Combined computational and experimental studies of tripropylammonium 2-sulfobenzoate protic ionic liquid

We present the results of experimental and computational studies of the physicochemical properties and structure of a newly synthesized tripropylammonium 2-sulfobenzoate (TPrA/SBA) protic ionic liquid (PIL). Quantum-chemical methods were used to evaluate the hydrogen-donor properties of the SBA molecule and to model the proton transfer between the acid and base molecules. The results revealed that the ionic liquid was formed through an acid-base interaction between the proton of the –SO₃H group in the acid and the nitrogen atom in the amine. Additionally, we conducted a molecular dynamics simulation to determine the hydrogen bond topology in the PIL bulk as well as the average number of hydrogen bonds between the ions. To provide further insights, we compared the structural parameters and properties of the TPrA/SBA ionic liquid with the data on the two other tripropylammonium-based PILs with hydrogen sulfate (SA) and triflate (TfO) anions.