Developing a novel imine derivative as a corrosion inhibitor for Q235 carbon steel in 1 M HCl solution: Experiments and theoretical calculations

Abstract

During oil and gas extraction, metals are inevitably exposed to acidic environments on a regular basis. Acid solutions, particularly hydrochloric acid, are employed in a multitude of industrial processes, including oil well acidising, steel pickling, ferroalloy pickling and acid cleaning. These applications frequently result in severe metal corrosion. To cope with corrosion, the superlative simple and effective method is to prevent corrosion inhibitors. Naphthyridinimides are not as effective as rust inhibitors, but their corrosion inhibition is significantly improved by the addition of Br ions. This thesis focuses on the synthesis of naphthylimine-type novel organic corrosion inhibitors and the corrosion inhibition mechanism, with the main content of 3,3′-(1,3,6,8-tetraoxo-1,3 6,8-tetrahydrobenzo[lmn] [3,8] phenanthroline-2,7-diyl) bis (N-ethyl -N, N-Dimethyl-1-propylamine) bromide (NDI-N-Br) on Q235 carbon steel in an acidic environment (1 M hydrochloric acid solution). The corrosion inhibition efficiencies of NDI-N-Br reached 93.53 % at 300 ppm at an ambient temperature of 298 K. The corrosion inhibitor NDI-N-Br forms a protective film on the metal surface and organizes the interaction between the metal matrix and the corrosive medium, providing a rust inhibiting effect. This thesis shows that this class of compounds can be well applied to acidic environments and provide ideas for the subsequent development of naphthylimide-based organic corrosion inhibitors.