The creation of carbon–carbon bonds is still a highly required topic in organic chemistry for the capacity to give a wide variety of new products of industrial value. Accordingly, the Knoevenagel condensation between activated methylene compounds and aldehydes is one of the most known carbon coupling reactions. In this work, the catalytic activity of imidazolium-based ionic liquids (1-butyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium chloride, 1-methyl-3-carboxymethylimidazolium chloride) was studied under solvent-free conditions and compared with that of sodium salts (sodium chloride, sodium acetate). Mass spectrometric techniques were used to monitor the formation of the reaction products and to detect the key intermediates of the process. Based on the catalyst employed different reaction mechanisms were highlighted, thus laying the foundation for the design of more specific and efficient catalysts.

中文翻译：

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离子液体催化的 Knoevenagel 缩合反应：质谱洞察反应机理

碳-碳键的创建仍然是有机化学中一个非常需要的主题，因为它能够提供各种具有工业价值的新产品。因此，活化的亚甲基化合物和醛之间的 Knoevenagel 缩合反应是最著名的碳偶联反应之一。在这项工作中，基于咪唑鎓的离子液体（1-丁基-3-甲基咪唑醋酸盐、1-丁基-3-甲基咪唑氯化物、1-甲基-3-羧甲基咪唑氯化物）的催化活性在无溶剂条件下进行了研究并进行了比较与钠盐（氯化钠，醋酸钠）。质谱技术用于监测反应产物的形成并检测该过程的关键中间体。基于所采用的催化剂，强调了不同的反应机制，