Nitrile-Ligated Pd Catalyst for Functional Olefin Copolymerization
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Solution Overview
Problem
Current catalyst systems face challenges in effectively copolymerizing olefins with mono and bis-functionalized polar vinyl monomers, particularly due to electron-poor C-C double bonds and steric demands, leading to limited incorporation of functional groups and inconsistent yields in insertion copolymerization reactions.
Innovation Solution
A nitrile ligated transition metal-phosphinobenzene-sulfonate complex is developed, which includes a weak coordinating acetonitrile group at the fourth coordination site, enabling the incorporation of functional groups like cyano and ester groups into ethylene monomers during copolymerization, and is used in a one-step process to produce a Pd-phosphinobenzene-sulfonate complex for insertion-copolymerization of mono and bis-functionalized polar vinyl monomers with ethylene.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If neutral Pd(II) complexes with phosphine-sulfonate ligands are used for copolymerization, then functional group tolerance is improved, but catalyst activity and monomer incorporation are reduced
Solution Approach 1:
The patent modifies the ligand structure by introducing electron-donating groups (such as alkyl and aryl substituents on the phosphine and sulfonate moieties) to adjust the electronic properties of the catalyst. This parameter change in ligand electronics enhances catalyst activity while preserving functional group tolerance, directly resolving the contradiction between adaptability and productivity.
Solution Approach 2:
The catalyst employs a composite ligand system combining phosphine and sulfonate groups in a specific arrangement (phosphine-sulfonate chelating system). This composite ligand structure provides both the functional group tolerance characteristic of sulfonates and the catalytic activity enhancement from phosphine, achieving a balance between the two opposing requirements.
2Productivity
If bulky α-diimine ligands are used with Pd or Ni complexes, then initial polymerization results are improved, but high degree of branching and catalyst degradation occur
Solution Approach 1:
The patent changes the ligand type from bulky α-diimine to phosphine-sulfonate, and adjusts electronic parameters by introducing electron-donating substituents. This parameter modification maintains high polymerization activity while significantly improving catalyst stability and reducing branching, resolving the contradiction between productivity and stability.
Solution Approach 2:
The phosphine-sulfonate ligand provides localized electronic donation to the metal center through specific donor atoms, creating optimal electronic environment for catalyst stability without the steric bulk that causes degradation. This local quality adjustment maintains activity while improving stability.
3Productivity
If early transition metal Ziegler-Natta catalysts are used, then polyolefin production is improved, but catalyst poisoning by functional groups occurs
Solution Approach 1:
Instead of using early transition metals that are highly active but sensitive to poisoning, the patent inverts the approach by using late transition metals (Pd(II)) with specially designed phosphine-sulfonate ligands. This inversion provides both activity and resistance to functional group poisoning simultaneously.
Solution Approach 2:
The phosphine-sulfonate ligand acts as an intermediary between the metal center and the functionalized monomers. It modulates the metal's reactivity to maintain high activity while protecting against poisoning by functional groups, resolving the contradiction between productivity and reliability.
4Productivity
If free radical polymerization is used for functionalized dienes, then polymer production is achieved, but control over branching and molecular weight is poor
Solution Approach 1:
The patent replaces free radical polymerization mechanism with coordination-insertion polymerization using Pd(II) catalysts. This mechanism substitution provides controlled living polymerization characteristics, enabling precise control over molecular weight, branching, and composition while maintaining high productivity.
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 catalyst system achieves consistent and controlled incorporation of functional groups into ethylene, producing high molecular weight copolymers with improved properties, such as poly(ethylene-co-ethyl-2-cyanoacrylate) and poly(ethylene-co-trifluoromethyl acrylic acid), suitable for applications in adhesives, binders, and other industrial uses, while reducing costs by using ethylene as a primary monomer.
Implementation Method 1
The mechanism includes the migratory insertion of a coordinated olefin into a metal alkyl bond via a four membered transition state
Implementation Method 2
nitrile ligated transition metal-phosphinobenzene-sulfonate complex of formula (I) as catalyst for insertion-copolymerization
Data Source
AI summary
The present invention discloses nitrile ligated transition metal-phosphinobenzene-sulfonate complex of formula (I) as catalyst for insertion-copolymerization of mono and bis functionalized vinyl monomers with ethylene or other olefins. In particular, the present invention discloses nitrile ligated metal-phosphinobenzene-sulfonate complex of formula (I) as catalyst for insertion-copolymerization of mono and bis functionalized vinyl monomers with ethylene and or other olefins and to the process for preparation thereof. The invention further discloses a process for the insertion-(co)polymerization of mono and bis functionalized vinyl monomers with olefms catalyzed by the catalyst of formula (I).