1996 Volume 45 Issue 3 Pages 138-145
The weight loss tests of the copper pieces immersed in HNO3 solutions added each of four kinds of p-substituted anilines (substituents: NO2, Cl, NH2, OH) show that the substituted anilines have high corrosion inhibition efficiencies of 70-90%. Similar weight loss tests for six kinds of p-substituted anilines (substitiuents: NO2, Cl, NH2, OH, NHCOCH3, CONH2) have done at each of temperatures 30°C, 50°C and 70°C of the solutions and the adsorption energies ΔH (kJ/mol) of each substituted aniline on the copper plane have been obtained in the order for the substituents NO2 (45.37)>CONH2(41.55)>Cl(37.82); NH2(37.82)>OH(28.72)>NHCOCH3 (23.89). The order is the same as that of the strength of substituents, and the strong substituent adsorbes strongly on the copper plane, and the substituent shows strong corrosion inhibition action. ATR IR spectra have been measured the copper pieces immersed in the HNO3 solutions added each of the four p-substituted anilines and the absorptions ν(H-Cu), ν(Cl-Cu), δ(H-Cu) and ν(O-Cu) have been found. The adsorption structures of the p-chloroaniline and p-phenylenediamine on the copper plane are shown and the structures offer a basis of corrosion inhibition mechanism for the p-substituted anilines
