Magnetically recyclable Pd/γ-AlOOH@Fe3O4 catalysts and their catalytic performance for the Heck coupling reaction
作者:Hao Yang、ShengFu Ji、XueFei Liu、DanNi Zhang、Da Shi
DOI:10.1007/s11426-014-5072-4
日期:2014.6
Novel magnetically recyclable Pd/γ-AlOOH@Fe3O4 catalysts were prepared using γ-AlOOH@Fe3O4 as a magnetic supporter and nano-Pd particles as the active catalytic component. The structure of the catalysts was characterized by XRD (X-ray diffraction), TEM (transmission electron microscopy), N2 adsorption-desorption, and a VSM (vibration sample magnetometer). The catalytic activity and recyclability for the Heck coupling reaction were investigated. Results showed that the magnetic γ-AlOOH@Fe3O4 possessed a core-shell structure, as well as that the nano-Pd particles were 6–8 nm and had been well dispersed in the γ-AlOOH shell. In the Heck coupling reactions, the magnetic Pd/γ-AlOOH@Fe3O4 catalysts exhibited good catalytic activity and recyclability. For the (0.021 mol%)Pd/γ-AlOOH@Fe3O4 catalyst, the bromobenzene conversion and product yield reached about 100% and 96.3%, respectively, under a 120°C reaction temperature and 12 h reaction time. After being recycled 8 times, the conversion of bromobenzene and the recovery of the catalyst were about 90% and 93%, respectively. The nano-Pd particles were kept well dispersed in the used Pd/γ-AlOOH@Fe3O4 catalyst.
新型磁性可回收Pd/γ-AlOOH@Fe3O4催化剂采用γ-AlOOH@Fe3O4作为磁性支撑体,纳米Pd颗粒作为活性催化成分制备而成。催化剂的结构通过XRD(X射线衍射)、TEM(透射电子显微镜)、氮气吸附-脱附以及VSM(振动样品磁强计)进行了表征。对Heck偶联反应的催化活性和可回收性进行了研究。结果显示,磁性γ-AlOOH@Fe3O4具备核壳结构,纳米Pd颗粒大小为6–8纳米,并在γ-AlOOH壳层中均匀分散。在Heck偶联反应中,磁性Pd/γ-AlOOH@Fe3O4催化剂表现出良好的催化活性和可回收性。对于(0.021 mol%)Pd/γ-AlOOH@Fe3O4催化剂,在120°C反应温度和12小时反应时间下,溴苯转化率和产物收率分别达到了约100%和96.3%。经过8次回收后,溴苯的转化率和催化剂的回收率分别约为90%和93%。纳米Pd颗粒在使用后的Pd/γ-AlOOH@Fe3O4催化剂中保持良好分散。