将原位生成的中间体与其他底物/中间体偶联是使涉及两种或多种反应物的催化反应的产物结果多样化的可行方法。环己酮肟是己内酰胺合成的关键前体(尼龙-6的单体),然而,它目前的生产使用不可持续的碳源,贵金属催化剂,和恶劣的条件。在这里,我们报道了通过苯酚和羟胺的电还原合成环己酮肟的第一项工作。在铜催化剂上的法拉第效率达到69.1%,伴随着相应的环己酮肟形成速率为82.0gh-1gcat-1。此外,苯酚的转化率高达97.5%。原位表征,对照实验,理论计算表明水平衡活化的重要性,苯酚,和羟胺基质上的最佳金属Cu催化剂,用于实现高性能环己酮肟的合成。此外,通过集成热催化,成功开发了将木质素升级为己内酰胺的串联催化路线,电催化,和Beckmann重新安排,从4.0g木质素原料中合成了0.40g己内酰胺。
Coupling in situ generated intermediates with other substrates/intermediates is a viable approach for diversifying product outcomes of catalytic reactions involving two or multiple reactants. Cyclohexanone oxime is a key precursor for caprolactam synthesis (the monomer of Nylon-6), yet its current production uses unsustainable carbon sources, noble metal catalysts, and harsh conditions. Herein, we report the first work to synthesize cyclohexanone oxime through electroreduction of phenol and hydroxylamine. The Faradaic efficiency reached 69.1% over Cu catalyst, accompanied by a corresponding cyclohexanone oxime formation rate of 82.0 g h-1 gcat-1. In addition, the conversion of phenol was up to 97.5%. In situ characterizations, control experiments, and theoretical calculations suggested the importance of balanced activation of water, phenol, and hydroxylamine substrates on the optimal metallic Cu catalyst for achieving high-performance cyclohexanone oxime synthesis. Besides, a tandem catalytic route for the upgrading of lignin to caprolactam has been successfully developed through the integration of thermal catalysis,
electrocatalysis, and Beckmann rearrangement, which achieved the synthesis of 0.40 g of caprolactam from 4.0 g of lignin raw material.