Derivatization of Alcohols Using (bmim)HSO4: A Green Approach for the Undergraduate Chemistry Laboratory

Alcohol is one of the functional groups detected as part of qualitative organic analysis. The final identification of alcohol involves the preparation of suitable crystalline derivative, usually the 3,5-dinitrobenzoate. According to the standard procedure, 3,5-dinitrobenzoic acid is first converted to 3,5-dinitrobenzoyl chloride by reaction with either phosphorous pentachloride (PCl5) or thionyl chloride (SOCl2). However, in this reaction, hazardous side products like phosphorous oxychloride (POCl3), hydrochloric acid (HCl) and sulphur dioxide (SO2) are produced. In the present method, we report the direct and benign conversion of alcohols to the corresponding 3,5-dinitrobenzoates using ionic liquid, (bmim)HSO4 under microwave irradiation.