Amine-functionalized mesoporous silica-supported copper catalysts SBA-15@amine–Cu and SBA-15@Oamine–Cu were prepared and proved to be efficient and reusable for homocoupling of terminal alkynes at room temperature with air as the oxidant. SBA-15@amine–Cu exhibited better recyclability than SBA-15@Oamine–Cu. The differences in the catalytic performances of the catalysts could be ascribed to catalyst structure and the interaction between copper and the supports. The as-prepared catalysts were systematically characterized by inductively coupled plasma atomic emission spectroscopy (ICP-AES), high resolution-transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and nitrogen physical adsorption. The analysis indicated that the mesoporous structure of the materials was retained during the immobilization process. XPS results suggested that the as-prepared catalysts were not obtained by a simple physical adsorption of CuCl on the supports. It is noted that, for aliphatic alkynes, the catalytic activity of SBA-15@amine–Cu is even higher than that of the homogeneous copper catalytic system and that of some previously reported heterogeneous systems.
胺功能化的介孔
二氧化硅负载
铜催化剂SBA-15@胺–Cu和SBA-15@O胺–Cu被制备出来,并证明在室温下以空气为氧化剂时,对于端炔的自偶联反应是高效且可重复使用的。SBA-15@胺–Cu的循环稳定性优于SBA-15@O胺–Cu。催化剂性能的差异可归因于催化剂结构以及
铜与载体之间的相互作用。通过电感耦合等离子体原子发射光谱(ICP-AES)、高分辨率透射电子显微镜(HR
TEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)和氮物理吸附对制备的催化剂进行了系统的表征。分析表明,在固定化过程中,材料的介孔结构得以保留。XPS结果表明,制备的催化剂并非简单地将CuCl物理吸附在载体上。值得注意的是,对于脂肪族
炔烃,SBA-15@胺–Cu的催化活性甚至高于均相
铜催化体系以及一些先前报道的非均相体系。