固体酸SO42-/ZrO2催化果糖制备5-羟甲基糠醛
Preparation of 5-Hydroxymethylfurfural from Fructose Catalyzed by Solid Acid SO42-/ZrO2
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摘要: 通过共沉淀-浸渍法制备了SO42-/ZrO2固体酸催化剂, 探究了5种不同焙烧温度(450~650 ℃)对催化剂活性的影响, 并采用X射线衍射(XRD)、透射电镜(TEM)、傅里叶红外光谱(FT-IR)等表征手段对催化剂的结构及理化性质进行了分析。研究表明: 当焙烧温度高于450 ℃时, 固体酸SO42-/ZrO2在2θ为30.1°均存在较为明显的四方相晶体结构;随着焙烧温度的升高, 催化剂的孔径存在一定程度的增大, 但比表面积总体呈降低趋势, 酸强度也存在一定程度的降低。在焙烧温度为550 ℃焙烧3 h时制备的固体酸SZ-550表现出较好的催化性能, 用于催化果糖脱水制备5-羟甲基糠醛(5-HMF)时, 在反应温度为120 ℃, 反应时间为90 min, 催化剂用量为30 mg的最佳反应条件下, 以二甲基亚砜(DMSO)为反应溶剂, 果糖转化率为99.91%, 5-HMF的得率为76.01%。XRD分析结果表明:固体酸SO42-/ZrO2明显的四方相ZrO2结构是其表现出较高催化活性的原因之一。Abstract: A solid acid catalyst SO42-/ZrO2 was prepared by coprecipitation-impregnation method. The effects of five different calcination temperatures on catalyst activity were investigated. The structure and physicochemical properties of the catalyst were analyzed by XRD, BET, TEM and FT-IR. The solid acid SZ-550 calcined at 550 ℃ for 3 h showed good catalytic performance. When it was used to catalyze the dehydration of fructose to prepare 5-HMF, the optimal reaction conditions were as follows: the reaction temperature of 120 ℃, the reaction time of 90 min, and the amount of catalyst of 30 mg with dimethyl sulfoxide(DMSO) as the reaction solvent. Under these conditions, the conversion rate of fructose was 99.91%, and the yield of 5-HMF was 76.01%. XRD results showed that the solid acid SO42-/ZrO2 had obvious tetragonal ZrO2 structure, which was one of the reasons for its high catalytic activity.