Newly Synthesized Azo Derived from Coumarine as Analytical Reagent and Metallic Corrosion Inhibitor

Abstract A new Coumarine derivatives azo dye; 8-(3-phenyl-5-pyrazolylazo)-7-Hydroxy-4-Methyl Coumarine were synthesized. The effect of pH on the spectra of the synthesized ligand, the chromogenic reaction and the stability constant of Co+ 2, Cu+ 2, Ni+ 2, and Zn+ 2 ion complexes with the synthesized ligand were studied and determined conductmetrically and spectrophotometrically. The optimum pH was determined for the complexes. 1:1and 2:1(L:M) stoichiometric complexes has been formed in solutions. The order of the stability constants of the complexes under study was; Co+ 2 + 2< Cu+ 2. These metal ions were determined using the ligand as indicator. The ligand can be used as acid-base indicator. The ability of controlling corrosion of carbon steel in 1M of acidic solution of hydrochloric was electrochemically proven at room temperature. The inhibition indicated with different tests including Open circuit potential (OCP), Potentiodynamic Polarization (PP) and Electrochemical Impedance Spectroscopy (EIS) tests. The adsorption of inhibitor indicated from PP test followed Longmuir isotherm. Adsorption constant and Gibbs free energy were also calculated and explained.