New telechelic compounds as corrosion inhibitors for steel in 1Â M HCl

Two new telechelic compounds have been synthesised and tested as inhibitors for the corrosion of steel in 1 M HCl solution. Weight loss measurements, potentiodynamic polarisation and impedance spectroscopy (EIS) methods are used. The inhibiting action increases with the concentration of methyl 4-{2-[(2-hydroxyethyl)thio]ethyl}benzoate (T2) and 11-[(2-hydroxyethyl)thio]undecan-1-ol (T3) to attain 92% at 10−3 M and 90% at 10−4 M, respectively. Good agreement between gravimetric and electrochemical methods (potentiodynamic polarisation and EIS) was observed. Polarisation measurements show also that T2 and T3 act as mixed inhibitors. The cathodic curves indicate that the reduction of proton at the steel surface happens with an activating mechanism. Adsorption of T3 on the steel surface obeys to the Langmuir adsorption model. Effect of temperature studied between 308 and 353 K shows that efficiency remains almost constant.