Infinite Dilution Activity Coefficients in the Smectic and Isotropic Phases of Tetrafluoroborate-Based Ionic Liquids

authors	Martins, MAR; Vilas-Boas, SM; Cordova, IW; Carvalho, PJ; Domanska, U; Ferreira, O; Coutinho, JAP; Pinho, SP
nationality	International
journal	JOURNAL OF CHEMICAL AND ENGINEERING DATA
keywords	2ND VIRIAL-COEFFICIENTS; ORGANIC SOLUTES; CHROMATOGRAPHY; MIXTURES; THERMODYNAMICS; HYDROCARBONS; ALCOHOLS; WATER; TEMPERATURE; TRANSITION
abstract	Inverse gas chromatography was used to obtain the activity coefficients at infinite dilution (gamma(infinity)(13)) of several organic solutes and water in the thermotropic ionic liquid crystal phases of both [C(12)mim][BF4] and [C(14)mim][BF4] and their isotropic phases. In the smectic to isotropic transition, a change in the linear representation of the natural logarithm of gamma(infinity)(13) with the reciprocal temperature was observed for [C(14)mim][BF4], and was more evident for alkanes, alkylbenzenes, esters, and alcohols, that can be related to structural modifications of the stationary phase. Results are interpreted in terms of the enthalpic and entropic contributions of solute-IL interactions. Selectivities and capacities of important separation problems, such as octane/benzene and cyclohexane/benzene, were calculated and compared with literature values for separating agents such as N-methyl-2-pyrrolidinone, sulfolane, and ionic liquids presenting the [BF4](-) anion combined with several imidazolium-based cations. It is shown that to achieve maximum separation efficiency, imidazolium cations with short alkyl chain lengths such as [C(2)mim][BF4] should be used, whereas high capacities require larger alkyl chain lengths.
publisher	AMER CHEMICAL SOC
issn	0021-9568
isbn	1520-5134
year published	2021
volume	66
issue	6
beginning page	2587
ending page	2596
digital object identifier (doi)	10.1021/acs.jced.1c00182
web of science category	10
subject category	Thermodynamics; Chemistry, Multidisciplinary; Engineering, Chemical
unique article identifier	WOS:000662181900025