The butoxylation of dodecylamine: reaction mechanism and kinetics

The reaction mechanism and kinetics of the butoxylation of dodecylamine were investigated experimentally using a semi-batch, fully liquid process at temperatures ranging from 120 °C to 150 °C and varying stoichiometric ratios of the reactants. In addition, the catalytic effect of adding 1-3%mol of twelve different functional organic species containing hydroxyl, aldehyde, amine, and/or amide functional groups was studied. It was found that only proton donating groups increase the observed reaction rate. In particular hydroxyl groups in combination with an amine group resulted in a strong acceleration of the reaction. Since the reaction intermediates mono-and dibutoxylated amines have this combination, an auto-catalytic reaction mechanism and corresponding rate law are proposed. The kinetic constants were fitted to the experimental data as a function of temperature, following an Arrhenius type of dependency. The results from the model describe the experimental data with 95% accuracy. Moreover, the results show that the butoxylation of dodecylamine, as a model reactant for a short substituted ethylene oxide, with fatty amines, follows the same mechanism and has similar kinetics as epoxide hardening reactions with amines.