Corrosion Inhibition Efficiency of Polytriethanolamine Surfactants for Pipe-Lines Carbon Steel in 1M HCl

Fifteen organic compounds were prepared from triethanolamine and its derivative. The triethanolamine was polymerized by condensation to get P4, P6, and P8 at different molecular weight. The P8 was ethoxylated at different ethylene oxide units (en) (40, 100, and 120) to obtain three compounds (E(en)P8). Every degree of ethoxylate was esterified with 1, 4, and 8moles of oleic acid to get on 9 ethoxylated polytriethanolamine esters (E(en)P8Om). The effect of adding these organic compounds on the electrochemical behavior of carbon steel in 1M HCl was investigated by using the weight loss technique. The reported results in this study show that the addition of these surfactants inhibits the corrosion of carbon steel. The inhibition efficiency (I%) for each inhibitor increases with increasing the concentration. The maximum inhibition efficiency (95%) was obtained by (E(40)P8O1) at 600ppm. The inhibitive efficiency was discussed on the light of chemical structure of the used inhibitors.