Polyamine Additive for Nitrile Extraction Phase Separation
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Solution Overview
Problem
Current methods for recovering catalysts and adiponitrile from hydrocyanation reaction products face issues such as emulsion phase stability, rag layer formation, and unwanted cyclization reactions due to the use of Lewis bases like water and ammonia, which can hydrolyze sensitive ligands or form complexes that promote undesirable reactions.
Innovation Solution
The use of polyamines, particularly bis-hexamethylene triamine, as Lewis base additives that form a solid complex with Lewis acids, which can be easily separated and removed, facilitating efficient countercurrent multistage liquid-liquid extraction and preventing cyclization reactions by being filtered out before distillation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If water or ammonia is added as Lewis base to enhance phase separation, then settling efficiency is improved, but hydrolysis of water-sensitive ligands occurs and unwanted cyclization reactions are promoted
Solution Approach 1:
A water-soluble Lewis base additive is introduced as an intermediary substance that preferentially complexes with the Lewis acid catalyst in the aqueous phase, preventing the Lewis acid from catalyzing unwanted reactions while still allowing the Lewis base to enhance phase separation. The additive acts as a mediator between the Lewis acid and the system, controlling its reactivity.
Solution Approach 2:
The invention changes the chemical parameters by selecting a specific water-soluble Lewis base additive with appropriate basicity and complexing characteristics. This parameter change allows the system to achieve enhanced settling while controlling the chemical reactivity to prevent hydrolysis and cyclization of sensitive compounds.
2Productivity
If extended extraction is performed to improve recovery efficiency, then catalyst and adiponitrile recovery is enhanced, but interfacial rag layer formation increases which hinders phase separation
Solution Approach 1:
The water-soluble Lewis base additive serves as an intermediary that modifies the interfacial properties between phases. By complexing with the Lewis acid in the aqueous phase, it reduces interfacial tension and prevents rag layer formation, allowing extended extraction to proceed without operational difficulties.
Solution Approach 2:
The Lewis base additive is introduced preliminarily into the system before extended extraction begins. This preliminary action prepares the system by establishing proper phase separation characteristics, preventing rag layer formation during the subsequent extended extraction process.
3Speed
If Lewis base is added to reduce emulsion phase size, then settling rate is enhanced, but rag layer build-up occurs in the settling section
Solution Approach 1:
The water-soluble Lewis base additive acts as an intermediary that modifies the behavior of the emulsion phase and rag layer formation. By complexing with the Lewis acid, it changes the interfacial properties to reduce stable rag layer build-up while maintaining enhanced settling rate.
Solution Approach 2:
The invention changes the chemical composition parameters by adding a specific water-soluble Lewis base that alters the physical-chemical properties of the emulsion phase and rag layer, reducing their stability and preventing excessive build-up while maintaining fast settling.
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 enhances the separation efficiency of catalysts and adiponitrile, reduces rag layer formation, and prevents unwanted cyclization reactions, allowing for effective recovery of adiponitrile while maintaining the integrity of sensitive ligands.
Implementation Method 1
polyamines, particularly bis-hexamethylene triamine, as Lewis base additives that form a solid complex with Lewis acids
Implementation Method 2
efficient countercurrent multistage liquid-liquid extraction
Data Source
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AI summary
Disclosed herein are methods for recovering phosphorus-containing ligand from mixtures comprising organic mononitriles and organic dinitriles, using liquid-liquid extraction. Also disclosed are treatments to enhance extractability of the phosphorus-containing ligand.