Ab initio study on the 1:2 reaction of CO2 with dimethylamine

The reaction between CO2 and the dimethylamine molecule in the presence of a second dimethylamine molecule is modeled by the ab initio RHF/3-21G method. Starting from the most stable 1:2 complex, the most effective reaction pathway turned out to be proton transfer between amine molecules followed by immediate proton transfer from one of the amine molecules to the CO2 moiety. The activation barrier for this pathway (9.54 kcal mol(-1) with respect to the 1:2 complex) is within the range of activation energy values found in kinetic studies for similar reactions with different hydroxylamines (from 9.2 to 13.0 kcal mol(-1)). The reaction product is the cyclic hydrogen bonded complex of dimethylcarbamic acid with dimethylamine. (C) 1997 Elsevier Science B.V.