The kinetics of CO2 absorption in aqueous solutions of MDEA + [bmim][BF4] were investigated using a stirred cell reactor where the relevant parameters were evaluated. The rate equation of the absorption reaction was found to be close to first order with respect to CO2 at temperatures ranging from 303 to 333 K and [bmim][BF4] concentration from 0 to 2.0 mol L-1. The activation energy decreased from 43.32 kJ mol(-1) to 8.65 kJ mol(-1) with increasing [bmim][BF4] concentration from 0 to 2.0 mol L-1 in aqueous 4 mol L-1 MDEA solution. Calculated results of the enhancement factor and Hatta number showed that the performance of CO2 absorption in the aqueous 4 mol L-1 MDEA + [bmim][BF4] solution almost obeyed the pseudo first order regime. (C) 2012 Elsevier B.V. All rights reserved.