Investigation of Potential Azeotrope Breakers Using DFT and COSMO Approach

Different combinations of cations (imidazolium, pyridinium, pyrrolidinium, phosphonium, and ammonium) and anions (basic anions, sulfate, phosphate, and borate) were studied based on the COSMO volume and quantum chemical parameters such as highest occupied molecular orbital/lowest unoccupied molecular orbital (HOMO/LUMO) energies, HOMO–LUMO energy gap, global hardness and softness, electronegativity, electrophilicity index, and chemical potential using the density functional theory (DFT) method. Further, the sigma profile and sigma potential for the selected cations and anions were generated using a COSMO-RS model. The activity coefficient at infinite dilution was also studied for the butanol–water system to find a greater degree of nonideality. A feasible entrainer for the azeotrope breaker for a butanol–water system is proposed.