Tricyclohexylphosphate—A Unique Member in the Neutral Organophosphate Family

Tricyclohexylphosphate (TcyHP) was synthesised and characterized. The extraction of U(VI) and Th(IV) by TcyHP in n‐dodecane was studied and compared with tributylphosphate (TBP). The feasibility of the separation of Th and U with TcyHP has been explored and reported. The solubility of TcyHP in water at room temperature has been measured. The stoichiometry of the TcyHP solvates with Th(NO3)4 and UO2(NO3)2 was evaluated. The enthalpy of extraction of U(VI) by TcyHP was measured. The results of column runs with TcyHP impregnated Amberlite XAD‐7 resin for studying the loading and elution behavior of uranium from nitric acid medium are also reported in this paper. Hexavalent actinides form third phase with neutral organophosphate extractants only at very high nitric acid concentrations and high metal loading. However the presence of the three closed ring alkyl moieties in TcyHP is seen to lead to certain unique features with regard to the third phase formation behavior. It has been observed, for instance, that U(VI) forms third phase with this extractant even with highly polar diluents like 1‐chlorooctane. Further, the tendency for third phase formation with U(VI) is even higher than in the case of Th(IV), in contrast to the trend observed so far with other extractants.