The dehydrogenation and aromatization of methane on modified ZSM-5 zeo
lite catalysts has been studied under non-oxidizing conditions with a
fixed bed continuous-flow reactor and with a temperature programmed re
actor. The results show that benzene is the only hydrocarbon product o
f the catalytic conversion of methane at high temperature (973 K). The
catalytic activity of ZSM-5 is greatly improved by incorporating a me
tal cation (Mo or Zn). H-2 and ethene have been directly detected in t
he products with a mass spectrometer during TPAR. A carbenium ion mech
anism for the activation of methane is suggested.