Gas-phase kinetics of N-substituted diacetamide

Article abstract of DOI:10.1002/kin.550260909

Gas-phase elimination reactions of number of N-substituted diacetamides have been studied. The rates of N-phenyl, 4-methoxyphenyl, 4-nitrophenyl, and benzyl diacetamide have been measured between 643-683, 642-693, 673-725, and 555-610 K, respectively. They undergo unimolecular first-order elimination reactions, for which log A = 12.8, 12.9, 12.8, and 11.0 s^-1 and E_a = 185.7, 191.4, 193.4, and 143.6 kJ mol^-1, respectively. The reactivity of these compounds has been compared with the unsubstituted diacetamide at 600 K. The kinetic data reveals that each of the N-aryldiacetamides is less reactive than the parent molecule. We attribute this observation to the resonance of the lone pair of electrons on the nitrogen with either the two carbonyl oxygen atoms or with the 6π electrons in the aromatic ring which will result in the stabilization of the N-aryldiacetamides related to the parent molecules.