Nitrogen-15 and Boron-11 NMR Spectroscopy of the System Acetonitrile / H-ZSM-5

Abstract

The interaction of adsorbed acetonitrile with microporous [Si,Al]-ZSM-5 and [Si,B]-ZSM-5 was investigated by solid state NMR.15N-CP MAS NMR of the system H-[Si,Al]-ZSM-5 / acetonitrile clearly shows the Bronsted and Lewis acid site interactions. Different coordination types of the complex ZSM-5/MeCN are considered. The accessibility of the acid sites of [Si,B]-ZSM-5, a material structurally analogous to zeolite ZSM-5, was studied by 11B-MAS NMR. The complexation of acetonitrile at the BO3 sites gives a narrow line at -4 ppm. In contrast to hydration phenomena of ZSM-5, the experiments show that acetonitrile is not capable of interacting with all of the BO3 sites of the borosilicate, presumably due to steric effects.