ADSORPTION OF AROMATICS IN NAY AND AIPO4-5 - CORRELATION WITH THE SORBENT PROPERTIES IN SEPARATIONS

The adsorption of benzene and o-xylene is studied by means of infrared spectroscopy on AlPO4-5 and NaY. These aromatics do not interact significantly with AlPO3-5, but changes in the packing of these molecules alter the shape of the infrared spectra. On NaY a strong cation-ir electron interaction is observed for the two hydrocarbons and for other aromatics. The selectivity in the separation of C8aromatics by weak adsorption on AlPO4-5 (preference for o-xylene) is related to the high cohesive energy of this hydrocarbon. The selectivity of these hydrocarbons by strong adsorption on NaY (preference for m-xylene) is related to the favored interaction of this isomer, which is the most basic, with the acidic Na+ions. © 1990, American Chemical Society. All rights reserved.