Phase Equilibria and Spectroscopic Identification of Structure II Hydrates with New Hydrate-Forming Agents (Cyclopropylamine and Cyclopentylamine)

초록

In this study, the phase equilibria of binary (cyclopropylamine (CPrA) + methane (CH4)) and (cyclopentylamine (CPeA) + CH4) hydrates were investigated using a conventional isochoric pressure-temperature trace method. The equilibrium temperatures of the binary (CPrA + CH4) and (CPeA + CH4) hydrates were higher than those of pure CH4 hydrate. The guest conformation and inclusion behaviors of the binary (CPrA + CH4) and (CPeA + CH4) hydrates were also examined through C-13 solid-state nuclear magnetic resonance spectroscopy, and the results confirmed the formation of structure II hydrates with new hydrate-forming agents, CPrA and CPeA, in the presence of CH4. The crystal structures and possible host-guest interactions of the proposed hydrate systems were investigated through Rietveld analysis using the direct space method, and the results demonstrated the formation of sII hydrates (with cubic Fd-3m) and the possibility of host-guest interactions in the binary (CPrA + CH4) and (CPeA + CH4) hydrates. These observations provide an improved understanding of the unique nature of host-guest inclusion phenomena.

키워드