GMMA Production via Aqueous Hydrolysis and Weak Base Neutralization
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Solution Overview
Problem
Existing methods for producing glyceryl mono methacrylate (GMMA) face challenges such as the use of toxic and ecologically hazardous reagents, residual acid contamination, and low purity due to the use of organic solvents and abrasive acidic ion exchangers, which are undesirable for high-purity applications like contact lenses.
Innovation Solution
A process involving the hydrolysis of isopropylideneglycerol methacrylate (IPGMA) in an aqueous medium with a mineral acid, followed by neutralization using a weak base with a pKb value above 3.0 in heterogeneous form, preferably a basic ion exchange resin, to minimize acidic residues and avoid organic solvents, ensuring high purity GMMA production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If barium hydroxide is used for neutralization, then the acidic reaction mixture can be neutralized, but the product contains high barium content (>1000 ppm) which is toxic and ecologically hazardous
Solution Approach 1:
The patent extracts and removes barium ions from the reaction mixture through filtration after neutralization, separating the harmful substance from the final product to achieve both effective neutralization and low barium content in the monomer
Solution Approach 2:
The patent changes the neutralization parameters by controlling pH to a specific range (6.5-7.5) and using controlled addition of barium hydroxide solution, optimizing the neutralization process to minimize barium residue while ensuring complete acid neutralization
2Manufacturing precision
If organic solvents like benzene or ether are used for extraction, then GMMA can be isolated from the reaction mixture, but the process becomes ecologically hazardous and toxic
Solution Approach 1:
The patent changes the extraction parameters by replacing organic solvents with water-based extraction and controlled evaporation, using temperature and pressure control to isolate GMMA without toxic substances, thereby maintaining purity while eliminating ecological hazards
Solution Approach 2:
The patent uses water as a safe, inexpensive extraction medium instead of expensive and toxic organic solvents, and employs controlled evaporation to remove water, achieving a greener and more economical process
3Productivity
If sulfuric acid is used for hydrolysis, then IPGMA can be converted to GMMA, but residual acid remains in the product which reduces stability
Solution Approach 1:
The patent implements continuous neutralization by gradually adding barium hydroxide solution while stirring, ensuring complete and uniform neutralization of residual sulfuric acid, which prevents acid-catalyzed degradation and maintains GMMA stability
Solution Approach 2:
The patent uses pH monitoring to control the neutralization process, adjusting the addition rate of barium hydroxide based on real-time pH measurements to achieve precise neutralization and ensure product stability
4Device complexity
If the reaction mixture is concentrated without organic solvent extraction, then the process becomes simpler, but the GMMA contains high barium content
Solution Approach 1:
The patent extracts barium sulfate precipitate from the reaction mixture through filtration before concentration, removing the source of barium contamination and enabling simple concentration to produce high-purity GMMA without complex extraction steps
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-purity GMMA with low acidic content, reducing the likelihood of protein and lipid deposits on contact lenses and improving the stability and quality of the monomer for polymer production.
Implementation Method 1
isopropylideneglycerol methacrylate (IPGMA)... is hydrolyzed
Implementation Method 2
the resulting mixture is brought into contact with a weak base in order to neutralize the acid present in the mixture, the base having a pKb value above 3.0 and is in heterogeneous form, preferably a basic ion exchange resin
Data Source
AI summary
The invention relates to a method for producing diols having a special structure, characterized by the formula (1) indicated below. These are substances comprising a C=C double bond in addition to two OH groups, such that, as monomers, they are suitable for producing polymers. Said polymers are preferably those that are used in the medical field, such as for devices and fixtures in the fields of ophthalmology, implants, prostheses, and hydrogel articles and particularly hard or soft contact lenses. The method comprises the hydrolysis of a corresponding cyclic precursor in an aqueous medium and in the presence of an acid dissolved in said aqueous medium, said hydrolysis taking place by splitting off a carbonyl compound, along with subsequent neutralization of the acid present in the reaction mixture by a base, the base having a pKb value above 0.18 and preferably above 3.0 and being present in a heterogeneous form.