Production of renewable aromatics from jatropha oil over multifunctional ZnCo/ZSM-5 catalysts

Abstract

The transformation of jatropha oil into aromatics using bimetallic ZSM-5 catalyst was investigated in a continuous downflow reactor. The effect of change in surface acidity was observed closely concerning the formation of C6–C8 aromatics; a balance Lewis and Brønsted acidic sites showed a strong correlation with light aromatics. Ce as a promoter modify the surface acidity, which enhanced the dehydro-deoxygenation reaction and improved the aromatic selectivity. Hence, Ce-promoted ZnCo/Z catalysts showed better performance compared to La-promoted ZnCo/Z. The 10Zn5Co5Ce/Z catalyst showed 87.6% oil conversion, with 81.9% total aromatics. The selectivity toward C6–C8 aromatics found to be 71.8%, with the presence of 35.3% xylenes and ethylbenzene. The Normalized XANES spectra suggest that the Co resides in the tetrahedrally coordinated environment in the ZnCo2O4 catalyst and such intensity of the pre-edge feature evidence for incorporating Co into the material framework. The optimised catalyst, i.e.,10Zn5Co5Ce/Z shows negligible coke deposition, and it was calculated to be 1.33 × 10−3 (gcoke/gcat h); further, the catalyst was regenerated for three consecutive cycles.