Efficient Lewis Acid Ionic Liquid Catalyzed Synthesis of the Key Intermediate of Coenzyme Q10 under Microwave Irradiation
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.
Molecules