On the Mechanism of the Extraction of Uranyl Nitrate by Tributyl Phosphate II. Infrared Study

Abstract

The complex formation of TBP in the systems-TBP-water, TBP-nitric acid, and TBP-uranyl nitrate was confirmed by means of infrared spectroscopy. The infrared spectra of uranyl nitrate in the system TBP-nitric acid-uranyl nitrate lead to the conclusion that the competition extraction of both uranyl nitrate and nitric acid takes place during the extraction process.

Determination of the Structures of Uranyl–Tri‐n‐butyl‐Phosphate Aggregates by Coupling Experimental Results with Molecular Dynamic Simulations

“…The classical bending/stretching vibrations of coordinated nitrate observed at ≈746 and 1527 cm −1 confirm the extraction of nitrate ions. The band usually observed at =1274 cm −1 cannot be separately distinguished from the P−O−C vibration band, which is consistent with data from the literature …”

“…Vibration bands near =3450–3500 and 1640 cm −1 indicate the presence of OH stretching and bending bands, respectively, due to coextracted water . A triplet band at =1057, 1020, and 990 cm −1 is assigned to the P−O−C group, whereas the band at =1270–1286 cm −1 is assigned to the P=O stretching vibration . For the more concentrated solution, namely, TBP 100 %, which contains 3.39 mol L −1 water, a broadening of the band at =1270 cm −1 and a shift of about 20 cm −1 to lower wavenumbers is observed.…”

“…For the more concentrated solution, namely, TBP 100 %, which contains 3.39 mol L −1 water, a broadening of the band at =1270 cm −1 and a shift of about 20 cm −1 to lower wavenumbers is observed. This is usually interpreted as the formation of a hydrogen bond between the P=O oxygen atom and extracted water molecules …”

“…[13d, 17] At riplet band at ñ = 1057, 1020, and 990 cm À1 is assigned to the PÀOÀCg roup, whereas the band at ñ = 1270-1286 cm À1 is assigned to the P=O stretching vibration. [18] For the more concentrated solution, namely,T BP 100 %, which contains 3.39 mol L À1 water,a broadening of the band at ñ = 1270 cm À1 and as hift of about 20 cm À1 to lower wavenumbers is observed. This is usually interpreted as the formation of ah ydrogen bond between the P=Oo xygen atom and extracted water molecules.…”

Solvent extraction properties of some bis(di-n-hexylphosphinyl) alkanes

“…Nitric acid extraction by TBP has been extensively studied by many authors (3, 60,105,107) and it is now taken as established that the main extracted species is anhydrous TBP-HNCy over a considerable range of nitric acid and TBP con centrations. Infrared spectral evidence indicates strong hydrogen bond formation between the phosphoryl oxygen and nitric acid (60,79,86).…”