Effect of H2S co-feeding on the performance of the Fe/SiO2 catalyst for isomerization and dehydrogenation of C5-monoolefin

Abstract

In this study, we aimed to produce isoprene, a diolefin, from a mono-olefin produced by the dehydrogenation of isopentane (iso-C₅). Specifically, we attempted to isomerise 2-methyl-2-butene (2M2B), a C₅ mono-olefin, followed by dehydrogenation to produce isoprene. The reaction characteristics of the Fe/SiO₂ catalysts were investigated in detail. In the presence of hydrogen sulphide (H₂S), 2M2B was converted to 2-methyl-1-butene (2M1B) and the target product, isoprene. However, in the absence of H₂S, only the isomerisation reaction proceeded, producing 2M1B; isoprene was not produced. Notably, the isoprene yield remained almost unchanged when the concentration of H₂S decreased. Furthermore, when isoprene was produced by mixing iso-C₅ and mono-olefins (2M2B and 2M1B), the amount of isoprene produced was significantly higher than that from iso-C₅ alone. These results indicate that our synthetic strategy is promising for isoprene production.