Methanol dehydration over ZrO2 supported-activated carbons

Resumen comunicación congreso internacionalDME is playing an important role due to its potential use as an alternative fuel in diesel engines. The use of this fuel produces lower NOx emissions, and less engine noise compared to traditional diesel fuels. Moreover, this compound is used as building block for many value-added chemicals such as lower olefins. DME is usually produced via catalytic dehydration of methanol over a solid acid. The use of activated carbons in catalytic processes, acting directly as catalyst and as catalyst support, is focussing much attention. They can be obtained from different types of lignocellulosic waste, producing not only an environmental but an economical profit. In this sense, the preparation of activated carbons with phosphoric acid produces catalytic supports with certain surface acidity, which have shown high activity for alcohol dehydration. In this study, ZrO2 supported activated carbons were prepared from an industrial byproduct as lignin for the methanol dehydration to DME. The activated carbon was prepared by chemical activation with H3PO4, using Alcell® lignin as precursor. The impregnation ratio value (H3PO4/lignin) used was 3. The impregnated sample was activated under N2 flow at 500 ºC for 2h, washed and dried. The activated carbon was loaded with different amounts of ZrO(NO3)2, dried at 120ºC for 24h, and calcined in air at 250ºC for 2h, obtaining ZrO2 loadings of 5 and 10%, respectively. For the sake of comparison, pure ZrO2 was also used. Catalytic tests were performed at atmospheric pressure in a fixed bed reactor, at different space times and partial pressures. The activated carbon (ACP) prepared shows a well-developed porous structure, with an apparent surface area higher than 2000 m2/g, and a high contribution of mesoporosity. After metal loading, a maximum decrease of 20% in all structural parameters of the ACP was observed.The results show that ZrO2 loading produces an enhancing in the catalytic activity of the carbon materials compared to the parent activated carbon (0.1 g·s/μmol, PCH3OH= 0.02 atm in helium and 350 ºC). In this sense, a methanol conversion of 25% was observed with the addition of 10% w/w ZrO2 (ACP-10Zr), at steady state conditions (Figure 1). ACP shows negligible conversion, at the same conditions and for pure ZrO2 the methanol conversion was of 10%. Very high selectivity to DME (~100%) was found at temperatures lower than 350 ºC. The methanol conversion increases with temperature, reaching a value of 67% at 475ºC, but a slight decrease in DME selectivity is observed, resulting in a higher production of light hydrocarbons, mainly CH4. The results suggest that the addition of only a 10% of ZrO2 over an activated carbon prepared by chemical activation with H3PO4 enhances significantly the performance of the catalyst, compared to pure ZrO2.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Functional Glyconanomaterials

Nanotechnology provides a new array of techniques and platforms to study biological processes including glycosystems [...

Covalent immobilization of Candida rugosa lipase at alkaline pH and their application in the regioselective deprotection of per-O-acetylated thymidine

Lipase from Candida rugosa (CRL) was stabilized at alkaline pH to overcome the inactivation problem and was immobilized for the first time by multipoint covalent attachment on different aldehyde-activated matrices. PEG was used as a stabilizing agent on the activity of CRL. At these conditions, CRL maintained 50% activity at pH 10 after 17 h incubation in the presence of 40% (w/v) of PEG, whereas the enzyme without additive was instantaneously inactive after incubation at pH 10. Thus, this enzyme was covalently immobilized at alkaline pH on three aldehyde-activated supports: aldehyde-activated Sepharose, aldehyde-activated Lewatit105 and heterofunctional aldehyde-activated EDA-Sepharose in high overall yields. Heterogeneous stable CRL catalysts at high temperature and solvent were obtained. The aldehyde-activated Sepharose-CRL preparation maintained 70% activity at 50 °C or 30% (v/v) acetonitrile after 22 h and exhibited high regioselectivity in the deprotection process of per-O-acetylated thymidine, producing the 3ʹ-OH-5ʹ-OAc-thymidine in 91% yield at pH 5.Fil: Rivero, Cintia Wanda. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Investigación en Biotecnología Sustentable; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Palomo, Jose M.. Consejo Superior de Investigaciones Científicas; Españ

Solid-Phase Lipase-CuNPs Biohybrids as Catalysts for One-Pot Parallel Synthesis of 2,3,4-Triacetyl-D-Gluconic Acid

Solid-phase lipase/metal nanobiohybrids, generated by growth of copper nanoparticles on enzyme matrixes immobilized on graphene, were used as heterogeneous catalysts with dual-activity for the regioselective production of 2,3,4-triacetyl-D-gluconic acid from α-peracetylated-glucose in a one-pot parallel process combining a lipase-mediated regioselective hydrolytic monodeprotection with a metal-catalyzed oxidation in aqueous media. A novel synthetic strategy, based on the in situ fabrication of Cu nanoparticles induced by lipase molecules specifically immobilized on a multi-layer graphene material by interfacial adsorption fixing them in the active open conformation, has been described. Thermomyces lanuginosus lipase was firstly used to prepare the functionalized multi-layer graphene from graphite as a biographene preparation (Biographene, BIOG), support used to successfully immobilize Candida rugosa lipase (CRL). This immobilized form BIOG-CRL was further used to create successful active bifunctional enzyme-metal nanoarchitectures. Two different Cu-lipase hybrids were synthesised, where Cu species and nanoparticles size were different depending on the methodology. Regioselectivity and stability of the hybrids were evaluated successfully in the production of monosaccharide building blocks, besides the robustness of the hybrids in recyclability experiments. These findings highlight the potential of these solid-phase nanoarchitectures as useful tools in the synthesis of complex glycoderivatives for use in food, medicine, and cosmetics

Synthesis of silver and gold nanoparticles-enzyme-polymer conjugate hybrids as dual-activity catalysts for chemoenzymatic cascade reactions

Novel hybrids containing silver or gold nanoparticles have been synthesized in aqueous media and at room temperature using enzymes or tailor-made enzyme-polymer conjugates, which directly induced the formation of inorganic silver or gold species. The choice of pH, protein, or bioconjugate strongly affected the final metallic nanoparticles hybrid formation. Using Candida antarctica lipase (CALB) in a solution, nanobiohybrids containing Ag2O nanoparticles of 9 nm average diameter were obtained. The use of tailor-made bioconjugates, for example, the CALB modified with dextran-aspartic acid polymer (Dext6kDa), resulted in a nanobiohybrid containing smaller Ag(0)/Ag2O nanoparticles. In the case of nanobiohybrids based on gold, Au(0) species were found in all cases. The Au-CALB hybrid contained spherical nanoparticles with 18 nm average diameter size, with a minor range of larger ones (>100 nm) while the AuNPs-CALB-Dext6kDa hybrid was formed by much smaller nanoparticles (9 nm, minor range of 22 nm), and also nanorods of 20-30/40-50 nm length. Using Thermomyces lanuginosus lipase (TLL), apart from the nanoparticle formation, nanoflowers with a diameter range of 100-200 nm were obtained. All nanobiohybrids maintained (dual) enzymatic and metallic activities. For instance, these nanobiohybrids exhibited exquisite dual-activity for hydrolysis/cycloisomerization cascades starting from allenic acetates. By merging the transition metal reactivity with the inherent lipase catalysis, allenic acetates directly converted to the corresponding O-heterocycles in enantiopure form catalysed by AgNPs-CALB-Dext6kDa, taking advantage of a kinetic resolution/cyclization pathway. These results showed the high applicability of these novel hybrids, offering new opportunities for the design of novel reaction cascades.Peer reviewe

Relación entre el grado de corrosión y el comportamiento mecánico de armaduras B500 SD corroídas

En este trabajo se discuten las herramientas de orden matemático necesarias para la presentación, a los alumnos de grado en edificación, de una metodología para el análisis de la incidencia de la corrosión de armaduras en su límite elástico y su resistencia a tracción, discutiendo los resultados de un ensayo a tracción

application in C-H activation catalysis

This work was supported by the Spanish Government, the Spanish National Research Council (CSIC). We also thank Dr Martinez from Novozymes. Publisher Copyright: © 2023 RSC.The effect of the temperature in the synthesis of Pd nanoparticles in the metal-enzyme biohybrids is evaluated. The effect on the formation, size, and morphology of nanoparticles was evaluated using C. antarctica B lipase as the protein scaffold. XRD analyses confirmed the formation of crystalline Pd(0) as the metal species in all cases. TEM analyses revealed spherical crystalline nanoparticles with average diameter size from 2 nm at 4 °C synthesis to 10 nm obtained at 50 °C synthesis. The thermal phenomenon was also critical in the final hybrid formation using more complex enzymes, where the relation of the protein structure and temperature and the influence of the latter has been demonstrated to be critical in the reducing efficiency of the enzyme in the final Pd nanoparticle formation, in the metal species, or even in the final size of the nanoparticles. Different Pd biohybrids were evaluated as catalysts in the C-H activation of protected l-tryptophan under mild conditions. Pd@CALB4 showed the best results, with >99% conversion for C-2 arylation in methanol at room temperature with a TOF value of 64 min−1, being 2 or 4 times higher than that of the other synthesized hybrids. This catalyst showed a very high stability and recyclability, maintaining >95% activity after three cycles of use.publishersversionpublishe

Disdrometer Performance Optimization for Use in Urban Settings Based on the Parameters that Affect the Measurements

[EN] There are currently different types of commercial optical disdrometers to measure the rainfall intensity, of which many are commonly used for monitoring road conditions. Having information about the amount of rain, the composition of the precipitation particles and visibility are essential to avoid accidents, which requires intelligent systems that warn drivers and redirect traffic. However, few studies related to Intelligent Transport Systems (ITS) have been performed regarding why these devices are not optimized for this type of applications. Therefore, this paper analyzes and evaluates the operating mode of these equipment through their theoretical model, which will allow the design of prototypes of disdrometers with different characteristics. In addition, this model will be implemented in a simulation program, through which an exhaustive study analyzing how the type of precipitation and its intensity affect the measures provided by the model will be conducted. In this way, the results will help optimize its operation to be thus used in urban settings, which will allow obtaining more accurate real-time information, better traffic management, and a reduction in the number of accidents.This research has been funded by the Universitat Politecnica de Valencia through its internal project "Equipos de deteccion, regulacion e informacion en el sector de los sistemas inteligentes de transporte (ITS). Nuevos modelos y ensayos de compatibilidad y verificacion de funcionamiento", which has been carried out at the ITACA Institute.Mocholí-Belenguer, F.; Martinez-Millana, A.; Mocholí Salcedo, A.; Milián Sánchez, V.; Palomo-Anaya, MJ. (2020). Disdrometer Performance Optimization for Use in Urban Settings Based on the Parameters that Affect the Measurements. Symmetry (Basel). 12(2):1-19. https://doi.org/10.3390/sym12020303S119122Frasson, R. P. de M., da Cunha, L. K., & Krajewski, W. F. (2011). Assessment of the Thies optical disdrometer performance. Atmospheric Research, 101(1-2), 237-255. doi:10.1016/j.atmosres.2011.02.014Krajewski, W. F., Kruger, A., Caracciolo, C., Golé, P., Barthes, L., Creutin, J.-D., … Vinson, J.-P. (2006). DEVEX-disdrometer evaluation experiment: Basic results and implications for hydrologic studies. Advances in Water Resources, 29(2), 311-325. doi:10.1016/j.advwatres.2005.03.018Peng, Y., Jiang, Y., Lu, J., & Zou, Y. (2018). Examining the effect of adverse weather on road transportation using weather and traffic sensors. PLOS ONE, 13(10), e0205409. doi:10.1371/journal.pone.0205409Rakha, H., Arafeh, M., & Park, S. (2012). Modeling Inclement Weather Impacts on Traffic Stream Behavior. International Journal of Transportation Science and Technology, 1(1), 25-47. doi:10.1260/2046-0430.1.1.25Malin, F., Norros, I., & Innamaa, S. (2019). Accident risk of road and weather conditions on different road types. Accident Analysis & Prevention, 122, 181-188. doi:10.1016/j.aap.2018.10.014Lolli, S., Di Girolamo, P., Demoz, B., Li, X., & Welton, E. J. (2017). Rain Evaporation Rate Estimates from Dual-Wavelength Lidar Measurements and Intercomparison against a Model Analytical Solution. Journal of Atmospheric and Oceanic Technology, 34(4), 829-839. doi:10.1175/jtech-d-16-0146.1Grossklaus, M., Uhlig, K., & Hasse, L. (1998). An Optical Disdrometer for Use in High Wind Speeds. Journal of Atmospheric and Oceanic Technology, 15(4), 1051-1059. doi:10.1175/1520-0426(1998)0152.0.co;2Hauser, D., Amayenc, P., Nutten, B., & Waldteufel, P. (1984). A New Optical Instrument for Simultaneous Measurement of Raindrop Diameter and Fall Speed Distributions. Journal of Atmospheric and Oceanic Technology, 1(3), 256-269. doi:10.1175/1520-0426(1984)0012.0.co;2Kathiravelu, G., Lucke, T., & Nichols, P. (2016). Rain Drop Measurement Techniques: A Review. Water, 8(1), 29. doi:10.3390/w8010029Illingworth, A. J., & Stevens, C. J. (1987). An Optical Disdrometer for the Measurement of Raindrop Size Spectra in Windy Conditions. Journal of Atmospheric and Oceanic Technology, 4(3), 411-421. doi:10.1175/1520-0426(1987)0042.0.co;2Atlas, D., & Ulbrich, C. W. (1977). Path- and Area-Integrated Rainfall Measurement by Microwave Attenuation in the 1–3 cm Band. Journal of Applied Meteorology, 16(12), 1322-1331. doi:10.1175/1520-0450(1977)0162.0.co;2Foote, G. B., & Du Toit, P. S. (1969). Terminal Velocity of Raindrops Aloft. Journal of Applied Meteorology, 8(2), 249-253. doi:10.1175/1520-0450(1969)0082.0.co;2Pruppacher, H. R., & Pitter, R. L. (1971). A Semi-Empirical Determination of the Shape of Cloud and Rain Drops. Journal of the Atmospheric Sciences, 28(1), 86-94. doi:10.1175/1520-0469(1971)0282.0.co;2Hasse, L., Grossklaus, M., Uhlig, K., & Timm, P. (1998). A Ship Rain Gauge for Use in High Wind Speeds. Journal of Atmospheric and Oceanic Technology, 15(2), 380-386. doi:10.1175/1520-0426(1998)0152.0.co;2Marshall, J. S., & Palmer, W. M. K. (1948). THE DISTRIBUTION OF RAINDROPS WITH SIZE. Journal of Meteorology, 5(4), 165-166. doi:10.1175/1520-0469(1948)0052.0.co;2Ulbrich, C. W. (1983). Natural Variations in the Analytical Form of the Raindrop Size Distribution. Journal of Climate and Applied Meteorology, 22(10), 1764-1775. doi:10.1175/1520-0450(1983)0222.0.co;2Ulbrich, C. W. (1985). The Effects of Drop Size Distribution Truncation on Rainfall Integral Parameters and Empirical Relations. Journal of Climate and Applied Meteorology, 24(6), 580-590. doi:10.1175/1520-0450(1985)0242.0.co;2Gertzman, H. S., & Atlas, D. (1977). Sampling errors in the measurement of rain and hail parameters. Journal of Geophysical Research, 82(31), 4955-4966. doi:10.1029/jc082i031p04955Brawn, D., & Upton, G. (2008). Estimation of an atmospheric gamma drop size distribution using disdrometer data. Atmospheric Research, 87(1), 66-79. doi:10.1016/j.atmosres.2007.07.006Zhang, G., Vivekanandan, J., Brandes, E. A., Meneghini, R., & Kozu, T. (2003). The Shape–Slope Relation in Observed Gamma Raindrop Size Distributions: Statistical Error or Useful Information? Journal of Atmospheric and Oceanic Technology, 20(8), 1106-1119. doi:10.1175/1520-0426(2003)0202.0.co;2Peng, Y., Abdel-Aty, M., Lee, J., & Zou, Y. (2018). Analysis of the Impact of Fog-Related Reduced Visibility on Traffic Parameters. Journal of Transportation Engineering, Part A: Systems, 144(2), 04017077. doi:10.1061/jtepbs.0000094Alves de Souza, B., da Silva Rocha Paz, I., Ichiba, A., Willinger, B., Gires, A., Amorim, J. C. C., … Schertzer, D. (2018). Multi-hydro hydrological modelling of a complex peri-urban catchment with storage basins comparing C-band and X-band radar rainfall data. Hydrological Sciences Journal, 63(11), 1619-1635. doi:10.1080/02626667.2018.1520390Tabary, P., Boumahmoud, A.-A., Andrieu, H., Thompson, R. J., Illingworth, A. J., Bouar, E. L., & Testud, J. (2011). Evaluation of two «integrated» polarimetric Quantitative Precipitation Estimation (QPE) algorithms at C-band. Journal of Hydrology, 405(3-4), 248-260. doi:10.1016/j.jhydrol.2011.05.02

Magnetic Field Generated by the Loops Used in Traffic Control Systems

[EN] In this paper, a detailed study about the value, in any point of space P(x, y, z), of the magnetic field generated by a rectangular loop that carries a current I has been made. The analysis focuses on the study of rectangular magnetic loops that are used as sensors in traffic control systems. The inductance of magnetic loops is calculated numerically in three different ways, and the optimal way of performing the numerical summation is derived, which takes into account the magnetic field singularity on the conductor itself. The calculations also take into account the distance between the different turns in the loop. Later, the results are compared with the most commonly used empirical methods for inductance calculation. This paper shows the great similarity between empirical and numerically calculated results and concludes with the experimental verification and validation of the obtained theoretical results. Thus, both the system to evaluate the results and the proposed numerical methods for inductance calculation can be used in other loops geometries. This methodology can also be used for the mutual inductance calculation that appears between a buried loop and any kind of vehicle geometry, whose oscillation frequency variation determines the magnetic signature. The mutual inductance calculation can be used to determine the signal level that can be exchanged between the loops on the pavement and those on the vehicle, which in turn can be used as a short-range communication system between vehicles and infrastructures, with applications such as vehicles classification, speed measurements, or communication between vehicles.This work was supported in part by the Ministry of Education of Spain and in part the company ETRA I+D S.A.Mocholí Salcedo, A.; Arroyo-Núñez, JH.; Milian-Sanchez, VM.; Palomo-Anaya, MJ.; Arroyo-Nunez, A. (2017). Magnetic Field Generated by the Loops Used in Traffic Control Systems. IEEE Transactions on Intelligent Transportation Systems. 18(8):2126-2136. https://doi.org/10.1109/TITS.2016.2632972S2126213618

Copper(i) as a reducing agent for the synthesis of bimetallic PtCu catalytic nanoparticles

Funding Information: This work received financial support from PT national funds (FCT/MCTES, Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) through the projects UIDB/50006/2020 and UIDP/50006/2020. S. N., C. L., J. L. C., A. F. L., and J. F. L. are thankful for the financial support from national funds (FCT/MCTES, Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) through project Met4Cat, EXPL/QUI-COL/0263/2021. This work was supported by the Spanish Government and the Spanish National Research Council (CSIC) (project PIE 201980E081). We thank the financial support by the PROTEOMASS Scientific Society (Portugal) (General Funding Grant 2022). S. N. thanks FCT/MCTEC (Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) Portugal for her doctoral grant associated with the Chemistry PhD program (SFRH/ BD/144618/2019). J. F. L. thanks FCT for the research contract through the Program DL 57/2016–Norma Transitória. A. F. L., J. F. L., S. N., J. L. C., and C. L. thank FCT/MCTES (Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) for the national funds received through the project SiSi4Bacter PTDC/QUI-COL/1517/2020. This work was carried out in part through the use of the INL user facilities. The authors thank Dr Jamila Djafari for the conceptualization and design of the graphical abstract. We also thank Ramiro Martínez from Novozymes for the gift of enzymes. Funding Information: This work received financial support from PT national funds (FCT/MCTES, Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) through the projects UIDB/50006/2020 and UIDP/50006/2020. S. N., C. L., J. L. C., A. F. L., and J. F. L. are thankful for the financial support from national funds (FCT/MCTES, Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) through project Met4Cat, EXPL/QUI-COL/0263/2021. This work was supported by the Spanish Government and the Spanish National Research Council (CSIC) (project PIE 201980E081). We thank the financial support by the PROTEOMASS Scientific Society (Portugal) (General Funding Grant 2022). S. N. thanks FCT/MCTEC (Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) Portugal for her doctoral grant associated with the Chemistry PhD program (SFRH/ BD/144618/2019). J. F. L. thanks FCT for the research contract through the Program DL 57/2016-Norma Transitória. A. F. L., J. F. L., S. N., J. L. C., and C. L. thank FCT/MCTES (Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) for the national funds received through the project SiSi4Bacter PTDC/QUI-COL/1517/2020. This work was carried out in part through the use of the INL user facilities. The authors thank Dr Jamila Djafari for the conceptualization and design of the graphical abstract. We also thank Ramiro Martínez from Novozymes for the gift of enzymes. Publisher Copyright: © 2023 RSCThis work investigates the potential utilization of Cu(i) as a reducing agent for the transformation of the platinum salt K2PtCl4, resulting in the production of stable nanoparticles. The synthesized nanoparticles exhibit a bimetallic composition, incorporating copper within their final structure. This approach offers a convenient and accessible methodology for the production of bimetallic nanostructures. The catalytic properties of these novel nanomaterials have been explored in various applications, including their use as artificial metalloenzymes and in the degradation of dyes. The findings underscore the significant potential of Cu(i)-mediated reduction in the development of functional nanomaterials with diverse catalytic applications.publishersversionepub_ahead_of_prin