Adsorption Properties and Inhibition of Carbon Steel Corrosion in Hydrochloric Acid Solution by Novel Diazepine Derivatives: Experimental and Theoretical Studies

Two benzodiazepine derivatives namely, 2,2,4,8-tetramethyl-2,3-dihydro-1hbenzo[ b][1,4]diazepine (thbd), 8-chloro-2,2,4-trimethyl-2,3-dihydro-1h-benzo[b][1,4] diazepine (cthbd) were examined as a corrosion inhibitor for carbon steel in 1.0 m hcl using electrochemical impedance spectroscopy (eis) and potentiodunamic polarization (pp). the results showed that both compounds are good inhibitors and their inhibition efficiencies increase with their concentrations to reache 92 % at 5×10^-3 m. the tafel polarization study revealed that both inhibitors act as a mixed type inhibitors. furthermore, it has been established that their adsorption follow the langmuir adsorption isotherm. in addition, the thermodynamic activation parameters for the corrosion reaction were calculated and discussed in relation to the stability of the protective layer. finally, quantum chemical parameters were calculated using the density functional theory method (dft) and monte carlo simulations. it is found that the correlation between theoretical and experimental results was discussed.