Quantum chemical calculation, molecular dynamics simulation and process design for separation of heptane - butanol using ionic liquids extraction

Abstract

Investigating energy-saving and environmentally friendly green solvents is an inevitable requirement for the sustainable development of liquid-liquid extraction. In this work, σ- profiles were drawn using COSMO-SAC model according to the extraction mechanism. Based on quantum chemistry method, the interaction energy, total charge density, deformed charge density and bond length of ionic liquids and butanol were calculated. According to the absolute value of the interaction energy, the hydrogen bond of the total charge density and the deformed charge density, the extractant with good extraction effect can be determined. The radial distribution function of ionic liquids was calculated at the molecular level through molecular dynamics simulation, and the extraction ability of ionic liquids were analyzed. According to the binary interaction parameters obtained from the liquid-liquid equilibrium data of 298.15 K ternary system, the extraction process was simulated. The minimum total annual cost was calculated when the required butanol recovery and heptane purity were achieved. Combining quantum chemical calculation and molecular dynamics simulation to select the best extractant, and verifying the feasibility of ionic liquids as extractant through the simulation process, is of great significance for the industrial application of ionic liquids.