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Theoretical studies of some sulphonamides as corrosion inhibitors for mild steel in acidic medium   
Yazarlar
Eno E Ebenso
Taner Arslan
Prof. Dr. Fatma KANDEMİRLİ
Kastamonu Üniversitesi, Türkiye
Ian Love
Öğretır Cemi̇L
Saracoğlu Murat
Umoren Savıour A
Özet
Density functional theory (DFT) at the B3LYP/6-31G (d,p) and BP86/ CEP-31G* basis set levels and ab initio calculations using the RHF/6-31G (d,p) methods were performed on four sulfonamides (namely sulfaacetamide (SAM), sulfapyridine (SPY), sulfamerazine (SMR), and sulfathiazole (STI)) used as corrosion inhibitors for mild steel in acidic medium to determine the relationship between molecular structure and their inhibition efficiencies (%IE). The order of inhibition efficiency obtained was SMR > SPY > STI > SAM which corresponded with the order of most of the calculated quantum chemical parameters namely EHOMO (highest occupied molecular orbital energy), ELUMO (lowest unoccupied molecular orbital energy), the energy gap (δE), the Mulliken chargeson the C, O, N, S atoms, hardness (η), softness (S), polarizability (α), dipole moment (μ), total energy change (δET), electrophilicity (ω), electron affinity (A), ionization potential (I), the absolute electronegativity (X), and the fraction of electrons transferred (δN). Quantitative structure activity relationship (QSAR) approach has been used and a correlation of the composite index of some of the quantum chemical parameters was performed to characterize the inhibition performance of the sulfonamides studied. The results showed that the %IE of the sulfonamides was closely related to some of the quantum chemical parameters but with varying degrees/order. The calculated %IE of the sulfonamides studied was found to be close to their experimental corrosion inhibition efficiencies. The experimental data obtained fits the Langmuir adsorption isotherm. The negative sign of the EHOMO values and other thermodynamic parameters obtained indicates that the data obtained supports physical adsorption mechanism. © 2009 Wiley Periodicals, Inc.
Anahtar Kelimeler
Ab initio calculation | Corrosion inhibitor | Density functional theory | Sulfonamides
Makale Türü Özgün Makale
Makale Alt Türü SSCI, AHCI, SCI, SCI-Exp dergilerinde yayımlanan tam makale
Dergi Adı International Journal of Quantum Chemistry
Dergi ISSN 0020-7608
Dergi Tarandığı Indeksler SCI-Expanded
Makale Dili İngilizce
Basım Tarihi 11-2010
Cilt No 110
Sayı 14
Sayfalar 2614 / 2636
Doi Numarası 10.1002/qua.22430
Makale Linki http://doi.wiley.com/10.1002/qua.22430