A ruthenium and palladium bimetallic system superior to a rhodium co-catalyst for TiO2-photocatalyzed ring hydrogenation of aniline to cyclohexylamine
A ruthenium and palladium bimetallic system superior to a rhodium co-catalyst for TiO2-photocatalyzed ring hydrogenation of aniline to cyclohexylamine
复制标题
DOI：
10.1016/j.jcat.2020.05.035
复制
发表时间：
2020-09
影响因子：
7.3
通讯作者：
S. Araki;Kousuke Nakanishi;A. Tanaka;H. Kominami
中科院分区：
文献类型：
--
作者：
S. Araki;Kousuke Nakanishi;A. Tanaka;H. Kominami
环己胺(CHA)是一种重要的化工原料。由于CHA的生产需要高温和过量的氢气(H2)和氨，因此开发在较温和的条件下使用安全化合物进行的简单反应对于实现可持续化学是必不可少的。本文报道了以草酸代替氢气为氢源的四氧化二钛光催化剂在室温水中催化苯胺环加氢制CHA的高选择性。在具有助催化剂的TiO2光催化剂中，Rh-TiO2表现出较高的CHA生成活性，而Pd-TiO2和Ru-TiO2的活性很小。当使用双金属光催化剂Ru/Pd-TiO2时，产率高于使用Rh-TiO2时的产率。用透射电子显微镜观察了负载在TiO2上的金属颗粒，用XPS研究了Ru和Pd的电子态。通过吸附实验研究了金属与AN、CHA之间的相互作用。在此基础上，讨论了加氢反应的活性中心。
Cyclohexylamine (CHA) is used as an important raw material in chemical industries. Since the production of CHA requires a high temperature and excess amounts of hydrogen gas (H2) and ammonia, the development of a simple reaction operated under milder conditions using a safe compound is indispensable for achieving sustainable chemistry. A highly selective ring hydrogenation of aniline (AN) to CHA over a titanium(IV) oxide photocatalyst having a co-catalyst in water at room temperature, in which oxalic acid was used as the hydrogen source in place of H2, is described in this paper. Among TiO2photocatalysts having co-catalysts, Rh-TiO2showed high activity for CHA production, while Pd-TiO2and Ru-TiO2showed negligible activity. When a bimetallic photocatalyst, Ru/Pd-TiO2, was used, the yield was larger than that when Rh-TiO2was used. Metal particles loaded on TiO2were observed by using TEM, and electronic states of Ru and Pd were evaluated by using XPS. Interactions among metal, AN and CHA were investigated through adsorption experiments. Based on the results, active sites for AN hydrogenation are discussed.