Quantum Chemistry Study on Imidazole and Its Derivatives as Copper Hydrochloric Acid Pickling Inhibitors

Table 3 Quantum Chemistry Parameters of Two Compounds Calculated with PM3 Prediction Compounds The quantum chemical parameters of the two compounds are substituted into the formulae (1), (2) and (3) obtained above, and the predicted corrosion inhibition rate is obtained. Both compounds were tested for corrosion inhibition at the same experimental conditions as the other imidazole compounds herein. The calculated results and experimental results are shown in Table 4. Table 4 Experimental values ​​and calculated values ​​of the corrosion inhibition rates of the two compounds. Inhibition rate/calculated experimental value Note: The deviation values ​​are shown in parentheses.

From the data in the table, the results of several relational predictions are in good agreement with the experimental results.

5 Conclusions The corrosion inhibition rate of imidazole and its derivatives in copper has a good correlation with its frontier molecular orbital energy level. The chemical adsorption of imidazole compounds on copper surfaces is the result of both coordination and feedback bonds. .

The net charge on the metal has a certain correlation, and the correlation with the sum of the net charges on the entire imidazole ring is better.

The inhibition of copper by the imidazole compound is a result of the "collective" action of the atoms on the imidazole ring, and the molecules of imidazole and its derivatives are adsorbed on the copper surface in a supine manner.

The correlation between the inhibition properties of the imidazole compounds and the respective quantum chemical parameters can be used to predict the corrosion inhibition properties of other imidazole compounds.