Separation of Boron Isotopes. II. The BF3 Anisole System

A new gas‐liquid countercurrent system has been developed for the separation of boron isotopes. This system utilizes the exchange reaction between BF₃ gas and the BF₃·methyl phenyl ether (anisole) complex. Quantitative dissociation of the complex is attained by heating, and recombination by cooling. Half‐time for the isotopic exchange has been shown to be less than three seconds. The single‐stage separation factor $$[{\mathrm{B}}^{10}{\mathrm{F}}_3·\mathrm{anisole}\mathrm{\hspace{0.17em}(}\mathrm{liq}\mathrm{.)/}{\mathrm{B}}^{11}{\mathrm{F}}_3·\mathrm{anisole}\mathrm{\hspace{0.17em}(}\mathrm{liq}\mathrm{.)/}{\mathrm{B}}^{10}{\mathrm{F}}_3\mathrm{\hspace{0.17em}(}\mathrm{gas}\mathrm{)/}{\mathrm{B}}^{11}{\mathrm{F}}_3\mathrm{\hspace{0.17em}(}\mathrm{gas}\mathrm{)]}$$ varies from 1.039 at 0°C to 1.028 at 30°C. Physical properties of the complex have been determined and solvent decomposition has been studied.