Adsorption Behavior of Short Alkyl Chain Imidazolium Ionic Liquidsat N-Butyl Acetate + Water Interface: Experiments and Modeling

The adsorption behavior of three amphiphilic ionic liquids (ils), 1-alkyl-3-methylimidazolium chloride {[cnmim][cl], n=68}at the interface of n-butyl acetate+ water system was studied with il concentration range of 1.00×104-1.00×101mol·dm3 and temperature range of 293.2-318.2 k. the ils behave as strongsurfactants in this chemical system and significantly reduce the interfacial tensionwith the order of their alkyl chain length and is consistent with their hydrophobicitynature. an almost linear decrease of interfacial tension with temperature was alsorelevant. the experimental data were satisfactorily reproduced with szyszkowskiequation, implying an ideal ils adsorption. in this regard, the langmuir maximuminterface excess and equilibrium adsorption constant were obtained at differenttemperatures for each il. accordingly, effectiveness of adsorption and adsorptiontendency increase with the alkyl chain length. at the saturated interface, increasingtemperature leads to declining langmuir maximum interface excess due to disruptingsurrounding water molecules around ils hydrophobic portions. however, adsorptiontendency of ils increases slightly with temperature