AbstractThe partition of thorium between nitric acid solutions and the solutions of some cyclohexyl‐ and benzyl‐alkylamines in benzene has been investigated at different concentrations of nitric acid and solvent, and at different temperatures. The extraction of nitric acid by these amines in benzene has also been examined. Further an infra‐red spectral study has been made of the organic solutions obtained. The mechanism of thorium extraction in this system is discussed on the basis of the results obt