Ethene and ethyne molecules interacting with Cu+ sites in zeolites—Quantitative infrared spectroscopic studies

Infrared spectroscopic studies have been carried out to address the question of the Cu+ cation migration from hexagonal prisms (SI) and cubooctahedra (SI′) to supercages upon adsorption of ethene and ethyne in CuNaY and CuNaX zeolites. The quantitative assessment of Cu+ content in supercages before ethene and ethyne adsorption was evaluated on the basis of carbon monoxide adsorption experiments and molar absorptivities of Cu+(CO) bands. The same procedure was adapted to estimate the concentration of Cu+ inside supercages in the presence of ethene and ethyne, where the appropriate molar absorptivities of Cdouble bond; length as m-dashC and Ctriple bond; length of mdashC bands was applied. This method seems to be complementary to XRD studies. Since it is insufficient to know the distribution of the cations between Sn positions, the actual number of the cationic sites engaged into the interaction with the reagents under the working conditions of the material was found with the use of IR spectroscopy.