高分散度Ru/C选择性催化对氯硝基苯加氢制备对氯苯胺

Highly Selective Hydrogenation of p-Chloronitrobenzene to p-Chloroaniline over Ru/C

研究了高分散度Ru/C在对氯硝基苯(p-CNB)加氢制备对氯苯胺(p-CAN)反应中的催化性能,考察了Ru负载量、溶剂种类、底物浓度、反应温度和压力等反应条件对反应的影响。结果表明,反应条件只影响p-CNB的加氢速率,但对p-CAN的选择性没有影响,p-CNB 100%转化时,p-CAN的选择性100%,没有脱氯副反应发生。催化剂的高活性和高选择性与纳米Ru在活性炭上的高分散度及催化剂的表面碱性有关。p-CNB浓度低于0.96mol/L时,还原反应对p-CNB宏观表现为零级反应。催化剂连续套用30次活性保持稳定。

The Ru/C catalyst was used in liquid phase selective hydrogenation of p-chloronitrobenzene （p-CNB） to p-chloroaniline. No dehalogenation was observed and the selectivity to p-chloroaniline was always 100% under various reaction conditions in the scope of our investigation. Change of reaction parameters only influences the reaction rate. The selectivity for p-chloroaniline was kept at 100% even when conversion of the substrate was as high as 100% over the Ru/C catalyst. The extremely high selectivity to p-chloroaniline was due to the high activity of nanon Ru on carbon as well as the characteristic surface basic properties of the Ru/C catalyst. When the concentration of p-CNB is below 0.96 mol/L, the hydrogenation rate was independent of the concentration of p-CNB, but dependent on the partial pressure of hydrogen. The catalyst exhibited extra-long stability, and retained the same activity and selectivity even after 30 times continuous running.