NMR studies of heterogeneous catalysis require that the environment be controlled during the measurement. We overcame this problem by using sealed microreactors which can be spun inside the NMR probehead. We have studied the conversion of methanol to gasoline on several molecular sieve catalysts, and other reactions need to be urgently examined. Experiments will be performed under in situ conditions using a high-temperature probehead, allowing us to observe all organic molecules as they are generated. The results will assist the understanding of important industrial processes and the design of shape-selective solids. Two processes will be examined:
1 . Isomerization of xylene, used as a test reaction of the
shape-selective properties of zeolites. The reaction is of commercial significance because it directs C-8-arene towards p-xylene.
2. Alkylation of aromatics. The directing power of a zeolite structure in the reaction of alkylbenzenes with methanol or formaldehyde manifests itself in the selective attack either at the aromatic nucleus or at the side chain. The process is important for the production of styrene and ethylbenzene. By monitoring the formation of intermediates light will be shed on the steric protection afforded to the aromatic nucleus by the wide-pore catalysts.