Fourier transform infrared spectroscopic study of surface acidity by pyridine adsorption on Mo/ZrO2-SiO2(Al2O3) catalysts

Novel sustainable biodiesel production from low-grade oleic acid via esterification catalyzed by characterized crystalline ZrO2/Al2O3

The depletion of fossil fuels and growing environmental concerns necessitate the exploration of renewable energy sources. Biodiesel, a promising alternative fuel derived from sustainable feedstock, has attracted considerable attention. This study investigates the catalytic esterification of oleic acid, a readily available fatty acid, with ethanol for biodiesel production using a novel heterogeneous catalyst, ZrO2/Al2O3. Crystalline ZrO2/Al2O3 was successfully synthesized and characterized using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area analysis, and Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption NH3-TPD to understand its structural and textural properties. The characterized ZrO2/Al2O3 was then employed to catalyze the esterification reaction. The influence of reaction parameters, including temperature, alcohol-to-oleic acid molar ratio, and catalyst loading, was systematically evaluated. Under optimal conditions (70 °C, 10:1 alcohol-to-oleic acid molar ratio, and 4 wt% catalyst loading), a remarkable 90.5% conversion of oleic acid to biodiesel was achieved. Furthermore, the catalyst exhibited reusability, demonstrating its potential for sustainable biodiesel production from low-grade oleic acid feedstock.

The Design of Sulfated Ce/HZSM-5 for Catalytic Decomposition of CF4

CF₄ has a global warming potential of 6500 and possesses a lifetime of 50,000 years. In this study, we modified the HZSM-5 catalyst with Ce and sulfuric acid treatment. The S/Ce/HZSM-5 catalyst achieves 41% of CF₄ conversion at 500 °C, which is four times higher than that over Ce/HZSM-5, while the HZSM-5 exhibits no catalytic activity. The effects of modification were studied by using NH₃-TPD, FT-IR of pyridine adsorption, and XPS methods. The results indicated that the modification, especially the sulfuric acid treatment, strongly increased the Lewis acidic sites, strong acidic sites, and moderate acidic sites on catalysts, which are the main active centers for CF₄ decomposition. The mechanism of acidic sites increases by modification and CF₄ decomposition is clarified. The results of this work will help the development of more effective catalysts for CF₄ decomposition.

Bioethanol Upgrading to Renewable Monomers Using Hierarchical Zeolites: Catalyst Preparation, Characterization, and Catalytic Studies

Bioethanol is one of the most promising renewable resources for the production of important monomers. To date, there have been various processes proposed for bioethanol conversion to renewable monomers. In this review, the catalytic bioethanol upgrading to various types of monomers using hierarchical zeolites as catalysts is illustrated, including the recent design and preparation of hierarchical zeolites for these catalytic processes. The characterizations of catalysts including textural properties, pore architectures, acidic properties, and active species are also exemplified. Moreover, the catalytic studies with various processes of monomer production from bioethanol including bioethanol dehydration, bioethanol to hydrocarbons, and bioethanol to butadiene are revealed in terms of catalytic activities and mechanistic studies. In addition, the future perspectives of these catalytic circumstances are proposed in both economic and sustainable development contexts.

Influence of acid–base properties on the Lebedev ethanol-to-butadiene process catalyzed by SiO2–MgO materials

The preparation method greatly influences morphology, acid–base properties and performance of SiO₂–MgO catalysts. Wet-kneaded catalysts possess an improved distribution, proximity and strength of acidic-basic sites, thus leading to higher butadiene yields.