Oil transesterification over calcium oxides modified with lanthanum

Investigations were conducted on a series of calcium and lanthanum oxides catalyst for biodiesel production. Mixed oxides catalyst showed a superior transesterification activity over pure calcium or pure lanthanum oxide catalysts. The catalyst activity was correlated with surface basicity and specific surface areas. The effects of water and free fatty acids (FFA) levels in oil feedstock, water and CO2 in air, mass ratio of catalyst, molar ratio of oil to methanol, and reaction temperature on fatty acid methyl ester (FAME) yield were investigated. Under optimal conditions, FAME yields reached 94.3% within 60 min at 58 °C. Mixed CaO-La2O3 catalyst showed a high tolerance to water and FFA, and could be used for converting pure or diluted unrefined/waste oils to biodiesel.

Graphical abstractA single-step method was developed for biodiesel production from unrefined or waste oils using a series of heterogeneous calcium and lanthanum mixed oxides. The catalyst activity was closely correlated with the surface basicity and specific surface area. A high yield (96%) of FAME was obtained within 3 h even using unrefined or waste oils.Figure optionsDownload full-size imageDownload as PowerPoint slide