Roles of Short- and Long-Chain Organic Matter in Methane Hydrate Formation: Insights from Molecular Dynamics Simulations

Organic matter is an essential component in the genesis of methane hydrate within marine sediments, with its complex side-chain structure playing a key role in methane hydrate formation. The study utilized molecular dynamics simulations to investigate the impact of six types of organic matter, varying in chain length and functional groups, on the formation of methane hydrate at the molecular level. The results demonstrated that both the amino and carboxyl groups and benzene rings of organic matter can disrupt the tetrahedral arrangement of the surrounding water molecules through hydrogen bonding, ultimately inhibiting methane hydrate formation. Additionally, organic matters with shorter alkyl side chains exhibit a higher propensity to form hydrogen bonds with water molecules compared with their counterparts with longer alkyl side chains. This interaction also suppresses methane hydrate formation, but the effect of the alkyl side chain length of organic matter on methane hydrate formation is random. These findings offer valuable and mechanistic insights into the influence of common organic matter on methane hydrate formation.