Abstract
The research on sustainable and efficient routes to produce valuable chemicals from renewable biomass has garnered considerable attention in recent years. Among these chemicals, 5-hydroxymethylfurfural (5-HMF) holds significant promise as a versatile platform molecule for various applications in the chemical industry. This study investigates the production of 5-HMF from glucose using zirconium-based metal-organic frameworks (Zr-MOFs) as environmentally friendly catalysts, an alternative to the traditional homogeneous catalysts. UiO-66 and its functionalized derivatives (e.g. UiO-66(NH2),UiO-66(COOH)2, and UiO-66(OH)2) were synthesized to study the effect of the functional groups on the dehydration reaction. The synthesized MOFs were fully characterized using powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), N2 adsorption-desorption, Infrared spectroscopy (IR), Pyridine-Fourier Transform Infrared spectroscopy (Py-FTIR), and scanning electron microscopy (SEM). The catalytic performance of the synthesized MOFswas evaluated for the dehydration of glucose to 5-HMF in DMSO and further optimized in other monophasic and biphasic systems. Results indicated that UiO-66(COOH)2 exhibited exceptional catalytic activity for the conversion of glucose to HMF, with a significantly higher HMF yield of 44 % compared to other reported MOF catalysts and to that of H2SO4, which yielded 35 % at a temperature of 140 °C and a 6 h reaction time. This is mainly attributed to the effect of the bifunctional active acid sites of the metal nodes and the functional group of the organic linker (free carboxylic groups), which acted as the main source of Lewis and Brønsted acid sites respectively, compared to UiO-66. Additionally, the results suggested that the catalyst with higher acid density, higher relative mesopority, and a moderate B/L ratio could enhance glucose dehydration regardless of the surface area. Furthermore, the catalyst demonstrated excellent reusability and stability, with a decrease of only 10 % after four reaction cycles. The recycled catalyst revealed no structural alterations in its framework. This study contributes to the growing body of research on Zr-based MOF as a stable and efficient catalyst for glucose valorization to produce 5-HMF under mild reaction conditions.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.