Synthesis and evaluation of newly E-octadec-9-enoic acid derivatives as sustainable corrosion inhibitors for mild steel in 1.0 M HCl

Abstract

Several new amide derivatives having varied aromatic characteristics prepared efficiently via nucleophilic acyl substitution reactions are tested for corrosion inhibition of mild steel in 1 M HCl at 20, 40, and 60 °C range by gravimetric methods. All compounds have shown very good inhibition efficiency (IE%) in acidic solutions. Increasing the temperature (in the presence of the inhibitor in the higher concentration (100–1000 μM) are found to increase the inhibition efficiency of the amide’s derivatives. Results from gravimetric measurements further revealed that Inh. 4 shows excellently at 60 °C giving IE% of 91.88 at 1000 μM. Thermodynamic parameters (ΔG^º_ads, ΔH^º_ads, and ΔS ^º_ads) for the adsorption process and kinetic parameters for the metal dissolution (or hydrogen evolution) reaction in the presence of the new derivatives were determined. Experimental results agree with the Temkin adsorption isotherm. The inhibition of corrosion in 1 M HCl, influenced by both physi- and chemisorption, was found to be under mixed control but predominantly under cathodic control as revealed by the potentiodynamic polarization measurements for Inh. 4. Frontier molecular orbital calculations predicted that the newly synthesized inhibitors with aromatic characteristics serve as donor-centers to the empty d-orbital of the metal atoms and would exhibit higher corrosion IE%.

Keywords:

• Acidic media
• corrosion inhibition
• E-octadec-9-enoic acid amides
• frontier molecular orbital
• mild steel

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

All data will be available upon request to corresponding author.

Additional information

Funding

The author gratefully acknowledged the financial support provided by Imam Abdulrahman Bin Faisal University through project number 2019-340-Sci. The author acknowledges the support received from Basic and Applied Scientific Research Center, Imam Abdulrahman Bin Faisal University, Saudi Arabia.