AbstractThe kinetics of the reactions of the primary and secondary amine groups in aqueous DETA solution were measured in a string of discs contactor at different concentrations and temperatures. The reaction rates of the primary amine group were performed at very low loading and for the secondary amine group H2SO4 was used to neutralize the primary amine groups. The reaction rates increase with increasing DETA concentration and temperature. The reaction order is found to be a broken-order and to vary slightly with the temperature. Both the termolecular and the zwitterion mechanisms were applied to interpret the experimental data and gave identical result. Both DETA and water contribute to the carbamate formation in the primary and secondary amine groups. The rate of CO2 absorbed in the primary amine group is faster than the secondary amine group and about 100 times higher.