Corrosion inhibition properties of two imidazolium ionic liquids with hydrophilic tetrafluoroborate and hydrophobic hexafluorophosphate anions in acid medium

The ionic liquids, 1-viny1-3-aminopropylimidazolium hexafluorophosphate ([VAIM][PF6]) and 1-vinyl-3-aminopropylimidazolium tetrafluoroborate ([VAIM][BF4]) acted as the corrosion inhibitors. Weight loss measurements showed the corrosion inhibition efficiencies of [VAIM][PF6] and [VAIM][BF4] were 90.53% and 54.01% at 45 degrees C, respectively. The ILs were mix-type inhibitors. Raising the temperature can have a decreased inhibition efficiency of [VAIM][BF4], while [VAIM][PF6] presented an opposite trend. In addition, [VAIM][PF6] obeyed Langmuir monolayer adsorption isotherm, while [VAIM][BF4] obeyed El-Awady kinetic-thermodynamic adsorption for blocking active sites. Moreover, Molecular Dynamic Simulations showed that [VAIM][PF6] owned a higher adsorption energy, which may be responsible for the more adsorption groups of [VAIM][PF6]. (C) 2017 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.