Poly(2,6-diphenyl-p-phenylene oxide) supported iron catalysts for the synthesis of lower olefins via Fischer–Tropsch reaction

A porous polymer, based on 2,6-diphenyl-p-phenylene oxide (PPPO) was used as support material for Fischer–Tropsch to Olefin (FTO) reaction. In an effort to understand the effect of support on the transport of reaction intermediates formed on the surface and its relation with the product selectivity, PPPO supported iron catalyst was prepared, characterized and tested under FTO conditions. Alkali promoters were used to improve the olefin selectivity. It was shown that iron oxide formed by the calcination of iron nitrate seemed to be less prone to reduction compared to the direct use of hematite. A high C2–C4 olefin to paraffin ratio (O/P) was achieved over the alkali promoted and PPPO supported iron catalysts. Alkali promotion apparently suppressed the hydrogenation of α-olefins to paraffins and methane formation but at the expense of catalytic activity. It was shown that highly stable catalysts with improved olefin selectivity can be prepared by using poly(2,6-diphenyl-p-phenylene oxide) polymeric supports.