Sulfation of metal-organic framework (MOF) nanocatalyst for esterification of oleic acid with methanol to produce biodiesel

Metal-organic frameworks (MOFs) represent tremendous potential as heterogeneous catalyst in renewable energy production. In this study, biodiesel production using the modified MOF nanocatalyst was investigated in the esterification reaction.

MOF nanocatalyst was prepared using solvothermal method and modified through sulfation process. The nanocatalysts was characterized by XRD, FT-IR, FE-SEM, TEM, N2 adsorption-desorption, and NH3-TPD techniques. The performance of the nanocatalysts was evaluated in the esterification reaction of free fatty acid (FFA) at different operating conditions.

The results showed the high crystallinity, appropriate textural properties (995.6 m2g-1), well-adjusted acidity, and high hydrophobicity. The sulfation degree of 4 cc g-1 resulted in the best nanocatalyst, which led to the highest FFA conversion (97%) at the optimal conditions: methanol to FFA ratio of 10:1, 3wt.% nanocatalyst, 160 °C, and 6 hours. Surprisingly, the developed nanocatalyst had a great reusability while the conversion reduction was only 8% after six sequence cycles.

These results proved the high capability of the developed nanocatalyst in the esterification reaction to produce biodiesel.