The direct cleavage of C−O bonds in lignin and its derivatives via hydrogenolysis is an essential reaction process for lignin conversion. Herein, we design a MgAlO supported Ru catalyst using a facile and green method involving ball milling and microwave heating. The optimal catalyst, 0.5Ru/MgAlO, displayed enhanced catalytic performance for 4−O−5 linkage scission compared to 0.5Ru/AlO and 0.5Ru/MgO, achieving a tuenover frequency of 352.9 h for diphenyl ether (DPE) conversion. 0.5Ru/MgAlO with low Ru loading achieved complete conversion of DPE, with 43.8% yield of cyclohexane (CHE) and 42.6% yield of cyclohexanol (CHL) after 2 h at 160 °C and 1.5 MPa H. The promising catalytic activity can be attributed to the abundant electron-rich Ru species with high dispersion formed on MgAlO, derived from the strong electron transfer from the support to Ru. The reaction mechanism for the direct cleavage of the 4−O−5 bond, followed by phenyl ring hydrogenation, was confirmed by rigorous experiments. This work provides an inspiring idea for developing efficient heterogeneous catalysts for the utilization of lignin resources via hydrogenolysis.

中文翻译：

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定制的 MgAl2O4 负载 Ru 催化剂用于二苯醚氢解中选择性 C-O 键断裂


通过氢解直接裂解木质素及其衍生物中的C−O键是木质素转化的重要反应过程。在此，我们使用球磨和微波加热等简便且绿色的方法设计了一种 MgAl2O 负载的 Ru 催化剂。与 0.5Ru/Al2O 和 0.5Ru/MgO 相比，最佳催化剂 0.5Ru/MgAl2O 表现出增强的 4−O−5 键断裂催化性能，二苯醚 (DPE) 转化的转换频率达到 352.9 h。低 Ru 负载量的 0.5Ru/MgAlO 实现了 DPE 的完全转化，在 160 °C 和 1.5 MPa H 下 2 小时后，环己烷 (CHE) 产率达到 43.8%，环己醇 (CHL) 产率达到 42.6%。这归因于 MgAl2O 上形成的丰富且高色散的富电子 Ru 物种，源自从载体到 Ru 的强电子转移。 4−O−5 键直接断裂，随后苯环氢化的反应机理已通过严格的实验得到证实。这项工作为开发高效的多相催化剂以通过氢解利用木质素资源提供了启发性的想法。