Fe_2O_3/AC催化剂上对甲基苯硫酚的水相催化氧化偶联

Catalytic oxidative coupling of p-thiocresol in aqueous phase over Fe_2O_3/AC catalysts

以对甲基苯硫酚为模型底物,空气为氧化剂,来研究硫醇水相催化氧化偶联制备二硫醚。以活性炭为载体,采用等体积浸渍法制备了一系列负载型氧化物催化剂,并考察了其在对甲基苯硫酚氧化偶联制备对甲苯二硫醚反应中的催化性能。反应结果表明,活性炭负载的铁氧化物具有最佳催化性能。采用N_2物理吸附、X射线衍射、X射线光电子能谱和透射电镜等表征手段对活性炭负载的铁氧化物催化剂进行了表征。表征结果表明,铁氧化物为高度分散在活性炭上的Fe_2O_3物种。以Fe_2O_3/AC为催化剂,当催化剂焙烧温度为400℃,Fe负载量为5%,在50℃下反应30min时,对甲苯二硫醚的收率高达97.4%;该催化剂循环使用5次后活性无明显下降。

p-Thiocresol was chosen as the model substrate to study the catalytic oxidative coupling of mercaptan to disulfides with air as oxidant. A series of supported metal oxides were prepared by the incipient-wetness impregnation method using activated carbon as the support. The catalytic oxidative coupling of p-thiocresol to p-toyldisulfide over the supported metal oxides catalysts was studied. The reaction results indicate the activated carbon supported iron oxide showed the best catalytic performance.The supported iron oxide catalysts were characterized by BET, XRD, XPS and TEM. The characterization results indicate iron oxide is in the form of Fe2 O3 and the nanoparticles are highly dispersed on the activated carbon. The best Fe2 O3/AC catalyst achieved a high yield of p-toyldisulfide(97.4%) with the reaction temperature of 50℃ for 30 min and the catalyst calcinated at 400℃ with Fe loading of 5%. The Fe2 O3/AC catalyst could be used for 5 times without significant loss of activity.