Synthesis of C4- and C5-olefins by novel alkane dehydrogenation with H2S co-feeding

In our previous study, an iron-supported silica (Fe/SiO2) catalyst exhibiting excellent activity toward propane dehydrogenation with hydrogen sulfide (H2S) co-feeding was identified. This study investigated the potential application of the Fe/SiO2 catalyst for the dehydrogenation of relatively larger molecules, such as iso-pentane (iso-C5), n-pentane (n-C5), and n-butane (n-C4). The reactivity evaluation showed that Fe/SiO2 exhibited a high activity toward iso-C5 dehydrogenation with H2S co-feeding, producing iso-amylenes, such as 2-methyl-1-butene, 2-methyl-2-butene, and isoprene. The total C5-olefin yield obtained using the Fe/SiO2 catalyst was higher than that obtained using Co/SiO2 and Ni/SiO2 catalysts. When Fe/SiO2 was applied to the dehydrogenation of n-C4 and n-C5 with H2S co-feeding, C4- and C5-olefins were obtained, respectively, with relatively high selectivities. In particular, the Fe/SiO2-catalyzed n-C4 dehydrogenation exhibited greater selectivity than iso-C5 and n-C5 dehydrogenations; the product of the n-C4 dehydrogenation was stable for 20 h. Figure Schematic diagram of dehydrogenation of iso-pentane with co-feeding H2S on Fe-based catalyst. Blown sphere is Fe cation and yellow cation is S anion. And FeSx catalyst was supported on SiO2 support. Dehydrogenation of iso-pentane proceeded on the catalyst with selectively and stably. [Display omitted] •Fe/SiO2 catalyst was highly active for iso-C5 dehydrogenation with H2S.•Fe/SiO2 catalyst displayed higher performance than the Co/SiO2 and Ni/SiO2.•Valuable olefins were obtained by the dehydrogenation of n-C4 and n-C5 with H2S.•n-C4 dehydrogenation showed higher selectivity than iso-C5 and n-C5 dehydrogenations.