Mycophenolic acid as a corrosion inhibitor of carbon steel in 3% wt. NaCl solution. An experimental and theoretical study
Por:
Rodríguez-Gómez F.J., Valdelamar M.P., Vazquez A.E., Del Valle Perez P., Mata R., Miralrio A., Castro M.
Publicada:
5 may 2019
Resumen:
Mycophenolic acid (IUPAC name:
(E)-6-(4-hydroxy-6-methoxy-7-methyl-3-oxo-1H-2-benzofuran-5-yl)-4-methyl
hex-4-enoic acid) is extracted from the fungus Penicillium
brevicompactum. In this work, corrosion inhibition under static
conditions and turbulent flow was tested in a 3% wt. NaCl solution by
means of two techniques: electrochemical impedance spectroscopy (EIS)
and polarization curves. The efficiency results showed that low
concentrations of mycophenolic acid are effective in static conditions,
staying practically constant when the concentration of the compound is
increased, with eta = 90%. The adsorption process is chemisorption at 0
rpm, while for 100 and 1000 rpm, it is a combined process. SEMEDS
confirmed the decrease of the corrosion products in the presence of
mycophenolic acid. These results revealed that mycophenolic acid is a
good corrosion inhibitor when applied to carbon steel. To obtain insight
into this behavior, the interaction between mycophenolic acid (MA) and a
steel surface, modeled by a cluster of iron atoms (Fe-6), was studied
using density functional theory calculations. The calculated
MA-Fe-6-cluster binding free energy agrees with the experimental results
and falls in the chemisorption regime. Using the reactivity Fukui
indices, we demonstrated that the metal surface is completely passivated
by the inhibitor, which is less reactive to different kind of attacks.
After adsorption of the inhibitor molecule, the properties of the iron
cluster remained almost unaltered, except for a small amount of charge
transferred from the inhibitor to the metal cluster. Global and local
parameters were successfully compared to calculated ones for other
organic inhibitors obtained from natural sources. (C) 2018 Published by
Elsevier B.V.
Filiaciones:
Rodríguez-Gómez F.J.:
Departamento de Ingeniería Metalúrgica, DEPg. Facultad de Química, UNAM, Del. Coyoacán, México D.F., 04510, Mexico
Valdelamar M.P.:
Departamento de Ingeniería Metalúrgica, DEPg. Facultad de Química, UNAM, Del. Coyoacán, México D.F., 04510, Mexico
Vazquez A.E.:
Departamento de Ingeniería Metalúrgica, DEPg. Facultad de Química, UNAM, Del. Coyoacán, México D.F., 04510, Mexico
Del Valle Perez P.:
Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Mexico City, 04510, Mexico
Mata R.:
Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Mexico City, 04510, Mexico
Miralrio A.:
Departamento de Física y Química Teórica, DEPg. Facultad de Química, UNAM, Del. Coyoacán, México City, 04510, Mexico
Castro M.:
Departamento de Física y Química Teórica, DEPg. Facultad de Química, UNAM, Del. Coyoacán, México City, 04510, Mexico
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