Dr. Cabezas-Cornejo, René

The dehydration of fructose to selectively produce 5‐HMF was catalytically developed in a new type of ionic liquids based on triazoles supported on alumina (Al2O3). The synthesis of triazoles by 1,3‐dipolar cycloaddition allows for creating a tailor‐made triazole, that was eventually used to design catalysts based on triazolium‐based ionic liquids. In this work, four catalysts based on triazolium‐ionic liquids supported on Al2O3 were synthesized to produce 5‐HMF from fructose in DMSO as the reaction solvent. According to their molecular structure, the catalysts were tagged as TR1/Al2O3, TR1‐HSO4/Al2O3, TR2/Al2O3, and TR2‐HSO4/Al2O3.

Suture materials based on poly (lactic acid) (PLA) were developed by means of two different methods: extrusion and electrospinning, which were followed by a supercritical CO2 impregnation treatment. Both suture materials obtained by these techniques were impregnated with naproxen and ibuprofen using supercritical CO2 as impregnation medium. The impregnation assays were carried out at two different pressures (12 and 15 MPa), a temperature of 40 °C and, a depressurization rate of 1 MPa/min. Depending on the drugs incorporated into the suture materials, the concentrations varied from 5.60 to 26.73 wt%. The addition of both drugs and, the preparation process itself caused different changes in the structural and thermal properties of the final suture materials. Finally, tests to quantify the kinetic release of both drugs were carried out in vitro by using a Franz diffusion cell, obtaining the concentration profiles of delivered compounds as a function of the time.

In this work, a study on the selective solvent extraction (SX) of molybdenum (Mo) and rhenium (Re) from a synthetic pregnant leach solution (PLS) has been carried out using nine different hydrophobic eutectic solvents (HES). Experiments were carried out using pure HES to evaluate the selective extraction and the subsequent stripping of these metal ions; then, the best HES was dissolved in kerosene to study the SX stoichiometry. Results indicated that only TOPO-based and N8881-Cl-based HES did not form emulsions, third phases or precipitates. These HES achieved a selective extraction because these obtained almost a 100% extraction towards Mo and Re from the PLS and very low extractions for Copper (Cu) and Iron (Fe) in one equilibrium stage. The stripping experiments showed that 95% of Mo and 22% of Re were stripped out from the loaded TOPO-based HDES, respectively, opening the possibility for the selective stripping of the metal species for further purification. Finally, the extraction stoichiometry was proposed based on an experimental slope analysis and the measurement of cations and anions transferred into the aqueous phase in which HES acts as a neutral extractant in the complexation of the Mo and Re salts. These promising results suggest that HES could be attractive for more sustainable mining industry.

Ionic liquids have attracted widespread attention due to their low melting points, low vapor pressure, and non-flammability. However, their application at industrial scale is uncommon due to high costs and low recovering efficiency of the ionic liquids within the process. To reduce the costs and environmental effects of ionic liquids, this study proposes to use industrial microwave irradiation to recover eight different ionic liquids from water. The heating kinetics and identification between dielectric and convective heat properties were studied. Imidazolium-based ionic liquids showed the best results, reaching higher temperatures in shorter periods of time. Ionic liquid (bis(trifluoromethylsulfonyl) trihexyl(tetradecyl) phosphonium imide ([P6,6,6,14][Tf2N]) reached a temperature of 398 K in 360 s). On the other hand, the ionic liquid (1-butyl-3-methylimidazolium methylsulfate ([bmim][CH3OSO3]) reached a temperature of 417 K in 150 s). the ionic liquid Microwave heating experiments (water/ionic liquids) demonstrated a 90% recovery in ∼200 s for 1-octyl-3-methylimidazolium chloride ([omim][Cl]). Finally, the time used to heat-up ionic liquids with microwave irradiation was 15 times shorter than the time employed with vacuum-assisted distillation. Therefore, microwave-assisted heating has shown to be an excellent form to heat ionic liquids to decrease the cost of the extraction process and improve their reusability.

In this work, the perstraction process was implemented to separate butanol, acetone and ethanol from a model fermentation aqueous solutions using [P6,6,6,14][Tf2N], which is a highly hydrophobic phosphonium based ionic liquid as receiving phase. Perstraction assays were carried out using a flat sheet dense membrane of polydimethylsiloxane (PDMS) to quantify the extraction percentage, transmembrane fluxes of butanol, water and butanol/water selectivity focused on the effect of the temperature difference between the feed and extractant phase. The results indicate that the fluxes of butanol were particularly high considering the PDMS membrane used in the experiments was relatively thick (160 µm). The highest average flux of butanol was obtained when the temperature of the aqueous phase was 60 °C and the temperature of the organic phase was 30 °C reaching a value of 6.3 · 10-3 kg h-1 m-2, showing a butanol-water selectivity of 58.2, generated by the different sensitivity to temperature of the vapor pressure of both compounds. Finally, this disruption technique combined with ILs could allow the design of a wide range of separation processes for purify a wide variety of molecules. In addition to this, the perstraction process could be considered as a good alternative for the selective separation of fermentation or reaction products with high commercial value.

Deep eutectic solvents (DES) are a category of a new class of solvents that can overcome some of the main drawbacks of typical solvents and ionic liquids (ILs). DES have been widely investigated and applied by the research community in several applications since their invention. Over the past years, the use of DES has been directed to the production of new materials and items for new products and processes. This is the case for the implementation of DES in various fields of chemical engineering directed to separations. DES have been very recently initiated to be combined into membranes for membrane processes. In this regard, this Review timely elucidates the current progress in utilizing this new generation of solvents in membrane preparation. In this work, different techniques, methods, and strategies for incorporating DES into polymer membranes for different concepts of membranes according to the final application have been reviewed. Particular emphasis has been devoted to the most relevant development works and results. After the current literature was analyzed, the main challenges and possibilities of DES in membranes were declared.

This study introduces a novel approach to separate succinic acid (SA) from fermentation mixtures using an asymmetric membrane based on the gelation of the ionic liquid [P6,6,6,14][PHOS] coated with two layers of cellulose acetate. The membrane was designed to explore the synergistic effect of polymer-ionic liquid interfaces according to the solution-diffusion theory. The gelation of the ionic liquid was achieved using 12-hydroxystearic acid at a concentration of 1.5%, allowing the use of ionic liquid gels as new materials for the generation of membranes. The perstraction performance of the membrane was evaluated over 5 h at two different temperatures (25◦C and 37◦C), with an initial feed solution concentration of 50 kg m− 3 for SA and glycerol and pure water as a receiving phase., Several flow rates and phase-volume ratios were studied anda mass transfer model based on the resistance-in-series theory was assessed to understand the behavior of each mass transfer stage considering the distribution in each interphase. Interestingly, optimal perstraction results were obtained at 37◦C, with an average transmembrane flux of 0.22 kg m-2h− 1 for SA, an extraction percentage of 43.1% for SA and 0.7% for glycerol, and a SA/glycerol selectivity of 54.98. Besides presenting a novel composite membrane, this study reports pioneering perstraction outcomes, highlighting its potential as an innovative SA separation strategy and structured new materials for selective extractions.

The separation of Levulinic (LA) acid and Formic acid (FA) from aqueous streams represents an important and challenging separation in biorefineries, where ionic liquids (ILs) provide a sustainable environment for liquid-liquid extractions of these acids. In this work, a COSMO-RS screening of bis (trifluoromethylsulfonil)imide [Tf2N]− based IL was first conducted and then followed by experimental validation to search for the most suitable cation for this separation. After the screening, ternary liquid-liquid equilibrium experiments at 298.15K and the subsequent data correlation using the Non-Random Two Liquid model (NRTL) were performed for future industrial implementation. Results indicated that the phosphonium cations, especially the trihexylthetradecyl phosphonium cation [P66614]+, produced the highest selectivity rates among all the experimentally measured ILs.

In this study, the theoretical design of ionic liquids (ILs) for predicting selective extraction of lithium from brines has been conducted using COSMO-RS. A theoretical model for the solvent extraction (SX) of the metal species present in brines was established considering extraction stoichiometry, the distribution of the extractants between aqueous and IL phases, and IL dissociation in the aqueous phase. Theoretical results were validated using experimental extraction percentages from previous works. Results indicate that, in general, the theoretical results for lithium extraction follow experimental trends, except from magnesium extraction. Finally, based on the model, an IL was proposed that was based on the phosphonium cation as the extractant, along with the phase modifier tributylphosphate (TBP) in an organic diluent in order to improve selectivity for lithium ex- traction over sodium. These results provide an insight for the application of ILs in lithium processing, avoiding the long purification times reported in the conventional process.

Cobalt (Co) stands out as one of the most critical metals in contemporary use, particularly due to its increasing demand in technological products and especially in electromobility. Over the years, ionic liquids (ILs) have provided a green alternative to volatile organic solvents in hydrometallurgy due to their outstanding properties, such as the negligible vapor pressure and their increased selectivity provided in separation processes, which opens the possibility to ramp up the Co-production while maintaining sustainable mining processes. Thus, this review offers a complete comprehensive and critical summary of published works on the use of ILs in the hydrometallurgy of Co, starting from the leaching from a primary source by conventional methods and then, from the pregnant leach solution (PLS) focuses on the advantages and disadvantages of solvent extraction (SX) in different aqueous media (chlorinated, nitrated, and sulfated) in which ILs are used to separate selectively Co from a multi-metal mixture. In the following section, its recovery from the loaded organic phase by acid stripping is discussed. Finally, this review provides the challenges that ILs should overcome to be viable for large-scale industrial applications and the opportunities that exhibit for selective recovery of Co from PLS capitalizing.