TiO<sub>2</sub>–ZrO<sub>2</sub> Composite Oxide as an Acid–Base Bifunctional Catalyst for Self-Condensation of Cyclopentanone
Jinmeng Wan, Lin Fu, Haixia Yang, Kai Wang, Fengcao Xi, Langsheng Pan, Yongfei Li, Yue‐Jin Liu
Abstract
TiO2–ZrO2 mixed oxides TZ-SG and TZ-ST were synthesized by a sol–gel method and a solvothermal method, respectively. The physicochemical properties of the TiO2–ZrO2 mixed oxides were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, pyridine Fourier transform infrared spectroscopy, NH3-temperature-programmed desorption (TPD), CO2-TPD, and N2 adsorption–desorption isotherms. The prepared TZ-ST was a stable and high-efficiency catalyst that combined the advantages of acidic and basic solid catalysts for cyclopentanone self-condensation. Compared with TZ-SG, TZ-ST exhibited higher catalytic activity in cyclopentanone self-condensation because of its high specific surface area and plentiful acid–base sites. In addition to its basicity, the acidity of TiO2–ZrO2 also had an important influence on its catalytic activity for cyclopentanone self-condensation. Under optimum reaction conditions (a catalyst/cyclopentanone mass ratio of 0.2:1, a reaction temperature of 140 °C, and a reaction time of 6 h), the dimer (C10) yield could reach 75.6% on TZ-ST.