Synthesis of gossypol acetic acid with [HMIm]HSO_4 ionic liquid as catalyst

With Bronsted acidic ionic liquid HSO4 as the catalyst,the synthesis of gossypol acetic acid was investigated.The effects of reacting conditions including temperature,reaction time,material ratio and amount of catalyst on the yield of the reaction were also investigated.The optimal reaction conditions were as follows: reaction temperature 10℃,volume ratio of gossypol to glacial acetic acid-HSO4 1∶1.0,amount of catalyst 6%(based on the mass of glacial acetic acid),reaction time 4 h.Under these conditions,the yield of gossypol acetic acid reached 93%.At the same time,the stability and acidity of ionic liquid(HSO4) were investigated using thermogravimetric analysis and UV spectroscopy detection.The ionic liquid HSO4 had a stable catalytic activity even after 4 cycling.