Characterization of zeolite basicity using probe molecules by means of infrared and solid state NMR spectroscopies

This work reviews the use of pyrrole, chloroform, methanol, as well as methoxy and nitrosonium groups generated ‘in situ’, as infrared and NMR probe molecules to characterize zeolites basicity. The main results reported in the bibliography about the correlation of the spectroscopic properties of the adsorbed molecule with the framework basicity, the host–guest interactions, and the limitations in the use of these molecules as probes for zeolite basicity are discussed. Special attention is paid to the results reported for the adsorption of pyrrole and halocarbons, most specially CHCl3 and CHClF2 over alkali-exchanged FAU-type zeolites using IR and NMR spectroscopies.