CuO(CoO,MnO)/SiO_2纳米复合气凝胶催化剂载体的制备及其在合成碳酸二苯酯中的应用

以正硅酸乙酯为硅源,以乙酸铜、乙酸钴和乙酸锰的水溶液为前驱体,采用溶胶–凝胶法和CO2超临界干燥工艺制备了CuO(CoO,MnO)/SiO2纳米复合气凝胶。采用场发射扫描电镜、透射电镜和电子散射能谱分析等对纳米复合气凝胶的微观结构和组成进行了表征。采用Brunauer–Emmett–Teller法测定了纳米复合气凝胶的比表面积、孔径及孔径分布。以纳米复合气凝胶为载体制备了负载型催化剂,用于催化合成碳酸二苯酯(diphenyl carbonate,DPC),并用气相色谱仪对反应液进行了分析。结果表明:纳米复合气凝胶的粒径为20～100nm,孔径为2～8nm,平均孔径为3.16nm,比表面积为664.4m2/g;过渡金属的摩尔含量为13.77%;催化合成DPC的质量收率达27.14%。

PREPARATION OF CuO(CoO,MnO)/SiO_2 NANOCOMPOSITE AEROGELS AS CATALYST CARRIERS AND THEIR APPLICATION IN THE SYNTHESIS OF DIPHENYL CARBONATE

CuO(CoO, MnO)/SiO_2 nanocomposite aerogels were prepared by using tetraethyl orthosilicate as Si source, and aqueous solution of Cu, Co and Mn acetates as the precursors via sol-gel process and CO_2 supercritical drying technique. The microstructure and composition of the CuO(CoO, MnO)/SiO_2 nanocomposite aerogels were characterized by field emission scanning electron microscopy, transmission electron microscopy and electron dispersive spectroscopy. The specific surface area, pore size and pore size distribution of the nanocomposite aerogels were determined by the Brunauer-Emmett-Teller method. Supported catalysts were prepared by using the CuO(CoO, MnO)/SiO_2 nanocomposite aerogels as catalyst carriers, and were used in the synthesis of diphenyl carbonate (DPC). The products were analyzed by gas chromatography. The results show that the CuO(CoO, MnO)/SiO_2 nanocomposite aerogels are porous, with a particle size distribution of 20-100 nm and a pore size distribution of 2-8 nm, an average pore size of 3.16nm, and a specific surface area of 664.4m~2/g. The mole fraction of transition metals in the nanocomposite aerogels is 13.77%. The yield in mass of DPC is up to 27.14% under the catalysis of the supported catalyst.