Abstract: The product distribution and the rate constants of the transformation of cyclohexane, methylcyclohexane and methylcyclopentane over ZnZSM-5 and HZSM-5 have been studied by the pulse microreactor technigue. It is found that the aromatic distribution produced over these two catalysts are completely different. Over ZnZSM-5, the cyclohexane and methyleyclopentane are mainly converted to benzene, methylcyclohexane to toluene, showing a nearly complete dehydrogenation behavior, while the transformation of these cycloalkanes over HZSM-5 leads to yield a BTX mixture, indicating a typical consecutive reaction scheme, catalyzed by a monofunctional acid catalyst. These reactions are proved to be of the first order. Their apparent rate constants and activation energies were measured in the temperature range of 370~450 ℃.
For the aromatization of the methylcyclopentane, the transformation appears to proceed by methylcyclopentane isomerization to cyclohexane, followed by dehydrogenation. The kinetic data shows that the first step, i.e. isomerization, is much faster than the cyclohexane dehydrogenation.
The relative reaction rates over...

Key words: Cyclohexane, Methycyclohexane, Methylcyclopentane, ZnZMS-5, HZSM-5, Aromatization, Pulse microreacton technique