ALDEHYDE SEPARATION BY POLYMER-SUPPORTED OLIGO(ETHYLENEIMINES)

Chlorosulfonated styrene (10%) divinylbenzene resin beads reacted with an excess of ethylenediamine (EDA), diethylenetriamine (DETA), and tr iethylenetetramine (TETA) to give the corresponding sulfonamides with pendant oligo(ethyleneimines). The resulting modified resins are usefu l in the separation of aldehydes from hydrocarbon mixtures. Sorption o f aldehydes occurs through formation of both Schiff base and five-memb ered (imidazoline) rings. Sorbed aldehydes can readily be stripped fro m the resins by treating with dilute acid solutions. Since the sulfami de bond has a reasonable stability toward acid-base hydrolysis, the lo aded resins can be regenerated and recycled by simple acid-base washin gs, without losing their activity. In the present study, sorption and desorption kinetics of acetaldehyde, benzaldehyde, and salicylaldehyde have been investigated under different conditions. The aldehyde sorpt ion obeys second-order kinetics. The method presented is applicable fo r all aromatic aldehydes. However, in the case of aliphatic aldehydes carrying an alpha-hydrogen, aldol condensation products form in soluti on. So aliphatic aldehydes and their aldol products are sorbed togethe r by the resins. This limits the recovery of aliphatic aldehydes. Cons equently, the resins described are cost effective sorbents for the rem oval and recovery of aromatic aldehydes from various mixtures. (C) 199 7 John Wiley & Sons, Inc.