活性炭固载钯催化剂的制备及催化Ullmann反应的研究

采用双氧水改性活性炭,增加表面酚羟基的含量,并与硅烷偶联剂(CH3O)3Si(CH2)3NH(CH2)2NH2]反应,引入双胺基官能团,络合氯化钯,制备了活性炭固载钯催化剂;同时采用Bohem滴定、元素分析(EA)、傅里叶变换红外光谱(FT-IR)、X射线光电子能谱(XPS)、透射电镜(TEM)、电感耦合等离子体质谱仪(ICP-MS)以及多晶X射线衍射(XRD)对制备的催化剂进行了表征,并研究了它对卤代芳烃Ullmann反应的催化性能.实验结果表明:催化剂中钯键载在载体上,钯在载体表面分布均匀,粒径在4 nm左右;该催化剂能够较好地催化卤代芳烃的Ullmann反应,具有较好的重复使用性能,4-碘苯甲醚反应的产率是90.5%,溴代芳烃偶联反应的最高收率为73.6%,氯代芳烃的最高收率为41.4%.催化剂AC-NH(CH2)2NH2-Pd重复使用7次后,溴苯偶联产物的收率为35.9%.

Preparation of Activated Carbon Immobilized Palladium Complex and Its Catalytic Application in Ullmann Reaction

Activated carbon anchored palladium complex was prepared via grafting silane coupling agent（CH2O） 3Si（CH2） 3NH（CH2） 2NH2 onto chemically modified activated carbon by H2O2,followed by the complexation palladium chloride.The prepared catalyst was characterized by bohem titration,elemental analysis（EA）,fourier transform infrared spectroscopy（FTIR）,X-ray photoelectron spectroscopy（XPS）,transmission electron microscopy（TEM）,inductively coupled plasma mass spectrometry（ICP-MS）,and X-ray diffraction（XRD）.The results indicated that palladium particales are immobilized on the carrier via coordination bond in this catalyst and evenly dispersed on the surface of carrier with 4 nm diameter.This immobilized catalyst exhibites higher catalytic activity and reuse capability in the Ullmann reaction of aryl halides.The yield of 4-Iodoanisole coupling is 90.5%.The highest coupling product yield of brominated aromatic is 73.6%,that of chlorinated aromatic is 41.4%.It can be recovered by simple filtration and reused up to 7 times with 35.9% yield.