Under low temperature and high pressure condition, various low molecular weight gas molecules like methane react with water then clathrate hydrate is made. Clathrate hydrates called gas hydrates have some structures such as sI, sII and sH etc. ‘Host’ water molecules make cage and then ‘guest’ gas molecules are entrapped. Gas hydrate is expected to replace petroleum energy. Because the amount of world gas hydrate is estimated more than twice as that of fossil fuel. Gas hydrates have infinite potential as the energy source of next generation.
In this study, at first, Hexamethyleneimine, 1-methylpiperidine, 2-methylpiperidine, 3-methylpiperidine and 4-methylpiperidine as isomers of C6H13N were revealed as new sH clathrate hydrate formers. They show fully soluble characteristics to water whereas already known sH formers such as methyl cyclohexane and 2, 2-dimethylbutane (neohexane) are immiscible or very slightly soluble to water. The L-H-V equilibrium P-T behavior of these new sH clathrate hydrates shows a tendency to shift to much milder condition than already known one. We particularly note that 1-methylpiperidine appears to be the best for promotion. To verify the distribution of CH4 molecules and crystal structure of clathrate hydrates, 600MHz solid state NMR, Raman spectroscopy and XRD pattern analysis were conducted. These noticeable properties of new formers are ex-pected to open new research fields to the hydrate community and contribute to hydrate-based technological applications with high energy efficiency.
At second, two new amine-type sII formers were suggested: pyrrolidine and piperidine. These guest com-pounds fail to form clathrate hydrate structures with host water, but instead, have to combine with light gase-ous guest molecules (methane) for enclathration. Two binary clathrate hydrates of (pyrrolidine + methane) and (piperidine + methane) were synthesized at various amine concentrations. 13C NMR and Raman analysis were done to identify the clat...