Nanotitania catalyzes the chemoselective hydration and alkoxylation of epoxides

[EN] Glycols and ethoxy- and propoxy-alcohols are fundamental chemicals in industry, with annual productions of millions of tons, still manufactured in many cases with corrosive and unrecoverable catalysts such as KOH, amines and BF3 center dot OEt2. Here we show that commercially available, inexpensive, non-toxic, solid and recyclable nanotitania catalyzes the hydration and alkoxylation of epoxides, with water and primary and secondary alcohols but not with phenols, carboxylic acids and tertiary alcohols. In this way, the chemoselective synthesis of different glycols and 1,4-dioxanones, and the implementation of nanotitania for the production in-flow of glycols and alkoxylated alcohols, has been achieved. Mechanistic studies support the key role of vacancies in the nano-oxide catalyst.A.L.-P. thanks the MICIIN (project code PID2020-115100GB-I00) for financial support. J.O.-M. thanks the Juan de la Cierva Program for the concession of a contract (IJC2018-036514-I). J.B.-S. thanks La Caixa Foundation grant (ID 100010434), code LCF/BQ/DI19/11730029.Oliver-Meseguer, J.; Ballesteros-Soberanas, J.; Tejeda-Serrano, M.; Martínez-Castelló, A.; Leyva Perez, A. (2021). Nanotitania catalyzes the chemoselective hydration and alkoxylation of epoxides. Molecular Catalysis. 515:1-11. https://doi.org/10.1016/j.mcat.2021.111927S11151

Intermolecular Carbonyl-olefin Metathesis with Vinyl Ethers Catalyzed by Homogeneous and Solid Acids in Flow

This is the peer reviewed version of the following article: M. Á. Rivero-Crespo, M. Tejeda-Serrano, H. Pérez-Sánchez, J. P. Cerón-Carrasco, A. Leyva-Pérez, Angew. Chem. Int. Ed. 2020, 59, 3846, which has been published in final form at https://doi.org/10.1002/anie.201909597. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] The carbonyl-olefin metathesis reaction has experienced significant advances in the last seven years with new catalysts and reaction protocols. However, most of these procedures involve soluble catalysts for intramolecular reactions in batch. Herein, we show that recoverable, inexpensive, easy to handle, non-toxic, and widely available simple solid acids, such as the aluminosilicate montmorillonite, can catalyze the intermolecular carbonyl-olefin metathesis of aromatic ketones and aldehydes with vinyl ethers in-flow, to give alkenes with complete trans stereoselectivity on multi-gram scale and high yields. Experimental and computational data support a mechanism based on a carbocation-induced Grob fragmentation. These results open the way for the industrial implementation of carbonyl-olefin metathesis over solid catalysts in continuous mode, which is still the origin and main application of the parent alkene-alkene cross-metathesis.Financial support by MINECO through the Severo Ochoa program (SEV-2016-0683), Excellence program (CTQ 2017-86735-P, CTQ 2017-87974-R), Retos Col. (RTC-2017-6331-5), and "Convocatoria 2014 de Ayudas Fundacion BBVA a Investigadores y Creadores Culturales" is acknowledged. M.A.R.-C. and M.T.-S. thank ITQ for the concession of a contract. This research was partially supported by the supercomputing infrastructure of Poznan Supercomputing Center.Rivero-Crespo, MÁ.; Tejeda-Serrano, M.; Perez-Sánchez, H.; Cerón-Carrasco, JP.; Leyva Perez, A. (2020). Intermolecular Carbonyl-olefin Metathesis with Vinyl Ethers Catalyzed by Homogeneous and Solid Acids in Flow. Angewandte Chemie International Edition. 59(10):3846-3849. https://doi.org/10.1002/anie.201909597S384638495910Becker, M. R., Watson, R. B., & Schindler, C. S. (2018). Beyond olefins: new metathesis directions for synthesis. Chemical Society Reviews, 47(21), 7867-7881. doi:10.1039/c8cs00391bGriffith, A. K., Vanos, C. M., & Lambert, T. H. (2012). Organocatalytic Carbonyl-Olefin Metathesis. Journal of the American Chemical Society, 134(45), 18581-18584. doi:10.1021/ja309650uLudwig, J. R., Zimmerman, P. M., Gianino, J. B., & Schindler, C. S. (2016). Iron(III)-catalysed carbonyl–olefin metathesis. Nature, 533(7603), 374-379. doi:10.1038/nature17432Ludwig, J. R., Phan, S., McAtee, C. C., Zimmerman, P. M., Devery, J. J., & Schindler, C. S. (2017). Mechanistic Investigations of the Iron(III)-Catalyzed Carbonyl-Olefin Metathesis Reaction. Journal of the American Chemical Society, 139(31), 10832-10842. doi:10.1021/jacs.7b05641For reviews on carbonyl olefin metathesis see:Schindler, C., & Ludwig, J. (2017). Lewis Acid Catalyzed Carbonyl–Olefin Metathesis. Synlett, 28(13), 1501-1509. doi:10.1055/s-0036-1588827T. H. Lambert Synlett2019 ahead of print.For examples of solid-catalyzed low-temperature alkene metathesis see:Mougel, V., Chan, K.-W., Siddiqi, G., Kawakita, K., Nagae, H., Tsurugi, H., … Copéret, C. (2016). Low Temperature Activation of Supported Metathesis Catalysts by Organosilicon Reducing Agents. ACS Central Science, 2(8), 569-576. doi:10.1021/acscentsci.6b00176Korzyński, M. D., Consoli, D. F., Zhang, S., Román-Leshkov, Y., & Dincă, M. (2018). Activation of Methyltrioxorhenium for Olefin Metathesis in a Zirconium-Based Metal–Organic Framework. Journal of the American Chemical Society, 140(22), 6956-6960. doi:10.1021/jacs.8b02837Van Schaik, H.-P., Vijn, R.-J., & Bickelhaupt, F. (1994). Acid-Catalyzed Olefination of Benzaldehyde. Angewandte Chemie International Edition in English, 33(1516), 1611-1612. doi:10.1002/anie.199416111Van Schaik, H.-P., Vijn, R.-J., & Bickelhaupt, F. (1994). Säurekatalysierte Olefinierung von Benzaldehyd. Angewandte Chemie, 106(15-16), 1703-1704. doi:10.1002/ange.19941061529For pure Bronsted acid-catalyzed reactions see:Ludwig, J. R., Watson, R. B., Nasrallah, D. J., Gianino, J. B., Zimmerman, P. M., Wiscons, R. A., & Schindler, C. S. (2018). Interrupted carbonyl-olefin metathesis via oxygen atom transfer. Science, 361(6409), 1363-1369. doi:10.1126/science.aar8238Catti, L., & Tiefenbacher, K. (2018). Brønsted Acid-Catalyzed Carbonyl-Olefin Metathesis inside a Self-Assembled Supramolecular Host. Angewandte Chemie International Edition, 57(44), 14589-14592. doi:10.1002/anie.201712141Catti, L., & Tiefenbacher, K. (2018). Brønsted-Säure-katalysierte Carbonyl-Olefin-Metathese in einer selbstorganisierten supramolekularen Wirtstruktur. Angewandte Chemie, 130(44), 14797-14800. doi:10.1002/ange.201712141For intermolecular reactions see:Ni, S., & Franzén, J. (2018). Carbocation catalysed ring closing aldehyde–olefin metathesis. Chemical Communications, 54(92), 12982-12985. doi:10.1039/c8cc06734aPitzer, L., Sandfort, F., Strieth‐Kalthoff, F., & Glorius, F. (2018). Carbonyl–Olefin Cross‐Metathesis Through a Visible‐Light‐Induced 1,3‐Diol Formation and Fragmentation Sequence. Angewandte Chemie International Edition, 57(49), 16219-16223. doi:10.1002/anie.201810221Pitzer, L., Sandfort, F., Strieth‐Kalthoff, F., & Glorius, F. (2018). Carbonyl‐Olefin‐Kreuzmetathese mittels Licht‐induzierter 1,3‐Diol‐Bildung‐ und Fragmentierungssequenz. Angewandte Chemie, 130(49), 16453-16457. doi:10.1002/ange.201810221Tran, U. P. N., Oss, G., Pace, D. P., Ho, J., & Nguyen, T. V. (2018). Tropylium-promoted carbonyl–olefin metathesis reactions. Chemical Science, 9(23), 5145-5151. doi:10.1039/c8sc00907dTran, U. P. N., Oss, G., Breugst, M., Detmar, E., Pace, D. P., Liyanto, K., & Nguyen, T. V. (2018). Carbonyl–Olefin Metathesis Catalyzed by Molecular Iodine. ACS Catalysis, 9(2), 912-919. doi:10.1021/acscatal.8b03769Lewis, J. D., Van de Vyver, S., & Román‐Leshkov, Y. (2015). Acid–Base Pairs in Lewis Acidic Zeolites Promote Direct Aldol Reactions by Soft Enolization. Angewandte Chemie International Edition, 54(34), 9835-9838. doi:10.1002/anie.201502939Lewis, J. D., Van de Vyver, S., & Román‐Leshkov, Y. (2015). Acid–Base Pairs in Lewis Acidic Zeolites Promote Direct Aldol Reactions by Soft Enolization. Angewandte Chemie, 127(34), 9973-9976. doi:10.1002/ange.201502939Fortea-Pérez, F. R., Mon, M., Ferrando-Soria, J., Boronat, M., Leyva-Pérez, A., Corma, A., … Pardo, E. (2017). The MOF-driven synthesis of supported palladium clusters with catalytic activity for carbene-mediated chemistry. Nature Materials, 16(7), 760-766. doi:10.1038/nmat4910Oliver-Meseguer, J., Boronat, M., Vidal-Moya, A., Concepción, P., Rivero-Crespo, M. Á., Leyva-Pérez, A., & Corma, A. (2018). Generation and Reactivity of Electron-Rich Carbenes on the Surface of Catalytic Gold Nanoparticles. Journal of the American Chemical Society, 140(9), 3215-3218. doi:10.1021/jacs.7b13696Rivero‐Crespo, M. A., Mon, M., Ferrando‐Soria, J., Lopes, C. W., Boronat, M., Leyva‐Pérez, A., … Pardo, E. (2018). Confined Pt 1 1+ Water Clusters in a MOF Catalyze the Low‐Temperature Water–Gas Shift Reaction with both CO 2 Oxygen Atoms Coming from Water. Angewandte Chemie International Edition, 57(52), 17094-17099. doi:10.1002/anie.201810251Rivero‐Crespo, M. A., Mon, M., Ferrando‐Soria, J., Lopes, C. W., Boronat, M., Leyva‐Pérez, A., … Pardo, E. (2018). Confined Pt 1 1+ Water Clusters in a MOF Catalyze the Low‐Temperature Water–Gas Shift Reaction with both CO 2 Oxygen Atoms Coming from Water. Angewandte Chemie, 130(52), 17340-17345. doi:10.1002/ange.201810251Tejeda-Serrano, M., Mon, M., Ross, B., Gonell, F., Ferrando-Soria, J., Corma, A., … Pardo, E. (2018). Isolated Fe(III)–O Sites Catalyze the Hydrogenation of Acetylene in Ethylene Flows under Front-End Industrial Conditions. Journal of the American Chemical Society, 140(28), 8827-8832. doi:10.1021/jacs.8b04669Ma, L., Li, W., Xi, H., Bai, X., Ma, E., Yan, X., & Li, Z. (2016). FeCl3 -Catalyzed Ring-Closing Carbonyl-Olefin Metathesis. Angewandte Chemie International Edition, 55(35), 10410-10413. doi:10.1002/anie.201604349Ma, L., Li, W., Xi, H., Bai, X., Ma, E., Yan, X., & Li, Z. (2016). FeCl3 -Catalyzed Ring-Closing Carbonyl-Olefin Metathesis. Angewandte Chemie, 128(35), 10566-10569. doi:10.1002/ange.201604349McAtee, C. C., Riehl, P. S., & Schindler, C. S. (2017). Polycyclic Aromatic Hydrocarbons via Iron(III)-Catalyzed Carbonyl–Olefin Metathesis. Journal of the American Chemical Society, 139(8), 2960-2963. doi:10.1021/jacs.7b01114Niyomchon, S., Oppedisano, A., Aillard, P., & Maulide, N. (2017). A three-membered ring approach to carbonyl olefination. Nature Communications, 8(1). doi:10.1038/s41467-017-01036-yWatson, R. B., & Schindler, C. S. (2017). Iron-Catalyzed Synthesis of Tetrahydronaphthalenes via 3,4-Dihydro-2H-pyran Intermediates. Organic Letters, 20(1), 68-71. doi:10.1021/acs.orglett.7b03367Groso, E. J., Golonka, A. N., Harding, R. A., Alexander, B. W., Sodano, T. M., & Schindler, C. S. (2018). 3-Aryl-2,5-Dihydropyrroles via Catalytic Carbonyl-Olefin Metathesis. ACS Catalysis, 8(3), 2006-2011. doi:10.1021/acscatal.7b03769Albright, H., Riehl, P. S., McAtee, C. C., Reid, J. P., Ludwig, J. R., Karp, L. A., … Schindler, C. S. (2018). Catalytic Carbonyl-Olefin Metathesis of Aliphatic Ketones: Iron(III) Homo-Dimers as Lewis Acidic Superelectrophiles. Journal of the American Chemical Society, 141(4), 1690-1700. doi:10.1021/jacs.8b11840Śliwa, M., Samson, K., Ruggiero–Mikołajczyk, M., Żelazny, A., & Grabowski, R. (2014). Influence of Montmorillonite K10 Modification with Tungstophosphoric Acid on Hybrid Catalyst Activity in Direct Dimethyl Ether Synthesis from Syngas. Catalysis Letters, 144(11), 1884-1893. doi:10.1007/s10562-014-1359-5Cabrero-Antonino, J. R., Leyva-Pérez, A., & Corma, A. (2015). Beyond Acid Strength in Zeolites: Soft Framework Counteranions for Stabilization of Carbocations on Zeolites and Its Implication in Organic Synthesis. Angewandte Chemie International Edition, 54(19), 5658-5661. doi:10.1002/anie.201500864Cabrero-Antonino, J. R., Leyva-Pérez, A., & Corma, A. (2015). Beyond Acid Strength in Zeolites: Soft Framework Counteranions for Stabilization of Carbocations on Zeolites and Its Implication in Organic Synthesis. Angewandte Chemie, 127(19), 5750-5753. doi:10.1002/ange.201500864Gassman, P. G., & Burns, S. J. (1988). General method for the synthesis of enol ethers (vinyl ethers) from acetals. The Journal of Organic Chemistry, 53(23), 5574-5576. doi:10.1021/jo00258a043Yamamoto, T., Eki, T., Nagumo, S., Suemune, H., & Sakai, K. (1992). Drastic ring transformation reactions of fused bicyclic rings to bridged bicyclic rings. Tetrahedron, 48(22), 4517-4524. doi:10.1016/s0040-4020(01)81224-2Nagumo, S., Matsukuma, A., Suemune, H., & Sakai, K. (1993). Novel ring cleavage based on intermolecular aldol condensation. Tetrahedron, 49(46), 10501-10510. doi:10.1016/s0040-4020(01)81545-3Suemune, H., Yoshida, O., Uchida, J., Nomura, Y., Tanaka, M., & Sakai, K. (1995). Asymmetric ring cleavage reaction based on crossed aldol condensation. Tetrahedron Letters, 36(40), 7259-7262. doi:10.1016/0040-4039(95)01504-bKumar, B. S., Dhakshinamoorthy, A., & Pitchumani, K. (2014). K10 montmorillonite clays as environmentally benign catalysts for organic reactions. Catal. Sci. Technol., 4(8), 2378-2396. doi:10.1039/c4cy00112ePérez-Ruiz, R., Miranda, M. A., Alle, R., Meerholz, K., & Griesbeck, A. G. (2006). An efficient carbonyl-alkene metathesis of bicyclic oxetanes: photoinduced electron transfer reduction of the Paternò–Büchi adducts from 2,3-dihydrofuran and aromatic aldehydes. Photochem. Photobiol. Sci., 5(1), 51-55. doi:10.1039/b513875bD’Auria, M., & Racioppi, R. (2013). Oxetane Synthesis through the Paternò-Büchi Reaction. Molecules, 18(9), 11384-11428. doi:10.3390/molecules180911384Mete, T. B., Khopade, T. M., & Bhat, R. G. (2017). Oxidative decarboxylation of arylacetic acids in water: One-pot transition-metal-free synthesis of aldehydes and ketones. 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Isolated Fe(III)-O Sites Catalyze the Hydrogenation of Acetylene in Ethylene Flows under Front-End Industrial Conditions

[EN] The search for simple, earth-abundant, cheap, and nontoxic metal catalysts able to perform industrial hydrogenations is a topic of interest, transversal to many catalytic processes. Here, we show that isolated FeIII¿O sites on solids are able to dissociate and chemoselectively transfer H2 to acetylene in an industrial process. For that, a novel, robust, and highly crystalline metal¿organic framework (MOF), embedding FeIII¿OH2 single sites within its pores, was prepared in multigram scale and used as an efficient catalyst for the hydrogenation of 1% acetylene in ethylene streams under front-end conditions. Cutting-edge X-ray crystallography allowed the resolution of the crystal structure and snapshotted the single-atom nature of the catalytic FeIII¿O site. Translation of the active site concept to even more robust and inexpensive titania and zirconia supports enabled the industrially relevant hydrogenation of acetylene with similar activity to the Pd-catalyzed process.This work was supported by the MINECO (Spain) (Projects CTQ2016-75671-P, CTQ2014-56312-P, CTQ2014-55178-R, and Excellence Units "Severo Ochoa" and "Maria de Maeztu" SEV-2016-0683 and MDM-2015-0538) and the Ministero dell'Istruzione, dell'Universita e della Ricerca (Italy) (FFABR 2017). M.M. thanks the mineco for a predoctoral contract. Thanks are also extended to the Ramon y Cajal Program (E.P.) and the "Suprograma atraccio de talent-contractes postdoctorals de la Universitat de Valencia" (J.F.-S.). A.L.-P. and J.F.S. also thank fBBVA for the concession of a young investigator grants.Tejeda-Serrano, M.; Mon, M.; Ross, B.; Gonell-Gómez, F.; Ferrando-Soria, J.; Corma Canós, A.; Leyva Perez, A.... (2018). Isolated Fe(III)-O Sites Catalyze the Hydrogenation of Acetylene in Ethylene Flows under Front-End Industrial Conditions. Journal of the American Chemical Society. 140(28):8827-8832. https://doi.org/10.1021/jacs.8b04669S882788321402

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Planeación estratégica aplicada a la mercadotecnia, estudio de caso: Pepsi-Cola

Seminario: Planeación estrategica creativ

Bimetallic nanosized solids with acid and redox properties for catalytic activation of C-C and C-H bonds

A new approach is presented to form self-supported bimetallic nanosized solids with acid and redox catalytic properties. They are water-, air- and H-2-stable, and are able to activate demanding C-C and C-H reactions. A detailed mechanistic study on the formation of the Ag-Fe bimetallic system shows that a rapid redox-coupled sequence between Ag+, O-2 (air) and Fe2+ occurs, giving monodisperse Ag nanoparticles supported by O-bridged diatomic Fe3+ triflimides. The system can be expanded to Ag nanoparticles embedded within a matrix of Cu2+, Bi3+ and Yb3+ triflimide.Financial support by the "Severo Ochoa" program, RETOS program (CTQ2014-55178 R) and Ramon y Cajal Program (A.L.-P.) by MINECO (Spain), and also by "Convocatoria 2014 de Ayudas Fundacion BBVA a Investigadores y Creadores Culturales" are acknowledged. The Electron Microscopy Service of the UPV is also acknowledged.Cabrero Antonino, JR.; Tejeda-Serrano, M.; Quesada Vilar, M.; Vidal Moya, JA.; Leyva Perez, A.; Corma Canós, A. 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Boundary Conditions for Promotion versus Poisoning in Copper-Gallium-based CO2–to–Methanol Hydrogenation Catalysts

Cu-Ga-based CO2-to-methanol hydrogenation catalysts are known to display a range of catalytic performance depending on their preparation. Here, using surface organometallic chemistry, we have prepared a series of silica-supported 3-6 nm Cu1-xGaxOy nanoparticles with a range of xGa to establish how the concentration of Ga and alloy formation affect the activity. Cu is always fully metallic in this series, while Ga is partially alloyed with Cu in the core and partially oxidized on the surface. These materials display a volcano-type activity behavior, where methanol formation is promoted when xGa < 0.13-0.18 and is suppressed at higher values, indicating a poisoning of the catalysts. In situ X-ray absorption spectroscopy shows that GaOx species over promoted Cu0.93Ga0.07-SiO2 catalyst are much more redox active than those over the poisoned Cu0.77Ga0.23-SiO2. In situ infrared spectroscopy detected methoxy intermediates over the promoted Cu0.93Ga0.07-SiO2 catalyst, while no formate or methoxy species could be observed over the poisoned Cu0.77Ga0.23-SiO2. The absence of reactive intermediates and irreversible oxidation of GaOx over poisoned catalyst suggests encapsulation of Cu by GaOx shell resulting in low activity

I Diretriz Latino-Americana para avaliação e conduta na insuficiência cardíaca descompensada I Latin American Guidelines for the assessment and management of decompensated heart failure

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