Conversion of Imidazole to N-(3-Aminopropyl)imidazole toward Enhanced Corrosion Protection of Steel in Combination with Carboxymethyl Chitosan Grafted Poly(2-methyl-1-vinylimidazole)

In this study, the synthesis route for preparing N-(3-aminopropyl)imidazole (APM) from imidazole has been reported via hydrogenation using Raney nickel catalyst. The inhibition performance of the resultant imidazoline product against pipeline steel corrosion has been investigated in CO, saturated acidic oilfield formation water. The contributions of carboxymethyl chitosan grafted poly(2-methyl-1-vinylimidazole) copolymer (polyCMCh-graft-polyMVI) newly synthesized from chitosan revealed a synergy of protective capacity in combination with APM. Corrosion inhibition by APM/graft copolymer conjugate is attributed to molecular adsorption and the formation of more stable protective inhibitor films on the steel surface compared to individual compounds. In-depth electrochemical corrosion investigation is reported by means of electrochemical impedance spectroscopy and potentiodynamic polarization as well as surface analytical techniques. Adsorbed ferrous carbonate phases are observed at acid pH with apparently amorphous morphologies. Modeled mechanisms of corrosion and corrosion inhibition have been illustrated from experimental evidence in line with the barrier performance on adsorbed films.