Polyalkylene Glycol Ester Synthesis via Controlled Anhydride Reaction
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Solution Overview
Problem
The existing processes for preparing poly-C2-C4-alkylene glycol mono(meth)acrylic acid esters suffer from low reaction rates and poor quality due to the surface-active properties of the macromolecular substances, leading to incomplete reactions and the presence of excess reagents, which affect the quality of the final products, especially when used as concrete plasticizers.
Innovation Solution
A process involving the reaction of acrylic or methacrylic anhydride with a poly-C2-C4-alkylene glycol compound in the presence of a base with limited solubility, maintaining a specific molar ratio and using controlled conditions to achieve high conversion rates and improved product quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If poly-C2-C4-alkylene glycol is derivatized with acrylic acid or methacrylic acid to prepare monoesters, then the desired macromonomers are produced, but the reaction rates are low due to the macromolecular nature of the starting material and end product
Solution Approach 1:
The patent changes the reaction parameters by using acid chlorides instead of carboxylic acids, which increases the reactivity and reaction rate. The use of excess acid chloride drives the reaction to completion despite the macromolecular nature of the substrates, thereby improving productivity while managing the complexity through parameter optimization
2Manufacturing precision
If excess acid chloride is used to drive the esterification reaction, then conversion is improved, but unreacted excess acid chloride remains in the crude product which interferes in further reactions and requires expensive removal by distillation
Solution Approach 1:
The patent extracts or removes the harmful excess acid chloride through careful control of reaction conditions and work-up procedures. By optimizing the reaction parameters and using appropriate purification methods, the harmful substance is separated from the desired product, maintaining high conversion while eliminating the interference in further reactions
Solution Approach 2:
The patent uses a controlled excess of acid chloride (not too large) to drive the reaction forward while minimizing the amount of excess reagent that would need to be removed. This partial excessive action achieves good conversion without generating excessive harmful byproducts that would require expensive removal
3Productivity
If poly-C2-C4-alkylene glycol mono(meth)acrylic acid esters are prepared by reaction with acid chloride, then the esters are formed, but the quality is not satisfactory due to incomplete reaction and presence of unreacted starting materials
Solution Approach 1:
The patent implements feedback control by monitoring the reaction progress and adjusting conditions to ensure complete conversion. The use of excess acid chloride acts as a driving force that pushes the equilibrium toward complete esterification, ensuring high quality product with minimal unreacted starting materials while maintaining good reaction rates
4Manufacturing precision
If the poly-C2-C4-alkylene glycol is fully converted to monoester, then product quality improves, but the surface-active properties make working-up and isolation problematic
Solution Approach 1:
The patent extracts the harmful surface-active properties by using specific work-up procedures that separate the amphiphilic monoester from the reaction mixture. Through careful control of the reaction conditions and appropriate purification methods, the surface-active product is isolated effectively despite its problematic properties during working-up
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 results in higher conversion rates, shorter reaction times, and the production of poly-C2-C4-alkylene glycol mono(meth)acrylic acid esters with enhanced plasticizing effects in cement-containing building materials, leading to superior performance as concrete plasticizers.
Implementation Method 1
the reaction of acrylic anhydride or methacrylic anhydride with a poly-C2-C4-alkylene glycol compound carrying at least one OH group in the presence of a base
Data Source
AI summary
A process for preparing poly-C2-C4-alkylene glycol mono(meth)acrylic acid esters by reacting (meth)acrylic anhydride with a poly-C2-C4-alkylene glycol carrying at least one OH group in the presence of abase having a solubility in the poly-C2-C4-alkylene glycol of not more than 10 g/l at 90° C.