Molecular insights into the heterogeneous crystal growth of tetrahydrofuran hydrate: Kinetic and interfacial properties

Abstract

The present work aimed to explore molecular insight into the tetrahydrofuran (THF) hydrate growth along its crystallographic face to consider the heterogeneous conditions. Molecular dynamic (MD) simulation results provided detailed dynamical aspects of water, and THF molecules at the interface of aqueous solution/hydrate slab by using the F₃ order parameter, and visual snapshots of the system at different times. Our simulations revealed that the interfacial properties of the hydrate phase can change the local structure of water molecules in the liquid phase and thus alter the kinetics of hydrate formation. Furthermore, the behavior of THF solution on the copper surface under the hydrate-forming conditions has been studied. It was found that the copper surface affected the THF solution by changing the distribution of THF and water molecules near the liquid-solid interface. Also, the MD simulation showed that a layer of THF molecules was adsorbed on the copper surface and subsequently, a dense water film was formed resulting in a strong resistance to order the water molecules around the THF for hydrate formation. These results are illustrative of how interfacial properties can affect the heterogeneous crystal growth of the hydrate phase.

Keywords: Copper surface; Hydrate; Interfacial properties; Molecular dynamics simulation; Tetrahydrofuran.