Li Guozhu, Zheng Shuyi, Wang Li, Zhang Xiangwen
Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China.
ACS Omega. 2020 Mar 24;5(13):7519-7528. doi: 10.1021/acsomega.0c00328. eCollection 2020 Apr 7.
Chemoselective hydrogenation of nitroarenes to anilines is of great importance for the manufacture of pharmaceuticals, fine chemicals, and dyes. In this study, a series of metal-free N-doped carbon nanotubes (NCNTs) have been prepared by the carbonization of in situ polymerized pyrrole on CNTs. The concentration of pyrrole, pyrolysis temperature, and the outside diameter of CNTs were investigated to improve the catalytic performance. As characterized by Raman and X-ray photoelectron spectroscopy (XPS), the optimal catalyst (NCNTs-800) possessed a unique structure doped with the same content of pyrrolic N and graphitic N. The activity and selectivity of NCNTs-800 have been evaluated for the selective hydrogenation of substituted nitroarenes. Highly selective hydrogenation of the nitro group of 12 different substrates has been achieved on NCNTs-800, even in the presence of a fragile iodo group. The hydrogenation reaction on N-doped CNTs from polypyrrole involved a mixture of different hydrogen species including nonpolar H radicals. In addition, stability and recyclability of NCNTs-800 have been tested.
硝基芳烃化学选择性加氢制苯胺在制药、精细化工和染料制造中具有重要意义。在本研究中，通过原位聚合吡咯在碳纳米管（CNTs）上碳化制备了一系列无金属的氮掺杂碳纳米管（NCNTs）。研究了吡咯浓度、热解温度和碳纳米管外径以提高催化性能。通过拉曼光谱和X射线光电子能谱（XPS）表征，最佳催化剂（NCNTs-800）具有独特的结构，掺杂有相同含量的吡咯氮和石墨氮。评估了NCNTs-800对取代硝基芳烃选择性加氢的活性和选择性。即使在存在易断裂的碘基团的情况下，在NCNTs-800上也实现了12种不同底物硝基的高选择性加氢。来自聚吡咯的氮掺杂碳纳米管上的加氢反应涉及包括非极性H自由基在内的不同氢物种的混合物。此外，还测试了NCNTs-800的稳定性和可回收性。
