Cyclic Amidine Metal Complex for High Molecular Weight Olefin Polymerization
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Solution Overview
Problem
Existing catalyst systems for olefin polymerization have a low affinity for α-olefins and polyenes, such as non-conjugated dienes, and are limited in producing high molecular weight polymers, especially at elevated temperatures.
Innovation Solution
A metal complex with a cyclic amidine ligand is developed, comprising a cyclopentadienyl-type ligand, a Group 4 metal, and an anionic ligand, which enhances the catalyst's affinity for α-olefins and polyenes, allowing for the production of high molecular weight polymers even at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional catalyst systems are used for olefin polymerization, then the polymerization process can proceed, but the molecular weight of the produced polymers is limited and affinity for α-olefins and polyenes is low
Solution Approach 1:
The patent modifies the chemical structure of the ligand by introducing a cyclic amidine moiety with specific substituents (R1-R8) that can be hydrogen, halogen, alkyl, or alkoxy groups. This structural parameter change in the catalyst component fundamentally alters its electronic and steric properties, enabling both high molecular weight polymer production and enhanced affinity for α-olefins and polyenes simultaneously
Solution Approach 2:
The catalyst system employs a composite ligand structure combining cyclopentadienyl-type (Cy) and cyclic amidine (Y) components coordinated to a Group 4 metal. This composite ligand architecture integrates the benefits of both structural motifs, creating a catalyst that achieves superior polymerization performance with high molecular weight polymers and improved monomer affinity
2Productivity
If conventional catalyst systems are used at elevated temperatures, then polymerization can proceed at higher rates, but the molecular weight of polymers decreases
Solution Approach 1:
The cyclic amidine ligand structure with its specific electronic properties (influenced by substituents R1-R8) creates a more stable catalyst center that maintains its activity and selectivity at elevated temperatures. This parameter change in the ligand structure allows the catalyst to resist deactivation and maintain high molecular weight polymer production even when polymerization is conducted at higher temperatures for increased 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
The metal complex significantly improves the polymerization process by increasing the molecular weight of polymers, achieving intrinsic viscosities up to 12 dl/g and weight average molecular weights up to 1,500,000 g/mol, and enables higher polymer concentrations at elevated temperatures.
Implementation Method 1
a catalyst system for olefin polymerization comprising an organometallic complex of a group 4 metal comprising an amidine ligand; and an activator
Data Source
AI summary
The present invention relates to a A metal complex of formula 1 CyYMLjXn (formula 1) wherein Cy is a cyclopentadienyl-type ligand; M is a metal of group 4; L is a neutral Lewis basic ligand wherein the number of said neutral ligands "j" is in the range of 0 to the amount that satisfies the 18-electron rule; X is an anionic ligand; n is an integer denoting the number of anionic ligands X and is 1 or 2, preferably is 2; Y is a cyclic amidine-containing ligand moiety represented by formula 2 wherein the amidine-containing ligand is covalently bonded to the metal M via the imine nitrogen atom N2; S is a -CH2- unit, and t is the integer number denoting the number of S and is in the range of 1-4, more preferably in the range of 1-2, most preferably is 1; Sub1 is an aliphatic cyclic or linear substituent comprising a group 14 atom through which Sub1 is bonded to the amine nitrogen atom N1; Sub2 is an optionally substituted C2 unit in which the 2 carbon atoms may be SP2 or sp3 hybridized.