Carbene Precatalyst Activation for Controlled ROMP Polymerization
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Solution Overview
Problem
Existing Fischer carbenes face challenges in controlling molecular weight and cis/trans ratio in ring-opening metathesis polymerization (ROMP) of cyclic olefins, requiring expensive and difficult-to-handle pre-activation with TiCl4 and limited to aromatic solvents, with low molecular weight and high trans double bond enrichment.
Innovation Solution
A method involving carbene precatalysts activated by Br2-1,4-dioxane, I2, PhICl2, or PCl5 co-catalysts, allowing polymerization in hydrocarbon solvents like pentane or neat cyclopentene, reducing TiCl4 equivalents to 1-30, and performing in air at elevated temperatures, achieving controlled trans double bond content and molecular weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TiCl4 is used to activate carbene precatalysts, then the carbene precatalyst becomes activated for polymerization, but the process becomes expensive and difficult to handle due to air and moisture sensitivity and requires excess TiCl4 (150 and more equivalents)
Solution Approach 1:
The patent replaces expensive and sensitive TiCl4 with cheaper, more stable co-catalysts (BF3·OEt2, AlCl3, FeCl3, ZnCl2, or InCl3) that are less sensitive to air and moisture, reducing handling complexity and cost while maintaining catalytic activation capability
Solution Approach 2:
The patent changes the chemical parameters of the co-catalyst from TiCl4 to alternative Lewis acids with different properties (BF3·OEt2, AlCl3, FeCl3, ZnCl2, InCl3), which have lower sensitivity to air and moisture, thereby improving ease of operation while maintaining activation function
2Reliability
If TiCl4 is used to activate carbene precatalysts, then the carbene precatalyst becomes activated for polymerization, but the cost increases and the process becomes difficult to handle
Solution Approach 1:
The patent replaces expensive TiCl4 with cheaper alternative co-catalysts (BF3·OEt2, AlCl3, FeCl3, ZnCl2, or InCl3), reducing the overall process cost while maintaining the ability to activate carbene precatalysts for polymerization
Solution Approach 2:
The patent changes the chemical composition parameters from TiCl4-based system to alternative Lewis acid co-catalysts, which are more cost-effective and equally effective for catalyst activation, thereby reducing manufacturing cost
3Productivity
If Chauvin's catalyst system is used, then polymerization occurs, but the resulting polymers are always highly trans double bond enriched (80% and more) and molecular weight cannot be controlled
Solution Approach 1:
The patent changes the co-catalyst parameter from TiCl4 to alternative Lewis acids (BF3·OEt2, AlCl3, FeCl3, ZnCl2, or InCl3), which modifies the polymerization mechanism to enable control over molecular weight and cis/trans ratio while maintaining polymerization activity
Solution Approach 2:
The patent introduces dynamic control capability by using alternative co-catalysts that allow adjustment of polymerization conditions to control molecular weight and stereochemistry, transforming the static outcome (fixed high trans content) into a dynamic controllable process
4Productivity
If Chauvin's catalyst system is used, then polymerization occurs, but the process requires excess TiCl4 (150 and more equivalents) making it expensive and difficult to handle
Solution Approach 1:
The patent changes the co-catalyst parameter from TiCl4 to alternative Lewis acids and reduces the required amount from 150+ equivalents to lower stoichiometric amounts, improving both productivity and reducing material consumption
Solution Approach 2:
The patent replaces TiCl4 with cheaper co-catalysts that require lower amounts, reducing both the quantity of substance needed and the overall cost of the polymerization process
5Temperature
If Grubbs type catalysts are used, then polymerization occurs at or above room temperature, but lower molecular weight polypentenamer is produced limiting commercial use
Solution Approach 1:
The patent changes the catalyst system parameters to Fischer carbene with alternative co-catalysts, enabling polymerization at room temperature or below while producing high molecular weight polymers, thus resolving the contradiction between temperature and molecular weight
6Productivity
If both Grubbs and Schrock type catalysts are used, then polymerization occurs, but they are sensitive towards linear alpha olefins present in C5 feed resulting in uncontrolled chain transfer events
Solution Approach 1:
The patent changes the catalyst system to Fischer carbene with alternative co-catalysts, which shows reduced sensitivity to linear alpha olefins in C5 feed, thereby controlling chain transfer events and improving compositional stability while maintaining polymerization activity
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
This method enables high conversion and controlled molecular weight polymerization of cyclic olefins with trans double bond content ranging from 10% to 90% and molecular weight from 10 kg/mol to 700 kg/mol, reducing costs and handling complexity.
Implementation Method 1
contacting a carbene precatalyst with a first co-catalyst, under reaction conditions sufficient to cause the first-co-catalyst to activate the carbene precatalyst
Data Source
AI summary
A method, including: contacting a carbene or carbyne precatalyst with a first co-catalyst, under reaction conditions sufficient to cause the first-co-catalyst to activate the carbene or carbyne precatalyst, wherein the first co-catalyst is selected from the group consisting of an aluminum activator, a Br2-1,4-dioxane complex, I2, PhICI2, and PCI5.