Guilherme Brígido Rosa

DES-water interactions: a computational spectroscopy view

Deep eutectic solvents are a novel class of solvents that present many promising advantages when compared to traditional organic solvents. However, their molecular structure and interactions are still very poorly understood, especially in the presence of water. This is vital, as the addition of water allows for an even higher system tuneability. This work has as a main objective the evaluation of how different DES systems, with different water affinities, change when different water quantities are added, and try to understand the underlying molecular changes and interactions. This study was based on quantum computational calculations and the Raman and infrared spectra of the DES systems: glycolic acid/betaine, phenylacetic acid/betaine and thymol/betaine. All systems were confirmed as true DES, except the one based on thymol. The systems based on glycolic acid and phenylacetic acid presented different responses to the increase in water content. While the former presented one behaviour for low water contents, and another for higher water contents, in the latter water had an almost monotonous effect.