Novel cationic gemini surfactants with different chain length as corrosion inhibitors for carbon steel in 1 M HCl

Three cationic gemini surfactants of the type N2,N3-dialkyl-N2,N2,N3,N3- tetramethylbutane diamminium bromide namely Ia, Ib and Ic have been synthesized. Their chemical structures were elucidated by the routine methodologies 1H-NMR, elemental analysis and mass spectroscopy. The surface active properties were examined and found to be influenced by the chemical structure of the surfactants. The synthesized cationic gemini surfactants were tested as corrosion inhibitors for pipeline carbon steel API X52 immersed in 1 M HCl solution, using weight loss method. The obtained data refer to very good inhibitive efficiencies vary with concentrations, and increase in the following order: Ia >Ib > Ic. The Quantum chemical parameters such as highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) energy levels, energy gap (EHOMO-ELUMO), the dipole moment and charge densities were calculated. The theoretical calculations were in good agreement with corrosion inhibition results.