Effect of Tolyltriazole on Iron Corrosion and the Hydrogen Evolution Reaction in H2SO4

The effect of tolyltriazole on the corrosion behavior of iron in sulfuric acid has been examined. The rate of hydrogen evolution on iron in the absence and presence of tolyltriazole was first order with respect to the hydrogen ion concentration. The experimental results indicate that the presence of adsorbed tolyltriazole on iron does not affect the mechanism of hydrogen evolution as had also been observed previously for benzotriazole. The corrosion rate of iron decreased as the concentration of tolyltriazole increased. After a concentration of about 4.7 millimolar tolyltriazole, the corrosion rate of iron did not appear to decrease with further increase in inhibitor concentration. The presence of 4.7 millimolar tolyltriazole decreased the corrosion rate to 0.026 mA/cm2 compared to 0.7 mА/cm2 for uninhibited iron. The adsorption of tolyltriazole on iron in H2SO4 followed Langmuir adsorption behavior.