Bis-aminophosphine Catalysts for Alkyl Acrylate Dimerization
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Solution Overview
Problem
Current catalysts for alkyl acrylate dimerization, such as tertiary phosphines and triaminophosphines, suffer from low activity, high toxicity, and the need for hazardous chemicals, making them unsuitable for industrial production due to low yields, high catalyst loadings, and generation of significant by-products.
Innovation Solution
A bis-aminophosphine catalyst with the formula (I), where R1 and R2 are linear alkyl groups or form a heteroaliphatic cycle, and R3 is an aryl group, is synthesized using a process involving haloaminophosphine intermediates and amines, offering a durable, reusable, and low-toxicity option for dimerization reactions with reduced tertiary alcohol and catalyst loadings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If tertiary phosphines (tributylphosphine or triphenylphosphine) are used as catalysts, then the dimerization reaction can proceed, but the catalyst activity is low and yields are moderate
Solution Approach 1:
The patent changes the chemical structure parameters of the phosphine catalyst by introducing amino groups at specific positions (using formula (I) with specific R1, R2, R3, R4 groups). This structural modification transforms ordinary tertiary phosphines into bis-aminophosphines with significantly enhanced catalytic activity, achieving over 90% conversion rates compared to the moderate yields with conventional phosphines.
2Productivity
If triaminophosphines are used as catalysts, then yields of 70-80% can be achieved, but significant amounts of by-products are generated and the catalyst is toxic
Solution Approach 1:
The patent applies local quality by strategically placing amino groups at specific positions (R1, R2, R3, R4) in the phosphine molecule rather than having three amino groups like triaminophosphines. This localized modification at key positions provides high catalytic activity and selectivity for dimer formation while reducing unwanted side reactions and by-product generation.
Solution Approach 2:
The patent converts the potential harm of highly reactive phosphine catalysts into benefit by using bis-aminophosphines that provide high activity with improved selectivity. The specific molecular structure converts what would be unselective high reactivity into beneficial selective catalysis, reducing harmful by-products while maintaining high yields.
3Productivity
If diphenylaminophosphines are used as catalysts, then the reaction can proceed, but low activity requires high phosphine loadings which increases cost
Solution Approach 1:
The patent changes the catalytic parameter by modifying the phosphine structure to include two amino groups in specific positions (formula (I)), which fundamentally alters the catalyst's electronic and steric properties. This structural parameter change enables high catalytic activity at very low loadings (0.1-5 mol%), eliminating the need for high phosphine loadings required by diphenylaminophosphines.
4Productivity
If proazaphosphatranes are used as catalysts, then up to 82% yield is obtained at 1 mol % loading, but the catalysts are complex and difficult to synthesize resulting in expensive catalyst costs
Solution Approach 1:
The patent adopts a simpler, more economical catalyst structure (bis-aminophosphines with formula (I)) that can be synthesized from readily available starting materials through straightforward reactions. This replaces the complex, expensive proazaphosphatrane catalysts while maintaining high catalytic activity and yield, making the process economically viable for industrial application.
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 bis-aminophosphine catalyst provides high selectivity and efficiency in alkyl acrylate dimerization with reduced by-product formation, allowing for industrial-scale production of hydrogenated and hydrolyzed alkyl acrylate dimers using low catalyst loadings and minimal tertiary alcohols.
Implementation Method 1
The use of specific phosphines as catalysts for the dimerization of alkyl acrylates via the Rauhut-Currier reaction has already been described in the prior art
Implementation Method 2
dimerization reaction of alkyl acrylates via the Rauhut-Currier reaction
Data Source
AI summary
The present invention relates to bis-aminophosphines which are useful as catalysts for the dimerization of alkyl acrylates. Furthermore, the present invention relates to a process for preparing bis-aminophophines, the use of these bis-aminophosphines as catalysts for dimerization reaction of alkyl acrylates and a process for obtaining dimers of alkyl acrylates using bis-aminophosphines as catalyst.