Investigation on the preparation of 2,2-difluoroethylamine by amination of 1-halo-2,2-difluoroethane

The synthesis of 2,2-difluoroethylamine via the amination of 1-halo-2,2-difluoroethane (halogen = Cl or Br) without catalyst and solvent was studied by experiment and theoretical calculation. In order to compare the difficulty in the amination of 1-halo-2,2-difluoroethane with NH₃, experimental investigations were carried through changing reaction temperature, molar ratio and reaction time. And experimental evidence demonstrated that 1-chloro-2,2-difluoroethane was more prone to amination than 1-bromo-2,2-difluoroethane under the same conditions. In addition, the reaction mechanism was investigated, and the formation complexity evaluated. Calculation of the transition states and rate constants, and analysis of the frontier molecular orbitals, indicated that the reaction rate of the amination of 1-chloro-2,2-difluoroethane was higher than that of 1-bromo-2,2-difluoroethane, which was consistent with the results of the experiment.