Glycolic Acid Production via Dehydration Recycle Stream
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Solution Overview
Problem
Current methods for producing glycolic acid from aqueous formaldehyde require high temperatures and pressures, expensive materials, and are inefficient due to excess water in the reaction, necessitating a more economical and robust process.
Innovation Solution
A process involving the dehydration of glycolic acid oligomers and methyl glycolate oligomers in a hydrocarboxylation reaction zone, followed by dehydration and splitting of the effluent to recycle streams, allowing for the production of glycolic acid at moderate temperatures and pressures using commercially available formaldehyde.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high temperature and pressure are used for hydrocarboxylation reaction, then reaction rate is improved, but equipment cost and operational complexity increase
Solution Approach 1:
The invention changes the water concentration parameter in the reaction system by introducing a dehydration stream, allowing the reaction to proceed at moderate temperatures and pressures while maintaining high reaction rates. This resolves the contradiction by modifying reaction conditions rather than relying on extreme parameters.
Solution Approach 2:
The dehydration stream acts as an intermediary component that modifies the reaction environment. By introducing this intermediate substance, the system achieves high productivity without requiring expensive high-pressure equipment, thus resolving the contradiction between reaction rate and equipment cost.
2Ease of manufacture
If aqueous formaldehyde is used as starting material, then raw material cost is reduced, but reaction efficiency decreases due to excess water
Solution Approach 1:
The invention extracts excess water from the reaction system by introducing a dehydration stream containing glycolic acid oligomers. This allows the use of economical aqueous formaldehyde while removing the harmful excess water that would otherwise decrease reaction efficiency, thus resolving the contradiction between raw material cost and reaction efficiency.
Solution Approach 2:
The invention converts the harmful effect of excess water (which decreases reaction rate) into a beneficial process feature. The dehydration stream selectively removes water while preserving the economical advantage of using aqueous formaldehyde, transforming what was a disadvantage into a controlled process parameter that maintains both cost-effectiveness and high efficiency.
3Productivity
If high pressure equipment is used, then reaction rate is improved, but material of construction cost increases
Solution Approach 1:
The invention changes the pressure parameter from high to moderate levels by introducing the dehydration stream. This parameter modification allows maintaining high reaction rates while using less expensive construction materials, resolving the contradiction between productivity and material cost.
4Productivity
If water concentration is reduced, then reaction rate is improved, but process complexity increases
Solution Approach 1:
The dehydration stream serves multiple functions simultaneously: it removes excess water to improve reaction rate, maintains the use of aqueous formaldehyde for cost-effectiveness, and operates under moderate conditions. This multi-functionality resolves the contradiction by achieving water concentration reduction without proportionally increasing process complexity.
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 effectively produces glycolic acid with a higher degree of polymerization, reducing water content and enabling the use of readily available formaldehyde, thus improving reaction efficiency and reducing costs.
Implementation Method 1
dehydration of the effluent to produce a first dehydration stream having a higher degree of polymerization (Dp) than the effluent and a water stream
Data Source
AI summary
Disclosed is a process for the production and purification of glycolic acid or glycolic acid derivatives by the carbonylation of aqueous formaldehyde. The water in the hydrocarboxylation zone is reduced via reaction with the ester bonds in a recycle stream comprising glycolic acid oligomers and/or methyl glycolate oligomers.