Study of Ionic Liquids as Entrainers for the Separation of Methyl Acetate–Methanol and Ethyl Acetate–Ethanol Systems Using the COSMO-RS Model

Abstract

The separation of the nonaqueous azeotropic systems methyl acetate−methanol and ethyl acetate−ethanol was investigated with 13 cations and 27 anions as entrainers to identify suitable ionic liquids using the COSMO-RS model. It is observed that the cations best suited are imidazolium > pyridinium > methyl pyrrolidinium > octyl quinolinium. The lengthening of the alkyl chain of cations was also studied as well as whether the shorter the alkyl chain, the better is the separation. It was also noticed that the efficacy of the anions is in the order

Separation of acetone and methanol azeotropic system using ionic liquid as entrainer

“…For [HMEA][Cl] and [HMEA][OAC], the difference presented in the influence on VLE behavior of acetone + methanol system all lies in the anion of ILs. The chloride atom has stronger electro-negativity than acetate which forms stronger hydrogen bond between ionic liquid and methanol, which makes acetone more volatile [18] …”

Separation of methyl acetate+methanol azeotropic mixture using ionic liquids as entrainers

“…Matsuda et al [14] measured the VLE data using 1-ethyl-3-methylimidazolium ethyl sulfate [EMIM] [EtSO 4 ]. Furthermore, Dhanalakshmi et al [15] compared the separation effects of several ILs with different cations and anions on this azeotropic system using COSMO-RS model. Dohnal [16] …”

Separation of benzene and thiophene with a mixture of N -methyl-2-pyrrolidinone (NMP) and ionic liquid as the entrainer

“…Traditionally, N-methyl-2-pyrrolidinone (NMP) has been used commercially as an entrainer in the extractive distillation process [24][25][26], but NMP is a volatile organic compound, which is inevitably entrained in the product stream. In recent years, ILs have been applied to extractive distillation processes for separating azeotropic or close-boiling mixtures [27,28] because of the unique advantages of these ILs over classical entrainers, such as negligible vapor pressure, wide range of the liquid phase, salt effect, chemical stability and non-flammability. The non-volatile character of ILs can prevent its presence in distillate streams, and allow the easy recovery of these solvents.…”