Macrocyclic inhibitor for corrosion of N80 steel in 3.5% NaCl solution saturated with CO₂

The inhibition of the corrosion of N80 steel in 3.5 wt.% NaCl solution saturated with CO₂ by the 1,2,4,7,9,10-hexaazacyclo-pentadeca-10,15-dien-3,5,6,8-tetraone (HPT) has been studied using Fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, scanning electrochemical microscopy (SECM), and scanning electron microscopy (SEM). Quantum chemical calculations were performed to elucidate and compare the molecular reactivity parameters of HPT while molecular dynamics studies were meant to investigate its binding properties on the metal surface. The results of the study indicate that HPT molecules have high tendency to interact with the metal surface by donating and accepting electrons.