5-Arylpyrimido-[4,5-b]quinoline-diones as new and sustainable corrosion inhibitors for mild steel in 1 M HCl: a combined experimental and theoretical approach
By Verma, Chandrabhan and Olasunkanmi, L. O. and Obot, I. B. and Ebenso, Eno E. and Quraishi, M. A.
Published in RSC Adv.
The Royal Society of Chemistry
2016
Abstract
The inhibition of mild steel corrosion in 1 M HCl by four 5-arylpyrimido-[4,5-b]quinoline-diones (APQDs), namely 5-(4-nitrophenyl)-5,10-dihydropyrimido [4,5-b]quinoline-2,4(1H,3H)-dione (APQD-1), 5-phenyl-5,10-dihydropyrimido[4,5-b]quinoline-2,4(1H,3H)-dione (APQD-2), 5-(4-hydroxyphenyl)-5,10-dihydropyrimido[4,5-b]quinoline-2,4(1H,3H)-dione (APQD-3) and 5-(2,4-dihydroxyphenyl)-5,10-dihydropyrimido[4,5-b]quinoline-2,4(1H,3H)-dione (APQD-4) has been investigated using weight loss, electrochemical, surface, and quantum chemical calculations and molecular dynamics simulation methods. The results showed that the inhibition efficiency ([small eta]%) increased with increasing concentration of the inhibitors. Among the studied compounds, APQD-4 exhibited the highest inhibition efficiency of 98.30% at 20 mg l-1 concentration. The studied compounds effectively retarded the corrosion of mild steel in 1 M HCl by adsorbing onto the steel surface, and the adsorption data conformed to the Langmuir adsorption isotherm. The results of potentiodynamic polarization measurements revealed that the studied compounds are cathodic-type inhibitors. Scanning electron microscopy (SEM) study confirmed the formation of adsorbed films of the inhibitor molecules on the steel surface. Quantum chemical calculations and molecular dynamics simulations were undertaken to corroborate experimental findings and provide adequate insight into the corrosion inhibition mechanisms and adsorption characteristics of the studied compounds.
Microsoft is Ending Support for Windows 7
Microsoft will discontinue support for Windows 7 on January 14, 2020 which means Gamry will also be discontinuing support for Windows 7. If you are upgrading to Windows 10, like many companies and institutions, you need to be running Version 7 of our s oftware . Please note that only USB and Ethernet-based instruments can run in Version 7. Eligible users can download the latest version of our software through our online Client Portal .
If you haven't already registered your instrument, you can do so through the Client Portal .
Please email Technical Support if you have any questions regarding this transition. Please be sure to include your instrument model and serial number when contacting us.