Ethane conversion: Kinetic evidence for the competition of consecutive steps for the same active centre

The kinetics of ethane dehydrogenation over catalysts with distinct aromatization properties unveiled some peculiar features of site ''bifunctionnality''. It was shown that the apparent activation energy of ethane dehydrogenation decreased as the aromatizing ability of the catalyst increased. The kinetic data were interpreted in terms of a homographic variation of the dehydrogenation rate with the selectivity to aromatics. The data fit well a scheme where dehydrogenation of ethane and aromatization of intermediate higher hydrocarbons take place competitively over the same active centre.