复合分子筛的合成及其在纤维素水解反应中的应用

采用水热晶化法制备了HUSY@MFI核壳结构复合分子筛。通过XRD、SEM、N_2吸附-脱附、NH_3-TPD及吡啶吸附红外等手段表征催化剂的结构和性质。结果表明,HUSY@MFI晶粒在形貌上呈椭球状,表面是鳞片状结构的MFI型分子筛,里面是光滑的HUSY型分子筛,焙烧模板剂前几乎没有或只有很少量的N_2能进入其孔道结构,致密的壳层MFI覆盖在HUSY型分子筛表面,形成了新的弱酸位,而中强酸强度和酸类型并没有受到影响,复合分子筛的表面酸量及总酸量减少。将所制备的HUSY@MFI复合分子筛催化剂应用于以离子液体1-乙基-3-甲基咪唑氯盐(Emim]Cl)为溶剂的纤维素水解反应中,与HUSY催化的纤维素水解相比,HUSY@M FI复合分子筛催化纤维素水解反应的速率较慢,葡萄糖收率由30.9%提高到41.3%。

Synthesis of composite zeolites and their performance in hydrolysis of cellulose

In this paper, core-shell composite zeolites (HUSY@MFI) were prepared by hydrothermal method. The composite zeolites were characterized by XRD, SEM, N₂-adsorption, NH₃-TPD and Py-FTIR. The results indicated that HUSY@MFI has both HUSY and MFI structure. Scanning Electron Microscope (SEM) reflects a core-shell morphology of HUSY@MFI. The particles displayed an elliptical sphere structure with scale-like surface. The growth of MFI shell results in a decrease of external acid density and the total acid sites. When the HUSY@MFI was used as catalyst instead of HUSY in hydrolysis of cellulose to glucose in 1-ethyl-3-methylimidazolium chloride (Emim]Cl), the glucose yield could be significantly improved from 30.9% to 41.3%.