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利用共沉淀法合成了S2O82-/ZrO2-SiO2(SZS)和S2O82-/ZrO2-TiO2(SZT)固体超强酸催化剂,通过XRD,FTIR,SEM对催化剂进行了表征;以酯化反应为探针,考察了催化剂的配比、浸渍液(NH4)2S2O8的浓度、浸渍时间及焙烧温度对酯化率的影响,初步探讨了SiO2或TiO2改性对S2O82-/ZrO2固体超强酸的结构和催化活性的影响。实验结果表明,SiO2或TiO2的引入对ZrO2的晶化和催化活性有不同的影响,引入SiO2比引入TiO2更易于覆盖催化剂的酸中心,且引入TiO2的SZT催化剂比引入SiO2的SZS催化剂更容易被S2O82-溶解形成硫酸盐;焙烧温度高于500℃后,固体酸表面的硫物种流失严重,同时由于SZS催化剂形成的晶面,因此SZS催化剂的活性比SZT催化剂下降明显。
The catalysts of S2O82- / ZrO2-SiO2 (SZS) and S2O82- / ZrO2-TiO2 (SZT) were synthesized by co-precipitation method. The catalysts were characterized by XRD, FTIR and SEM. The effect of SiO2 / TiO2 modification on the structure and catalytic activity of S2O82- / ZrO2 solid superacid was investigated. The influences of the ratio of catalyst, the concentration of impregnating solution (NH4) 2S2O8, the impregnation time and the calcination temperature on the esterification rate were investigated. influences. The experimental results show that the introduction of SiO2 or TiO2 has different effects on the crystallization and catalytic activity of ZrO2. The introduction of SiO2 is easier to cover the acid sites of the catalyst than the introduction of TiO2. The introduction of TiO2 into SZT catalyst is easier than the introduction of SiO2 S2O82- dissolves to form sulphate. When the calcination temperature is higher than 500 ℃, the sulfur species on the surface of solid acid lose seriously, and the activity of SZS catalyst decreases more obviously than that of SZT catalyst due to the crystal surface formed by SZS catalyst.