RESUMEN
In this study, the catalytic activity of bifunctional SiO2/Zr catalysts prepared by template and chelate methods using potassium hydrogen phthalate (KHF) for crude palm oil (CPO) hydrocracking to biofuels was investigated. The parent catalyst was successfully prepared by the sol-gel method, followed by the impregnation of zirconium using ZrOCl2·8H2O as a precursor. The morphological, structural, and textural properties of the catalysts were examined using several techniques, including electron microscopy energy-dispersive X-ray with mapping, transmission electron microscopy, X-ray diffraction, particle size analyzer (PSA), N2 adsorption-desorption, Fourier transform infrared-pyridine, and total and surface acidity analysis using the gravimetric method. The results showed that the physicochemical properties of SiO2/Zr were affected by different preparation methods. The template method assisted by KHF (SiO2/Zr-KHF2 and SiO2-KHF catalysts) provides a porous structure and high catalyst acidity. The catalyst prepared by the chelate method assisted by KHF (SiO2/Zr-KHF1) exhibited excellent Zr dispersion toward the SiO2 surface. The modification remarkably enhanced the catalytic activity of the parent catalyst in the order SiO2/Zr-KHF2 > SiO2/Zr-KHF1 > SiO2/Zr > SiO2-KHF > SiO2, with sufficient CPO conversion. The modified catalysts also suppressed coke formation and resulted in a high liquid yield. The catalyst features of SiO2/Zr-KHF1 promoted high-selectivity biofuel toward biogasoline, whereas SiO2/Zr-KHF2 led to an increase in the selectivity toward biojet. Reusability studies showed that the prepared catalysts were adequately stable over three consecutive runs for CPO conversion. Overall, SiO2/Zr prepared by the template method assisted by KHF was chosen as the most prominent catalyst for CPO hydrocracking.
RESUMEN
In this preliminary research, the catalytic activity of isopropyl alcohol conversion to diisopropyl ether through dehydration reaction catalyzed by zeolite-Ni and zeolite-Ni(H2PO4)2 was comparatively described. The natural zeolite was treated with 1% HF and 6 N HCl prior to modifications using the impregnation method. Isopropyl alcohol conversion was examined at a mild temperature of 150 °C for 3.5 h on the reflux system with various catalyst loadings. X-ray diffraction and Fourier transform infrared analysis confirmed the successful impregnation of nickel and nickel phosphate into the zeolite. Scanning electron microscopy analysis revealed a cubic-like structure on zeolite-Ni(H2PO4)2, whereas homogenously distributed nickel species were observed on the zeolite-Ni catalyst. Energy-dispersive X-ray spectroscopy analysis reinforced the accomplishment of zeolite modifications. The N2 physisorption isotherms showed a decline in the surface area and total pore volume of the zeolite because of the blocking of pores. The zeolite-Ni(H2PO4)2 catalyst had higher acidity than unmodified zeolite and zeolite-Ni catalysts, which inherently suggested that the presence of phosphate groups results in higher catalytic activity toward isopropyl alcohol. The highest catalytic activity was attained by 8 mEq/g metal loading zeolite-Ni(H2PO4)2 with isopropyl alcohol conversion of 81.51%, diisopropyl ether yield, and selectivity of 40.77 and 33.16%. The reusability study suggested that the zeolite-Ni(H2PO4)2 catalyst was still active and had sufficient catalytic activity stability toward isopropyl alcohol after the third cycle was reused. This nickel phosphate-based modified zeolite was adequately potential for diisopropyl ether production through isopropyl alcohol dehydration.
