Production of Biofuel Additives from Glycerol Etherification Using Zirconia Supported Phosphotungstic Acid

Abstract

Using etherification to convert glycerol into biofuel additives is an effective way to solve the current problem of excess glycerol. In this study, a series of environmentally friendly (x)HPW/ZrO 2 catalysts were synthesized for the etherification of glycerol and tert-butyl alcohol (TBA). The internal microstructure and acidity analysis of the synthesized samples were derived from BET, XRD, Raman spectroscopy, FTIR, SEM, NH 3 -TPD and Py-FTIR. The results revealed that the synthesized catalysts retained the complete Keggin structure of phosphotungstic acid (HPW) which supported on it. The (15)HPW/ZrO 2 catalyst with suitable structure and acidity had an excellent catalytic effect on the etherification reaction. Driven by the (15) HPW/ZrO 2 catalyst, the optimal reaction conditions were determined from parameters of reaction temperature, time, molar rate of glycerol and TBA, and catalyst dosage. 93.2% glycerol conversion and 42.5% selectivity of multi-substituted tert-butyl glycerol ethers (DTBG + TTBG) were obtained under optimal conditions. In addition, even after a total of four consecutive reactions, (15)HPW/ZrO 2 catalyst still demonstrated relatively good catalytic activity.

Catalytic performance of HPW/TiO2–SnO2–ZrO2 in soybean oil epoxidation under hydrodynamic cavitation

“…The diffraction peaks of HPW were not observed in the HPW/ SnO 2 -ZrO 2 spectrograph, indicated that HPW is well dispersed on the surface of SnO 2 -ZrO 2 . [29] The diffraction peaks of HPW/TiO 2 -SnO 2 -ZrO 2 spectra appeared at about 2θ = 25.6°, 37.9°, 48.3°, 53.8°, 55.0°, 62.7° and 75.0°, these diffraction peaks were attributed to anatase TiO 2 . It has been proved that anatase titanium dioxide show high catalytic activity.…”

“…These peaks are due to the interaction of pyridine with Brønsted(B) and Lewis(L) acid sites present on the catalyst surface. Liu et al [29] found that the parent ZrO 2 was mainly Lewis acid site and the total acid content was low by compared the Py-FTIR of HPW loaded with 0-15% ZrO 2 . With the increase of HPW loaded, the total acidity of the catalyst increased, especially the Brønsted acid.…”