Epoxide Diester Synthesis via Quaternary Ammonium Catalyst
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Solution Overview
Problem
Current methods for preparing (meth)acrylic acid diesters suffer from low yields, excessive use of expensive (meth)acrylic acid anhydrides, and unwanted polymerization, making them inefficient and economically unfavorable for industrial-scale production.
Innovation Solution
A process involving the reaction of an epoxide with a (meth)acrylic acid anhydride in the presence of a catalyst, such as a halide of magnesium or a rare earth element trifluoromethanesulfonate, combined with a chromium (III) salt and a co-catalyst like a tertiary amine or quaternary ammonium salt, to achieve high yields and minimize anhydride excess.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If acylation of diols with (meth)acrylic acid anhydride is carried out in the presence of sulfuric acid, then the reaction can proceed, but undesired polymerization occurs and product yields are only moderate
Solution Approach 1:
The patent employs a quaternary ammonium salt as an intermediary catalyst that mediates the acylation reaction between (meth)acrylic acid anhydride and diol. This intermediary catalyst enables the reaction to proceed at moderate temperatures without triggering the polymerization that occurs with sulfuric acid, thus resolving the contradiction between achieving acceptable reaction rates and avoiding harmful polymerization side reactions.
2Manufacturing precision
If (meth)acrylic acid anhydride is used in a large excess to achieve high conversion of sterically hindered diols, then conversion increases, but economic costs increase and recovery becomes difficult
Solution Approach 1:
The patent changes the reaction parameters by using a quaternary ammonium salt catalyst that enables high conversion of sterically hindered diols under milder conditions with reduced anhydride excess. The catalyst modifies the reaction pathway to be more efficient, allowing near-stoichiometric amounts of anhydride to achieve high conversion, thereby resolving the contradiction between achieving high conversion and minimizing reagent excess.
3Manufacturing precision
If acylation requires at least one equivalent of anhydride per equivalent of alcoholic functionalities, then complete acylation can be achieved, but less than 50 wt.-% of employed anhydride becomes incorporated into the desired product
Solution Approach 1:
The quaternary ammonium salt acts as an intermediary that facilitates a more efficient acylation mechanism, reducing the stoichiometric excess of anhydride required. The catalyst enables complete acylation of alcoholic functionalities while minimizing the formation of undesired methacrylic acid byproduct, thus improving the incorporation efficiency of the anhydride into the desired diester product.
4Productivity
If reaction is carried out at elevated temperatures to improve reaction rate, then productivity increases, but undesired dehydration of sterically hindered diols occurs
Solution Approach 1:
The patent changes the temperature parameter by conducting the reaction at moderate temperatures (below the threshold that causes dehydration) while using a quaternary ammonium salt catalyst to maintain acceptable reaction rates. This parameter change resolves the contradiction between achieving high productivity through elevated temperature and avoiding harmful dehydration of sterically hindered diols.
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 process achieves high product yields (>40% by gas chromatography) with reduced reaction times and lower catalyst amounts, enabling efficient and cost-effective production of (meth)acrylic acid diesters suitable for industrial scales.
Implementation Method 1
The invention relates to a process for preparation of a diester of formula (I) by reacting an epoxide of formula (III) with a (meth)acrylic acid anhydride of formula (II) in the presence of a catalyst
Data Source
AI summary
The invention relates to a method for preparation of diesters from anhydrides of carboxylic acids.