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

Abstract

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 8 moles 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 1 M 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 600 ppm. The inhibitive efficiency was discussed on the light of chemical structure of the used inhibitors.

Keywords:

• Corrosion inhibitors
• ethoxylation reaction
• polymeric surfactants
• polytriethanolamine