Icosahedron cage occupancy of structure-H hydrate helped by Xe -1,1-, cis -1,2-, trans-1,2-, and cis-1,4-dimethylcyclohexanes

Large pressure depression of methane hydrate by adding 1,1-dimethylcyclohexane

“…All of them show a large pressure depression from the equilibrium pressure of pure methane (as a representative of natural-gas) hydrate system. From a previous study on the icosahedron cage occupancy of DMCH isomers in the presence of Xe help gas, we found that 1,1-DMCH gives by far the largest pressure depression in the DMCH isomers (Sugahara et al, 2005).…”

Four-Phase Equilibrium Relations Including Clathrate Hydrate Phase in a Ternary System of Xenon, Benzene, and Water

“…The size of guest species as well as pressures and temperatures determine which structure is formed. The smallest guest species is hydrogen (H 2 ). , One of the largest guest species is a dimethylcyclohexane (DMCH) stereoisomer. − DMCHs do not generate any gas hydrates by itself without the existence of small gas molecules called help gases. The 1,1-DMCH, cis -1,2-DMCH, and cis -1,4-DMCH generate the sH hydrate with assistance of methane (CH 4 ), while the other DMCH stereoisomers cannot generate it.…”

“…The 1,1-DMCH, cis -1,2-DMCH, and cis -1,4-DMCH generate the sH hydrate with assistance of methane (CH 4 ), while the other DMCH stereoisomers cannot generate it. In the case of using xenon (Xe) as help gas, the cis -1,4-DMCH does not generate the sH hydrate . That is, the help gas affects whether the sH hydrate is formed or not.…”

“…It has been reported that cyclohexane and C 6 H 6 form the sII hydrates with the assistance of methane , and Xe . Neither toluene nor o -xylene, which is a benzene derivative, generates any clathrate hydrate even in the presence of CH 4 , while both methylcyclohexane (MCH) and cis -1,2-DMCH generate the sH hydrate in the presence of CH 4 and Xe. , The benzene ring is larger than the cyclohexane ring, although the number of the cyclic carbons is the same. The size of the C 6 H 6 molecule would be a little bit too large for the 5 12 6 4 -cage of sII hydrate.…”

“…In the case of using xenon (Xe) as help gas, the cis-1,4-DMCH does not generate the sH hydrate. 8 That is, the help gas affects whether the sH hydrate is formed or not. CH 4 is a superior help gas to Xe.…”