SO_4^(2-)-TiO_2/Al_2O_3超强酸催化合成新型香料

Study on Synthesis of New Perfumers Catalyzed by SO_4~2--TiO_2/Al_2O_3 Solid Superacid

通过浸渍法制备了SO42--TiO2/Al2O3固体超强酸催化剂,用Hammett指示剂法测定了其酸强度;以乙酰乙酸乙酯和1,3-丙二醇、1,3-丁二醇为原料,合成了新型香料2-甲基-2-乙酸乙酯基-1,3-二氧六环和2,4-二甲基-2-乙酸乙酯基-1,3-二氧六环,考察了催化剂的焙烧温度、TiO2的负载量、反应温度、反应物配比、催化剂用量等因素对反应的影响以及催化剂的重复使用性。结果表明,在425～575℃温度范围内,SO42--TiO2/Al2O3体系可以形成超强酸;在新型香料的合成中具有催化活性高、催化速率快、化学稳定性好,重复使用性佳、无环境污染;在最佳条件下,两种香料的收率分别可达83.5％和83.6％,质量分数为99.1％。

SO42--TiO2/Al2O3 solid superacid was prepared by impregnation method. The acidic strength was by ham-mett indicator method.New perfumers(2 - methyl - 2 - ethyl acetate - dioxane and 2,4 - dimethyl - 2 - ethyl acetate -dioxane) were synthesized from ethyl acetoacetate and propanediol as well as butanediol on the SO42--TiO2/Al2O3 solid superacid catalyst. The effects of calcining temperatures, loaning amounts of TiO2, quantities of catalysts, ratio of reactants and repeatability was discussed.It was shown that the SO42--TiO2/Al2O3 soild superacid was formed when activating temperatures was higher than 425 - 500℃ temperature range, SO42--TiO2/Al2O3 soild superacid has high catalytic activities and rate, good chemical stability, good repeatability and little waste discharged. In optimum conditions, the yields of 2 - methyl -2 - ethyl acetate - dioxane and 2,4- dimethyl - 2 - ethyl acetate - dioxane are 94.5% , respectively. The purity of products is 99.1%.