N，N′-二甲基-N，N′-二辛基丙二酰胺萃取铀(Ⅵ)的研究

The novel unsymmetrical extractant N，N′-dimethyl-N，N′-dioctylmalonamide (DMDOMA) was prepared by reaction of diethyl malonate with N-methyl octanamine. The extraction mechanism and the behavior of uranyl nitrate with DMDOMA employed cyclohexane as diluent were studied. The effects of concentrations of nitric acid, sodium nitrate, extractant and also the temperature on the extraction were considered. The stoichiometry of the extracted species is and the coordination of extracted species was suggested based on the IR data. The value of ΔH of extraction is -26.9 ± 0.80 kJ·mol^-1. The value of the apparent extraction constant is 133.88 ± 17.92, which shows that the optimization of extractant structure improves the extractability of malonamide for uranyl nitrate.