Production of biodiesel through the transesterification of Jatropha seed oil catalyzed by S-1 and TS-1 zeolite supported molybdenum catalysts

Microporous and mesoporous silicalite-1 (S-1) and titanium silicalite-1 (TS-1) zeolite supported molybdenum (Mo) catalysts were synthesized and applied in the transesterification of Jatropha seed oil (JO) to produce biodiesel. Various analytical results have revealed that the MoO₃ species are highly dispersed on their surface without destroying the zeolite framework and pore structure. Compared with the mesoporous 7Mo/mesoporous S-1 and 7Mo/mesoporous TS-1 catalysts, the microporous 7Mo/S-1 and 7Mo/TS-1 catalysts exhibit high Mo species contents and surface acidity, indicating that Mo species can enter the inner surface of mesoporous zeolites. However, the Mo species on the outer surface of catalysts are only activity centers owing to the accessibility between the Mo species and JO. Therefore, compared with the low activity of the S-1 and TS-1 catalysts, the 7Mo/S-1 catalyst exhibited the highest catalytic performance, with a JO conversion of 95.7% and a biodiesel selectivity of 99.9%. Finally, 7Mo/S-1 demonstrated good catalytic stability, regeneration performance and broad substrate versatility, and the fuel properties of the as-synthesized biodiesel conformed to the current international standard. The influence of the pore structure and Mo species on the catalytic activity has been clarified, providing a theoretical and practical foundation for developing efficient heterogeneous catalysts for biodiesel production.