New Separations Technology for Aromatic Chemicals

Separations among substituted aromatic isomers, which are very difficult or impossible by conventional means, can be accomplished by liquid-phase adsorption. Efficient commercial implementation of liquid-phase adsorption for bulk separations has been accomplished via a simulated moving-bed technique. This technique, which can generally be applied to bisubstituted isomers (e.g., cresols, chloronitrobenzenes, nitrotoluenes), is described through the use of laboratory, pilot-plant, and commercial examples.