Study on the Extraction of Strontium With Amido Podand

By using n -octanol and kerosen as diluent, the extraction behavior of strontium from nitric acid solution is studied with N,N,N',N'-tetrabutyl-3-oxa-pentanediamide(TBOPDA), N,N,N',N' -tetraisobutyl-3-oxa-pentanediamide (TiBOPDA) and N,N,N',N'-tetrabutyl-3,5-dioxa-octanediamide(TBDOODA). The extraction equilibrium is an exothermic reaction. The composition of the extraction complex and the extraction mechanism are also examined. The extraction reaction is 2NO - 3+Sr 2+ + i S oSr(NO 3) 2· i S o, i =3 for TBOPDA and TiBOPDA, i =2.5 for TBDOODA. The Δ H is -55.79, -50.48, -53.11 kJ·mol -1, the Δ S is -122.9, -117.6, -141.6 J·mol -1 ·K -1, and the Δ G is -19.16, -15.44, -10.91 kJ·mol -1 for TiBOPDA, TBOPAD and TBDOODA, respectively. After extracting Sr, the shift of absorption peaks of CO and C—O—C for pure TBOPDA is 15 and 11 cm -1, respectively._