Inhibition of copper corrosion in acid solution by N-1-naphthylethylenediamine dihydrochloride monomethanolate: experimental and theoretical study: part-1

摘要

Inhibition of corrosion of copper in 2M HNO_3 by N-1-naphthylethylenediamine dihydrochloride monomethanolate (N-NEDHME) has been studied by use of weight loss, electrochemical polarization, and electrochemical impedance spectroscopy (EIS) measurements. The result obtained reveal that this organic compound is a very good inhibitor and its inhibition efficiency increases with increasing concentration, reaching 94% at 10~(-3) M at 303 K. The potentiodynamic polarization study indicated that this compound acts as a cathodic type corrosion inhibitor. EIS results indicate that the change in the impedance properties (R_t and C_(dl)) with concentration of inhibitor was because of the formation of a protective layer on the surface of copper. Quantum chemical calculations using DFT at the B3LYP/6-31G* level of theory was further used to calculate some electronic properties of the molecule in order to ascertain any correlation between the inhibitive effect and molecular structure of N-NEDHME. The effect of temperature between 303 and 343 K and calculation of activation data will be discussed in Part 2.