Studies of Thorium Nitrate Complexation in Aqueous Solutions by a Liquid-Liquid Extraction Method - Application to the Calculation of Thorium Distribution in the Thorex Processes

Apparent molar volumes and viscosity B-coefficients of caffeine in aqueous thorium nitrate solutions at T=(298.15, 308.15, and 318.15)K

“…This facile movement of water molecules seems to increase when Th(NO 3 ) 4 appears in the investigated ternaries. This fact, substantiated by the extensive hydrolysis [40,41] It is reported [39] that in the crystal structure, caffeine molecules possess a hydrophilic centre at the imidazole nitrogen atom, N9, (figure 1) susceptible to hydrogen bonding and that the hydrated water molecule effloresces via a molecular escape tunnel through the crystallographic a-face of the lattice (space group P2 1 /c). However, the various possible interactions between caffeine and Th(NO 3 ) 4 in water can roughly be summarized as follows: (i) interaction of N9(caffeine) and Th 4+ ion, (ii) interaction of N9(caffeine) and H + ion, (iii) interaction of C@O (2) and Th 4+ ion, (iv) interaction of C@O (6) and Th 4+ ion, (v) interaction of C@O (2) and H + ion, (vi) interaction of C@O (6) and H + ion, (vii) interaction of N1(caffeine) and NO À 3 ion, (viii) interaction of N3(caffeine) and NO À 3 ion, (ix) interaction of N7(caffeine) and NO À 3 ion, and (x) ionic-hydrophobic interactions between ions of Th(NO 3 ) 4 and non-polar part of caffeine molecules.…”

“…Table 7 shows that the values of the viscosity B-coefficient for caffeine in the solvent systems studied are positive and the trends in B-values support the results discussed earlier on the basis of / V values. However, the values of the A-coefficient are either small positive or negative for the experimental solutions indicating the presence of weak solute-solute interactions and their irregular behaviour may be due to the hydrolysis of Th(NO 3 ) 4 in aqueous solutions [40,41]. Also the DB values listed in table 6 and graphically depicted in figure 2 as a function of molarity of Th(NO 3 ) 4 in aqueous solutions at the experimental temperatures support the results obtained from D/ V values discussed earlier.…”