Ruthenium NHC Catalyst ROMP Process
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current ring-opening metathesis polymerization (ROMP) processes using ruthenium catalysts are hindered by the need for expensive and hazardous activating agents, and require large amounts of catalysts, posing safety risks and inefficiencies.
Innovation Solution
A process involving a ruthenium compound of the formula RuX1X2L1aL2b, where X1 and X2 are anionic ligands, L1 is an uncharged π-binding ligand, and L2 is an N-heterocyclic carbene, is used, with a chain transfer agent added in a specific molar ratio, to facilitate ROMP at temperatures between 0°C to 250°C, reducing catalyst amounts and eliminating the need for hazardous activating agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ruthenium catalysts are used for ROMP, then polymerization can proceed, but large amounts of catalyst are required and hazardous activating agents must be added
Solution Approach 1:
The patent modifies the catalyst structure by incorporating specific N-heterocyclic carbene ligands with electron-donating groups, changing the electronic parameters of the ruthenium center to enhance its activity and reduce the required catalyst amount
Solution Approach 2:
The invention replaces expensive and hazardous activating agents with a stable, pre-formed ruthenium-NHC catalyst system that does not require additional activating steps, eliminating safety risks while maintaining catalytic function
2Reliability
If hazardous activating agents are used to activate ruthenium catalysts, then catalyst activity is achieved, but safety risks and environmental hazards increase
Solution Approach 1:
The patent converts the potential harm of requiring activating agents into a benefit by designing a catalyst system where the NHC ligand pre-activates the ruthenium center, turning a safety hazard into a built-in catalytic feature
Solution Approach 2:
The N-heterocyclic carbene ligand acts as an intermediary that stabilizes the ruthenium center and facilitates substrate activation without requiring additional hazardous activating agents, mediating between the catalyst and monomer safely
3Reliability
If complex multi-step catalyst synthesis is used, then active ruthenium catalysts are produced, but process complexity and cost increase
Solution Approach 1:
The patent employs pre-synthesized stable N-heterocyclic carbene ligands that can be stored and handled easily, performing the complex ligand synthesis in advance under optimized conditions rather than during the polymerization process
Solution Approach 2:
The catalyst system is segmented into separate components (ruthenium salt and NHC ligand) that can be prepared independently and combined simply, reducing overall synthesis complexity while maintaining catalytic 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 approach enhances the activity of the catalyst while reducing costs and safety risks, achieving efficient polymerization with improved safety and reduced catalyst usage.
Implementation Method 1
ring-opening metathetic polymerization (ROMP) of cycloalkenes enables an elegant and atom-efficient route to linear polymers
Implementation Method 2
L2=N-heterocyclic carbene of the formula IIa, IIb or IIc
Data Source
AI summary
The present invention relates to a process for preparing polymers by means of ring-opening metathetic polymerization, consisting of the following steps:a) providing a reaction mixture consisting of a cycloalkene or a cycloalkene mixture, b) adding a ruthenium compound of the general formula RuX1X2L1aL2b (I) where a=0 or 1, b=1 or 2, such that a+b=2;X1, X2=independently selected anionic ligands; L1=uncharged π-binding ligand; L2=N-heterocyclic carbene of the formula IIa, IIb or IIc; c) adding a chain transfer agent in a molar ratio in the range from 1:5 to 1:1000 based on the cycloalkene or the sum total of the cycloalkenes in the cycloalkene mixture, d) converting at a temperature within a range from 0° C. to 250° C.