Hydrodeoxygenation of palmitic acid over zeolite-supported nickel catalysts

Abstract In this study, Ni and Ni/Mo catalysts supported on zeolite ZSM-5, aka Ni/ZSM-5 and Ni-Mo(R)/ZSM-5, were successfully prepared by the incipient wetness impregnation method to hydrotreat heterogeneously the palmitic acid with an aim for the production of green diesel. Various instruments, such as XRD, SEM, BET, XPS, NH3-TPD and H2-TPR, were employed to characterize these catalysts. The hydrodeoxygenation (HDO) reaction of palmitic acid was carried out in an autoclave at 300 °C with an initial pressure of hydrogen at 35 bar. With Ni-Mo(R)/ZSM-5 catalysts priorly reduced in H2 at 500 °C, the conversion of palmitic acid could reach near 99% after 4 h of HDO reaction at 300 °C. Furthermore, a significant portion of isomerized paraffins appeared in the product, as revealed by GC-MS. That is, both hydrodeoxygenation and hydroisomerization reactions took place conjointly on palmitic acid with Ni-Mo(R)/ZSM-5 catalysts.