Experimental and theoretical investigation of 4-Methyl-2,3-dihydro-1H-1,5-benzodiazepin-2-one on the corrosion and inhibition behavior of steel in acidic solution

Abstract

The effect of 4-methyl-2,3-dihydro-1H-1,5-benzodiazepin-2-one ( MDBO ) on the inhibition of steel corrosion was studied in an acid medium. This inhibiting action against corrosion of steel in a corrosive solution was studied at 298 K using potentiodynamic polarization curves, weight loss measurements and electrochemical impedance spectroscopy (EIS) and complementary with density functional theory (DFT) methods. The inhibiting action increases with the concentration of ( MDBO ) compound to attain 89.53% at 10 -3 M. Polarization measurements also show that the 4-methyl-2,3-dihydro-1H-1,5-benzodiazepin-2-one ( MDBO ) acts essentially as a mixte type inhibitor. The cathodic curves indicate that the reduction of proton at the steel surface happens with an activating mechanism. ( MDBO ) adsorbs on the steel surface according to Langmuir adsorption model. Effect of temperature is also made in the 298–328 K range. Activation parameters are determined and discussed. For establish the correlation between experimental data and theoretical results, some quantum chemical parameters for the tested compound were evaluated for supply more idea on the mechanism of inhibition of the dissolution process.