[en] Application of TSILs (Task Specific Ionic Liquids) to separation science has increased enormously due to their unique characteristics of high thermal stability and low volatility. The present study concerns about using underlying principles of computational quantum chemistry to observe and analyse the fundamental interactions between Ionic Liquids containing amine based functional groups and conventional solvents involved in Zr-Hf solvent extraction systems such as DIBK (diIsobutylketone), TBP (tributylphosphate) and di (2-ethylhexyl) phosphoric acid (P204) using a two-tier approach comprising of thermodynamic spontaneity and interaction energy calculations. The interactions of 1,3 butyl methylamine imidazoliumhexafluorophosphate (TSIL) and DIBK (System I) in isolated gas phase conditions are studied using B3LYP hybrid DFT method at 6-31G(d) level basis set. Similarly, the bare species, namely the TSIL and DIBK are also studied at the same level. The interaction energy calculations are also performed and the values are found to be negative consistent with the fact that the ionic liquid has significant affinity with the DIBK phase. Thermochemical data, generated from frequency calculations at 298.15K and 1atm were also performed for the system as well as the individual monomers. The thermodynamic spontaneity of the system is well justified by calculation of the interaction parameters for thermal enthalpies and thermal free energies (Refer Table)