METHOD FOR SYNTHESIZING RARE EARTH METAL EXTRACTANT

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PROBLEM TO BE SOLVED : To provide a method for synthesizing a rare earth metal extractant capable of improving the yield of a synthesized product and the efficiency of synthetic process, and reducing the cost of the dialkyl diglycol amic acid of the metal extractant without using diglycolic anhydride of a synthetic raw material and dichloromethane of a reaction solvent in a conventional synthetic method. SOLUTION : The method for synthesizing the rare earth metal extractant comprising the dialkyl diglycol amid acid as an extractant component includes reacting the diglycolic acid of X mol in an esterification agent of Y mol regulated so that the molar ratio of Y/X may be ≥2.5 at a reaction temperature of ≥70°C for a reaction time of ≥1 h, condensing the reaction product under a reduced pressure to remove the unreacted components and a reaction residue and to provide a reaction intermediate product, adding, as a reaction solvent, a nonpolar or low polar solvent which is an organic solvent forming an organic phase in solvent extraction of the rare earth metal and which can dissolve the dialkyl diglycol amid acid, and reacting the reaction intermediate product with the dialkylamine of Z mol while regulating the molar ratio Z/X may be ≥0.9. The invention has a large utility value because the dialkyl diglycolic acid having excellent ability for separating light rare earth elements can efficiently be synthesized in high yield at a low cost without using expensive diglycolic anhydride and the harmful dichloromethane. COPYRIGHT : (C)2012, JPO&INPIT