Infrared spectroscopic monitoring of surface effects during gas hydrate formation in the presence of detergents

The main objective of this study is to expand the understanding on the role of surfactants during gas hydrate formation at surfaces. It is shown that in situ studies using mid-infrared (MIR) evanescent field absorption spectroscopy utilizing silver halide fiberoptic waveguides routed through a pressurized cell enables detailed spectroscopic observations of detergent-related surface processes during sodium dodecyl sulfate (SDS) mediated gas hydrate formation. Thereby, processes involving the key molecular players- water, SDS, and propane gas - were spectroscopically monitored in close vicinity of the fiber surface, thus providing evidence for the role of SDS as a promoter of gas hydrate growth. Based on insight on the individual contributions of the involved molecules, a mechanism for the SDS-induced decrease of hydrate nucleation time is proposed.