Thermodynamics Research Center / ThermoML | Fluid Phase Equilibria

ABSTRACT

A large number of room-temperature ionic liquids (RTILs) have been prepared and characterized to date, but the majority of them are based on halogenated counter anions which limits their application due to toxicological, ecological and economic reasons. To overcome these problems, a new class of ILs has been recently introduced: Bio-ILs composed entirely of biomaterials. Choline based ILs are promising examples of this type of compounds. A series of ILs was recently synthesized using the choline cation and various naturally derived anions. In this work, we present data on surface tension, between 293.15 K and 393.15 K, and wettability of three choline based ILs: choline propionate, choline tiglate, and choline H-maleate. From the contact angle values observed on the hydrophobic substrate and the temperature dependence of the surface tension, the polarity of these compounds was estimated using the Fowkes approach and the Eotvos equation, respectively. Although these ILs present strong hydrogen bonding, low surface tension values were obtained in comparison with other ILs with the same characteristic (e.g. [C2OHmim][BF4]). In contrast, their polarity is very high when compared with that of water which confirms their solvent ability.