Composition and structure of complexes formed in the reaction of uranyl di(2-ethylhexyl)phosphate and tributyl phosphate or di-N-octyl sulfoxide in benzene solutions

Abstract

This paper reprots of31P NMR and IR studies of the interaction of tributyl phosphate (TBP) and di-n-octyl sulfoxide (DOSO) with polymer molecules of uranyl di-2-ethylhexyl phosphate (UO2X2)p (I) in C6H6 sulutions. Detailed interpretations of the31P NMR spectra and the vas(POO) IR bands and determination of the fraction of nonequivalent phosphorus atoms of X− anions and uranium (VI) atoms as well as the concentration of U(VI)-bonded TBP in I have shown that only a single TBP or DOSO molecule is coordinated to the uranium atoms of polymer I at CTBP=0.1–2 M or CDOSO=0.1–0.5 M. In the case of 100% TBP, two TBP molecules are coordinated to some U(VI) atoms. Distribution of TBP (DOSO) molecules along the polymer chain agrees with the mean statistical value. The portion of terminal chalate POO-groups of X− anions is determined. The dependence of the degree of (UO2X2)p·nL (L=TBP, DOSO) polymerization on CL is obtained. Saturation of solutions with water only slightly affects the terminal POO-groups and has no effects on the distribution of L along the polymer chain of I.