VAPOR-LIQUID EQUILIBRIUM IN THE SYSTEM METHYL ACETATE – METHANOL – 1-BUTYL-1-METHYLPYRROLIDINIUM TRIFLUORO-METHANESULFONATE

Salts with large organic ions, including those related to ionic liquids, are effective separating agents (entrainer) for azeotropic mixtures. The creation of processes for separating azeotropic mixtures by the action of salts – the processes of extractive, and in this case, salt rectification is based, among other things, on data on phase equilibria in such systems. The article is devoted to the study of the isobaric vapor-liquid equilibrium in the methyl acetate–methanol–1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate system at 101.3 kPa and organic salt concentrations (in mole fraction) of 0.08, 0.10 and 0.25. The azeotropic mixture methyl acetate–methanol is a by-product of some organic synthesis processes. For the separation of this system by salt rectification, it is proposed to use the ionic liquid 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate. The effect of trifluoromethanesulfonate on the vapor-liquid equilibrium and the breaking of the azeotropic mixture was studied in a modified Othmer still using the head space gas chromatographic method. Thus, it was established for the first time that the use of 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate as a separating agent promotes the destruction of the methyl acetate–methanol azeotropic mixture. The concentration of methyl acetate in the vapor phase increases with the concentration of pyrrolidinium salt in the methyl acetate-methanol mixture. Thus, 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate has a salting-out effect. Pyrrolidinium salt with trifluoromethanesulfonate anion has been demonstrated lower efficiency as a separating agent compared to ionic liquid with the same cation and dicyanamide anion. The electrolyte Non Random Two Liquid model was used to describe the vapor-liquid equilibrium. This model demonstrated high accuracy in calculating the concentration of mixed solvent components in the vapor phase. The average absolute deviation between the calculated and experimental data on the concentration of mixed solvent components in the vapor phase was 0.006. To separate the mixed solvent into components, a calculated concentration by NRTL model of 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate of 0.186 mole fraction is required. For citation: Evdokimov A.N., Kurzin A.V., Tarazanov A.A. Vapor-liquid equilibrium in the system methyl acetate – methanol – 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2026. V. 69. N 3. P. 16-22. DOI: 10.6060/ivkkt.20266903.7295.