Dicarboxylic Acid Recovery via Two-Stage Acidification
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Solution Overview
Problem
Existing processes for recovering dicarboxylic acids from mixtures obtained by oxidative cleavage of vegetable oils face challenges such as low recovery yields due to the formation of secondary condensation products at high temperatures and the breakdown of dicarboxylic acids during direct acidification.
Innovation Solution
A two-stage acidification process is employed, where the mixture of triglycerides of dicarboxylic acids is first hydrolysed in the presence of a basic aqueous solution, then partially acidified to separate the aqueous phase, and finally the aqueous phase is acidified to a strongly acidic pH to recover the dicarboxylic acids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If evaporation and distillation are used to separate dicarboxylic acids from the organic phase, then separation efficiency is improved, but secondary condensation products form and product loss increases
Solution Approach 1:
The invention changes the separation method from thermal processes (evaporation/distillation) to a chemical precipitation process using acidification. By adjusting pH parameters and using water solubility differences, the process achieves effective separation without high temperatures that cause condensation and product loss.
Solution Approach 2:
The invention replaces the mechanical/thermal separation system (evaporation and distillation equipment) with a chemical separation system based on acid-base reactions and solubility differences. This substitution eliminates the need for high-temperature processing that leads to secondary condensation products.
2Productivity
If direct acidification to strongly acidic pH is performed, then dicarboxylic acids are recovered, but breakdown of dicarboxylic acids occurs and recovery is impaired
Solution Approach 1:
The invention performs preliminary separation of the organic phase before final acidification. By removing the organic phase at intermediate pH, the subsequent acidification of the aqueous phase occurs without the presence of organic compounds that would catalyze breakdown reactions, thus preserving dicarboxylic acid integrity while maintaining high recovery yield.
Solution Approach 2:
The acidification process is segmented into two stages: first acidification to intermediate pH for organic phase separation, then second acidification to strongly acidic pH for complete dicarboxylic acid recovery. This segmentation prevents the breakdown that would occur during prolonged exposure to strongly acidic conditions.
3Productivity
If basic hydrolysis is used to efficiently separate dicarboxylic acids, then hydrolysis efficiency is improved, but aqueous phase separation is limited due to monocarboxylic acids and other residues
Solution Approach 1:
The invention uses pH adjustment as an intermediary mechanism to enable separation after basic hydrolysis. By controlling pH to precipitate organic phase components while keeping dicarboxylic acids in the aqueous phase, the process overcomes the limitation of direct aqueous phase separation and achieves both high efficiency and purity.
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 significantly increases the recovery yield of dicarboxylic acids by up to 80% compared to direct acidification, while minimizing the formation of secondary products and preserving the integrity of the dicarboxylic acids.
Implementation Method 1
a) hydrolysing said mixture of triglycerides of dicarboxylic acids in the presence of a basic aqueous solution
Implementation Method 2
d) acidifying the aqueous phase separated in step c) to a pH of 3 or below, thus obtaining dicarboxylic acids
Data Source
AI summary
Process for obtaining dicarboxylic acids from a mixture of triglycerides of dicarboxylic acids comprising the steps of a) hydrolysing said mixture of triglycerides of dicarboxylic acids in the presence of a basic aqueous solution, resulting in a hydrolysis product emulsion; b) acidifying the product from step a) until the emulsion is separated; c) separating an aqueous phase containing dicarboxylic acids in partly dissociated form and glycerol from the product of step b), d) acidifying the aqueous phase separated in step c) to a pH of 3 or below.