Organic synthesis and inhibition action of novel hydrazide derivative for mild steel corrosion in acid solutions

By Abdallah, Zeinab A.; Ahmed, Mohamed S. Mohamed; Saleh, M. M.
Published in Materials Chemistry and Physics NULL 2016

Abstract

Abstract A new derivative of hydrazide family, 2-(2-hydrazinyl-1,6-dihydro-6-oxopyrimidin-4-yl) acetohydrazide (HDOP) is synthesized and used as a corrosion inhibitor for mild steel both in 1 M {HCl} and 0.5 M H2SO4 solutions. A facial synthesis of a novel hydrazinyl hydrazide derivative is accomplished via a one-pot synthesis. Reaction of ethyl 2-(1,2,3,6-tetrahydro-6-oxo-2-thiopyrimidin-4-yl)acetate (1) with hydrazine hydrate in an ethanol refluxing produces the target hydrazinyl hydrazide derivative in a good yield. Different techniques such as IR, {NMR} and mass spectroscopy are used for characterization of the obtained products. The inhibition of mild steel corrosion using {HDOP} in different concentrations is studied by electrochemical impedance spectroscopy and polarization measurements. The inhibition efficiency (IE) of {HDOP} is found to be higher in {HCl} than that in {H2SO4} solution. This is attributed to the stronger adsorption of Cl? on the iron surface which enables better synergism between Cl? and the protonated inhibitor. The {HDOP} acts mainly as a cathodic inhibitor (in both acid solutions) and an inhibition efficiency of ?89% was obtained in the {HCl} solution. The free energy of adsorption obtained by applying Langmuir adsorption isotherm predicts physisorption of {HDOP} on the iron surface in the {HCl} solution.

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