A mechanistic investigation on the ethanol self-condensation reaction (Guerbet reaction) catalyzed by a bis(pyridylimino)isoindolate Ru(II) catalyst was performed using a specifically designed continuously-stirred tank reactor (CSTR). Leveraging vapor–liquid equilibrium, the homogeneous catalyst was maintained in the reactor at a constant concentration by dissolving it in a non-volatile solvent while volatile substrates were fed continuously. The activity of the catalyst was monitored by analyzing the vapor exiting the reactor (reagents and products) using an in-line gas chromatograph. The formation of C₆ products demonstrates the catalyst's reactivity towards butanol, and the detection of solely saturated products implies that hydrogenation is fast under the reaction conditions. These observations led us to perform a detailed study of the hydrogenation step that provided evidence for a hydrogen-transfer pathway. The corresponding reaction mechanism for the Guerbet reaction was established.

中文翻译：

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流动反应器中均相钌格尔伯特催化剂的机理研究

使用专门设计的连续搅拌釜反应器 (CSTR)对双(吡啶亚氨基)异吲哚酸 Ru( II ) 催化剂催化的乙醇自缩合反应 (Guerbet 反应) 进行机理研究。利用气液平衡，均相催化剂在反应器中保持恒定浓度，方法是将其溶解在非挥发性溶剂中，同时连续加入挥发性底物。通过使用在线气相色谱分析离开反应器的蒸气（试剂和产物）来监测催化剂的活性。C ₆的形成产物证明了催化剂对丁醇的反应性，并且仅检测到饱和产物意味着在反应条件下加氢速度很快。这些观察结果使我们对氢化步骤进行了详细研究，为氢转移途径提供了证据。建立了相应的 Guerbet 反应反应机理。