595. The isotopic exchange of gaseous hydrogen with liquid aliphatic amines. Part II

The isotopic exchange of hydrogen between gaseous deuterium and liquid aliphatic amines has been studied. Like the exchange between deuterium and ammonia, these reactions are catalyzed by aliphatic alkali amides. The rates of exchange of deuterium, deuterium hydride, and tritium hydride with methyl-, dimethyl-, and ethyl-amine in presence of lithium, sodium, and potassium amide were measured. An energy of activation of 3.6 kcal./mole was found for these reactions, to be compared to 7.6 kcal./mole for the exchange with ammonia. As in the exchange of deuterium with water, the exchange with methanol is catalyzed by methoxide ion; the energy of activation is 23.8 kcal./mole, the same as for the exchange with water. The measured rates of exchange, energies of activation, and activities of the different catalysts confirmed the assumption that the catalyst molecule initiates the exchange by a rate-determining association with a deuterium molecule, and that transfer of a hydrogen atom from a solvent molecule to the complex concludes the exchange.