Liquid-Liquid Extraction of Aniline Compound

Koch Modular Process Systems has extensive experience in process optimization related to extracting components from solutions that are too difficult or cannot be economically separated through distillation. This process is known as liquid-to-liquid extraction (LLE) or solvent extraction (SX).

The client was looking to convert an existing batch process into a continuous process using an extraction column. Koch Modular Process Systems was engaged to solve client’s difficult separation involving liquid-to-liquid extraction of an aniline compound from a toluene-rich feed stream using a mildly acetic aqueous phase as the solvent.


Client engaged Koch Modular to purify its product from a toluene solution and to remove an Aniline Compound impurity.  Koch modular initially attempted pilot testing utilizing a Scheibel © Column due to appropriate density differences between the toluene feed phase and the aqueous phase solvent.

However, during initial testing with the organic phase continuous and dispersed aqueous phase, excessive coalescing of the aqueous droplets on the metal internals led to poor column operation.  Switching the phases (aqueous continuous) was operationally better, but resulted in poor efficiency due to the Marangoni effect which favors mass transfer form continuous to phase.


Pilot testing switched to the KARR ®Column using PTFE plates, allowing for excellent operation with the aqueous phase continuous while also providing the optimal direction of mass transfer.


Following successful pilot testing, Koch Modular designed a KARR® Column tailored to client’s feedstock wetting characteristics delivering the required specification of less than 1 part per million of the aniline compound within the raffinate.