CO2 absorption properties of Brønsted acid–base ionic liquid composed of N,N-dimethylformamide and bis(trifluoromethanesulfonyl)amide

The solubilities of CO 2 and the liquid densities in a Bronsted acid–base ionic liquid, [DMFH][Tf 2 N], composed of N , N -dimethylformamide (DMF) and bis(trifluoromethanesulfonyl)amide (HTf 2 N) have been investigated at high pressures and at different temperatures. The results were compared with those in DMF and a typical 1-butyl-3-methylimidazolium analogue with the same anion, [BMIM][Tf 2 N]. The mole fraction scaled solubilities of CO 2 in the three liquids showed a slight increase in the following order, DMF 2 N] 2 N], whereas more remarkable difference was observed in the volume scaled concentrations of CO 2 , [BMIM][Tf 2 N] 2 N] « DMF, mainly due to the bulkiness of liquid entities.