The Self-Disproportionation of Enantiomers (SDE) of α-Pinene via Evaporation off Silica Gel and Foam Fractionation—Validation of the Plausibility of SDE via Gas Chromatography (GC) for α-Pinene

α-Pinene is an intriguing monoterpene as it has been reported to undergo the self-disproportionation of enantiomers (SDE) phenomenon via gas chromatography (GC), only compound decisively demonstrate this. Examples SDE involving gaseous phase—sublimation aside—are extremely rare. Attempts replicate GC results were unsuccessful, though authors argued convincingly for difficulty observing phenomenon. However, we could effect α-pinene evaporation off silica gel and by foam fractionation—albeit magnitude both was very slight—to confirm that can processes a phase thus validate plausibility report. The indications are molecular associations responsible various observations occur not in or bulk but rather two-dimensional (2D) adsorbed monolayers based on conventional functional group-based intermolecular interactions instead are, most likely, result homo- heterochiral packing differences 2D monolayers—a well-known chiral-based association effect. These also first reports occurrence using adsorptive bubble separation process (foam fractionation) other than sublimation, GC, distillation.