| 초록 |
Quaternary ammonium salts (QASs) form semi-clathrate hydrates under higher temperature and lower pressure conditions when compared with the pure hydrate systems. These semi-clathrate hydrates have vacant small cages which can be used for capturing small-sized gas molecules, while the large cages are occupied by the TBA cation. The TBAC semi-clathrate hydrates are expected to have similar properties to the broadly studied QASs such as Tetra-n-butyl ammonium bromide (TBAB) and tetra-n-butyl ammonium fluoride (TBAF). In this study, semi-clathrate phase equilibria of TBAC•29.7H2O were measured in the presence of various guest gases of CH4, CO2, and N2. The experimental results were compared with TBAB and TBAF. The guest molecules encaged in the semi-clathrate lattices were examined using NMR and Raman spectroscopy. In addition, thermal properties of TBAC were obtained using a differential scanning calorimeter (DSC). The dissociation enthalpy of TBAC•29.7H2O was found to be 148.6 kJ/mol•semi-clathrate. Through this work, TBAC semi-clathrate hydrates are anticipated for a good candidate as gas storage and separation application. |
