Dry and wet lab studies for some benzotriazole derivatives as possible corrosion inhibitors for copper in 1.0 M HNO<inf>3</inf>

Abstract

With contrast to the traditional techniques of identifying and synthesizing new corrosion inhibitors in wet lab, a prior dry-lab process, followed by a wet-lab process is suggested by using cheminformatics tools. Quantum chemical method is used to explore the relationship between the inhibitor molecular properties and its inhibition efficiency. The density function theory (DFT) is also used to study the structural properties of three selected benzotriazole derivatives namely, benzotriazole-1-carboxamide (BCA), 1H-benzotriazole-1-acetonitrile (BAN) and benzotriazole-1-carbonyl chloride (BCC) in aqueous phase. It is found that when the benzotriazole derivatives adsorb on the copper surface, molecular structure influences their interaction mechanism. The inhibition efficiencies of these compounds showed a certain relationship to highest occupied molecular orbital (HOMO) energy, Mulliken atomic charges and Fukui indices. A wet lab study has been carried out using weight loss, Tafel polarization and impedance measurements to evaluate their inhibition performance in 1.0 M HNO3 solutions at 25 °C. Adsorption takes place by a direct chemisorption on the exposed copper surface, while it most probably occurs via hydrogen bonding on the oxidized surface. BCA was the most effective among the tested inhibitors, while BCC was less effective than BAN. Results obtained from dry-lab process are in good agreement with those recorded from wet-lab experiments. © 2009 Elsevier Ltd. All rights reserved.