ABSTRACT
Examination of the influence of H2S on the reaction of thiophene under atmospheric pressure between 300 and 400°C shows a complex behaviour : the usual inhibiting effect switches to a promoting effect well evidenced when the reaction is performed at high temperature. Moreover, the apparent activation energy gradually decreases with increasing temperature. These features were modelled by a kinetic expression assuming dearomatization of the thiophene ring as the key step. The reaction is governed by both hydrogen and hydrogen sulfide which provide the proton-like species reacting with adsorbed thiophene. The relative contribution of these two components to the overall rate depends on the experimental conditions.
