Quantum chemical calculations, synthesis and corrosion inhibition efficiency of ethoxylated-[2-(2-{2-[2-(2-benzenesulfonylamino-ethylamino)-ethylamino]-ethylamino}-ethylamino)-ethyl]-4-alkyl-benzenesulfonamide on API X65 steel surface under H2S environment

The effect of four novel nonionic surfactants based on sulphonamide as corrosion inhibitors for X-65 type carbon steel in oil well formation water under H2S environment was investigated by electrochemical measurements. The obtained results revealed that synthesized surfactants perform as acceptable corrosion inhibitors. Scanning electron microscopy (SEM) was used to examine surface morphology in the absence and presence of inhibitors molecules. It was found that the inhibition efficiency depends on the ethylene oxide content in the molecule. The quantum chemical calculations were carried out to study the molecular geometry and electronic structure of obtained derivatives. The energy gap between the highest occupied molecular orbital and lowest unoccupied molecular orbital has been calculated using the theoretical computations to reflect the chemical reactivity and kinetic stability of compounds. (C) 2015 Elsevier B.V. All rights reserved.