酸性离子液体催化β-萘甲醚酰化反应

Acylation of β-Methoxy naphthalene catalyzed by Acidic Ionic Liquid

摘要:

采用水为溶剂一步法合成对甲苯磺酸吡啶离子液体([Py]Tsa)，利用傅里叶红外光谱(IR)，核磁共振波谱(NMR)，热分析(TG-DTA)对其进行了表征。以β-萘甲醚与乙酸酐酰基化为探针反应，研究[Py]Tsa催化反应活性、确定反应条件。结果表明，在反应温度150 ℃，反应时间5 h，乙酸酐/β-萘甲醚摩尔比值为1.5，离子液体/β-萘甲醚质量比2.53，转化率最高达58.88 %，2-甲氧基-1-萘乙酮作为主产物，选择性达98.28 %；离子液体简单再生后可重复利用，催化活性没有明显降低。对产物进行了分离提纯，应用傅里叶红外光谱，核磁共振波谱，热重分析进行表征，确定了反应的两种产物。

Abstract:

Pyridinium 4-Toluenesulfonate ionic liquid (IL) was synthesized in water by a one-step synthetic method. The ionic liquid was characterized by infrared spectrum (IR), nuclear magnetic resonance spectrum (NMR) and Thermal analysis (TG-DTA). Friedel-Craft acylation of β-Methoxynaphthalene using acetic anhydride as acylation reagent was then studied as a probe reaction. The effect of catalytic activities of the ionic liquid and reaction conditions on the catalytic reaction were researched. The results indicated that, under the optimal reaction conditions, namely nacetic anhydride: nβ-Methoxynaphthalene=1.5:1, mIL : mβ-Methoxynaphthalene= 2.53, reaction temperature at 150°C for 5h, the conversion of β-Methoxynaphthalene was up to 58.88 % and the selectivity towards 2-methoxy-1-acetonaphthone reached to 98.28 %. The ionic liquid could be recycled and reused for several times without significant loss of activity. The product has been separated, purified and confirmed by infrared spectrum, nuclear magnetic resonance spectrum and thermal analysis. Two products of the reaction were identified.