采用溶剂热法合成了MIL-100(Cr),通过双溶剂浸渍法负载Pd纳米粒子制备负载型Pd/MIL-100催化剂。以溴苯与苯硼酸偶联合成联苯为模型反应,考察了溶剂、碱助剂、温度等因素对Suzuki偶联反应性能的影响。结果表明,以V(EtOH)∶V(H₂O)=2∶1为溶剂、K₂CO₃为碱助剂,在60℃反应0.5 h,溴苯转化率达到97%,目标产物联苯选择性>99%;催化剂对于对位和间位供电子基团取代的芳基硼酸具有良好的底物适用性;Pd/MIL-100催化剂循环使用3次仍保持良好的催化活性及稳定性。XRD、XPS、ICP及TEM表征结果表明,催化剂失活的主要原因是由于Pd纳米粒子在MIL-100表面发生了迁移团聚。

MIL-100(Cr) is synthesized through solvothermal method,and used to support Pd nanoparticles through a double-solvent impregnation method to prepare Pd/MIL-100,a supported catalyst.Taking the coupling reaction of bromobenzene and phenylboronic acid to synthesize biphenyl as a model reaction,the effects of solvents,base auxiliary,substrate concentration,temperature as well as catalyst dosage on the catalytic activity of the prepared catalyst in Suzuki coupling reaction are investigated.The conversion rate of bromobenzene reaches 97% and the selectivity of biphenyl exceeds 99% when EtOH/H₂O (2∶1) is used as solvent,K₂CO₃ as base auxiliary,and the reaction has performed for 30 min at 60℃.Moreover,Pd/MIL-100 catalyst shows a good substrate applicability for a series of aryl boronic acids by para- and meta-substituted electron donor groups.Recycling experiments show that Pd/MIL-100 catalyst maintains good catalytic activity and stability after 3 consecutive runs.The deactivation mechanism for the catalyst is analyzed by means of XRD,XPS,ICP and TEM.It is discovered that the migration and aggregation of Pd nanoparticles on the surface of MIL-100 is the main reason for the deactivation.

李千帆(1999-),女,硕士研究生,研究方向为金属有机骨架材料的制备及其催化,liqianfan66@126.com。