Hydrodesulphurization of Thiophene: Ii. Reactions Over a Chromia Catalyst

The hydrodesulphurization of thiophene to butane and H2S over chromia has been studied by flow and microreactor techniques. The sulphided, i.e. mixed oxide–sulphide, catalyst showed improved desulphurization activity compared to pure chromia, while butene hydrogenation activity was reduced by a factor of at least 103. The apparent activation energy of the flow reaction was 24–25 kcal/mole. No organosulphur compounds were found among the products. The reaction proceeded predominantly via butadiene and butene intermediates, with a preference for 1-butene; their rates of hydrogenation as well as the rates of isomerization of the butenes have been compared as a function of temperature. The reaction also partly went to completion at the original desulphurization site, without the desorption of intermediates, presumably by a series of analogous steps on the surface.