One-step production of biodiesel from Jatropha oils with high acid value at low temperature by magnetic acid-base amphoteric nanoparticles

Biodiesel production from Jatropha oils with high acid value at low temperature was catalyzed with synthesized novel magnetic acid-base amphoteric nanoparticles (< 46 nm). Alkaline oxides (ZnFe2O4, ferrihydrite, zincite, maghemite and magnetite) concerted with acidic -COOFe structure, benefited the one-pot esterification and transesterification of Jatropha oils with high acid value to produce biodiesel without additional pretreatment. The strong magnetism of catalyst helped catalyst separation for recycle in continuous biodiesel production. Jatropha biodiesel yield of 100% at 160 degrees C within 4 h, with methanol/oil molar ratio of 40/1 and catalyst dosage of 7 wt% was achieved, while the catalyst can be cycled for at least 10 times with biodiesel yield > 94.3% at acid value of 6.3 mg KOH/g. No obvious saponification was observed during the reactions and storage.