INVESTIGATION OF INHIBITION EFFECT OF NIFEDIPINE ON API 5L X- 52 STEEL CORROSION IN HYDROCHLORIC ACID.
AbstractThis study is to establish a correlation between inhibition efficiency and some of the electronic properties of the molecular structure of Nifedipine drug as a corrosion inhibitor for API 5L X-52 steel in hydrochloric acid.This was evaluated using gravimetric and potentiodynamic polarization measurements at 303 K, 313 K 323 respectively with Quantum chemical calculation.From the range of vlues obtained for activation energy (16.31-45.94 kJ mol-1) and free energy of adsorption -61.48 to -41.20 kJ mol-1, a physical and chemical adsorption mechanism were propose for the adsorption of the inhibitor on the steel surface, in addition the adsorption reveal spontaneous reaction. The quantum chemical study results show that the prefer site for nucleophilic attack resides at O1, N13, O16, O17 and O18. Electrophilic attack was also expected to occur at C3, C11 and N14 and the results agreed with experimental results. Keywords Corrosion inhibition efficiency, theoretical, molecular structure, nifedipin, Electrochemical.