Browsing by Author "Cea-Klapp, Esteban"
Now showing 1 - 6 of 6
Results Per Page
Sort Options
- ItemAssessing the Effect of Deep Eutectic Solvents on α-Chymotrypsin Thermal Stability and Activity(2024) Gajardo-Parra, Nicolás F.; Cea-Klapp, Esteban; Chandra, Anshu; Canales Muñoz, Roberto; Garrido, José Matías; Held, Christoph; Guajardo Ramírez, Nadia VerónicaOptimizing the liquid reaction phase holds significant potential for enhancing the efficiency of biocatalytic processes since it determines reaction equilibrium and kinetics. This study investigates the influence of the addition of deep eutectic solvents on the stability and activity of α-chymotrypsin, a proteolytic enzyme with industrial relevance. Deep eutectic solvents, composed of choline chloride or betaine mixed with glycerol or sorbitol, were added in the reaction phase at various concentrations. Experimental techniques, including kinetic and fluorometry, were employed to assess the α-chymotrypsin activity, thermal stability, and unfolding reversibility. Atomistic molecular dynamics simulations were also conducted to assess the interactions and provide molecular-level insights between α-chymotrypsin and the solvent. The results showed that among all studied mixtures, adding choline chloride + sorbitol improved thermal stability up to 18 °C and reaction kinetic efficiency up to two-fold upon adding choline chloride + glycerol. Notably, the choline chloride + sorbitol system exhibited the most substantial stabilization effect, attributed to the surface preferential accumulation of sorbitol, as corroborated by the computational analyses. This work highlights the potential of tailoring liquid reaction phase of α-chymotrypsin catalyzed reaction using neoteric solvents such as deep eutectic solvents to enhance α-chymotrypsin performance and stability in industrial applications.
- ItemAssessing 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.
- Item(-)-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.
- ItemInfluence 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.
- ItemInterfacial properties of fluorinated (F)-gases in azeotropic condition(2022) Gonzalez-Barramuno, Bastian; Cea-Klapp, Esteban; Polishuk, Ilya; Canales, Roberto, I; Quinteros-Lama, Hector; Matias Garrido, JoseThe interfacial behavior in refrigerant mixtures has a major impact on heat transfer coefficients during the vaporization and condensation stages. Therefore it is appropriate to have robust models to predict their properties. In this work, molecular dynamic simulations together with density gradient theory combined with the statistical associating fluid theory of variable range employing a Mie potential (SAFT-VRMie) have been employed to model and understand the interfacial behavior in systems of azeotropic refrigerant mixtures of fluorinated gases (R32, R125, R134a, R143a, and R152a) blended with propane (R290). It is demonstrated that despite the high-non ideal behavior in these mixtures, both approaches are capable of reproducing the minimum in surface tension (aneotropy) as a function of composition and temperature for the considered mixtures. It is concluded that the minimum occurs close but not equal to the azeotropic condition. Besides, it is also observed that the azeotropic condition acts as a switching point, in which R290 starts to accumulate at the interface positively. In contrast, in all mixtures, mixtures F-gases do not exhibit surface activity. Finally, the involving azeotropic condition was reduced, without loss of rigor, to a simpler problem that involves the VLE of a pseudo-pure component, in which molecular properties are characterized to be used in molecular simulations. (c) 2022 Elsevier B.V. All rights reserved.
- ItemUnveiling Molecular Features Controlling the Solubility of Hydrofluorocarbons in Fluorine-Based Eutectic Solvents(2025) González-Barramuño, Bastián; Cea-Klapp, Esteban; Gajardo Parra, Nicolás Felipe; Canales Muñoz, Roberto; Quinteros-Lama, Héctor; Garrido, José MatíasThis work investigates the solubility and solvation mechanisms of fluorinated refrigerant gases in fluorine-based deep eutectic solvents (FESs) using COSMO-RS and molecular dynamics simulations. Three FESs based on perfluoropentanoic acid (PFPA) as a hydrogen bond donor were evaluated to understand how ionic and molecular hydrogen-bond acceptors influence the absorption of HFCs (R125, R134a, and R32). The molecular models were validated through computed densities and activity-coefficient-based thermodynamics, confirming their liquid behavior. Structural and energetic analyses, including distribution functions and free-energy perturbation, show that the solubility is driven by synergistic fluorinated dispersion interactions, ionic polarization, and PFPA self-association. These specific interactions between PFPA fluorinated domains and ionic species define the eutectic network and govern HFC uptake, providing a rational basis for designing advanced fluorinated solvents for refrigerant recovery in a circular economy context.