Asymmetric Diorganomagnesium Cocatalyst for Amine-Terminated Block Copolymers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing catalytic systems for preparing ethylene and 1,3-diene copolymers suffer from low catalytic activity, particularly in metallocene activation reactions, and there is a need for more efficient synthesis of block copolymers with amine functional groups at the chain end.
Innovation Solution
A novel asymmetric diorganomagnesium compound is used as a co-catalyst in a catalytic system comprising a rare-earth metallocene, enabling the polymerization of ethylene and 1,3-diene to form block copolymers with amine functional groups at the chain end, using a specific synthesis process involving anionic polymerization and reaction with a halide of organomagnesium compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a metallocene-based catalytic system is used to prepare ethylene and 1,3-diene copolymers, then the polymerization can proceed with living homopolymer formation, but the catalytic activity is low and requires equal moles of metallocene and cocatalyst
Solution Approach 1:
The invention changes the chemical structure parameters of the cocatalyst by introducing a polymer chain with a specific amine functional group at the end. This structural modification enables the cocatalyst to activate the metallocene more efficiently, achieving high catalytic activity with only 0.05-2 equivalents relative to the metallocene, thus resolving the contradiction between catalytic activity and cocatalyst quantity required
Solution Approach 2:
The cocatalyst is designed as a composite structure combining a polymer chain (from anionic polymerization of dienes or vinylaromatic compounds) with a terminal amine functional group. This composite structure provides both the solubility and stability characteristics of polymers and the high reactivity of amine groups, enabling efficient metallocene activation with reduced cocatalyst quantities
2Reliability
If conventional organomagnesium compounds are used as cocatalysts, then the polymerization can occur, but the catalytic residue content in the final polymer is high
Solution Approach 1:
The invention uses a specially designed organomagnesium cocatalyst with a polymer chain structure that allows it to fulfill its catalytic activation function and then be easily removed or decomposed. The cocatalyst acts as a temporary, disposable component that enables the reaction but does not persist as harmful residue in the final polymer product, thereby improving polymer quality while minimizing substance loss as residues
3Shape
If anionic polymerization is used to prepare living homopolymer, then block copolymer structure can be achieved, but the process requires multiple steps and complex synthesis
Solution Approach 1:
The invention merges the anionic polymerization step that creates the living homopolymer with the subsequent cocatalyst activation and polymerization steps. The organomagnesium compound formed in situ from the living homopolymer and organomagnesium halide serves as the cocatalyst, eliminating the need for separate purification and handling steps, thus achieving block copolymer structure with simplified synthesis process
Solution Approach 2:
The living homopolymer is prepared in advance through anionic polymerization with a retained active end, which then directly reacts with organomagnesium halide to form the active cocatalyst. This preliminary preparation of the living polymer with its reactive end group eliminates the need for complex intermediate processing steps, reducing overall synthesis complexity while maintaining block copolymer structure
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 process achieves high catalytic activity and low catalytic residue content, resulting in cost-effective production of block copolymers with amine functional groups, suitable for applications such as rubber compositions in tires.
Implementation Method 1
contacting of a living anionic polymer with the halide of an organomagnesium compound
Implementation Method 2
asymmetric diorganomagnesium compound as a co-catalyst in a catalytic system comprising a rare-earth metallocene
Implementation Method 3
polymerization of a second monomer in the presence of a catalytic system... the second monomer being ethylene or a mixture of ethylene and a comonomer
Data Source
AI summary
The invention relates to a diorganomagnesium compound having the formula RB-Mg-RA, where RA is a polymer chain of a 1,3-diene, an aromatic α-monoolefin or a mixture thereof having an amine function, RB comprises a benzene ring substituted by the magnesium atom, one of the carbon atoms of the benzene ring in the ortho position of the magnesium is substituted by methyl, ethyl, isopropyl or forms a ring with the carbon atom that is its closest neighbour and is in the meta position of the magnesium, the other carbon atom of the benzene ring in the ortho position of the magnesium is substituted by methyl, ethyl or isopropyl, on condition that if one of the two carbon atoms in the ortho position is substituted by isopropyl, the second carbon atom in the ortho position is not substituted by isopropyl. Used as a co-catalyst of a rare earth metallocene, the diorganomagnesium of the invention enables the synthesis of amine functional polymers.