Mechanistic Investigation of Isobutanol/Isobutyl Acetate Separation by Extraction Using Low-Transition Temperature Mixtures

In this work, low-transition temperature mixtures (LTTMs)are usedfor the first time in the separation of isobutanol (IBA) and isobutylacetate (IBAC) by extraction, and the relationship between weak interactionsand phase equilibrium behavior is systematically investigated. LTTMsare screened using the conductor-like screening model segment activitycoefficient (COSMO-SAC), with ethylene glycol as the hydrogen bonddonor (HBD) and benzyltrimethylammonium chloride, choline chloride,and tetramethylammonium chloride as the hydrogen bond acceptor (HBA).The effectiveness of the screened LTTMs is further demonstrated throughliquid-liquid equilibrium (LLE) experiments, and the NRTL modelis chosen to correlate the experimental data for process design. Finally,quantum chemical calculations provide insights into the effect ofthe structure of LTTMs on the LLE of the IBA/IBAC system, and theresults show that the extraction properties are mainly dependent onthe type of HBAs and increase with the enhanced electron-donatingability of the moiety.