Experimental and theoretical investigation of 3,3′-diamino dipropyl amine: Highly efficient corrosion inhibitor for carbon steel in 2 N HCl at normal and elevated temperatures

Abstract

3,3′-diaminidipropylamine (DADPA) was investigated as anti-pitting and anti-cracking agent for carbon steel (CS) in 2 N HCl at three temperatures. Different electrochemical and surface characterization techniques were used. Molecular Dynamics Simulation (MDS) and Frontier Molecular Orbital (FMO) studies were carried out by Density Functional Theory (DFT). The kinetic and thermochemical parameters like hardness, electrophilicity, nucleophilicity, electron donating and accepting tendency, work function, back donation energy, Proton Affinity (PA), Carbon steel/DADPA interaction energy, binding energies, etc., were investigated and discussed at length. Frequency calculation on geometry optimized structure was carried out to obtain IR spectra. The mechanism of inhibition was investigated both by the theoretical and experimental techniques. DADPA shows 86.43% corrosion inhibition efficiency for CS in 2 N HCl and was proved to be a very good anti-pitting and anti-cracking agent for CS at normal and high temperatures. The Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and BOD/COD ratio of wastewater was found to be with in the permissible limit.