Browsing by Author "Matias Garrido, Jose"

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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.
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    Interfacial 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, Jose
    The 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.