Ruthenium Catalyst System with Phosphite Inhibitor for ROMP
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Solution Overview
Problem
Current catalytic systems for Ring Opening Metathesis Polymerization (ROMP) of dicyclopentadiene (DCPD) using ruthenium salicylaldimine/chlorosilane catalysts lack an efficient inhibitor to control the polymerization rate, which is essential for processes requiring extended working life of the monomer/catalyst mixture without compromising the thermal and physical properties of the polymer.
Innovation Solution
A catalytic system comprising a ruthenium metal, a multidentate Schiff salicylaldimine base ligand, a nucleophilic carbene ligand, and a phosphite inhibitor, where the phosphite is used in specific molar ratios to control the initiation rate of the polymerization reaction without affecting the polymer's properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If conventional ruthenium salicylaldimine/chlorosilane catalytic systems are used for ROMP of DCPD, then high catalytic activity is achieved, but the working life of the monomer/catalyst mixture is too short for processes requiring extended handling time
Solution Approach 1:
The patent introduces phosphite compounds as intermediary substances that temporarily interact with the ruthenium catalyst to form inhibited complexes. These phosphite-catalyst complexes act as mediators that reduce the catalytic activity during storage and handling, then release the active catalyst when needed for polymerization, thus extending working life without permanently reducing productivity
Solution Approach 2:
The patent modifies the catalytic system by adding phosphite compounds that change the chemical parameters of the system. The phosphites alter the electronic and steric environment of the ruthenium center, reducing its activity toward monomer polymerization. This parameter change allows the system to maintain low activity during storage while retaining the capability for high activity polymerization when activated
2Duration of action of moving object
If gel modification additives such as phosphines or pyridine are added to extend working life, then polymerization rate is reduced, but the thermal and physical properties of the resulting polymer deteriorate
Solution Approach 1:
The patent employs phosphite compounds that serve as temporary, consumable inhibitors during the storage phase. These phosphites are designed to be easily removable or decomposable, allowing the system to function as a disposable protective agent that extends working life without leaving harmful residues that would compromise the final polymer properties
Solution Approach 2:
The patent converts the potentially harmful effect of catalyst activity (which causes premature polymerization and reduces working life) into a benefit by using phosphites to control and delay this activity. The same catalytic system that causes the problem is transformed into a solution where the activity is temporarily suppressed and then unleashed at the appropriate time, improving working life without sacrificing polymer quality
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 phosphite inhibitor effectively extends the working life of the catalytic system while maintaining the polymer's thermal and physical properties, offering a superior method to modify polymerization rates compared to conventional retardants.
Implementation Method 1
a catalytic system comprising: (a) a precatalyst comprising: (i) a ruthenium metal... (b) a precatalyst activator wherein the precatalyst activator is selected from chlorosilanes... (c) an inhibitor wherein the inhibitor is selected from the group consisting of phosphites
Implementation Method 2
the phosphite inhibitor effectively extends the working life of the catalytic system while maintaining the polymer's thermal and physical properties, offering a superior method to modify polymerization rates
Data Source
AI summary
The present invention relates to a catalytic system comprising a precatalyst, a precatalyst activator and an inhibitor. Further, the invention relates to the use of this catalytic system in ring-opening metathesis polymerisation reactions.