HZSM-5固载离子液体催化合成烷基糖苷及其动力学

Catalytic synthesis of alkyl glycosides by HZSM-5 supported ionic liquid and its kinetics

以自制苯并噻唑离子液体([HBth]HSO_(4))为活性组分,HZSM-5分子筛为载体,通过过量溶剂浸渍法制备了固载型苯并噻唑离子液体催化剂([HBth]HSO_(4)/HZSM-5),并用于催化合成烷基糖苷。通过FTIR、原位红外光谱、TG、N_(2)物理吸附-脱附、FESEM-EDS和XRD对催化剂结构进行了表征。结果表明,[HBth]HSO_(4)被成功地引入到HZSM-5的表面及孔道内。当催化剂用量为1.5%(以葡萄糖与辛醇的总质量为基准,下同)、反应温度为105℃、n(正辛醇)∶n(无水葡萄糖)=6∶1时,辛基糖苷得率达148.86%。底物拓展及催化剂稳定性结果表明,[HBth]HSO_(4)/HZSM-5对烷基糖苷及其衍生物都具有良好的催化效果,且催化剂能稳定循环使用4次。活性组分流失是催化剂失活的主要原因。通过对烷基糖苷催化合成机理和动力学的研究,确定了动力学方程。

Benzothiazole ionic liquid supported on HZSM-5 catalyst([HBth]HSO_(4)/HZSM-5)was prepared via excess solvent impregnation using benzothiazole ionic liquid([HBth]HSO_(4))as active component and hydrogen HZSM-5 molecular sieved as support.The resulting catalyst was used as catalyst for synthesis of alkyl glycosides.The catalyst was characterized by FTIR,in-situ infrared spectroscopy,TG,N_(2)physical adsorption and desorption,FESEM-EDS and XRD.The results indicated that[HBth]HSO_(4)was successfully loaded onto the surface and pores of HZSM-5.Under the conditions of amount of catalyst being 1.5%(on the basis of the total of glucose and octanol,the same as below),reaction temperature of 105℃and n(octanol)∶n(anhydrous glucose)of 6∶1,the yield of octyl glycoside reached up to 148.86%.The substrate expansion and catalyst stability results suggested that[HBth]HSO_(4)/HZSM-5 had a good catalytic effect on alkyl glycosides,and the catalyst could be reused for four times without significant deactivation.After studying the catalytic synthesis mechanism and kinetics of alkyl glycosides,the kinetic equation was determined.