An efficient synthesis of a valuable intermediate of coenzyme Q10 by microwave-assisted Lewis acidic ionic liquid (IL)-catalyzed Friedel-Crafts alkylation is reported. The acidity of six [Etpy]BF4-based ionic liquids was characterized by means of the FT-IR technique using acetonitrile as a molecular probe. The catalytic activities of these ionic liquids were correlated with their Lewis acidity. With increasing Lewis acid strength of the ionic liquids, their catalytic activity in the Friedel-Crafts reaction increased, except for [Etpy]BF4-AlCl3. The effects of the reaction system, the molar fraction of Lewis acid in the Lewis acid ILs and heating techniques were also investigated. Among the six Lewis acid ionic liquids tested [Etpy]BF4-ZnCl2 showed the best catalytic activity, with a yield of 89% after a very short reaction time (150 seconds). This procedure has the advantages of higher efficiency, better reusability of ILs, energy conservation and eco-friendliness. The method has practical value for preparation of CoQ10 on an industrial scale.
报告了一种通过微波辅助
路易斯酸离子液体(IL)催化的Friedel-Crafts烷基化方法高效合成
辅酶Q10的有价值中间体。采用FT-IR技术,以
乙腈作为分子探针对六种[Etpy]BF4基
离子液体的酸性进行了表征。这些
离子液体的催化活性与其
路易斯酸性相关。在
离子液体的
路易斯酸性强度增加的情况下,除了[Etpy]BF4-
AlCl3外,它们在Friedel-Crafts反应中的催化活性也随之提高。还研究了反应体系、
路易斯酸在
路易斯酸离子液体中的摩尔比例和加热技术的影响。在测试的六种
路易斯酸离子液体中,[Etpy]BF4-ZnCl2表现出最佳的催化活性,在非常短的反应时间(150秒)内获得了89%的产率。这一过程具有更高的效率、更好的
离子液体重复使用性、节能和环保的优点。该方法在工业规模生产CoQ10方面具有实际价值。