Separating High-Boiling Carboxylic Acid Vinyl Esters via Anhydride Conversion
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Solution Overview
Problem
The separation of high-boiling carboxylic acid vinyl esters and high-boiling carboxylic acids through distillation is challenging due to their close and high boiling points, making it difficult to achieve on an industrial scale, especially when mixtures with different chain lengths are involved, and existing methods require complex process steps or are limited in applicability.
Innovation Solution
Converting the high-boiling carboxylic acid into its corresponding anhydride using a low-boiling anhydride or reactive distillation with a low-boiling carboxylic acid vinyl ester in the presence of a catalyst, allowing for the subsequent separation of the carboxylic acid vinyl ester without requiring complex solid-liquid separation steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If distillation is used to separate high-boiling carboxylic acid vinyl ester and carboxylic acid mixtures, then separation is attempted, but the process becomes increasingly difficult and impractical as molecular weight increases due to very high and close boiling points
Solution Approach 1:
The patent transforms the separation problem from a physical distillation process to a chemical reaction process. By changing the parameter from boiling point difference (physical property) to reactivity difference (chemical property), the separation becomes feasible. The carboxylic acid reacts with alcohol to form ester and water, while the vinyl ester remains unreacted, enabling separation through simple filtration or decantation instead of complex distillation.
Solution Approach 2:
The patent introduces an intermediary substance (alcohol) that selectively reacts with one component (carboxylic acid) but not the other (vinyl ester). This intermediary enables the separation by forming a new compound (ester) that can be easily separated from the original mixture, avoiding the need for direct separation of the two high-boiling components.
2Manufacturing precision
If sodium hydroxide is added to convert carboxylic acid to sodium salt for separation, then the vinyl ester can be separated by filtration, but complex solid-liquid separation steps and additional chemical process steps are required
Solution Approach 1:
Instead of converting carboxylic acid to its salt form (as in prior art), the patent inverts the approach by reacting carboxylic acid with alcohol to form ester. This reverse strategy avoids salt formation and the associated complex solid-liquid separation steps, achieving separation through simpler liquid-liquid or solid-liquid separation of the ester product and unreacted vinyl ester.
Solution Approach 2:
The patent extracts the carboxylic acid component from the mixture by converting it to ester through reaction with alcohol. This extracted ester can then be easily separated from the vinyl ester, avoiding the need for complex filtration and conversion steps required by the sodium salt method.
3Manufacturing precision
If fractional distillation is used to separate vinyl stearate from stearic acid, then some separation is achieved, but the process requires precise design and cannot handle mixtures with different chain lengths effectively
Solution Approach 1:
The patent replaces the mechanical distillation system with a chemical reaction system. Instead of relying on boiling point differences (mechanical/physical separation), the system uses selective chemical reaction between carboxylic acid and alcohol. This substitution makes the process adaptable to various chain lengths and compositions, as the chemical reactivity difference remains consistent regardless of molecular weight variations.
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 enables the selective separation of high-boiling carboxylic acid vinyl esters from carboxylic acids with high purity and simplicity, making them accessible on an industrial scale without the need for complex chemical process steps, and allows for the reuse of the resulting anhydride in transvinylation reactions.
Implementation Method 1
converting the carboxylic acid into its corresponding anhydride or into an ester with an alcohol
Implementation Method 2
in the presence of a catalyst
Data Source
AI summary
The invention relates to a method for separating a mixture containing at least one carboxylic acid vinyl ester of general formula R'-C(O)O-CH=CH2 and at least one carboxylic acid of general formula R'-COOH, wherein R' in either case can be an aliphatic group having 12 to 22 C atoms or a cycloaliphatic group having 12 to 22 C atoms, or an aromatic group having 12 to 22 C atoms, and R' can be identical or different, characterized in that the carboxylic acid is converted to its anhydride R'-C(O)-O-C(O)-R' and the carboxylic acid vinyl ester is subsequently separated.