Novel WO3/SO42--ZrO2–TiO2 double bridge coordination catalyst hfor oxidation of cyclohexene

Abstract

A solid super acid WO3/SO42--ZrO2–TiO2 catalyst was prepared with adjustable acidity via double bridge connection strategy for oxidation of cyclohexene (CHE) to adipic acid (AA). XRD, SEM and N2 adsorption-desorption isotherm indicated that WO3 was successfully decorated and was highly dispersed on SO42--ZrO2–TiO2 surface. An obvious stretching vibration peak (1125-1055 ​cm−1) in FT-IR illustrated that connection effect between SO42− and ZrO2–TiO2 was double bridge connection. NH3-TPD profile appeared a strong acid center peak (516 ​°C), while this center of solid super acid catalyst could reduce decomposition rate of H2O2 directly, and increase reaction time between CHE and H2O2 meanwhile. The marked catalytic performance was attributed to the synergistic effect between WO3 and SO42--ZrO2–TiO2. DFT calculation was employed to further analyze reaction process and system energy.