Production of green diesel from karanja oil (Pongamia pinnata) using mesoporous NiMo-alumina composite catalysts

Abstract

NiMo-alumina catalysts with a small quantity of Mo showed ordered mesoporous structure. For 4.3 mmol total metals content, mesoporous structure, however, became disorder for 1.7 mmol and higher Mo content. The C18 alkane was the leading product among hydrocarbons (C15–C22) formed during hydrodeoxygenation of karanja oil. The catalytically active NiMo complex and Mo oxide species with lower oxidation states were substantial in NiMo catalysts with the modest quantity of both Mo and Ni and relatively small for the other two extremes. The catalytic activity and selectivity to C18 alkane were thus enhanced with the rise in Mo content up to 3.4 mmol. The catalytic activity was also improved with growing total metals content and temperature. The optimum catalyst (0.9 mmol Ni and 3.4 mmol Mo) showed the complete conversion of oxygenates with 13 wt% < C18, 75 wt% C18, and 12 wt% > C18 alkanes at 340 °C and 4 h reaction.