Effects of Chlorine and Bromine in Quinoline Quaternary Ammonium Salts on Its Corrosion Inhibition Performance

Two different quinoline quaternary ammonium salts were successfully synthesized using quinolone as matrix, benzyl chloride and benzyl bromide as link agents respectively. Weight loss measurement, electrochemical testing, electron scanning microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to evaluate the corrosion inhibition performance in individual use and compound use of the two inhibitors. The experiment results show that benzyl quinolinium bromide (BQB) compound with synergistic agent had an inhibition efficiency of 98.73% and the corrosion inhibition performance of BQB is better than that of benzyl quinolinium chloride (BQC). The adsorption of BQC and BQB molecules on carbon steel surface is a spontaneous and exothermic process which obeys the Langmuir isothermal adsorption model. However, the Gibbs free energy and the activation energy of BQB are higher than those of BQC.