Ultrafiltration Separation of Dicarboxylic Acids from Aqueous Mixtures

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Solution Overview

Problem

Current methods for separating and purifying long chain dicarboxylic acids from aqueous mixtures are not economically viable and lack efficiency and selectivity, making it difficult to obtain high-purity dicarboxylic acids.

Innovation Solution

A process involving the conversion of mono- and dicarboxylic acids into a salt form by adjusting the pH to 8 or greater, followed by ultrafiltration, where the monocarboxylic acids are selectively retained in the retentate and the dicarboxylic acids pass into the permeate, allowing for their recovery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional separation methods (crystallisation, distillation, liquid/liquid extraction) are used, then dicarboxylic acids can be separated from aqueous mixtures, but the processes are economically unfavourable and lack efficiency and selectivity

Engineering Contradiction:

Improveeconomic viabilityVSAvoidpurity of dicarboxylic acids

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention changes the chemical state parameter of the acids by converting them to salt form through pH adjustment to 8 or greater. This parameter change enables selective retention of monocarboxylic acid salts in the retentate during ultrafiltration while dicarboxylic acid salts pass into the permeate, achieving both economic viability and high purity separation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention introduces an intermediary substance (base) to convert the carboxylic acids into their salt forms. This intermediary enables the ultrafiltration process to selectively separate monocarboxylic acids from dicarboxylic acids based on their different retention behaviors in salt form, resolving the contradiction between economic feasibility and separation efficiency

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If pH is adjusted to convert acids to salt form for ultrafiltration, then selective separation is achieved, but additional process steps are required

Engineering Contradiction:

Improveselectivity of separationVSAvoidnumber of process steps

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention merges the pH adjustment step with the ultrafiltration process into a integrated separation system. The pH adjustment to convert acids to salts is performed immediately before ultrafiltration, and the subsequent acidification of the permeate to recover dicarboxylic acids is combined with the filtration process, reducing overall process complexity while maintaining high selectivity

Inventive Principle:

Principle #5Merging (Combining)

3Manufacturing precision

If ultrafiltration is used to separate monocarboxylic acids from dicarboxylic acids in salt form, then high purity dicarboxylic acids are obtained, but energy and resources are consumed for pH adjustment and subsequent acidification

Engineering Contradiction:

Improvepurity of separated acidsVSAvoidenergy for pH adjustment and acidification

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The invention applies the discarding and recovering principle by directing the permeate containing dicarboxylic acid salts to an acidification step where the acids are recovered in high purity form. The monocarboxylic acid salts retained in the retentate are discarded or can be processed separately. This selective recovery approach minimizes energy consumption compared to treating the entire mixture, as only the permeate stream requiring acidification is processed

Inventive Principle:

Principle #34Discarding and recovering

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 separates and purifies long chain dicarboxylic acids from monocarboxylic acids, achieving high purity and efficiency, suitable for use in both fermentation and conventional chemical processes, while being economically favorable.

Implementation Method 1

subjecting the said aqueous mixture to ultrafiltration

Methodology Applied

Scientific EffectUltrafiltration: Semipermeable Membrane

Implementation Method 2

the monocarboxylic acids are selectively retained in the retentate and the dicarboxylic acids pass into the permeate

Methodology Applied

Scientific EffectSize exclusion: Filter (physical)

Implementation Method 3

converting the mono- and dicarboxylic acids into a salt form by adjusting the pH to 8 or greater

Methodology Applied

Scientific EffectpH adjustment:

Implementation Method 4

The permeate is then acidified and the dicarboxylic acids are recovered from the acidified permeate

Methodology Applied

Scientific EffectAcidification:

Data Source

PatentUS10099991B2Process for the separation of dicarboxylic acids from aqueous mixtures

Publication Date: 2018.10.16 NOVAMONT SPA

AI summary

This invention relates to a process for the separation of dicarboxylic acids from aqueous mixtures of CV8C24 mono- and dicarboxylic acids. In particular this invention relates to a process for the separation and purification of the said mixtures which uses an ultrafiltration stage.