Hexamethylene-1,6-bis(N-D-glucopyranosylamine) as a novel corrosion inhibitor for oil and gas industry: Electrochemical and computational analysis

An amine-functionalized glucose namely hexamethylene-1,6-bis(N-d-glucopyranosylamine) (HGA) was synthesized and characterized. The corrosion inhibition behavior of HGA on API X60 steel in 3.5 wt% NaCl saturated with CO₂ was evaluated by electrochemical impedance spectroscopy (EIS), electrochemical frequency modulation (EFM), linear polarization resistance (LPR), potentiodynamic polarization (PDP) and scanning electron microscopy (SEM). The adsorption of HGA on the API X60 mild steel surface obeyed the Langmuir isotherm. The results of potentiodynamic polarization indicated that the HGA molecule behaved as a mixed type inhibitor by reducing both the anodic and the cathodic electrochemical reactions. The maximum corrosion inhibition efficiency obtained was 91.82% at a concentration of 2.27 × 10^-4 M (100 ppm). HGA reduced the extent of localized pitting corrosion on the steel surface. The inhibitor is protonated in the system and assumes a parallel orientation during adsorption on the steel. The oxygen and nitrogen atoms serve as reactive centers for adsorption, based on quantum chemical calculations and Monte Carlo simulations in the protonated form.