Chromeno-carbonitriles as corrosion inhibitors for mild steel in acidic solution: electrochemical, surface and computational studies

Three novel N -hydrospiro-chromeno-carbonitriles namely, 2-amino-7,7-dimethyl-1′,3′,5-trioxo-1′,3′,5,6,7,8-hexahydrospiro[chromene-4,2′-indene]-3-carbonitrile (INH-1), 3-amino-7,7-dimethyl-2′,5-dioxo-5,6,7,8-tetrahydrospiro[chromene-4,3′-indoline]-2-carbonitrile (INH-2) and 3′-amino-7′,7′-dimethyl-2...

Full description

Saved in:
Bibliographic Details
Published in:RSC advances 2021-01, Vol.11 (4), p.2462-2475
Main Authors: Quadri, Taiwo W, Olasunkanmi, Lukman O, Akpan, Ekemini D, Alfantazi, Akram, Obot, I. B, Verma, Chandrabhan, Al-Mohaimeed, Amal M, Ebenso, Eno E, Quraishi, M. A
Format: Article
Language:English
Subjects:
Charge transfer
Chemistry
Corrosion
Corrosion inhibitors
Corrosion mechanisms
Corrosion tests
Indene
Low carbon steels
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Three novel N -hydrospiro-chromeno-carbonitriles namely, 2-amino-7,7-dimethyl-1′,3′,5-trioxo-1′,3′,5,6,7,8-hexahydrospiro[chromene-4,2′-indene]-3-carbonitrile (INH-1), 3-amino-7,7-dimethyl-2′,5-dioxo-5,6,7,8-tetrahydrospiro[chromene-4,3′-indoline]-2-carbonitrile (INH-2) and 3′-amino-7′,7′-dimethyl-2,5′-dioxo-5′,6′,7′,8′-tetrahydro-2 H -spiro[acenaphthylene-1,4′-chromene]-2′-carbonitrile (INH-3) were synthesized using the principles of green chemistry and applied as corrosion inhibitors for mild steel in acidic medium using computational simulations and experimental methods. Experimental and computational studies revealed that inhibition effectiveness of the INHs followed the sequence: INH-3 (95.32%) > INH-2 (93.02%) > INH-1 (89.16%). The investigated compounds exhibit mixed-type corrosion inhibition characteristics by blocking the active sites on the surface of mild steel. EIS study revealed that the INHs behave as interface-type corrosion inhibitors. EDX analyses supported the adsorption mechanism of corrosion inhibition. A DFT study carried out for gaseous and aqueous forms of inhibitor molecules indicated that interactions of INHs with the mild steel surface involve charge transfer phenomenon or donor-acceptor interactions. A Monte Carlo (MC) simulation study revealed that only a fractional segment of the molecule lies parallel to the steel surface, since the INH molecules are not completely planar. The results of computational studies and experimental analyses were in good agreement. Three novel N -hydrospiro-chromeno-carbonitriles, INH-1, INH-2 and INH-3 were synthesized using the principles of green chemistry and applied as corrosion inhibitors for mild steel in acidic medium using computational simulations and experimental methods.
ISSN:2046-2069
2046-2069
DOI:10.1039/d0ra07595g