Sorption of single enantiomers and racemic mixture of (+/−)-α-pinene into Nafion membranes

Abstract

The aim of this work was to elucidate the sorption of α-pinene in the membranes of solution-cast and melt-extruded Nafion. The extruded membrane was Nafion® 115 in H+ form (DuPont). The cast Nafion membrane was prepared by casting from a 20 wt.% solution of Nafion® (H+ form) in lower aliphatic alcohols and water. (+)-α-pinene, (−)-α-pinene and racemic mixture sorption isotherms were determined by a gravimetric method using the sorption balance. It was found that the sorption of α-pinene in the Nafion membrane is a stereoselective process. The sorption of α-pinene in cast Nafion is much higher than in extruded Nafion. The sorption of (+)-α-pinene in the extruded Nafion membrane is quite low while the sorption of (−)-α-pinene approaches zero. The sorption of (−)-α-pinene in the cast Nafion membrane is high while the sorption of (+)-α-pinene is low.