INHIBITION EFFICIENCY IN PETROLEUM ENVIRONMENT BY DIPHENYLAMINE | Journal of Applied Chemical .....

The inhibitory properties of diphenylamine (DPA) on steel (A515) in sour medium were investigated using a Potentiostat/Galvanostat instrument at (75oC) with four concentrations: 1x10-5, 1x10-4, 1x10-3, and 1x10-2 M. The inhibited surfaces were identified using FTIR spectra. These approaches are reasonably consistent and show that DPA is an effective inhibitor, with protection efficiencies ranging from 65.24 to 85.81 percent for experimental doses. Thermodynamics of adsorption demonstrated a negative change in free energy, indicating a spontaneous adsorption process. The exothermic process and decrease in disorder of inhibition with DPA are confirmed by negative values of change in enthalpy and entropy.

Diphenylamine is a mixed type inhibitor that affects both Tafel slopes and follows the Langmuir adsorption isotherm. According to calculations, 1x10-2 M provided the best protection efficiency of 85.81 percent.

Please see the link :- https://www.ikprress.org/index.php/JACSI/article/view/2897