Studies on adsorption and corrosion inhibitive properties of quinoline derivatives on N80 steel in 15% hydrochloric acid

This paper deals with the N80 steel corrosion protection study in 15% HCl which was carried by three quinoline derivatives namely 3-acetyl-1-(4-methylbenzylideneamino) quinolin-2-one (AQ-1), 3-acetyl-1-(4 hydroxy benzylideneamino) quinolin-2-one (AQ-2), 3-acetyl-1-(3-nitrobenzylideneamino) quinolin-2(1H)-one (AQ-3) using gravimetric, electrochemical, and quantum chemical studies. Tafel polarization showed that AQs are mixed type inhibitors but dominantly affect cathodic reaction more. The observed results reveal that AQ-1 is the best inhibitor. All the three inhibitors were found to obey the Langmuir adsorption isotherm. Scanning electron microscopy (SEM) micrographs supports the protection of the N80 steel by AQs. Quantum chemical study reveals that the inhibitors have a tendency to get protonated and this protonated form has greater tendency to get adsorbed onto the N80 steel surface.