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采用溶胶-凝胶法结合超临界流体干燥技术制备了Al2O3气凝胶载体,以浸渍法制得Al2O3气凝胶负载磷钨酸固体酸催化剂(HPW/Al2O3)。利用N2吸附-脱附、X射线粉末衍射(XRD)、NH3程序升温脱附(NH3-TPD)、傅立叶变换红外光谱(FTIR)、吡啶吸附红外光谱(Py-IR)等手段对HPW/Al2O3催化剂的织构、结构、表面性质等进行了表征,并考察了该催化剂在四氢呋喃聚合反应中的催化性能。结果表明,HPW/Al2O3催化剂负载量在50%~70%能较好地保留HPW的Keggin结构,具有强的Br nsted酸性特征,催化剂的酸量与酸强度随HPW负载量的提高呈递增趋势,而聚合物的收率及相对分子质量(以下简称分子量)与催化剂的酸量间存在线性关系,酸量越大,收率越高,分子量越低。
Al2O3 airgel carrier was prepared by sol-gel method combined with supercritical fluid drying technology. Al2O3 airgel supported phosphotungstic acid solid acid catalyst (HPW / Al2O3) was prepared by impregnation method. The effects of N2 adsorption-desorption, X-ray powder diffraction (XRD), NH3-TPD, Fourier transform infrared spectroscopy (FTIR) and Py- The structure, surface properties and so on were characterized, and the catalytic performance of the catalyst in the polymerization of tetrahydrofuran was investigated. The results showed that the loading of HPW / Al2O3 catalyst in 50% ~ 70% retained the Keggin structure of HPW well and had strong Br nsted acidity. The acidity and acid strength of HPW / Al2O3 catalyst increased with the increase of HPW loading. However, there is a linear relationship between the yield and molecular weight of the polymer (hereinafter referred to as molecular weight) and the amount of acid in the catalyst. The larger the amount of acid is, the higher the yield is and the lower the molecular weight is.