Theobromine as an Aluminium Corrosion Inhibitor in 1M HCL: Experimental and QSPR Studies

The performance of Theobromine (TB) in aluminium corrosion inhibition has been tested. The corrosion inhibition efficiency and the effects of iodide ions were assessed, using mass loss method. The results show that the inhibition efficiency increases with increasing concentration in TB, but decreases with increasing temperature. Adsorption of TB onto the aluminium surface was approximated by the modified Langmuir adsorption isotherm. The thermodynamic adsorption and activation functions were determined. The presence of iodide ions in the environment of the metal led to an increase in inhibition efficiency for temperatures lower than 313 K, but a decrease in corrosion inhibition is remarked for temperatures higher than the mentioned temperature. DFT calculations based on B3LYP/6-31G (d) led to global and local parameters. Some selected sets of these descriptors were correlated with corrosion inhibition efficiency.