Imidazolines containing single-, twin- and triple-tailed hydrophobes and hydrophilic pendants (CH2CH2NH)nH as inhibitors of mild steel corrosion in CO2–0.5 M NaCl

Abstract

Inhibition of mild steel corrosion in CO₂–0.5 M NaCl (40 °C, 1 atm; 120 °C, 10 bar) by a new series of imidazolines having single-, twin- and triple-tailed phenyl substituents at C(2) and N(1) pendants of CH₂CH₂NH₂ and (CH₂CH₂NH)₂CH₂CH₂NH₂ have been examined. Imidazolines containing twin-tailed (3,5-dioctyloxyphenyl) hydrophobes outperformed their single- and triple-tailed counterparts as well as two commercial imidazolines. The triamine pendant imparted better inhibition at higher temperature and pressure. The XPS study confirmed the presence of an imidazoline film covering the metal surface. The imidazolines prefer to be adsorbed on the metal surface rather than micellization.