Kinetic study on the reaction between CO2 and tertiary amine catalyzed by zinc(II) aza-macrocyclic complexes

In this work, the kinetics study on the reaction between CO 2 and tertiary amine catalyzed by zinc(II)-1,4,8,11-tetraazacyclotetradecane complexes (CM) and zinc(II)-1,4,7,10-tetraazacyclododecane complexes (CN) was carried out in a stopped-flow device. The effects of the catalyst concentration, type of tertiary amines, and temperature on the reaction rate ( ν ) and catalytic activity ( φ ) were studied. It was found that the catalyst concentration, tertiary amine with higher p K a , and temperature had positive effects on ν . ν in N -methyl diethanolamine solution with 10.0 mol m −3 CM and CN were 16.62 and 26.05 folds than the uncatalyzed ν at 298 K, respectively. φ increased with increasing catalyst concentration, decreasing temperature and tertiary amine's p K a . In addition, the kinetics behavior of tertiary amine-CM/CN-CO 2 systems conformed to the Michaelis–Menten model. The activation energies in catalytic systems were 4%–15% lower than that in the non-catalytic systems.