Separating Boron Isotopes by Means of Chemical Exchange with Boronic Acid

Abstract—A study is performed of the phase and isotopic equilibria of a two-phase system containing aqueous solution of boric and tartaric acids–tri-n-octylamine in o-xylene system at a temperature of 295 ± 2 K. It is shown that at 0.5 M concentrations of tartaric acid in the aqueous solution and tri-n-octylamine in the organic phase, changing the initial content of boric acid in the aqueous phase in the range of 0.070–0.75 M reduces the distribution coefficient D of boron from 120 ± 21 to 1.9 ± 0.1. It is shown that the considered system is characterized by relatively high values of single isotope effect ε ranging from 0.0180 ± 0.0035 to 0.033 ± 0.0035 at H₃BO₃ concentrations of 0.3–0.75 M. This is comparable to the values of ε for such efficient industrial technologies as chemical exchange rectification of BF₃⋅(CH₃)₂O (ε = 0.016) and chemical isotope exchange employing BF₃·anisole complex (ε = 0.024–0.030).