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 SO 2-4/ZrO 2

通过共沉淀-浸渍法制备了SO_(4)^(2-)/ZrO_(2)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SO_(4)^(2-)/ZrO_(2)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SO_(4)^(2-)/ZrO_(2)明显的四方相ZrO_(2)结构是其表现出较高催化活性的原因之一。

A solid acid catalyst SO_(4)^(2-)/ZrO_(2)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 SO_(4)^(2-)/ZrO_(2)had obvious tetragonal ZrO_(2)structure,which was one of the reasons for its high catalytic activity.