KINETICS OF REACTIONS OF CARBON-DIOXIDE WITH DIGLYCOLAMINE AND MORPHOLINE

It is reported that in industrial plants, diglycolamine may be dehydrated to morpholine. In this work, the kinetics of reactions of carbon dioxide with aqueous diglycolamine and morpholine solutions were studied at various temperatures and amine concentrations, using a stopped-flow technique. Reaction rates for monoethanolamine were also examined for comparison. Diglycolamine reacts with CO2 according to a second-order mechanism with a rate constant of 4517 m3 kmol-1 s-1 at 298 K and an activation energy of 39.35 kJ mol-1. The reaction between carbon dioxide and aqueous morpholine was faster than that of diglycolamine but it did not follow simple kinetics. The reaction between CO2 and morpholine in methanol was briefly investigated and was found to be third order (second order in amine). © 1990.