The thermodynamics of the mass transfer process of fuel oxygenates (MTBE and ETBE) from aqueous phase to air by batch air stripping (BAS) has been studied in this work. This study analyzes the influence of the aeration flow and the temperature. The Mackay approach was used in order to calculate the Henry's law constant for each operational condition and they were compared with those obtained by static methods. The thermodynamics functions of the process, aqueous free excess enthalpy of solution ([image omitted]) and enthalpy of air-water transfer (waHi) for both compounds were calculated and compared with literature values. Finally the effect of the cosolvency of tert butyl alcohol (TBA) was analyzed.