal center and the fluorinated alkyl chains. It provides a stable coordination environment for the metal while also serving as the attachment point for the solubility-enhancing fluorinated groups, mediating between catalytic function and solubility 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 procatalyst exhibits enhanced solubility in aliphatic hydrocarbons, increasing process flexibility and enabling the production of ethylene-based polymers with tailored properties.
Implementation Method 1
M is titanium, zirconium, or hafnium, each independently being in a formal oxidation state of +2, +3, or +4; each X independently is a monodentate ligand that is neutral, monoanionic, or dianionic; each Z independently is O, S, N(C1-C40)hydrocarbyl, or P(C1-C40)hydrocarbyl
Data Source
AI summary
A procatalyst for the polymerization of ethylene and optionally one or more alpha-olefins having the structure shown in formula (I) below. Formula (I) is provided. Also provided is a polymerization process using the inventive procatalyst.