ChemInform Abstract: On the Question of Aromatic Ring Expansion-Contraction for Conversions with a ZSM-5 Catalyst.

Abstract

Toluene, labeled with {sup 14}C in either the methyl position or uniformly in the aromatic ring, did not undergo a measurable amount of either ring expansion-contraction or ring degradation to produce ethene at temperatures up to 350{degrees}C. Ethylbenzene dealkylation and disproportionation and xylene isomerization occur to produce equilibrium mixtures of diethylbenzenes or xylenes under these reaction conditions; hence, ring expansion-contraction must be much slower than these isomerization reactions.