高岭土负载SO42-/ZrO2-TiO2催化剂的制备及其在缩酮合成中的应用

以经H2SO4处理焙烧的高岭土为载体，制备了以其负载的SO2-4/ZrO2-TiO2固体酸催化剂。 用FT-IR、XRD和NH3-TPD等测试技术表征了催化剂的微观结构及酸强度，考察了对环己酮乙二醇缩酮反应的催化活性及稳定性。 结果表明，酸化处理使高岭土表面酸量增加，但酸强度变化不大，而其负载SO2-4/ZrO2-TiO2后，经500 ℃焙烧3 h其酸量及酸强度显著升高。 环己酮用量为0.2 mol、乙二醇0.24 mol、催化剂1.2 g、带水剂环己烷15 mL，回流反应70 min后，缩酮收率可达96.8%，催化剂重复使用5次收率保持在90%以上。

Preparation of Kaolinite Supported SO_4~(2-)/ZrO_2-TiO_2 Catalyst and Its Application in Cyclohexanone Ethylene Ketal Synthesis

Acid activated and kaolinite supported SO2-4/ZrO2-TiO2 was prepared as a solid acid catalyst. The structure and acid strength of the catalyst was studied by FT-IR, XRD and NH3-TPD. The activity and stability of the catalyst for the synthesis of cyclohexanon ethylene ketal were investigated. The results showed that the acid amount of kaolinite was increased with increasing acid activation, and the acid strength was significantly enhanced after supporting SO2-4/ZrO2-TiO2 and calcinations at 500 ℃ for 3 h. When the molar ratio of cyclohexanone to ethylene is 1∶1.2, the loading of catalyst is 1.2 g and the volume of cyclohexane is 15 mL, the yield of cyclohexanone ethylene ketal from 0.2 mol cyclohexanon feed could reach 96.8% after 70 min reaction. The catalyst was used repeatedly for 5 times with the yield still larger than 90%.