TEMPERATURE SWITCHED IN-SITU H-1 AND C-13 MAS NMR-STUDIES OF THE CATALYTIC CONVERSION OF METHANOL ON ZEOLITE ZSM-5

We have observed the time dependence of the first steps of the methanol to hydrocarbons conversion (MTG process) in zeolite H-ZSM-5 at 230 degrees C using the MAS (magic-angle spinning) technique with a laser heating system. It was found that the concentration of protons in the species with stronger polarized O-H bonds increases during the reaction up to 60 % at equilibrium. Moreover, the appearance of carbon monoxide during the conversion of methanol to hydrocarbons were elucidated.