稀土改性固体超强酸催化剂SO2-4/TiO2-La2O3的制备及其催化性能

制备了稀土改性固体超强酸SO24-/TiO2-La2O3环境友好催化剂,并以丁酸丁酯的合成作为探针反应,系统考察了原料摩尔比n(La3+)∶n(Ti4+)、硫酸浸渍时间、焙烧温度、活化时间等制备条件对SO24-/TiO2-La2O3催化活性的影响.实验表明:制备催化剂的适宜条件是原料摩尔比n(La3+)∶n(Ti4+)=1∶34,浸渍浓度为0.8 mol.L-1,浸渍时间为24 h,焙烧温度为480℃,活化时间3 h.利用优化条件下制备的催化剂SO24-/TiO2-La2O3催化合成缩醛(酮),在醛/酮与二元醇(乙二醇,1,2-丙二醇)的投料摩尔比为1∶1.5,催化剂的用量占反应物总投料质量的0.5%,反应时间为1 h条件下,10种缩醛(酮)的产率为41.4%～95.8%.

PREPARATION AND CATALYTIC ACTIVITY OF SO2-4/TiO2-La2O3

SO42-/TiO2-La2O3,a novel solid superacid,was prepared and its catalytic activities at different synthetic conditions were analyzed with esterification of n-butanoic acid and n-butyl alcohol as probing reaction.The optimum conditions were as follow: mole ratio of n(La3+)∶n(Ti4+) of 1∶34,the soaked consistency of H2SO4 of 0.8 mol·L-1,the soaked time of H2SO4 of 24 h,the calcining temperature of 480 ℃,the calcining time of 3 h.The catalyzer prepared under the optimal conditions was applied in the catalytic synthesis of ten important ketals and acetals as catalyst and exhibited high catalytic activity.The yields of ketals and acetals can reach 41.4%～95.8% when the molar ratio of aldehyde/ketone to glycol is 1∶1.5,the mass ratio of the catalyst used in the reactants is 0.5%,and the reaction time is 1.0 h.