MULTINUCLEAR NMR AND CATALYTIC INVESTIGATIONS OF DEACTIVATION OF ZEOLITE H-ZSM-5

Coke formation and catalyst deactivation by the reaction of methanol over a zeolitic catalyst based on H-ZSM-5 for various stream gases (N2, H2 or C4H10) were studied by13C CP MAS NMR,29Si MAS NMR,129Xe NMR and catalytic test reactions with different stream gases (N2, H2, C4 H10). The rate of deactivation varies in the order N2 < H2 < C4H10, which can be explained by cracking of paraffinic, olefinic and alkylaromatic coke deposits under the influence of the hydrogenating properties of the stream gas. © 1990 J.C. Baltzer A.G. Scientific Publishing Company.