Abstract: STUDIES ON THE SYNTHESIS OF HBMPPT AND ITS SOLVENTEXTRACTION MECHANISM OF U() FROM NITRIC ACIDAuthor Yu ShaoningMa LiWang Tengjiao (Naval Medical Research Institute, Shanghai 200433) Yang YanzhaoBao Borong (Institute of Nuclear Research, the Chinese Academy of Sciences,Shanghai 201800) ABSTRACT The extraction agent HBMPPT (4benzoyal2, 4dihydro5methyl2phenyl3Hpyrazol3thione) is synthesized from PMBP. The solvent extraction of U() from nitric acid solution by HBMPPT in benzene has been studied. The extraction ability of HBMPPT is not so high as that of its precursor (PMBP). The distribution ratio of U() increases with the increasing pH of the aqueous phase. When the pH increases, the distribution ratio of U() increases linearly with the slope of 1.56. When the concentration of HBMPPT increases, the distribution ratio of U() increases rapidly. lgDlgc(HBMPPT) is linear with the slope of 143. The extraction mechanism is the cation exchange, forming UO2(BMPPT)2 and UO2NO3(BMPPT). Key words U()HBMPPTSynthesisSolvent extraction