Intra-/inter-molecular synergistic inhibition effect of sulfonate surfactant and 2-benzothiazolethiol on carbon steel corrosion in 3.5% NaCl solution

A sulfonate surfactant (CHT) was synthesized, reacted with 2-benzothiazolethiol (MBT) to obtain CHMT to investigate the intramolecular synergistic inhibition effect of CHT and MBT. Meanwhile, a mixture of CHT and MBT in a 1:1 mol ratio (CHT + MBT) was used to investigate the intermolecular synergistic inhibition effect of CHT and MBT. The results from electrochemical experiment and theoretical studies indicated that CHMT and CHT + MBT strongly inhibited the corrosion of carbon steel in 3.5 % NaCl solution compared to MBT or CHT, revealing intramolecular and intermolecular synergistic action between CHT and MBT. Additionally, the mechanisms of intramolecular and intermolecular synergistic effects were proposed.