Homogeneous Exchange Reaction Between Hydrogen and Deuterium

The homogeneous exchange reaction between hydrogen and deuterium has been reinvestigated, to see whether a more satisfactory quantitative test of the transition state method could be obtained in this simple chemical reaction. The reaction was studied in the temperature range from 916°K to 1010°K, where the heterogeneous contribution from the walls was found to be negligible. Preventing air from diffusing into the reaction vessel trough the walls, exchange rates lower by a factor of 2.0 than those obtained by previous authors were found in the whole temperature interval. The total activation energy was determined as 59.8±0.4 kcal/mole. The validity of the transition state method was tested by extrapolation of the experimental data to a lower temperature region (283°—373°K) where independent experimental data were available. Comparison of the extrapolated values with the experimental ones leads to a very good agreement.