Corrosion inhibition characteristics of 2-[(E)-[5-methoxy-1-[4-(trifluoromethyl)phenyl]pentylidene]amino]oxyethanamine on steel in simulated oilfield acidizing solution

Abstract

The purpose of this research is to investigate the viability and efficiency of 2-[(E)-[5-methoxy-1-[4-(trifluoromethyl)phenyl]pentylidene]amino]oxyethanamine (MPPOE) as a non-toxic organic inhibitor of mild steel corrosion in oilfield acidizing environment at simulated surface to down-hole temperatures (30–90 °C). Electrochemical and weight loss techniques were used in the study while the well acidizing solution was simulated using 1 M and 15% HCl. Maximum inhibition efficiency of 94.4% and 80.4% were obtained with 10 × 10−5 M MPPOE in 1 M and 15% respectively at 30 °C. Effectiveness of MPPOE decreased with increase in temperature and increased with increase in its concentration. Addition of synergistic compounds such as glutathione to MPPOE increased the efficiency from 88% and 74% to 94% and 85% in 1 M and 15% HCl respectively at 90 °C with higher efficiencies at lower temperatures. UV–Visible spectroscopy revealed possibility of complex surface film formation due to adsorption of MPPOE on MS surface. Adsorption of MPPOE, as best approximated by Langmuir adsorption model, was spontaneous and exothermic, involving both physical and chemical interactive forces. EIS measurement revealed that the corrosion was controlled by charge transfer process. PDP measurements showed that MPPOE acted as a mixed type inhibitor. Inhibition efficiency values obtained from the different techniques were comparable. SEM micrographs of MS surface reveal reduction of MS surface pitting in the presence of MPPOE. Blends of MPPOE can be applied as alternative steel corrosion inhibitor in petroleum production. Keywords: Adsorption, Charge transfer resistance, Corrosion inhibitor, EIS, SEM