Understanding Deep Eutectic Solvent Formation via the Liquid Structure of Thermally Decomposing Ammonium Salts and Their Eutectic Mixtures

Due to thermal decomposition, the liquid structures of salts and salt-rich DESs are inaccessible. By combining ultra-fast scanning calorimetry with micro-XRD we can overcome this limitation and experimentally follow the evolution of the liquid structure with temperature and the addition of a molecular compound. Together with state-of-the-art MD simulations, the dependency of the DES’s liquid structure (long-range polar/apolar domains, ion charge alternation, and short-range intramolecular structural features) on the chemical nature of its constituents is unveiled. Such insights are critical towards understanding the extraordinary melting point depressions and solvent performance observed for DESs.