A study of the sorbate-sorbent interactions in xylenes/zeolite Y systems by FT-Raman spectroscopy

The adsorption of three (p-, m-, o-) xylene isomers inside zeolite Y with different charge balancing cations including Na+, K+, Ba2+ was studied by FT-Raman spectroscopy. Our Raman data indicate the formation of a n-complex between the xylene and cation as evidenced by observing the weakening of the C-C bonds in the aromatic ring. The strong interaction between a sorbate and a cation results in that the methyl groups of xylene are forced to interact with the local zeolite framework, namely, the six-membered ring that plays host to the cation, leading to an increase in vibrational frequency of methyl groups, upon adsorption. For a given cation, no significant differences were observed for the strength of interaction with any of the three isomers at a loading of I molecule per supercage. (C) 2004 Elsevier Inc. All rights reserved.