The Role of Unsaturated Bonds in C18 Fatty Acid on the Corrosion Inhibitory Effect of Mild Steel in CO2 Medium

The newly synthesized dissymmetric cocogem surfactants, N,N′-bis(propyl-2-ol)-1,6-hexane diammonium octanoate oleate - NNBHOO and N,N′-bis(propyl-2-ol)-1,6-hexane diammonium octanoate linolenate - NNBHOL, were employed in the potentiodynamic polarization method to investigate the corrosion protection of carbon steel in a 1% sodium chlorine solution saturated with carbon dioxide. According to experimental results, both compounds - NNBHOO and NNBHOL in particular - have a high inhibitory efficiency when it comes to protecting carbon steel in 1% sodium chlorine solution that has been saturated with carbon dioxide. The protective effects of NNBHOO and NNBHOL inhibitors increase to 99.4% when their concentrations in the media rise to 100 ppm. These inhibitors were found to belong to the mixed type inhibitor group by analyzing their polarization curves. The adsorption process’s thermodynamic data were computed and discussed. Since the linolenic acid residue of the NNBHOL compound has three unsaturated double bonds, its adsorption energy at a concentration of 100 ppm is higher compared to NNBHOO.