SO_4~(2-)-TiO_2/γ-Al_2O_3固体超强酸催化剂上的缩醛(酮)反应

通过浸渍法制备了SO42--TiO2/γ-Al2O3新型固体超强酸催化剂,以苯甲醛和乙二醇为原料合成了苯甲醛乙二醇缩醛。考察了催化剂的焙烧温度、带水剂的种类和体积、TiO2的质量分数、苯甲醛与乙二醇的摩尔比、催化剂的质量和回流时间对反应的影响以及催化剂稳定性对反应的影响。结果表明,在焙烧温度为500℃,甲苯为带水剂,甲苯体积为20 mL,TiO2的质量分数为10%,苯甲醛与乙二醇的摩尔比为1∶1.2,催化剂的质量为1.1 g,回流时间为1.5 h的反应条件下,苯甲醛乙二醇缩醛的收率可达96.1%,产品的纯度为99.6%。SO42--TiO2/γ-Al2O3新型固体超强酸催化剂在其它缩醛(酮)的合成中也具有良好的催化活性。

Catalytic Synthesis of Acetals or Ketals With γ-Al_2O_3 Supported SO_4~(2-)-TiO_2 Solid Superacid Catalyst

SO~(2-)_4-TiO_2/γ-Al_2O_3 solid superacid catalysts were prepared by impregnation method.Benzaldehyde ethylene glycol acetal was synthesized from benzaldehyde and ethylene glycol on SO~(2-)_4-TiO_2/γ-Al_2O_3 solid superacid catalyst.The effects of calcination temperature of catalyst,mass fraction of TiO_2,molar ratio of benzaldehyde and ethylene glycol,catalyst mass,types and mass of water-carrying reagent,refluxing time and catalyst stability on reaction were investigated.The results show that the calcination temperature is 500 ℃,the mass fraction of TiO_2 is 10%,the mass of catalyst is 1.1 g,the molar ratio of benzaldehyde and ethylene glycol is 1∶1.2,20 mL toluene is water-carrying reagent,1.5 h refluxing time.Under the optimum conditions,the yield and purity of a benzaldehyde ethylene glycol acetal were 96.1% and 99.6%,respectively.SO~(2-)_4-TiO_2/γ-Al_2O_3 solid superacid catalyst has good catalytic activity in the synthesis of other acetals(or ketals).