Browsing by Author "Canales, Roberto I."

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    Assessing Thermodynamics Models for Phase Equilibria and Interfacial Properties Relevant to the Hydrogenation of Carbon Dioxide
    (American Chemical Society, 2024) Cea-Klapp, Esteban; González-Barramuño, Bastián; Gajardo-Parra, Nicolás F.; Karelovic, Alejandro; Quinteros-Lama, Héctor; Canales, Roberto I.; Garrido, José Matías
    © 2024 American Chemical Society.The catalytic hydrogenation of carbon dioxide has become a novel technology of economic and environmental interest that allows the production of value-added products as energy alternatives to the current demand. As product distributions are highly dependent on process conditions such as reaction temperature, pressure, and H2/CO2 ratio, it is necessary to have reliable thermodynamic models that can characterize mixtures of reactants with products over a wide range of conditions. In this contribution, the accuracy of two hydrogen models applied through equations of state (EOS) framed within variations of the statistical associating fluid theory (SAFT) is compared. These models include perturbed-chain SAFT (PC-SAFT) EOS and SAFT of variable range and Mie potential (SAFT-VR Mie) EOS. This is accomplished by the depiction of the thermodynamic behavior of mixtures of hydrogen in the context of the hydrogenation of carbon dioxide, estimating the thermodynamic behavior of the relevant mixtures. In all of the cases, zero values for the binary adjustable parameters have been implemented, and both models of hydrogen were fitted from a hydrogen+decane mixture. Available experimental data of high-pressure phase equilibria, critical loci, and interfacial tensions is used to determine the accuracy of the hydrogen models by contrasting their respective predictive capabilities, determining that the overall performance of the one applied in the SAFT-VR Mie EOS is inferior compared to the PC-SAFT one. The average absolute deviations between model calculations and experimental data for vapor-liquid equilibrium are 35.8 % (pressure), 3.10 % (liquid composition), and 2.60 % (vapor composition) for PC-SAFT, and 26.3, 3.27, and 2.65% for SAFT-VR Mie, respectively.
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    Comparison of the electrochemical decarbonation of different-grade limestones used in cement manufacturing
    (2023) Ramirez-Amaya, Dario; Dreyse, Paulina; Martinez, Natalia P.; Troncoso, Felipe; Navarrete, Ivan; Noel, Martin; Canales, Roberto I.; Gonzalez, Marcelo
    Electrochemical decarbonation (ED) of CaCO3 is a promising method to reduce CO2 emissions from limestone calcination for cement manufacturing. Most cement plants are located near accessible deposits of limestone; therefore, the feasibility of ED deployment depends on the efficiency of natural limestone decarbonation, which has variable CaCO3 content. Accordingly, this research compares the ED efficiency of different limestones (CaCO3 content between 84 % and 68 %) and the chemical and physical characteristics of precipitate materials (PM) obtained from this process. The obtained PMs were comprised mainly of Ca(OH)(2) (similar to 59 %) and had similar particle size distributions. At the same time, the efficiency of Ca(OH)(2) precipitation, energy consumption, and CaO recovery were comparable to the ED of a pure CaCO3 reagent (>99 %). The PMs were found to have higher CaO content and lower loss on ignition than the feedstock material, independent of the type of limestone, facilitating the future ED implementation in cement manufacturing.
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    COSMO-RS-based solvent screening and experimental analysis for recovering added-value chemicals from the bio-oil aqueous phase
    (ELSEVIER, 2025) Lorenzo Llanes, Junior; Palomar, Jose; Escalona, Nestor; Canales, Roberto I.
    Bio-oil's aqueous phase (BAP) has received particular interest for recovering value-added chemicals. To this end, liquid-liquid extraction (LLE) has proven its suitability for bio-oil fractionation and product recovery. The present work aimed to assess greener solvents (e.g., bio-based and terpene-based) for recovering acetic acid and acetol as model compounds of the BAP via physical and reactive LLE. A solvent screening (>2000 compounds) based on the distribution coefficient (K-d) of each solute in the solvent/water biphasic system estimated by COSMO-RS was used. Then, the solvents' environmental, safety, and human health impacts were assessed. The selected candidates were used to validate the COSMO-RS predictions through LLE measurements. In the reactive LLE, the selected extracting solvents were mixed with trioctylamine (TOA) or tributyl phosphate (TBP) used as the reactive extractants. Finally, the temperature and extractant fraction effects were assessed in terms of the K-d for the best diluent + extractant pairs. For acetic acid, 2-methyltetrahydrofuran (K-d = 1.8) outperformed the rest of the solvents during the physical extraction, whereas for acetol, 2-methyl-2-butanol (K-d = 0.44) was the solvent with the best performance. Moreover, attractive K-d values were obtained for acetic acid (K-d = 0.91) and acetol (K-d = 0.37) using 2-phenylethanol. In the reactive LLE, TOA-based extractants improved the acetic acid K-d up to 10 times compared to the physical extraction, with no improvement on acetol. For TBP-based extractants, no clear improvements were observed. Acetic acid selectivity was maximized at 293 K, and a TOA mass fraction between 40 and 50 % for all the diluents.
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    (-)-Epicatechin Solubility in Aqueous Mixtures of Eutectic Solvents and Their Constituents
    (2024) Bastias-Barra, Arturo I.; Gajardo-Parra, Nicolas F.; Cea-Klapp, Esteban; Arroyo-Avirama, Andres F.; Garrido, Jose Matias; Held, Christoph; Perez-Correa, Jose R.; Canales, Roberto I.
    (-)-Epicatechin is a polyphenol present in diverse natural sources. It shows positive human health effects, which makes it interesting for the pharmaceutical and food industries. Conventional solvents used for polyphenol extraction are mostly toxic and flammable, leaving unwanted impurities in the final product. Thus, solubility of (-)-epicatechin at 101.3 kPa and 293.15, 303.15, and 313.15 K was experimentally measured in water and binary systems composed of 25 wt % of water + 1,3-propanediol (13PD), glycerol (Gly), and two deep eutectic solvents based on choline chloride as hydrogen-bond acceptor and the previous polyols as hydrogen-bond donors (DES1 and DES2). Solubility results in water were obtained using spectrophotometric and gravimetric methodologies. Overall, (-)-epicatechin solubility varies widely among the studied solvents but only slightly within the experimental temperature range. Solvents in ascending order according to (-)-epicatechin solubility are water < Gly + water < 13PD + water < DES2 + water < DES1 + water. The solubility of (-)-epicatechin is significantly enhanced by introducing choline chloride into the investigated hydrogen-bond donors (HBDs) at a molar ratio of 1:3, accompanied by 25 wt % water. Perturbed-chain statistical associating fluid theory (PC-SAFT) solubility calculations were in quantitative agreement with experimental data.
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    Influence of Hydrogen Bond Acceptors and Water Content on Surface Tension in Glycol-Based Eutectic Mixtures
    (2024) Aravena, Paulo; Cea-Klapp, Esteban; Gajardo-Parra, Nicolas F.; Olea, Andres F.; Carrasco, Hector; Matias Garrido, Jose; Canales, Roberto I.
    One of the environmental concerns in the chemical industry is using organic solvents that are not environmentally friendly. Eutectic mixtures, also called deep eutectic solvents (DESs), have emerged as their substitutes due to favorable properties, including biodegradability, tunability, and low cost, among others. DESs show applications in extractions, biocatalysis, etc. To expand their uses, it is crucial to characterize their properties and understand their interactions with other solvents. In this study, the surface tension of DESs between 30 and 60 degrees C at 101.3 kPa was measured. The DESs were prepared using choline chloride or betaine as the hydrogen bond acceptor (HBA) and a glycol (ethylene glycol, 1,2-propanediol, 1,3-propanediol, or 1,4-butanediol) as the hydrogen bond donor (HBD) in different molar ratios. The surface tension of DESs + water mixtures was measured over the entire range of compositions. To assess the effect of temperature, HBD chain length, and water content, PC-SAFT coupled with the density gradient theory was used to model the surface tension. Furthermore, molecular dynamics simulations were conducted to gain a molecular understanding of the components at the interface. The molecular insights obtained from these simulations and the experimental data can help reduce the number of experiments when designing DESs for chemical processes.
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    Solubility of beta-carotene in ethanol- and triolein-modified CO2
    (ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 2011) Araus, Karina A.; Canales, Roberto I.; del Valle, Jose M.; de la Fuente, Juan C.
    Modification of an experimental device and methodology improved speed and reproducibility of measurement of solubility of beta-carotene in pure and modified SuperCritical (SC) CO2 at (313 to 333) K. Solubilities of beta-carotene in pure CO2 at (17 to 34) MPa ranged (0.17 to 1.06) mu mol/mol and agreed with values reported in literature. The solubility of beta-carotene in CO2 modified with (1.2 to 1.6) % mol ethanol increased by a factor of 1.7 to 3.0 as compared to its solubility in pure CO2 under equivalent conditions. The concentration of triolein in equilibrated ternary (CO2 + beta-carotene + triolein) mixtures having excess triolein reached values (0.01 to 0.39) mmol/mol corresponding to its solubility in pure SC CO2 under equivalent conditions. Under these conditions, the solubility of beta-carotene in triolein-modified CO2 increased by a factor of up to 4.0 in relation with its solubility in pure CO2 at comparable system temperature and pressure, reaching an uppermost value of 3.3 mu mol/mol at 333 K and 32 MPa. Unlike in the case of ethanol, where enhancements in solubility where relatively independent on system conditions, solubility enhancements using triolein as co-solvent increased markedly with system pressure, being larger than using (1.2 to 1.6)% mol ethanol at about (24 to 28) MPa, depending on system temperature. The increase in the solubility beta-carotene in SC CO2 as a result of using ethanol or triolein as co-solvent apparently does not depend on the increase in density associated with the dissolution of the co-solvent in CO2. Enhancements may be due to an increase in the polarizability of SC CO2, which possibly growths markedly as triolein dissolves in it when the system pressure becomes higher. (C) 2011 Elsevier Ltd. All rights reserved.