Tetrabutylammonium chloride based ionic liquid analogues and their physical properties

During the past few years, there has been a surge in interest and research in the arena of utilizing deep eutectic solvents (DESs) as green solvents. This manifested in applying DESs in a variety of industrial applications. Most of the reported work in this field was directed toward the choline chloride-based DES. Recently, the area of DES synthesis was widened by considering other quaternary ammonium and phosphonium salts. In this work tetrabutylammonium chloride (TBAC) is used as a salt for the synthesis of three different DES systems based on three different hydrogen bond donors (HBDs), namely, glycerol, ethylene glycol, and triethylene glycol. Screening tests for each DES system was performed to identify salt:HBD ratios that exhibit a minimum freezing point, and at least three such ratios were selected for each system. Physical properties including melting point, density, viscosity, surface tension, refractive index, conductivity, and pH were measured for the three DES systems at different temperatures ranging from (293.15 to 353.15 K). It is worth mentioning that this class of DES exhibits a wide range of properties that can be tailored toward specific chemical and other engineering applications.