Temperature-dependent Raman Spectroscopic Observation for Structural Transformation and Guest Dynamics of Gas Hydrates and Hydroquinone Clathrates
نویسندگان
چکیده
Clathrates are crystalline inclusion compounds formed by a physically stable reaction between host and guest molecules. Gas hydrate and hydroquinone (HQ) clathrate are one of the most studied and welldefined clathrate compounds. In this study, guest-free, CO2-loaded, CH4-loaded and CO2/CH4-loaded HQ clathrates were synthesized by gas-phase reaction and recrystallization. In addition, pure CO2 and CH4 hydrates were prepared using a high-pressure reactor. The structural transformation and guest dynamics of the HQ clathrates and the gas hydrates were observed by temperature-dependent Raman spectroscopy. These results provide useful information on the structural integrity and the guest-host interaction of clathrate compounds.
منابع مشابه
Semiconducting Clathrates Meet Gas Hydrates: Xe24[Sn136]
Semiconducting group 14 clathrates are inorganic host-guest materials with a close structural relationship to gas hydrates. Here we utilize this inherent structural relationship to derive a new class of porous semiconductor materials: noble gas filled group 14 clathrates (Ngx[M136], Ng = Ar, Kr, Xe and M = Si, Ge, Sn). We have carried out highlevel quantum chemical studies using periodic Local-...
متن کاملMolecular Dynamics Simulations of Guest – Host Hydrogen Bonding in Structure I, Ii, and H Clathrate Hydrates
The standard picture is that clathrate hydrates form when hydrophobic guest molecules are compressed with water under high pressure-low temperature conditions. In the ice-like hydrate framework, water molecules form molecule-sized cavities that encapsulate the guests and minimize water-hydrophobic guest interactions. This picture, however, must be modified by observations that many water solubl...
متن کاملThermal Properties and Transition Behavior of Host –guest Compounds under High Pressure
The thermal properties and transition behavior of the host-guest inclusion compounds: urea, thiourea, Dianin’s compound, clathrate hydrates and hydroquinone have been reviewed. In particular, we summarize their thermal conductivities, heat capacities and transitions at high pressures. Two of the systems: urea inclusion compounds and clathrate hydrates, show unusual glass-like thermal conductivi...
متن کاملExperimental Measurement of Methane and Ethane Mole Fractions during Gas Hydrate Formation
The super-saturation condition has to be provided to form gas hydrates. Consequently, the prediction of the guest molecule fraction in the aqueous phase is crucial in the study of the gas hydrate kinetics. In the present work, several experiments were carried out in a semi-batch reactor in order to determine the mole fraction of methane and ethane during gas hydrates formation (growth stage...
متن کاملEffects of the CO2 Guest Molecule on the sI Clathrate Hydrate Structure
This paper analyzes the structural, energetic and mechanical properties of carbon dioxide hydrate clathrates calculated using finite cluster and periodic ab initio density-functional theory methodologies. Intermolecular interactions are described by the exchange-hole dipole moment method. The stability, gas saturation energetics, guest-host interactions, cage deformations, vibrational frequenci...
متن کامل