Theoretical Study of the Aliphatic-Chain Length’s Electronic Effect on the Corrosion Inhibition Activity of Methylimidazole-Based Ionic Liquids

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• 作者：Carolina Zuriaga-Monroy ; Raúl Oviedo-Roa ; Luisa E. Montiel-Sánchez ; Araceli Vega-Paz ; Jesús Marín-Cruz ; José-Manuel Martínez-Magadán
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2016
• 出版时间：March 30, 2016
• 年：2016
• 卷：55
• 期：12
• 页码：3506-3516
• 全文大小：689K
• ISSN：1520-5045

文摘

Density Functional Theory based studies about the inhibition of corrosion affecting the cathode hematite surface by coverage with an methylimidazole-based ionic liquid, IL, were performed. Inhibition performance is tuned through the length of aliphatic chains C_n attached to the imidazolium aromatic ring, where n = 1, ..., 20. Frontier molecular orbitals and energy gaps for single ILs and a pristine (11̅2) hematite surface, the energy difference between ILs and hematite-surface, Fukui indices for the ILs, and adsorption energies and charge transfers for ILs/hematite surface systems were calculated. Results show that adsorption activity is due to the donation/back-donation bonding among the imidazolium aromatic ring of the ILs and the exposed iron atoms of the hematite surface. Dispersive long-range interactions from the ILs alkyl tails allow a closer bonding of the corrosion inhibitor molecules to the hematite surface; the charge transfer between the IL and the hematite is in C₁₈. The optimal alkyl chain size is 18 and this is in full agreement with the reported experimental alkyl chain size that produces high inhibitory properties of related vinylimidazolium ILs.