苯乙酮1,3-丙二醇缩酮的绿色催化合成

Green Catalytic Synthesis of Acetophenone 1,3-Propandiol Ketal

采用直接浸渍-焙烧法制备了SO42--T iO2/A l2O3新型固体超强酸催化剂(简称SO42--T iO2/A l2O3催化剂),用Ham-m ett指示剂法测定了SO42--T iO2/A l2O3催化剂的酸强度;以苯乙酮和1,3-丙二醇为原料合成了苯乙酮1,3-丙二醇缩酮。考察了SO42--T iO2/A l2O3催化剂的焙烧温度、T iO2负载量、SO42--T iO2/A l2O3催化剂用量、原料配比、回流时间、带水剂的种类和用量对反应的影响。最佳的反应条件为:T iO2负载量(质量分数)10%、SO42--T iO2/A l2O3催化剂焙烧温度500℃、催化剂用量为反应物料总质量的5.5%、n(苯乙酮)∶n(1,3-丙二醇)=1∶1.2、带水剂甲苯20mL、回流时间1.5h;在最佳反应条件下,苯乙酮1,3-丙二醇缩酮的收率可达96.5%,产品的纯度为99.6%。SO42--T iO2/A l2O3催化剂制备简单、催化活性高、重复使用性好,产品收率高,后处理简便,无三废污染,符合节能环保、绿色催化的发展趋势。

Acetophenone 1, 3-propandiol ketal was synthesized from acetophenone and 1, 3- propandiol over SO4^2- -TiO2/Al2O3 solid superacid catalyst. The catalyst was prepared by impregnationcalcination process. The acidic strength of catalyst was determined by Hammett indicator method. The effects of calcination temperature of catalyst, loading amount of TiO2, catalyst dosage, mole ratio of reactants, types and amount of entrainer, and refluxing time on the reaction were discussed. The optimal conditions were： TiO2 loading amount （mass fraction）10%, catalyst calcination temperature 500 ℃, mass fraction of catalyst in total feedstock 5.5 %, n （acetophenone） ： n （1,3-propandiol） = 1 ： 1.2, toluene（entrainer） 20 mL and refluxing time 1.5 h. Under optimum conditions, yield and purity of acetophenone 1,3-propandiol ketal were 96.5% and 99.6%, respectively. Preparation of SO4^2- -TiO2/ Al2O3 solid superacid catalyst was simple in procedure. The obtained catalyst was high in activity,good in repeatability, and high in product yield, with convenient final treatment and nopollution of＂ three wastes＂, which conformed to the requirement of energy saving and environment protection as well as green catalysis.