Size and packing related adsorption effects in the liquid phase adsorption of aromatics and alkenes on FAU type zeolites

摘要

Batch adsorption experiments with binary liquid hydrocarbon mixtures allowed to detect two size related packing effects in zeolite NaY.Already at low concentration,aromatics (benzene,toluene,m-xylene and mesitylene) are very selectively adsorbed from their mixtures with 1-octene and heptane.While benzene,toluene and m-xylene are able to fill >90% of the supercage volume,the maximum adsorption capacity for mesitylene amounts only 69% of the supercage volume.This unexpected capacity reduction is attributed to a different pore filling mechanism.Alkenes (hexene,octene,dodecene) are selectively adsorbed from their mixtures with decane.An increase in selectivity is observed with decreasing chain length of the alkene,because small alkenes pack more efficiently compared to large alkenes in the supercages of NaY.