Adsorption and Corrosion Inhibition Characteristics of Some Thiophene-3-Carbohydrazide Derivatives on Low Carbon Steel in Hydrochloric Acid Solutions
Abd El-Aziz S. Fouda *
Department of Chemistry, Faculty of Science, Mansoura University, Mansoura-35516, Egypt
M. A. Diabb
Department of Chemistry, Faculty of Science, University of Damietta, Damietta 34517, Egypt
Doaa A. Badawya
Department of Chemistry, Faculty of Science, Mansoura University, Mansoura-35516, Egypt
*Author to whom correspondence should be addressed.
Abstract
New compounds namely amino-N'-(3-(hydroxyimino)butan-2-ylidene)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbohydrazide (1), amino-N'-(thiophen-2-ylmethylene)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbohydrazide (2) and amino-N'-(1-(pyridin-2-yl)ethylidene)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbohydrazide (3) were synthesized and used as corrosion inhibitors for carbon steel in 1 M hydrochloric acid at 25°C using different monitoring techniques. Potentiodynamic polarization studies showed that these derivatives were mixed type inhibitors. The effect of temperature on the corrosion behavior of carbon steel in 1 M HCl in presence and absence of these compounds at were studied. The adsorption of these inhibitors on carbon steel surface from hydrochloric acid obeyed the Langmuir adsorption isotherm. Quantum chemical method is used to explore the relationship between the inhibitors molecular properties and their inhibition efficiency.
Keywords: Corrosion inhibition, C- steel, HCl, thiophene 3-carbohydrazide derivatives EFM, EIS