LAUSR

CMPPC, 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde was synthesised from 3-methyl-1-phenyl-5-pyrazolone, and its corrosion protection properties for mild steel in HCl were studied using mass loss studies, impedance spectroscopy, polarisation studies, adsorption studies and basic quantum chemical calculations. The protection efficiency decreases with an increase in temperature and acid concentration but increases with an increase in the concentration of the inhibitor. Electroanalytical screening reveals that the molecule behaves like a mixed-type inhibitor. CMPPC adsorbs on the metal surface, and the phenomenon obeys Langmuir adsorption isotherm pattern. Various kinetic and thermodynamic parameters are calculated using Arrhenius and Van’t Hoff approaches. Molecular dynamics simulations are employed using computational chemistry protocols. The results indicate that the CMPPC offers maximum interaction on Fe(111) plane of the metal surface.