Magnesium Catalysts for Acylation of Sterically Hindered Alcohols
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Solution Overview
Problem
Current methods for preparing (meth)acrylic acid esters from (meth)acrylic acid anhydrides suffer from low product yields, excessive use of expensive anhydrides, and inefficient catalyst usage, particularly when dealing with sterically hindered alcohols and phenols, due to unwanted polymerization and dehydration issues.
Innovation Solution
A process using salts of magnesium or rare earth elements as catalysts to facilitate the reaction between (meth)acrylic acid anhydrides and substrates, allowing for high product yields, reduced anhydride excess, and efficient catalyst separation, suitable for industrial-scale production of di- or poly(meth)acrylates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If acids such as sulphuric acid are used as catalysts for acylation of alcohols with (meth)acrylic acid anhydrides, then the reaction can proceed, but undesired polymerisation of the anhydrides occurs and product yields are only moderate
Solution Approach 1:
The patent changes the chemical nature of the catalyst from traditional Brønsted acids (sulphuric acid) to Lewis acids (metal halides, metal triflates, or solid acid catalysts). This parameter change in catalyst type selectively promotes the acylation reaction while suppressing the polymerisation side reaction, thereby improving product yield without generating harmful polymerisation byproducts.
Solution Approach 2:
The patent employs catalysts that can be easily separated and removed from the reaction mixture, such as solid acid catalysts that can be filtered off or water-soluble catalysts that can be washed away. This allows for clean product isolation without extensive purification steps, improving both yield and process efficiency.
2Productivity
If (meth)acrylic acid anhydrides are used in large excess to achieve reasonable conversion of sterically hindered alcohols and phenols, then conversion improves, but economic cost increases and recovery of unreacted excess is difficult
Solution Approach 1:
The patent changes the reaction conditions by using Lewis acid catalysts that significantly enhance the reactivity of (meth)acrylic acid anhydrides toward sterically hindered alcohols and phenols. This parameter change allows the reaction to proceed efficiently with stoichiometric or near-stoichiometric amounts of anhydride, eliminating the need for large excess and simplifying product isolation.
Solution Approach 2:
The Lewis acid catalyst acts as an intermediary that activates the (meth)acrylic acid anhydride, making it more reactive toward sterically hindered substrates. This mediation allows the reaction to proceed with high conversion using minimal excess of the expensive anhydride, and the catalyst itself can be easily separated and recovered.
3Productivity
If tertiary amines are used as catalysts for acylation of polyvinyl alcohols with activated (meth)acrylic acid anhydrides, then the reaction proceeds, but a relatively large amount of tertiary amine is required and separation from product mixture generates considerable aqueous waste
Solution Approach 1:
The patent replaces tertiary amine catalysts with Lewis acid catalysts that do not require large amounts and can be easily removed. Solid acid catalysts can be filtered off directly, and water-soluble catalysts can be washed away with minimal water, dramatically reducing aqueous waste generation while maintaining high reaction efficiency.
Solution Approach 2:
The Lewis acid catalyst serves as an effective intermediary that activates the anhydride for reaction with the alcohol substrate. The catalyst is used in small amounts, facilitates the reaction efficiently, and can be easily separated from the product mixture, avoiding the waste generation problems associated with tertiary amine catalysts.
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 approach achieves high conversion rates and product yields with short reaction times and low catalyst amounts, enabling cost-effective and environmentally friendly industrial production of (meth)acrylic acid esters.
Implementation Method 1
reaction between (meth)acrylic acid anhydride of Formula (I) and a substrate in the presence of a salt of magnesium or of a rare earth element, whereby a product mixture comprising the (meth)acrylic acid ester is formed
Data Source
AI summary
The invention relates to a method for preparation of (meth)acrylic acid esters from (meth)acrylic acid anhydrides. Wherein the method for preparation of the (meth)acrylic acid ester, comprises at least step (a) as follows: (a) reacting a (meth)acrylic acid anhydride of Formula (I):wherein R1 is a hydrogen atom or a methyl group; with a substrate in the presence of a first catalyst to form a product mixture comprising the (meth)acrylic acid ester; and wherein:the substrate is selected from the group consisting of: primary alcohols; secondary alcohols; tertiary alcohols; and phenols; andthe first catalyst comprises a salt of magnesium or of a rare earth element.