title: Molecular interactions in 1-butanol + IL solutions by measuring and modeling activity coefficients.
abstract: Molecular interactions in 1-butanol + ionic liquid (IL) solutions have been investigated by measuring and modeling activity-coefficient data. The activity coefficients in binary solutions containing 1-butanol and an IL were determined experimentally: the ILs studied were 1-decyl-3-methyl-imidazolium tetracyanoborate ([Im10.1](+)[tcb](-)), 4-decyl-4-methyl-morpholinium tetracyanoborate ([Mo10.1](+)[tcb](-)), 1-decyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide ([Im10.1](+)[ntf2](-)), and 4-decyl-4-methyl-morpholinium bis(trifluoromethylsulfonyl)imide ([Mo10.1](+)[ntf2](-)). The methods used to determine the activity coefficients included vapor-pressure osmometry, headspace-gas chromatography, and gas-liquid chromatography. The results from all of these techniques were combined to obtain activity-coefficient data over the entire IL concentration range, and the ion-specific interactions of the ILs investigated were identified with 1-butanol. The highest (1-butanol)-IL interactions of the ILs considered in this work were found for [Im10.1](+)[tcb](-); thus, [Im10.1](+)[tcb](-) showed the highest affinity for 1-butanol in a binary mixture. The experimental data were modeled with the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT). PC-SAFT was able to accurately describe the pure IL and (1-butanol)-IL data. Moreover, the model was shown to be predictive and extrapolative with respect to concentration and temperature.
authors.affiliation: Laboratory of Thermodynamics, Department of Biochemical and Chemical Engineering, Technische Universität Dortmund, Emil-Figge-Str. 70, 44227 Dortmund, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Nann
authors.forename: Jan
authors.initials: J
authors.lastname: Mündges
authors.forename: Christoph
authors.initials: C
authors.lastname: Held
authors.forename: Sergey P
authors.initials: SP
authors.lastname: Verevkin
authors.forename: Gabriele
authors.initials: G
authors.lastname: Sadowski