Thiols as Volatile Corrosion Inhibitors for Top-of-the-Line Corrosion

The effectiveness of hexanethiol, decanethiol, and 11-mercaptoundecanoic acid for CO₂ corrosion inhibition of carbon steel exposed to top-of-the-line conditions has been investigated. Weight loss measurements were used to measure the corrosion rate in the absence and presence of these volatile inhibitor compounds. After the experiments, steel surfaces were characterized by scanning electron microscopy and energy-dispersive x-ray spectroscopy. In addition, surface characterization of adsorbed decanethiol molecules on carbon steel was performed using x-ray photoelectron spectroscopy. The results suggest the formation of an adsorbed inhibitor film on the steel surface, leading to a decrease in corrosion rate. Persistency experiments were also performed to evaluate the residence time for inhibitors adsorbed on carbon steel. Among the inhibitors tested, decanethiol showed very good corrosion inhibition properties as well as high persistency.