Synthesis of 5‐ethoxymethylfurfural from glucose catalyzed by porous tetra‐component metal oxides solid acid

Abstract

The production of 5-ethoxymethylfurfural (EMF) from cheap and abundant glucose feedstock has attracted a great deal of attention because of its potential applications. Herein, three porous tetra-component metal oxide solid acid catalysts (SO 4 2À /ZFSA-A, SO 4 2À /ZFSA-F-10, SO 4 2À /ZFSA-F-20)containing both Brønsted and Lewis acid sites have been successfully synthesized and can efficiently catalyze the synthesis of EMF from glucose.Particularly, the SO 4 2À /ZFSA-A, SO 4 2À /ZFSA-F-10, and SO 4 2À /ZFSA-F-20 catalysts were prepared under the template of sodium alginate, 10% F127, and 20% F127, respectively. The prepared catalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), N 2 -adsorption-desorption isotherm, X-ray photoelectron spectroscopy (XPS), thermogravimetry (TG), temperature-programmed desorption of ammonia (NH 3 -TPD), and pyridine infrared spectra (Py-FTIR). The characterization results indicated that all three catalysts have a porous structure. The pore distribution of the SO 4 2À /ZFSA-A catalyst is mainly macroporous and mesoporous, while the SO 4 2À /ZFSA-F-10 and SO 4 2À /ZFSA-F-20 catalysts are mainly mesoporous. The SO 4 2À /ZFSA-F-20 catalyst exhibited the highest catalytic performance due to its large specific surface area, desirable mesoporous structure, high total acidity (especially strong and super strong acidity), and appropriate Lewis/Brønsted acid ratio. By applying SO 4 2À / ZFSA-F-20, the formation of EMF from glucose was successfully catalyzed and EMF was obtained at a yield of 34.56% after 12 h at 160 C. This yield is much higher compared with most other results achieved by solid acids catalysis. In addition, the reaction parameters such as reaction temperature, reaction time, glucose amount, and catalyst dosage were shown to have a significant effect on the catalytic performance. Notably, the SO 4 2À /ZFSA-F-20 catalyst exhibited good reusability, as its activity did not significantly diminish after four rounds of repeated experiments and was successfully reactivated after calcination.