Production of biodiesel from Calophyllum inophyllum oil using a cellulose-derived catalyst

Calophyllum inophyllum oil is non-edible with high potential as biodiesel feedstock. This study addressed the multiple stages involved in producing biodiesel from C. inophyllum oil by synthesizing a solid acid catalyst from freely available biomass. Microcrystalline cellulose used as the starting material was pyrolyzed to obtain a polycyclic aromatic carbon capable of binding SO3H groups upon sulfonation in concentrated sulfuric acid. Esterification activity of the catalyst towards the free fatty acid found in C. inophyllum oil was superior to the catalyst obtained from d-glucose. The catalyst was also capable of one-pot production of biodiesel from the feedstock with acid value of 29.5 mg KOH/g. High conversion to fatty acid methyl esters (∼99 wt.%) was achieved using 1:15 M ratio of oil to methanol with a catalyst loading of 5 wt.% at 180 °C for 4 h. The catalyst also displayed high catalytic stability by retaining about 85% of its original activity. This work shows that the catalyst can replace homogeneous catalysts currently employed to produce biodiesel from C. inophyllum oil.