O/W微乳体系制备固体超强酸SO42-/SnO2-Ta2O5及其表征

采用十二烷基苯磺酸钠（SDBS）-乙醇-环己烷O/W微乳体系制备了固体超强酸SO42-/SnO2-Ta2O5，对催化剂进行了傅里叶变换红外光谱、热重、X射线衍射表征，对催化剂的制备条件进行正交实验优化，并进行了稳定性考察。结果表明，催化剂的最佳制备条件为：SnCl4浓度0.1 mol/L、SnCl4溶液/SDBS/乙醇/环己烷质量比500﹕1﹕0.5﹕15、Ta2O5/SnO2质量比6%、陈化时间24 h、浸渍液硫酸浓度3.0 mol/L、焙烧温度550 ℃、焙烧时间3 h。将此条件下制备的SO42-/SnO2-Ta2O5用于催化乙酸与正丁醇的酯化探针反应，酯化率为99.3%。与常规水体系制备的催化剂相比，SDBS的O/W微乳体系有利于催化剂活性、稳定性的提高。

PREPARATION AND CHARACTERIZATION OF SOLID SUPERACID SO42-/SnO2-Ta2O5 BY O/W MICROEMULSION METHOD

A type of solid superacid catalyst SO42-/SnO2-Ta2O5 was prepared by O/W micro-emulsion method in SDBS/ethanol/cyclohexane system, and the physicochemical properties of the prepared solid superacid samples were characterized by XRD, FT-IR and TG-DTA. The catalyst preparation conditions was optimized by orthogonal experiment and the optimum conditions were obtained as follows: a SnCl4 solution concentration of 0.1 mol/L, the mass ratios of SnCl4 solution: SDBS: ethanol: cyclohexane were 500︰1︰0.5︰15, Ta2O5/SnCl4 mass ratio of 0.06, an aging time of 24 h, the concentration of sulphuric acid impregnating solution was 3.0 mol/L and calcination at 550 ℃ for 3 h. The catalytic performance of this SO₄^2-/SnO₂-Ta₂O₅ catalyst prepared under optimum conditions was evaluated using esterification of acetic acid and n-butanol as probe reaction, its esterification rate reached 99.3%. As compared with catalyst prepared in conventional water system, catalyst prepared in SDBS micro-emulsion system exhibited better catalytic activity and stability.