Biodiesel Production From Oleic Acid Using Biomass-Derived Sulfonated Orange Peel Catalyst

Biodiesel, as an alternative fuel for petroleum-based fuel, has recently acquired significant attention. The current study focused on using biowaste to produce catalysts for low-cost biodiesel manufacturing. Orange peels (OP) were used to make carbon-based solid acid catalysts with sulfonic acid group (–SO3H) density of 1.96 mmol g−1 via a “one-pot” carbonization-sulfonation treatment. Under the optimized reaction conditions (15:1 MeOH to oleic acid molar ratio, 7 wt.% catalyst loading w.r.t oleic acid, 80°C reaction temperature, 60 min reaction time), 96.51 ± 0.4% conversion of oleic acid to methyl oleate (a biodiesel component) was obtained. The catalyst displayed high recyclability and stability on repeated reuse, with a negligible decrease in biodiesel conversion up to 5 catalytic cycles.