新型酸性离子液体催化的Knoevenagel缩合反应

摘要

研究了一类新型酸性离子液体催化的Knoevenagel缩合反应，结果表明，该催化剂适用于一系列芳香/杂环醛与α­取代活性亚甲基化合物间的反应，反应可在室温下进行，反应时间短且收率良好(92%~98%)。该反应体系操作简单，产物易分离。提出了可能的反应机理并对机理进行了验证。该离子液体重复使用5次后仍具有较高的反应活性。%A series of novel multiacidic ionic liquids ( [ TEOA ] [ CF3 COO ] ) based on triethanolamine were synthesized through the two­step method and introduced as catalysts for Knoevenagel condensation of complex active methylene compounds. [ TEOA] [ CF3 COO] showed the best catalytic performance. The reactions were carried out at room temperature and the amount of catalyst was only 2%( molar fraction) . The reaction system was applicable to a wide range of aromatic/heteroaromatic aldehydes with the complex α­substituted active methylene compounds affording the products in excellent yields ( 92%—98%) within minutes. The reaction system was operationally simple and the desired products could be easily separated from the reaction mixture. A plausible mechanism for the Knoevenagel reaction catalyzed by [ TEOA] [ CF3 COO] was proposed and the relevant evidences were given. In addition, the ionic liquid could be regenerated and recycled five times without a significant loss of activity.