Recycling Light Phase in Liquid-Liquid Extractors
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Solution Overview
Problem
The recovery of diphosphonite-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 a recycling mechanism, where a portion of the light phase is recycled from the settling section to the mixing section, enhancing the separation of emulsion phases and reducing rag layer formation, thereby improving the extraction efficiency of diphosphonite-containing compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid-liquid extraction is used to recover diphosphonite-containing compounds from hydrocyanation reaction product mixtures, then catalyst and ligand recovery is achieved, but emulsion phases and rag layers form which impede phase separation
Solution Approach 1:
The patent introduces an intermediary substance (such as a surfactant or demulsifier) to break down the emulsion phases and prevent rag layer formation. This intermediary acts as a mediator between the organic and aqueous phases, facilitating clean phase separation while maintaining the extraction efficiency of diphosphonite-containing compounds.
Solution Approach 2:
The patent modifies operational parameters such as temperature, pH, or mixing intensity to prevent emulsion stabilization. By changing these parameters, the system avoids the formation of stable emulsion phases that lead to rag layers, thereby ensuring reliable phase separation without compromising the extraction process.
2Productivity
If extended period extraction is performed to improve recovery efficiency, then more diphosphonite-containing compounds are extracted, but rag layer formation increases and halts phase separation
Solution Approach 1:
The patent applies preliminary action by adding phase separation aids or demulsifiers before the extraction process begins, or at the onset of emulsion formation. This preliminary intervention prevents the cumulative buildup of rag layers during extended extraction periods, allowing continuous operation without interruption.
Solution Approach 2:
The patent implements continuous phase separation mechanisms that operate throughout the extended extraction period. By maintaining continuous action rather than batch processing, the system prevents emulsion stabilization and rag layer formation, ensuring both high productivity and reliable phase separation over extended operation.
3Object-generated harmful factors
If ammonia or amine is added to remove rag layer as in prior art, then rag layer is removed, but this approach is not effective for diphosphonite ligands
Solution Approach 1:
The patent applies local quality by selecting specific demulsifying agents that are tailored to the chemical properties of diphosphonite ligands rather than using universal agents like ammonia. This localized approach targets the specific interfacial properties of diphosphonite-containing emulsions, making the rag layer removal effective where prior art fails.
Solution Approach 2:
The patent changes the chemical parameters of the demulsifying agent to match the requirements of diphosphonite ligand systems. By adjusting parameters such as molecular structure, polarity, or functional groups of the separation aid, the system achieves effectiveness for diphosphonite-specific emulsions that differ from the phosphite systems addressed in prior art.
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
The recycling of the light phase leads to reduced emulsion phase size, increased settling rate, and enhanced recovery of diphosphonite-containing compounds, potentially preventing shutdowns due to rag layer buildup and improving overall extraction efficiency.
Implementation Method 1
a light phase separates from a heavy phase in the settling section
Implementation Method 2
contacting the feed mixture with extraction solvent in the multistage countercurrent liquid-liquid extractor
Implementation Method 3
the light phase comprises extraction solvent and extracted diphosphonite-containing compounds
Data Source
Figure 1~3
Figure 4
AI summary
Disclosed herein are methods for recovering diphosphonite-containing compounds from mixtures comprising organic mononitriles and organic dinitriles, using liquid-liquid extraction. Also disclosed are treatments to enhance extractability of the diphosphonite-containing compounds.