Examinando por Autor "Aguilar-Galindo, Fernando"

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Acidity reduction using ionic liquids: Extraction, kinetic, and theoretical study
(Elsevier, 2023-07-15) Arenas-Fernández, Plácido; Aguilar-Galindo, Fernando; Suárez, Inmaculada; Coto, Baudilio
Naphthenic acids (NAs) are toxic compounds naturally present in most petroleum sources with a highly variable concentration depending on their origin. Their occurrence in crude oil can produce severe corrosion problems and catalyst deactivation in oil refineries, consequently impacting their economic value and productivity. Thus, extracting and recovering the NA from crude oil is necessary. In this work, the extraction capacity of two ionic liquids (ILs) of different nature has been studied: 1-ethyl-3-methylimidazolium acetate, [EMIm][OAc], and trihexyltetradecylphosphonium dicyanamide, [P14,6,6,6][CCN2]. In addition, kinetic data were obtained for [P14,6,6,6][CCN2], and a theoretical kinetic model was developed to adjust the experimental data. Two extraction mechanisms have been analyzed using molecular dynamics computational simulations and quantum mechanical calculations. Molecular dynamic results show that a cluster of IL is first formed in each extraction process, and NA molecules are deposited on its surface. Different outcomes are obtained for diffusion coefficient values and radial distribution function. Furthermore, the quantum chemistry calculations show that a proton transfer is thermodynamically favorable in the case of [EMIm][OAc], thus extraction mechanism occurs through a neutralization reaction, whereas for [P14,6,6,6][CCN2], it is not, pointing to a physical extraction.
Influence of the carboxylate anion on the CO2 absorption mechanism using based-imidazolium ionic liquid
(Elsevier, 2025-01) Murillo-Criado; Aguilar-Galindo, Fernando; Serrano, Isabel; Gonzalez, Miguel A.; Tojo, Emilia; Suárez, Inmaculada; Coto, Baudillo; Tenorio, Maria Jose
The reduction of atmospheric carbon dioxide (CO₂) levels is contingent upon the implementation of strategies such as the curtailment of fossil fuel usage, the adoption of renewable energy sources, and the utilization of CO₂ capture and utilization technologies. Although direct air capture (DAC) presents a significant opportunity for global mitigation, industrial efforts have primarily concentrated on pre-combustion, oxyfuel, and post-combustion capture methods to enhance environmental sustainability. Nevertheless, the economic viability of CO₂ reuse remains a significant concern, and the development of innovative solutions is imperative. In this study, the influence of the carboxylate anion on CO2 absorption process using imidazolium-derived ionic liquids (ILs) is compared. 1-Butyl-3-methylimidazolium formate ([BMIm][HCOO]), 1-butyl-3-methylimidazolium acetate ([BMIm][OAc]), and 1-butyl-3-methylimidazolium propionate ([BMIm][C3H5OO]) have been analyzed. The efficacy of the capture process was assessed by quantifying the formation of an IL-CO₂ adduct using nuclear magnetic resonance (NMR) and attenuated total reflection infrared spectroscopy (ATR-IR). Furthermore, this work studies, using Density Functional Theory (DFT) and COSMO modelling, the difference in the spontaneity of the proton transfer from the cation [BMIm]+ to the carboxylate anions of the ionic liquids used in CO2 absorption process. Based on experimental and modelling data, [BMIm][OAc] was identified as the optimal IL candidate, presents a CO2 molar fraction absorbed at 30 °C and 1 bar of 0.203, compared to 0.083 for [BMIm][HCOO] and 0.190 for [BMIm][C3H5OO]. Moreover, theoretical simulations support these results with the calculation of the acid deprotonation equilibrium constants with the highest value being obtained for [BMIm][OAc]