Investigations on the Physicochemical and Radiolytic Degradation Properties of Tri-n-butylphosphate–Ionic Liquid in the Presence of Nitric Acid

Presence of a Molecular Ligand alters the Solvent Behavior of an Ionic Liquid: A Combined Physicochemical Properties, FTIR Spectroscopy and Dynamic Light Scattering Investigation

“…The equilibrium concentration of nitric acid increases from 0.16 m to 1 m upon equilibrating 0.1 m T2EHDGA/IL phase with the initial aqueous phase acidity of 0.5 m to 5 m . This extracted acid plays a crucial role in determining the physicochemical properties of the solution [16,18] . In this context, the viscosity and density of the acid saturated TEHDGA/IL phase were measured and plotted in Figure 7B.…”

“…Nitric acid extraction by [C 4 mim][NTf 2 ] has been reported elsewhere which suggests that the extraction of nitric acid increases from 0.03 m to 0.8 m with an increase in the concentration of initial nitric acid in the aqueous phase from 0.5 m to 6 m. [16,18] Since T2EHDGA is a polar and strongly coordinating ligand, the presence of its 0.1 m in IL phase would certainly enhance the acid uptake capacity and the same is portrayed in Figure 7A. The equilibrium concentration of nitric acid increases from 0.16 m to 1 m upon equilibrating 0.1 m T2EHDGA/IL phase with the initial aqueous phase acidity of 0.5 m to 5 m. This extracted acid plays a crucial role in determining the physicochemical properties of the solution.…”

“…The physicochemical properties of IL, [C 4 mim][NTf 2 ] has already been elaborated in our previous literature. [16,18] As reported, the viscosity and density of IL are reported to be ∼ 40 mPa s and ∼ 1.434 g cm À 3 respectively at 298 K. These values decrease gradually to ∼ 12 mPa s and 1.381 g cm À 3 respectively with an increase in temperature to 333 K. On the contrary, these properties for T2EHDGA have been reported to be 280 mPa s and 0.907 g cm À 3 respectively at 298 K which is far away from the values for IL phase alone under the same experimental temperature. [26] In consequence, it is apparent that gradual addition of T2EHDGA in IL phase enhances the viscosity of the mixture as shown in Figure 1.…”

“…The data for [C 4 mim][NTf 2 ] has been referred from our recently published literature for comparison. [18] It is observed that the IL phase alone ([C 4 mim][NTf 2 ]) undergoes direct single-step decomposition at ∼ 750 K with the onset decomposition at ∼ 675 K. On the contrary, T2EHDGA exhibits stability up to ∼ 590 K with two-step decomposition (at 524 K and 593 K) with an onset temperature of decomposition at 450 K.This result is in good agreement with the thermal stability analysis of T2EHDGA by calorimetric study. [37] This discrepancy is attributed to the presence of a tridentate core bearing two carbonyls and one etheric linkage (À COÀ CH 2 À OÀ CH 2 À COÀ ) in T2EHDGA skeleton.…”

“…In this context, there is a couple of recent literature those describe the measurement of various thermophysical properties of IL solvents containing various extractants. [16][17][18][19] The authors' main idea in these literature reports was to evaluate various physicochemical parameters of IL based solvent systems already employed for the extraction of metal ions. Nevertheless, the details of the inherent understanding of the interaction of the ligand and IL phase present in the solution have not been explored yet.…”