Browsing by Author "Gajardo-Parra, Nicolas F."

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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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    Hydrogen bond donor and alcohol chain length effect on the physicochemical properties of choline chloride based deep eutectic solvents mixed with alcohols
    (2022) Cotroneo-Figueroa, Vincenzo P.; Gajardo-Parra, Nicolas F.; Lopez-Porfiri, Pablo; Leiva, Angel; Gonzalez-Miquel, Maria; Garrido, Jose Matias; Canales, Roberto, I
    Deep eutectic solvents are mixtures typically composed by a hydrogen bond donor and a hydrogen bond acceptor. They have appeared as an alternative of ionic liquids in several processes due to their tunability, biodegradability and low cost. Recently, deep eutectic solvents have been studied as potential solvents for different applications. Then, their physicochemical properties need to be characterized for understanding the interaction between its constituents and with other compounds. Deep eutectic solvents prepared for this work are based on choline chloride mixed with ethylene glycol, 1,3-propanediol or 1,4-butanediol at a 1:3 mol ratio. FT-IR spectra was obtained for comparing the different structures of those deep eutectic solvents. Density and viscosity of the prepared deep eutectic solvents were measured from 293.15 K to 333.15 K at 101.13 kPa. Also, the same properties at the same temperature and pressure conditions were obtained for the mixtures of the three deep eutectic solvents with four alcohols: methanol, ethanol, 1-propanol or 1-butanol. Physicochemical (i.e density and excess volume) and transport properties (i.e viscosity) were measured and predicted using PC-SAFT and Free Volume Theory, respectively, for understanding the effect of the temperature variation, the length of the alcohol chain, and length of the hydrogen bond donor on the configurational aspects of the mixture. Subsequently, a prediction of the excess molar enthalpy was performed with COSMO-RS in order to assess the behavior of the same variables on different type of intermolecular interactions from the energetic point of view. The results suggest that mixing each deep eutectic solvent with an alcohol produce negative molar excess volumes and molar excess enthalpies, observing a higher affinity between unlike species. (C) 2021 Elsevier B.V. All rights reserved.
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    Impact of deep eutectic solvents and their constituents on the aqueous solubility of phloroglucinol dihydrate
    (2021) Gajardo-Parra, Nicolas F.; Do, Hoang T.; Yang, Mengyi; Perez Correa, Jose Ricardo; Garrido, Jose Matias; Sadowski, Gabriele; Held, Christoph; Canales, Roberto, I
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    Improving the separation of guaiacol from n-hexane by adding choline chloride to glycol extracting agents
    (2022) Arroyo-Avirama, Andres F.; Ormazabal-Latorre, Sebastian; Jogi, Ramakrishna; Gajardo-Parra, Nicolas F.; Pazo-Carballo, Cesar; Ascani, Moreno; Virtanen, Pasi; Matias Garrido, Jose; Held, Christoph; Maki-Arvela, Paivi; Canales, Roberto, I
    Bio-oil is an important candidate to replace oil-derived products since it origins from renewable sources such as biomass. However, oxygenated bio-oil-based compounds require upgrading and further separation and purification for obtaining valuable compounds. Guaiacol is an important lignin derivative obtained from bio-oil, and it is a precursor for obtaining high-value-added molecules through heterogeneous catalysis. Alkanes are typical solvents for the guaiacol catalytical upgrading, so it is important to understand the extraction of guaiacol or guaiacol-like molecules from alkanes systems. This work reports the potential applicability of glycols and their corresponding eutectic mixtures with choline chloride as liquid-liquid extracting agents of guaiacol from n-hexane. The liquid-liquid equilibrium of six ternary systems composed of guaiacol +n-hexane + glycol or eutectic mixture is reported at 313.15 K and 101.3 kPa. Glycols selected as hydrogen bond donors were ethylene glycol, 1,2-propanediol, and 1,4butanediol, while choline chloride was chosen as the hydrogen bond acceptor for preparing three eutectic mixtures using the glycols mentioned earlier. Density and viscosity of pure components and binary mixtures composed of guaiacol + glycols or guaiacol + eutectic mixture were measured at temperatures between 293.15 K and 333.15 K at 101.13 kPa. Density and liquid-liquid equilibrium data were modeled with PC-SAFT, and binary parameters were only used between the studied glycols and guaiacol. The results showed that the constituents of the eutectic mixtures did not distribute in the n-hexane phase, which was validated by NMR and GC. The viscosity of the pure components was correlated using PCSAFT + Free Volume Theory, which allowed predicting the viscosity of mixtures by using binary parameters that were fitted to viscosity-independent data. The results obtained show that there is a high affinity between the guaiacol and the eutectic mixtures, based on observations about the negative excess volumes and the liquid-liquid equilibria. The eutectic mixtures are better for extracting guaiacol than their respective glycol-based constituents since they have higher selectivity and distribution coefficients and are larger miscibility gaps with the n-hexane phase compared to the studied glycols.(c) 2022 Elsevier B.V. All rights reserved.
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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.