Designing Novel Quinoline Derivative as Corrosion Inhibitorfor Aluminium in Hydrochloric Acid Solutions

In this research, novel quinoline derivative as aluminium corrosion inhibitor was designed by utilizing twenty three (23) molecules of quinoline derivatives tested each as corrosion inhibitors for the aluminium in HCl solution; experimentally through weight loss method, and theoretical investigations using quantitative structure activity relationship (QSAR). The inhibition efficiencies of the quinoline derrivatives obtained from the weight lossshows that some quinoline derivatives such as 5-MeQ, 5-ClQ, 8-TMeQ, 6-ACQ and 7-OHQ inhibits the corrosion better than others as indicated by percentage inhibition efficiency (IE). Quantum chemical calculation indicated that the most popular parameters which play a prominent role are the eigenvalues of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), the HOMO-LUMO gap (ΔE), chemical hardness and softness and the number of electrons transferred from inhibitor molecule to the metal surface. Base on the several physicochemical descriptors and investigation of the adsorption of these molecules on the aluminium surface by the QSAR study of twenty three quiniline derivatives with the aid of material studio, a model was developed and validated. On the basis of the physicochemical parameters, predicted inhibition efficiency of 97.7% obtained using experimental inhibition efficiencies at 303K in 0.4MHCl and 0.2g/mol inhibitor concentration, and the correlation matrix from the QSAR study; 5-chloro,7-hydroxy-quinoline (5-Cl,7-OH-C9H5N) was designed and accepted as new efficient and effective quinoline derivative inhibitor for aluminium corrosion in HCl acid solution.