The Isotopic Exchange Reaction between U(IV) and U(VI) Ions in a Mixed System of Acidic Solution and Cation Exchange Resin,(I)

The Isotopic Exchange Reaction between U(IV) and U(VI) Ions in a Mixed System of Acidic Solution and Cation Exchange Resin, (II)

“…1 that (1) at moderate acidities the apparent rate constant kRona has a minus third order dependence on hydrogen ion concentration just as has kt, and (2) the value of K 4 ,3k• is 5X 10- N. DISCUSSION The experimental fact that the value of p is found to be 3.0, that is, that the apparent 225 exchange rate is inversely proportional to the third power of hydrogen ion concentration in both the resinous phase and solution system leads to the suggestion that the U(N)-U(vr) isotopic exchange in either case should be interpreted by a similar reaction mechanism.…”

“…The preceding paperm showed that the exchange of uranium isotopes between U (N) and U (VI) ions in a mixed system of acidic solution and cation exchange resin was realized through two exchange paths: (1) the first exchange process-" U (N) -U (VI) isotopic exchange occuring in the resinous phase", and (2) the second exchange process-"V(VI)-V(VI) isotopic exchange between the resinous and solution phases". These paths were expressed as kl (u<sl(VI) )r+Cu< 8 l(N) )r ~ (u< 8 l(VJ) )r+Cu< 5 l(N) )r.…”

“…The investigation described in the present paper has been made to obtain information on 1 (1) The kinetics of U (N) -U (VI) isotopic exchange: The effect of cation exchanger on the rate of isotopic exchange, (2) The mechanism of U (N)-U (VI) isotopic exchange: The relation of the isotopic exchange rate to the degree of hydrolysis of U (N), the rate-determining step in the exchange path, and the interpretation of the apparent activation energy and the apparent exchange rate treated in the preceding paper.…”