Experimental investigation of density, viscosity, and surface tension of aqueous tetrabutylammonium-based ionic liquids

The physical properties such as density, dynamic viscosity, and surface tension of aqueous tetrabutylammonium-based ionic liquids were measured experimentally by varying temperature (283.4 to 333.4 K) and concentration of ILs (10-50 wt%) at an interval of 10 K and 10 wt% respectively. In this study, the aqueous tetrabutylammonium-based ionic liquids namely tetrabutylammonium acetate [TBA][OAC], tetrabutylammonium bromide [TBA][Br], and tetrabutylammonium hydroxide [TBA][OH] was used to investigate the influence of temperature and concentration of ILs on the physical properties data was examined. It is observed that both density and surface tension increase with increasing concentration of [TBA][Br], whereas the opposite trend is observed for [TBA][OAC] and [TBA][OH] respectively. This is due to stronger molecular interaction between [TBA][Br] and water compared to other ILs. The dynamic viscosity of all aqueous ILs increases with increasing IL concentration. The measured physical properties of ILs decrease as temperature increases. Furthermore, the experimental data is correlated and compared with that of the calculated model; the agreement was satisfactory.

Automated summary

Experimental measurements were carried out on the physical properties of aqueous tetrabutylammonium-based ionic liquids, showing that density and surface tension increase with higher concentration of [TBA][Br], while dynamic viscosity increases with increasing IL concentration. The interaction between [TBA][Br] and water was found to be stronger compared to other ILs, resulting in unique trends seen in the physical properties. Additionally, the experimental data was satisfactorily correlated and compared with the calculated model.