Background: A density functional theory (DFT) study of some selected eco-friendly
chitosan derivatives was performed, recently used as corrosion inhibitors for steel in 0.1M and 0.5M
HCl. Correlation between observed and predicted inhibition efficiencies is based on QSAR by some
Methods: We extracted the optimum molecular descriptors for the chitosan derivatives group under
study and it was found that these descriptors have a proper effect on increasing the inhibition
efficiency that was proved by applying the theoretical calculations (non-linear regression) on two
models of chitosan derivatives (ChI and ChII). The quantum chemical descriptors most relevant to
the corrosion inhibitors potential effect have been calculated in the aqueous phase. They include:
EHOMO, ELUMO, dipole moment (D), molecular area (MA), molecular volume (MV), the charge on
common oxygen (O Charge), the charge on common nitrogen (N Charge), nuclear repulsion energy
(NRE), final single point energy (E) and total positive charge (TPC).
Results: The optimum parameters resulted using multiple linear regression are EHOMO, CCO, CCN,
and D. Using these optimum parameters, the models designed show good results in their inhibition
effect on steel at the same environment of the chitosan derivatives group under study.
Conclusion: Experimental explanation showed good results from modelling prediction, where the
corrosion rate decreases markedly with increasing the concentration of the designed inhibitors till
the optimum concentration where the rate becomes constant. SEM on the optimum inhibitor
concentration proved the high inhibition efficiency obtained.