Corrosion Inhibition of Some Organic Compounds on Low Carbon Steel in Hydrochloric Acid Solution

The effect of N-[N'-(4-methoxyphenyl) benzenesulphonamido]-3-carboxy-4-methyl-4(4-methylphenyl)-3-butenamide 1, N-(N'-phenylbenzenesulphonamido)-3-carboxy-4methyl-4-(4-methylphenyl)-3-butenamide 2, and N-[N'-(4-chlorophenyl) benzenesulphonamido]-3-carboxy-4-methyl-4-(4-methylphenyl)-3-butenamide 3, on the corrosion of low carbon steel in 1 M hydrochloric acid solution has been studied by weight loss measurements and potentiodynamic technique over the temperature range 30-60 degrees C. Results obtained showed that protection efficiency increased with the increase in concentration of the different organic compounds used and decreased with the increase in temperature. Langmuir adsorption isotherm at all temperatures was studied. The phenomenon of physical adsorption is proposed from the values of E-a and Delta G degrees(ads). Results obtained showed that compound 1 is the best inhibitor, and the protection efficiency follows the order: 1 > 2 > 3.