Extraction of cesium from nitric acid solutions by bis-[4(5),4′(5′)-alkanoylbenzo]-21-crown-7 in nitrobenzene or nitromethane was investigated.The results show that under the conditions of higher acidity and higher sodium concentration,the extraction efficiency of bis-[4(5),4′(5′)-alkanoylbenzo]-21-crown-7 was superior to that of DB21C7.The composition of the complexes was determined indirectly by measuring the conductance of cesium nitrate-crown ether in nitromethane solution.It indicated that these crown ethers probably formed 1∶1∶1 Cs^+∶crown∶nitrae complex ion pair in the organic phase.The extraction equilibrium was also discussed.
