A series of PEG-based imidazolium toluenesulfonates (PEG-based functionalized ionic liquids) with long ether chain were synthesized and their ability to reversibly absorb gaseous sulfur dioxide was investigated. Physical properties (densities

surface tensions and viscosities) of the ILs had been measured during absorption process. All the ILs showed good absorption and regeneration capacity. The absorption capacity of ILs increased with increasing length of ether chain on the cation. The absorption capacity achieved more than 5.51 mole SO2 per mole IL at 20℃

and the absorbed SO2 gas can be readily and completely desorbed from the ILs at 80℃. The new ILs could absorb SO2 by physical interactions at the experimental conditions under 1H NMR and Raman spectrum investigation. Densities of the ILs increased when the ILs absorbed SO2 and turned to be saturated

at same time

surface tensions decreased and viscosities lowered sharply.