| 초록 |
This study made an important discovery on two F-gases (c-C4F8 and C3F8) which form sH hydrate in presence of suitable help gas molecules. Since C3F8 and c-C4F8 molecules have large molecular sizes (7.66 Å and 7.68 Å, respectively), those molecules have not been expected to be enclathrated in sI or sII hydrate cages. However, this study discovered that c-C4F8 molecules can be enclathrated in sH large (51268) cages in presence of CH4 as help gas, which was demonstrated through PXRD and 13C NMR spectroscopy. In addition, C3F8 was found to act as a dual hydrate former between sH and sII hydrates according to help gas molecules. Via 13C NMR and Raman spectroscopy, C3F8 was confirmed to form sH hydrate with CH4, while forming sII hydrate in presence of SF6. The discovery of c-C4F8 and C3F8 as sH hydrate former is very meaningful, since there have been no gas-phase sH hydrate former investigated until present. The overall results obtained in this study provide invaluable information of various properties of F-gas hydrates, and they are expected to be useful sources for gas hydrate application fields in the future. |
