sym-Trisubstituted 1,3,5-Triazine Derivatives as Promising Organic Corrosion Inhibitors for Steel in Acidic Solution

Triazine derivatives, namely, 2,4,6-tris(quinolin-8-yloxy)-1,3,5-triazine (T3Q), N(2),N(4),N(6)-tris(pyridin-2-ylmethyl)-1,3,5-triazine-2,4,6-triamine (T3AMPy) and 2,2′,2′′-[(1,3,5-triazine-2,4,6-triyl)tris(azanediyl)] tris(ethan-1-ol) (T3EA) were synthesized and their inhibition of steel corrosion in hydrochloric acid solution was investigated using electrochemical techniques. The corrosion protection of the prepared compounds increased with increasing concentration and reached up to 98% at 250 ppm. The adsorption of T3Q, T3AMPy, and T3EA on the steel surface was in accordance with the Langmuir adsorption isotherm. The electrochemical results revealed that T3Q, T3AMPy and T3EA act as excellent organic inhibitors and can labeled as mixed type inhibitors. The efficiencies of the tested compounds were affected by the nature of the side chain present in the triazine ring, where T3EA gave the least inhibition while T3Q and T3AMPy gave higher and almost the same inhibition effects. The inhibition efficiencies obtained from the different electrochemical techniques were in good agreement.