Study on the corrosion inhibition properties of some quinoline derivatives as acidizing corrosion inhibitors for steel

Abstract

In this paper, four quinoline quaternary ammonium salts were synthesized using quaternization reaction, which were benzyl quinolion (BQL), naphthylmethyl quinolinium chloride (NQL), benzyl-8-hydroxy quinolinium chloride (BHQ) and naphthylmethyl 8-hydroxy quinolinium chloride (NHQ). The corrosion inhibition properties of the quinoline derivatives as corrosion inhibitors on P110 steel in 20% HCl solution at 60°C at different concentrations were investigated by weight loss and electrochemical measurements. The results showed that as the concentration of corrosion inhibitor increases, the corrosion rate decreased and the inhibition efficiency improved. Among various corrosion inhibitors at the same concentration, their inhibition efficiencies can be ranked from lowest to highest as follows: QL(quinoline)<8-HQ(8-hydroxyquinoline)<BQL<BHQ<NQL<NHQ. The inhibitors synthesized from 1-chloromethyl naphthalene, NQL and NHQ, exhibited excellent inhibition property, in which the inhibition efficiencies reached to 99.8% and 99.9% even with concentration of 0.1%. It also demonstrated the adsorption of all inhibitors on the steel surface followed Langmuir adsorption isotherms, in which QL and 8-QH exhibited as physical adsorption, BQL and BHQ exhibited as mixed adsorption and NQL and NHQ exhibited as chemical adsorption. The inhibition mechanism of inhibitors was also investigated with scanning electron microscopy (SEM), quantum chemical analyses and molecular dynamics simulations, which proved BHQ and NHQ can facilitate an increase in electron cloud density on the benzene ring, thereby enhancing corrosion inhibition performance.