层状Cu/SiO_(2)催化剂的制备及其草酸二甲酯加氢性能研究

Selective hydrogenation of dimethyl oxalate over layered Cu/SiO_(2) catalysts

以层状硅酸铜为前驱体制备了不同焙烧温度下的层状Cu/SiO_(2)催化剂。利用N2吸脱附、XRD、FT-IR、SEM、TEM、XPS等手段对催化剂的结构性质进行表征。结果表明,500℃下焙烧得到的催化剂比表面积大、Cu物种分散度最高、Cu颗粒尺寸均一,前驱体中层状硅酸铜的质量分数最高,还原后Cu^(+)相对含量最高。将该催化剂应用于草酸二甲酯(DMO)选择性加氢制乙醇酸甲酯(MG),在2 MPa、200℃、H_(2)/DMO物质的量的比为100的反应条件下DMO的转化率为98.5%,MG的选择性为52.1%,并且层状Cu/SiO_(2)催化剂表现出良好的稳定性。

Layered Cu/SiO_(2)catalysts are prepared at different calcination temperatures using copper phyllosilicate as precursor.The structural properties of the catalysts are characterized by means of N2adsorption and desorption, X-ray diffraction(XRD),fourier transform infrared spectroscopy(FT-IR),scanning electron microscope(SEM),transmission electron microscope(TEM) and X-ray photoelectron spectroscopy(XPS).The results show that the catalysts calcined at 500℃ have large specific surface area, the highest Cu species dispersion, uniform Cu particle size, and the highest content of copper phyllosilicate in the precursor, resulting in the highest content of Cu^(+)after reduction.The conversion of dimethyl oxalate is 98.5% and the selectivity of methyl glycolate is 52.1% when this catalyst is applied to the selective hydrogenation of dimethyl oxalate to methyl glycolate under the conditions of 2 MPa, 200℃ and H_(2)/DMO=100.The catalyst exhibits an excellent stability.