Room temperature molten carboxylate salt hydrates

摘要

The mono- and dihydrates of tetraethylammonium acetate, [(C_2H_5)_4N]CH_3CO_2, where found to be liquids at room temperature even though the corresponding tetrahydrate is a solid. The lower hydrates were synthesized by prolonged drying of the tetrahydrate. The monohydrate melts at 18 deg C.The ~(13)C NMR and ~1H NMR spectra of the monohydrate were consistent with the proposed structure. The monohydrate was stable with respect to decomposition for over one year under N_2 at ambient temperature. Both hydrates exhibited large and reversible absorption of CO_2 at 50 deg C. Spectroscopic data were consistent with absorption of CO_2 as bicarbonate. The related tetraethylammonium propionate salts containing 2 and 0.9 mol H_2O/mol salt were also found to be liquids at room temperature.