Liquid-liquid-phase equilibria studies of systems containing acidic ionic liquid (IL) + ethylacetate + ethanol or acetic acid are reported, and the influence of the alkyl chain length on the cation on the liquid-liquid equilibra (LLE) was measured. The ILs used are 1-methylimidazolium hydrogen sulfate ([HMIM][HSO 4 ]), 1-ethyl-3methylimidazolium hydrogen sulfate ([EMIM][HSO 4 ]), and 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM][HSO 4 ]). The experimental data was obtained at (313.2 ( 0.5) K and correlated with the UNIQUAC model to obtain the binary interaction parameters. All studied systems were of type I, with ethylacetate + IL as immiscible pairs.

The ternary liquid-liquid equilibria for four systems containing an alcohol (1-propanol or 1-butanol) or acetic acid + ester + the ionic liquid 1-ethyl-3-methylimidazolium hydrogen sulfate [EMIM][HSO 4 ] were studied at (313.2 ( 0.5) K. In this paper, we investigated the effect of the alkyl chain on the alcohol and ester on the phase equilibria for these systems containing reactants and products of esterification reactions. The measurements were done by headspace gas chromatography. All studied systems are of type I, with ester and [EMIM][HSO 4 ] as the only immiscible pair. The increase of the alkyl chain length on alcohol and ester leads to bigger immiscibility regions and better solubility of the alcohol in the ester phase. The distribution of the acetic acid between the two phases is almost independent of the esters for the measured systems and is dependent mainly on the ionic liquid. The obtained information on the influence of the alkyl chain on the equilibrium can be used to roughly estimate the behavior of unknown systems as illustrated on several examples.

The esterification of ethanol, 1-propanol and 1-butanol with acetic acid in three ionic liquids with HSO4 - anion and 1-alkyl-3-methylimidazolium cation was investigated. The ionic liquids are 1-methylimidazolium hydrogen sulfate [HMIM][HSO4], 1-ethyl-3-methylimidazolium hydrogen sulfate [EMIM][HSO4] and 1-butyl-3-methylimidazolium hydrogen sulfate [BMIM][HSO4], which have catalytic activity. Data and modeling on the reaction conversions and the distribution of the compounds between the phases is reported here. Trends for the change in the liquid-liquid equilibrium, with parameters like alkyl chain length on the cation or the alcohol, are discussed and used to estimate the phase behavior of similar esterification systems.

Experimental results (and a correlation) are presented for the liquid−liquid equilibrium of an example for the Biphasic Acid Scavenging utilizing Ionic Liquids (BASIL) process: for the binary system (butylacetate + 1-methyl imidazolium chloride) and for the partitioning of 1-butanol and 1-methyl imidazole to the coexisting liquid phases at temperatures from (363 to 373) K.

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