Kinetic deuterium isotope effects in the thermal dehydration stages of CuSO4 · 5 H2O

The kinetic deuterium isotope effects in three stages of thermal dehydration of CuSO4 · 5 H2O were examined by means of TG. The activation energies and frequency factors of the hydrate for the first and third dehydration stages were practically equal to those of the deuterium analogue, whereas these parameters of the hydrate for the second dehydration stage were a little larger than those of the deuterium analogue. The kinetic deuterium isotope effects in these stages are correlated with deuterium isotope effects in the thermal stabilities of hydrated copper sulfates reported earlier. The reliability of such a kinetic isotope effects is also discussed briefly in connection with ambiguities incidental to the evaluation of kinetic parameters by means of thermal analyses.