Thermophysical properties of neat and radiolytically degraded acidic extractants present in room temperature ionic liquid

The thermophysical properties of a couple of acidic extractants, namely bis(2-ethylhexyl)phosphoric acid (D2EHPA) and bis(2-ethylhexyl)diglycolamic acid (HDEHDGA), dissolved in the room temperature ionic liquid diluent 1-butyl-3-methylimidazolium bis(trifluoromethanesulphonyl)imide ([C₄mim][NTf₂]) were investigated. The physical properties such as density, viscosity, and refractive index were measured as a function of various parameters such as temperature, concentration of extractant, and concentration of nitric acid. The viscosity of the gamma-ray irradiated solution composed of 0.06 M D2EHPA/[C₄mim][NTf₂] and 0.06 M HDEHDGA/[C₄mim][NTf₂] was compared with unirradiated solution. The phase separation time (PST) was determined for both irradiated and unirradiated samples after acid equilibration. Thermogravimetry analysis was carried out for the solvent system composed of D2EHPA, HDEHDGA, [C₄mim][NTf₂], and 0.06 M D2EHPA(or HDEHDGA)/[C₄mim][NTf₂] to understand the thermal stability of the ionic liquid system.