Synthesis of biodiesel from rapeseed oil catalyzed by alkaline ionic liquid [Bmim]OH

The alkaline ionic liquid [Bmim]OH was prepared,and it was used to synthesize biodiesel from rapeseed oil by transesterification.Effects of molar ratio of methanol to rapeseed oil,reaction temperature,reaction time and ionic liquid dosage on the transesterification and stability of the ionic liquid were investigated.The optimum reaction conditions were obtained as follows:molar ratio of methanol to rapeseed oil 16∶1,reaction temperature 150℃,reaction time 4 h,dosage of ionic liquid 6%(based on the mass of rapeseed oil).The yield of biodiesel reached 96.2% under the optimum conditions.The ionic liquid was stable,and its activity did not decrease after using for 5 times.