Separation of methyl acetate methanol azeotropic mixture using 1-ethyl-3-methylimidazolium trifluoromethanesulfonate

Abstract

In this work, potential use of ionic liquid 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([Emim][triflate]) in the extractive distillation of a methyl acetate–methanol mixture forming an azeotrope was studied. The primary objective was to design the separation process for the production of highly concentrated methyl acetate. The process is proposed to be run in two distillation columns, an extractive distillation column and a regeneration column for the ionic liquid (IL) solvent recovery. Within the design calculation of the extractive distillation column, column parameters such as the number of theoretical plates, position of the feed input plate, solvent consumption, and reflux ratio for the required content of methyl acetate (MA) in the distillate (99.5 mole % of MA) were optimized. The objective of the IL regeneration was to obtain highly concentrated IL (more than 99 mole % of IL). For IL regeneration, a distillation column was proposed. Operating conditions of the regeneration column such as pressure and thermal conditions of feed (temperature and vapor-to-liquid mole ratio) were optimized. For the regeneration column, the number of theoretical plates, reflux ratio, and position of the feed input plate were determined. To represent the vapor–liquid equilibrium (VLE) of the ternary system at the atmospheric pressure and binary VLE at reduced pressures, the original NRTL model was used; its parameters were evaluated from the VLE data of the corresponding binaries taken from literature. Based on the results of columns simulation, heat consumption required in the extractive and regeneration column reboilers and condensers was evaluated. In conclusion, energy-saving alternatives are proposed.