ISOTOPIC TRACER STUDIES OF PROPANE REACTIONS ON H-ZSM5 ZEOLITE

Reactions of C-13-labeled alkanes show that chain growth and cyclizati on reactions on H-ZSM5 require the initial formation of the correspond ing alkene and its extensive participation in rapid oligomerization/be ta-scission reactions before cyclization occurs. The role of alkene in termediates was established by the initial formation of predominantly unlabeled products from mixtures of propene and propane-2-C-13 reactan ts. Aromatic products of propane-2-C-13 reactions on H-ZSM5 contain si milar fractions of C-13-atoms and binomial isotopomer distributions. S equential formation, rapid intramolecular isomerization, and beta-scis sion reactions of long surface chains must occur during each aromatiza tion turnover in order to form such binomial C-13 isotopomer distribut ions.