Direct Hydroxylation of Phenol to Dihydroxybenzenes by H2O2 and Fe-based Metal-Organic Framework Catalyst at Room Temperature

A semi-crystalline iron-based metal-organic framework (MOF), in particular Fe-BTC, that contained 20 wt.% Fe, was sustainably synthesized at room temperature and extensively characterized. Fe-BTC nanopowders could be used as an efficient heterogeneous catalyst for the synthesis of dihydroxybenzenes (DHBZ), from phenol with hydrogen peroxide (H2O2), as oxidant under organic solvent-free conditions. The influence of the reaction temperature, H2O2 concentration and catalyst dose were studied in the hydroxylation performance of phenol and MOF stability. Fe-BTC was active and stable (with negligible Fe leaching) at room conditions. By using intermittent dosing of H2O2, the catalytic performance resulted in a high DHBZ selectivity (65%) and yield (35%), higher than those obtained for other Fe-based MOFs that typically require reaction temperatures above 70◦C. The long-term experiments in a fixed-bed flow reactor demonstrated good Fe-BTC durability at the above conditionsThe authors thank the financial support by Consejo Nacional de Ciencia y Tecnología (CONACYT) for the grant number 764635 and the project 256296; and to TNM for the supporting project 5627.19.P. Also, to the Spanish Ministerio de Ciencia, Innovación y Universidades (MICINN) and FEDER program (EU) through the projects: CTM2016-76454-R (MICINN) and RTI2018-095052-B-I00 ((MCIU/AEI/FEDER, UE

Energetic evaluation of swing adsorption processes for CO2 capture in selected MOFs and zeolites: Effect of impurities

We present a systematic computational study of Mg-MOF-74, CuBTC and zeolite 13X for CO2 separation from multi-component flue gas mixtures. The impurities' impact was evaluated at the molecular level and process conditions. Adsorption isotherms and isosteric heats of adsorption of pure (CO2, N2, O2, H2O, SO2 and NO2) components, binary and ternary mixtures were obtained from Grand Canonical Monte Carlo simulations. Working capacities, purities, recoveries and exergetic performances were evaluated for VSA/PSA/TSA processes. Results show that NO2 has a negligible effect in the studied range. For H2O and SO2 the energy requirements are reduced as the impurity content increases and recovery and purity increase, up to an 'optimal' point where a competition for CO2 preferred adsorption sites produces a sharp drop in purity and the energetic index grows exponentially. The minimum energy requirement were obtained for TSA at a desorbing temperature of 443 K in the three materials, with impurities of 1% H2O for CuBTC, 0.5% H2O for Mg-MOF-74 and 0.02% H2O for 13X, obtaining values of 1.13, 0.55 and 0.58 GJ/tCO2, respectively. Hybrid VTSA processes with impurities content in the feed mixture and CCS specifications achieve energy performances of 0.36 GJ/tCO2 and 0.46 GJ/tCO2 with Mg-MOF-74 and 13X, respectively. Mg-MOF-74 stands up as an attractive material for VTSA processes, presenting higher working capacities, purities and second-law efficiencies, with lower energy consumptions, also showing a better 'buffer' behavior than zeolite 13X when trace impurities are present. This work represents the first quantitative assessment of the process performance of MOFs adsorbents in swing adsorption process for CO2 capture considering impurities effects. Results reinforce the validity of molecular simulations for guiding the optimization of these processes

Structured reactors based on 3D Fe/SiC Catalysts: understanding the effects of mixing

The application of structured reactors provides a number of advantages in chemical processes. In this paper, two different three-dimensional (3D) Fe/SiC catalysts with a square cell geometry have been manufactured by Robocasting: monoliths (D = 14 and H = 15 mm) and meshes (D = 24 and H = 2 mm) and studied in the catalytic phenol oxidation by hydrogen peroxide (H2O2) for the sustainable production of dihydroxybenzenes (DHBZ). The fluid dynamics, catalytic performance, reaction rates, external mass transport limitation, and catalyst stability have been compared in three different reactors, monolithic fixed-bed reactor, multimesh fixed-bed reactor, and monolithic stirrer reactor, at selected operating conditions. The results show that the mechanical stirring of the 3D Fe/SiC monoliths avoids the external mass transfer limitation caused by the presence of oxygen bubbles in the channels (produced from the HOx· species in autoscavenging radical reactions). In addition, the backmixing has a positive effect on the efficient consumption of H2O2 but an adverse effect on the phenol selectivity to DHBZ since they are overoxidized to tar products at longer contact times. On the other hand, the wall porosity, and not the backmixing, affects the susceptibility of the 3D Fe/SiC catalyst to the Fe leaching, as occurs in the mesh structures. In conclusion, the monoliths operating under plug-flow and external mass transfer limitation in the monolithic fixed-bed reactor (MFB) provide an outstanding phenol selectivity to DHBZ and catalyst stabilityThis work is supported by the following agencies and grants: the Spanish Government under projects RTI2018-095052-BI00 (MICINN/AEI/FEDER, UE) and EIN2020-112153 (MCINN/AEI/10.13039/501100011033), the latter was also supported by the European Union through “NextGenerationEU/PRTR”, Community of Madrid under project S2018/ EMT-4341, and CSIC project I-COOP+ 2019 (ref COOPB20405). P.L. acknowledges the Community of Madrid and the European Social Fund for the financial support received through the contract PEJ-2019-AI/IND-14385. The authors thank Juliana Mejía for her technical assistanc

Enhanced fluid dynamics in 3D monolithic reactors to improve the chemical performance: experimental and numerical investigation

Three-dimensional (3D) Fe/SiC monoliths with parallel interconnected channels and different cell geometries (square, troncoconical, and triangular) were manufactured by robocasting and used as catalytic reactors in hydroxylation of phenol using hydrogen peroxide to produce dihydroxybenzenes; the reaction was performed at Cphenol,0 = 0.33 M, Cphenol,0:CH2O2,0 = 1:1 M, WR = 3.7 g, T = 80-90 °C, and τ = 0-254 gcat·h·L-1 with water as a solvent. The values of the apparent kinetic rate constants demonstrated the superior performance of the triangular cell monoliths for hydrogen peroxide decomposition, phenol hydroxylation, and dihydroxybenzene production reactions. A computational fluid dynamic model was validated with the experimental results. It demonstrated that the triangular cell monoliths, with a lower channel hydraulic diameter and not-facing interconnections, provided a higher internal macrotortuosity that induced an oscillating flow of the liquid phase inside the channels, leading to an additional transverse flow between adjacent parallel channels. This behavior, not observed in the other two geometries, resulted in a better overall performanceThe authors thank the financial support by the Community of Madrid through the project S2018/EMT-4341 and the Government of Spain through the projects: PGC2018- 095642-B-I00 and RTI2018-095052-B-I00 (MCIU/AEI/ FEDER, UE). Also, G. Vega acknowledges the Universidad Autónoma de Madrid for the predoctoral contrac

Cavidad de Stafne de localización inusual en el sector anterior mandibular

La típica cavidad de Stafne, localizada en el sector posterior de la mandíbula, es una entidad relativamente poco frecuente, pero cuando el defecto se sitúa en la región anterior mandibular, es bastante raro, habiéndose descrito hasta ahora sólo 36 casos en la literatura científica. La mayoría de estos defectos aparecen entre la quinta y la sexta décadas de la vida, están localizados en el área de caninos y premolares, y muestran también una predilección por el sexo masculino. El canal dentario inferior, uno de los hitos anatomo-radiológicos principales que ayudan al diagnóstico de la cavidad de Stafne en la zona posterior, raramente está presente anteriormente al agujero mentoniano. Por ello, por su apariencia radiográfica más variable que en el defecto posterior, por soler encontrarse superpuesta a los ápices de los dientes, y por la rareza de presentación en el sector anterior mandibular, es mucho más difícil establecer un diagnóstico definitivo de cavidad de Stafne en esta localización, y por tanto es más fácil que pueda haber un error en el diagnóstico, sobre todo inicialmente. Presentamos un nuevo caso, en un varón de 68 años, en el que el diagnóstico fue fortuito, y revisamos especialmente sus aspectos etiopatogénicos, clínicos, y de diagnóstico diferencial.The typical Stafne's cavity, located on the posterior portion of the mandible, is a relatively uncommon entity. However, when the defect is located in the anterior region of the mandible, it is quite rare, having thus far been described in only 36 cases in the scientific literature. Most of these defects appear in the fifth and sixth decades of life, are localized to the area of the canines and premolars, and have a predilection for males. The inferior dental canal, one of the anatomical-radiographic landmarks that aid in the diagnosis of Stafne's cavity in the posterior region, is rarely present anterior the mental foramen. For this reason, because of its more variable radiographic appearance compared to the posterior defect, its tendency to be superimposed over the apices of the teeth, and the rarity of its localisation to the anterior mandible, it is much more difficult to establish a definitive diagnosis of a Stafne's cavity in this location. It is therefore more likely that a diagnostic error can occur, especially early on. We present a new case in a 68-year-old male in which the diagnosis was serendipitous, and we review in particular the aetiology and pathogenesis, clinical aspects, and differential diagnoses for this condition

Monolithic stirrer reactors for the sustainable production of dihydroxybenzenes over 3D printed Fe/γ-Al2O3 monoliths: kinetic modeling and CFD simulation

The aim of this work is to evaluate the performance of the stirring 3D Fe/Al2O3 monolithic reactor in batch operation applied to the liquid-phase hydroxylation of phenol by hydrogen peroxide (H2O2 ). An experimental and numerical investigation was carried out at the following operating conditions: CPHENOL,0 = 0.33 M, CH2O2,0 = 0.33 M, T = 75–95◦C, P = 1 atm, ω = 200–500 rpm and WCAT ~ 1.1 g. The kinetic model described the consumption of the H2O2 by a zero-order power-law equation, while the phenol hydroxylation and catechol and hydroquinone production by Eley–Rideal model; the rate determining step was the reaction between the adsorbed H2O2, phenol in solution with two active sites involved. The 3D CFD model, coupling the conservation of mass, momentum and species together with the reaction kinetic equations, was experimentally validated. It demonstrated a laminar flow characterized by the presence of an annular zone located inside and surrounding the monoliths (u = 40–80 mm s−1 ) and a central vortex with very low velocities (u = 3.5–8 mm s−1 ). The simulation study showed the increasing phenol selectivity to dihydroxybenzenes by the reaction temperature, while the initial H2O2 concentration mainly affects the phenol conversio

3D printing of cubic zirconia lattice supports for hydrogen production

The demand for hydrogen has extraordinarily grown during the last years, being one of the most attractive forms of fuels to produce green energy. Cubic zirconia ceramics are considered promising catalytic supports, and the additive manufacturing of porous 3D structures based on these ceramics could enhance their catalytic performance. Herein, lightweight highly porous (up to 88%) 3D patterned 8 mol% yttria-stabilized cubic zirconia (8YSZ) scaffolds are manufactured by robocasting from pseudoplastic aqueous-based inks to produce catalytic supports for the hydrogen (H2) production. These scaffolds are thermally treated at temperatures ranging between 1000 and 1400 ◦C and, hence, mechanically and electrically characterized. 3D 8YSZ structures sintered at 1200 ◦C, with an appropriate balance between high porosity (86%) and compressive strength (3.7 MPa), are impregnated with palladium (Pd) catalytic nanoparticles and employed in the catalytic dehydrogenation of renewable formic acid (FA) using a fixed-bed reactor. 3D Pd/8YSZ catalyst leads to the continuous production of CO-free H2 with a FA conversion of 32% at T =55 ◦CThis work was supported by the Spanish Government through RTI2018-095052-B-I00, PID2019-105079RB-I00 (MICINN/AEI/FEDER, UE), PID2021-125427OB-I00 (MICINN/AEI/FEDER, UE) and EIN2020- 112153 (MCINN/AEI/10.13039/501100011033) projects, the latter also supported by the European Union through “NextGenerationEU/ PRTR”. M. Koller gratefully acknowledges funding within “Support for International Mobility of Researchers of the Institute of Thermomechanics, Czech Academy of Sciences, part II”, no. CZ.02.2.69/0.0/ 0.0/18_053/0017555 of the Ministry of Education, Youth and Sports of the Czech Republic funded from the European Structure and Investment Funds (ESIF). G. Vega acknowledges the Universidad Aut´onoma de Madrid for the Predoctoral contract. The authors thank J. Mejía for her permanent technical assistance in the catalytic experiment

Functional Heterogeneity of Mouse and Human Brain OPCs: Relevance for Preclinical Studies in Multiple Sclerosis.

Besides giving rise to oligodendrocytes (the only myelin-forming cell in the Central Nervous System (CNS) in physiological conditions), Oligodendrocyte Precursor Cells (OPCs) are responsible for spontaneous remyelination after a demyelinating lesion. They are present along the mouse and human CNS, both during development and in adulthood, yet how OPC physiological behavior is modified throughout life is not fully understood. The activity of adult human OPCs is still particularly unexplored. Significantly, most of the molecules involved in OPC-mediated remyelination are also involved in their development, a phenomenon that may be clinically relevant. In the present article, we have compared the intrinsic properties of OPCs isolated from the cerebral cortex of neonatal, postnatal and adult mice, as well as those recovered from neurosurgical adult human cerebral cortex tissue. By analyzing intact OPCs for the first time with 1H High Resolution Magic Angle Spinning Nuclear Magnetic Resonance (1H HR-MAS NMR) spectroscopy, we show that these cells behave distinctly and that they have different metabolic patterns in function for their stage of maturity. Moreover, their response to Fibroblast Growth Gactor-2 (FGF-2) and anosmin-1 (two molecules that have known effects on OPC biology during development and that are overexpressed in individuals with Multiple Sclerosis (MS)) differs in relation to their developmental stage and in the function of the species. Our data reveal that the behavior of adult human and mouse OPCs differs in a very dynamic way that should be very relevant when testing drugs and for the proper design of effective pharmacological and/or cell therapies for MS.post-print753 K

Understanding the active sites of boron nitride for CWPO: An experimental and computational approach

[EN] Hexagonal boron nitride (h-BN) has been explored as a catalyst for degrading persistent organic pollutants in wastewater by Catalytic Wet Peroxide Oxidation (CWPO). Herein, the superior activity of the h-BN on the phenol degradation (model pollutant) compared to other metal-free catalysts, such as carbon-based ones, and the lower selectivity to CO encourage the potential application of h-BN catalysts in CWPO processes. Through a combined density functional theory calculations, experimental reactions and catalyst characterization approach, a comprehensive study on the reaction mechanism has been conducted. According to this, only defected B atoms in the h-BN layer, protonated as B-(OH), decompose the hydrogen peroxide into highly reactive hydroxyl radicals. The radical species diffuse towards inner h-BN regions and react with the phenol adsorbed by π-π interaction on the h-BN surface. Oxidation by-products cause carbonaceous deposits and progressive deactivation of the h-BN catalyst that can be directly regenerated by burning off in air.The authors thank the financial support by the Community of Madrid and the Government of Spain through the projects: S2018/EMT- 4341 and RTI2018-095052-B-I00 (MCIU/AEI/FEDER, UE), respectively. The work done at the University of Sevilla was funded by Spanish Ministerio de Ciencia e Innovación and EU-FEDER, grant PID2019-106871 GB-I00, and the Junta de Andalucía-FEDER, grant: US-1381410. Also, G. Vega acknowledges the Community of Madrid for the Predoctoral contract PEJD-2018-PRE/AMB-9019, co-financed by the European Social Fund through the Youth Employment Operational Program and the Youth Employment Initiative (YEI) 2018. J. Carbajo thanks the financial support by the Government of Spain for a grant under the Juan de la Cierva_Incorporación programme (IJCI-2017- 32682). The authors would like to thank A. Pérez for performing the BET and TGA measurements

Aprendizaje por refuerzo profundo aplicado a juegos sencillos

En este proyecto estudiaremos el campo del aprendizaje por refuerzo profundo, con el objetivo de lograr una aplicación estable en problemas clásicos de control. Para lograrlo investigaremos sus bases: el aprendizaje por refuerzo y las redes neuronales, comprobando cuáles son sus puntos fuertes y débiles. Después combinaremos lo aprendido para, progresivamente, mejorar el rendimiento y la estabilidad de nuestros agentes. En busca de una mayor comprensión de su funcionamiento, todas las implementaciones de los agentes y algoritmos serán hechas por nosotros mismos. Todo ello será puesto a prueba a través del conocido sistema OpenAI Gym. Todo el código fuente referente a este proyecto puede encontrarse en: https://github.com/delcanovega/TFG-DR