New Amine/Phenylglycedyl Ether Adducts for Mild Steel Protection in 1 M HCl: Experimental and Computational Study

Abstract

The key objective of this study is to ascertain the effect of structure and increased molecular size on the corrosion inhibition potential of two synthesized amines, when compared to their precursor compounds. The product amines were N-(2-hydroxy-3-phenoxy) ethanolamine (NHPE), N,NÀ Di-(2-hydroxy-3-phenoxypropyl) ethanolamine (NNHPE) synthesized from monoethanolamine (MEA) and phenyl glycidyl ether (PGE) as starting materials. Both starting and product amines were characterized using FTIR spectroscopy. The corrosion inhibition potentials were assessed using experimental and quantum theoretical modeling and calculations. Some key electronic properties such as highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies, gap energy, dipole moment and surface area, were calculated and discussed. The various approaches adopted in this study were in reasonable agreement and the following average inhibition efficiency trend was obtained: NNHPE (75.7 %) > NHPE (68.3 %) > PGE (64.2) > MEA (61.0).