Theoretical study of methanol as inhibitor and cyclopentane as stabilizer of dodecahedron methane hydrate cage

Abstract

Density Functional Theory (DFT) based simulations have been performed to explain the role of methanol as an inhibitor and the role of cyclopentane as a promoter for methane hydrate. Interaction energy, Mullikan charges and electrostatic potential parameters for combined system of methanol and dodecahedron methane hydrate as well as cyclopentane and dodecahedron (512) methane hydrate cage are calculated using B3LYP functional (with and without dispersion function) and 6-31G(d) basis set. Methane hydrate formation inhibition by methanol and methane hydrate stabilization by cyclopentane is critically analyzed based on electrostatic potential and Mullikan charge. It is observed that hydrogen bond between water molecules of clathrate 512 cages become stronger in presence of cyclopentane and weaker in presence of methanol. It is also found that methanol breaks some hydrogen bonds of water molecules.