Preparation of the WO_X/MCM-41 Solid Acid Catalyst and the Catalytic Performance for Solketal Synthesis

Abstract

In the present work, an efficient and stable WO X / MCM-41 solid acid catalyst was prepared by the wet impregnation method. The characterization of powder X-ray diffraction, transmission electron microscopy, ultraviolet−visible, H 2 temperature-programmed reduction, X-ray photoelectron spectroscopy, NH 3 temperature-programmed desorption, and N 2 adsorption− desorption isotherms confirmed that the impregnation amount and calcination temperature of WO X speciation affected the dispersity and acidity of the resulting catalyst. This WO X /MCM-41 solid acid catalyst was subsequently applied in the ketalization reaction of glycerol and acetone to produce solketal. By catalyst screening and reaction condition optimization, WO X /MCM-41 obtained by impregnating 20 wt % and calcining at 350 °C exhibited the highest solketal yield and catalytic stability.

Sustainable Upgrade of Bioderived Glycerol to Solketal through Acetalization over Metal-Free Mordenite Catalysts

“…However, very high metal content (20 wt %) led to the agglomeration of metal particles. Moreover, the recyclability study showed that the catalyst activity was decreased after each run due to the partial blockage of acidic sites . Similarly, a WO x -promoted TiO 2 -ZrO 2 catalyst is also reported for the glycerol acetalization, but the catalyst showed poor recyclability .…”

“…Moreover, the recyclability study showed that the catalyst activity was decreased after each run due to the partial blockage of acidic sites. 20 Similarly, a WOx-promoted TiO 2 -ZrO 2 catalyst is also reported for the glycerol acetalization, but the catalyst showed poor recyclability. 21 Careful observation of the abovementioned reports suggests that the metal-modified catalysts have some shortcomings like metal leaching, metal particle agglomeration, and usage of expensive metals, which make it uneconomical to be used at a larger scale.…”

Activated Bentonite Nanocomposite for the Synthesis of Solketal from Glycerol in the Liquid Phase

“…However, the use of these catalysts presents several environmental issues and, for this reason, heterogeneous catalysts have been employed in recent years. Several solids can be mentioned, such as exchange resins [16], zeolites [17], modified activated carbon [18,19], silica-included heteropolyacids [20], and modified clays [21].…”

Conversión catalítica de glicerol en compuestos oxigenados para su uso en combustibles e industria química: Obtención de solketal

“…Huang et al [77] impregnaron óxidos de tungsteno sobre sílices MCM-41 con relaciones másicas de tungstato de amonio a MCM-41 entre 1 y 30%, y luego fue calcinado a 350 y 550 °C por 6 h. Los resultados de TPD de NH3 mostraron que la acidez total de los materiales aumenta con la cantidad de tungstato de amonio utilizada en la síntesis, pero a su vez se observa un aumento en la cantidad de sitios ácidos débiles a costa de una disminución de sitios ácidos fuertes. Los autores asocian este fenómeno con la aglomeración parcial de las especies WO3 que son formadas al calcinar una excesiva cantidad de tungstato de amonio, los cuales cubren los sitios activos.…”