A novel water-bath microwave method used for synthesis of hydroxyl ammonium ionic liquids was reported.A series of hydroxyl ammonium ionic liquids (ILs) consisting of ethanolamine

diethanolamine

triethanolamine or dimethylethanolamine as cations

and formic acid

acetic acid or lactic acid as anions were synthesized.Taking ethanolamine lactate ionic liquid as an example

the result of orthogonal experiment (L9(34)) showed the optimal synthesis conditions were 65 ℃

wave power of 300 W for 30 min with the molar ratio of 1︰1.1 (ethanolamine vs lactic acid).Under these conditions

the yield of the other eight ILs except dimethylethanolamine salts reached above 90%.Because of its higher capacity for absorption of SO2

ethanolamine lactate was selected as the better absorbent with the capacity of SO2 in ethanolamine lactate 1.063 (SO2 vs ethanolamine lactate).The results showed that the appropriate absorption temperature for SO2 was 25 ℃

desorption temperature was 90 ℃

and desorption time was 60 min.It was also found that water-bath microwave was able to accelerate the desorption of SO2.