二氧化锆负载碱金属催化剂的制备及其催化葡萄糖转化性能

Preparation of Zirconium Dioxide Supported Alkali Metal Catalyst and Its Catalytic Performance for Glucose Conversion

采用浸渍法和离子交换法制备了3种碱金属(Na、K、Cs)负载于二氧化锆(ZrO_(2))的催化剂,考察了其在不同反应温度和反应时间下对葡萄糖脱水制备5-羟甲基糠醛(5-HMF)的催化效果。通过X射线衍射(XRD)、电感耦合等离子体质谱仪(ICP-MS)、N_(2)等温吸附-脱附、热重(TGA)和CO_(2)吸附量热等表征手段,研究3种催化剂的结构和性能,分析ZrO_(2)负载碱金属促进葡萄糖脱水转化为5-HMF的反应机理。结果表明:K/ZrO_(2)催化剂的晶粒最小、比表面积最大、热稳定性最好,其催化效率最高;在最佳反应温度200℃下,K/ZrO_(2)催化葡萄糖的转化率最高可达97%,5-HMF的收率可达15%,转化率和选择性随反应时间变化很小,催化剂稳定性较好。

Three alkali metal(Na,K,Cs)catalysts supported on zirconium dioxide(ZrO_(2))were prepared by impregnation method and ion exchange method,and their catalytic effects on the dehydration of glucose to 5-hydroxymethylfurfural(5-HMF)at different reaction temperatures and reaction time were investigated.By means of X-ray diffraction(XRD),inductively coupled plasma mass spectrometry(ICP-MS),N_(2)isothermal adsorption-desorption analysis,thermal gravimetric analyzer(TGA)and CO_(2)adsorption calorimetric,this paper studies the structure and performance of these three catalysts,and further analyzes the mechanism of ZrO_(2)supported alkali metal for promoting the conversion of glucose into 5-HMF by dehydration.The results show that K/ZrO_(2)catalyst has the smallest crystalline grain,largest specific surface area,and best thermal stability,so its catalytic efficiency is the highest.At the optimal reaction temperature of 200℃,the conversion rate of K/ZrO_(2)catalyzed glucose can reach up to 97%,the yield of 5-HMF can reach 15%,and the conversion rate and selectivity change little over time,indicating that the catalyst has good stability.