Lewis Base Additive for Emulsion Control in Liquid-Liquid Extraction
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Solution Overview
Problem
The recovery of diphosphite-containing compounds from hydrocyanation reaction product mixtures is hindered by the formation of emulsion phases and rag layers in multistage countercurrent liquid-liquid extractors, which impede phase separation and catalyst extraction efficiency.
Innovation Solution
A process involving a multistage countercurrent liquid-liquid extractor with the addition of a Lewis base to the settling section, which enhances the settling of emulsion phases, reduces rag formation, and increases the extraction of diphosphite-containing compounds into the light phase, using aliphatic or cycloaliphatic hydrocarbons as extraction solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid-liquid extraction is used to recover diphosphite-containing compounds from hydrocyanation reaction product mixtures, then catalyst recovery is achieved, but emulsion phases and rag layers form which impede phase separation
Solution Approach 1:
A Lewis base is introduced as an intermediary substance that reacts with the Lewis acid catalyst to form a complex, thereby modifying the interfacial properties and preventing emulsion formation. The Lewis base acts as a mediator between the catalyst and the extraction system to eliminate the harmful emulsion phase.
Solution Approach 2:
The chemical composition parameters of the extraction system are changed by adding a Lewis base, which alters the interfacial tension and phase behavior. This parameter change transforms the system from one that forms stable emulsions to one that achieves clean phase separation.
2Productivity
If continuous extraction operation is maintained, then productivity is improved, but rag layers accumulate at the interface which eventually halt the process
Solution Approach 1:
The Lewis base is added in advance to prevent rag layer formation before it can accumulate to problematic levels. This preliminary anti-action eliminates the need for continuous rag removal and maintains uninterrupted operation.
Solution Approach 2:
By preventing rag layer formation through the Lewis base addition, the extraction process maintains continuous operation without interruptions for rag removal, ensuring uninterrupted productivity.
3Productivity
If emulsion phases are allowed to form during extraction, then mixing and contact between phases is enhanced, but separation time increases and efficiency decreases
Solution Approach 1:
The Lewis base serves as a mediator that modifies the phase interaction characteristics, allowing for effective mass transfer during mixing while preventing stable emulsion formation during separation, thus reducing separation time without compromising extraction efficiency.
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 approach reduces the size and formation rate of emulsion phases and rag layers, thereby improving the separation efficiency and recovery of diphosphite-containing compounds, ensuring continuous operation and increased catalyst recovery.
Implementation Method 1
wherein a complex of Lewis acid and Lewis base is formed in the settling section in the mixer-settler of the first stage
Implementation Method 2
contacting the feed mixture with extraction solvent from the second stage of the multistage countercurrent liquid-liquid extractor in the mixing section of the mixer-settler of the first stage to form a mixed phase comprising a light phase and a heavy phase, wherein the light phase comprises extraction solvent and extracted diphosphite-containing compounds
Implementation Method 3
passing the mixture from step (b) to a settling section in the mixer-settler of the first stage, wherein the mixed phase separates into the light phase and the heavy phase
Data Source
Figure 1~3
AI summary
Disclosed herein are methods for recovering diphosphite-containing compounds from mixtures comprising organic mononitriles and organic dinitriles, using liquid-liquid extraction. Also disclosed are pre-treatments to enhance extractability of the diphosphite-containing compounds.