KINETICS OF THE REACTION BETWEEN CARBON-DIOXIDE AND TERTIARY-AMINES

The reaction between carbon dioxide and amines is of great technical importance and has been the subject of many investigations.1We have shown that the reaction for secondary amines in anhydrous ethanol2and in aqueous solution3is exclusively second-order in amine and that the zwitterion intermediate postulated by Danckwerts4is probably of negligible significance in the mechanism. The reaction with tertiary amines has also been studied, but the data are less controversial. The product of the reaction is an alkylammonium hydrogen carbonate rather than the alkylammonium carbamate formed with a primary or secondary amine. Hydrogen carbonate ions are also formed by the direct reaction of carbon dioxide with water and with hydroxide ion, so that the following reactions occur in aqueous alkaline media. When an aqueous. © 1990, American Chemical Society. All rights reserved.