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| Synthesis of Xanthenes Catalyzed by Ionic Liquid 1-Ethyl-3-(4-sulfobutyl)-1H-imidazol-3-ium -p-Toluenesulfonate |
| TIAN Xiao-yue1a, ZHANG Yong-hong1a, SUN Ya-dong1a, WANG Duo-zhi1b, LIU Chen-jiang1a |
| a. The Key Laboratory of Oil and Gas Fine Chemicals, Ministry of Education & Xinjiang Uygur Autonomous Region; b. College of Chemistry and Chemical Engineering, 1. Xinjiang University, Urumqi 830046, China |
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Abstract Brnsted acidic ionic liquid, 1-ethyl-3-(4-sulfobutyl)-1H-imidazol-3-ium -p-toluenesulfonate(IL1), was prepared using 1-ethylimidazole as raw material. A series of xanthenes were synthesized by condensation reaction of aromatic aldehydes with 5,5-dimethyl-1,3-cyclohexanedione or 1,3-cyclohexanedione catalyzed by IL1 under solvent-free conditions. The structures were characterized by 1H NMR, 13C NMR and ESI-MS. The results indicated that 5 mol% IL1 as catalyst, reaction at 80 ℃ for 40 min, the yields were 78%~95%. The catalytic activity of IL1 keep stable with the yields of 86%~89% after recycling of three times.
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Received: 15 April 2015
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2016, Vol. 24 
