Thermochemistry of Pyridinium Based Ionic Liquids with Tetrafluoroborate Anion

Enthalpies of vaporization of five pyridinium based ionic liquids (ILs): 1‐ R ‐pyridinium (with R = ethyl, butyl‐, and hexyl), 1‐butyl‐3‐methyl‐pyridinium, and 1‐butyl‐4‐methyl‐pyridinium with tetrafluoroborate anion were studied using Quartz Crystal Microbalance (QCM). Enthalpies of solution of these ionic liquids were measured by high‐precision solution calorimetry. Gas‐phase enthalpies of formation of ILs were calculated by using the high‐level quantum‐chemical method G3MP2. From combination of experimental and theoretical results, enthalpies of formation of aqueous pyridinium based cations were derived for the first time.