LAUSR

Abstract In this study, an addition reaction occurred between epoxidized soybean oil and 4-(dimethylamino)benzenethiol to produce a thiol adduct (TA). The produced TA had been emulsified using a nonionic emulsifier blend (Tween 20, Span 20, and Span 80) to be a water-miscible emulsified thiol adduct (ETA). The ETA emulsion was investigated as a corrosion inhibitor for API X52 carbon steel in 1 m HCl using weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) techniques. The surface morphologies of the carbon steel were characterized by scanning electron microscopy and energy dispersive X-ray. The effect of temperature was investigated. It was found that the emulsified adduct behaves as an excellent corrosion inhibitor with high inhibition efficiency of 94.7% with 0.005 m concentration. The polarization data indicate that the emulsified adduct acted as a mixed-type inhibitor. The adsorption of the emulsified adduct on the carbon steel surface has been found to follow the Langmuir isotherm.