Synthesis of diamide extractants for extraction of neodymium

The aim of this study was to prepare a series of amide extractants and to assess their properties as potential metal extractants for the rare earth metal neodymium. A number of diamide and a monoamide were synthesized with different substituting group, including alkyl chains. Cyclohexyl chains and ail chains. The general method for synthesizing these extractants was to react relevant acyl chlorides with secondary amines in a basic medium. The yields for diamide were in the range 32-50% and the yield was 90% for monoamide. A systematic investigation was carried out on the extraction properties of the extractants synthesized using the neodymium ion Nd3+ to monitor the extraction of a typical trivalent rare earth species. The effects of the variables: diluent type, structure of diamide, aqueous acidity and salting-out agents, on the extraction of Nd3+ are discussed. The effect of aqueous acidity on the distribution ratios proved that there was competition between the metal ion and HNO3 for the diamide coordination sites. When the nitric acid concentration in the aqueous phase was varied, maximum extraction was observed in the region of 3 M HNO3 for all eight diamide investigated. From the results it can be concluded that the diamide are effective extractants for neodymium in the region of 3 M HNO3. The neodymium can be stripped by very dilute HNO3