One-pot synthesis of nano-crystalline MCM-22

[EN] Nano-crystalline MCM-22 zeolite was synthesized in a one-pot procedure by the use of an organosilane (dimethyl-octadecyl-(3-trimethoxysilylpropyl)-ammonium chloride, TPOAC) in the zeolite synthesis gel. This crystal growth inhibition procedure introduced mesopores in the MCM-22 crystallites. The lower mechanical stability of the nano-crystalline MCM-22 zeolite compared with bulk MCM-22 can be countered to some extent by pillaring. The increased external surface of the microporous zeolite domains resulted in increased accessibility of the Bronsted acid sites, as followed from the better performance in liquid-phase benzene alkylation with propylene as compared with bulk MCM-22. The increased accessibility of the internal acid sites in Mo-loaded hierarchical MCM-22 was also evident from the improved benzene selectivity during methane aromatization. Silylation of hierarchical Mo/MCM-22 was detrimental for the catalytic performance in MDA. The nano-crystalline MCM-22 has physico-chemical and catalytic properties intermediate between those of MCM-22 and ITQ-2 with the benefit over ITQ-2 that it can be synthesized in a single step. (C) 2015 Elsevier Inc. All rights reserved.Funding from the 7th Framework Program of the European Commission through the Collaborative Project Next-GTL (agreement no 229183) and financial support by the Spanish Government-MINECO through "Severo Ochoa" (SEV 2012-0267), Consolider Ingenio 2010-Multicat (CSD2009-00050) and MAT2012-31657 are acknowledged. Marta E. Martinez Armero thanks MINECO for economical support through pre-doctoral fellowship for doctors training (BES-2013-066800). The authors thank B. Esparcia for technical assistance.Tempelman, CHL.; Portilla Ovejero, MT.; Martínez Armero, ME.; Mezari, B.; De Caluwe, NGR.; Martínez, C.; Hensen, EJM. (2016). One-pot synthesis of nano-crystalline MCM-22. Microporous and Mesoporous Materials. 220:28-38. https://doi.org/10.1016/j.micromeso.2015.08.018S283822

ITQ-39 zeolite, an efficient catalyst for the conversion of low value naphtha fractions into diesel fuel: The role of pore size on molecular diffusion and reactivity

ITQ-39, a multipore zeolite with interconnected 12- and 10-ring channel systems, effectively catalyzes the alkylation of two low value naphtha fractions for the production of diesel range alkylaromatics. A catalytic and molecular dynamics study allows us to conclude that its higher selectivity to the desired diesel fraction and, especially, its longer catalyst life as compared to beta or MCM-22, conventionally used as heterogeneous alkylation catalysts, are due to the combined contribution of its small nano-sized crystallites, moderate Brønsted acidity and unique framework topology. The small diffusion coefficients obtained for alkylaromatics on ITQ-39 as compared to those corresponding to the large pore beta zeolite evidence the significant diffusional problems of most of the reactants and products through the channels of the ITQ-39 structure. Thus, alkylation reactions on this zeolite seem to occur mainly on the most external acid sites (external surface, pore mouths), whereas the zeolite structure contributes positively by preventing undesired reactions to occur, which would result in lower selectivity to the monoalkylated products and in a faster catalyst deactivation.Financial support by the Spanish Government-MINECO through “Severo Ochoa” (SEV 2012-0267), Consolider Ingenio 2010-Multicat, MAT2012-37160 and MAT2012-31657, by the European Union through ERC-AdG-2014-671093 – SynCatMatch and by the Generalitat Valenciana through the Prometeo program (PROMETEOII/2013/011) is acknowledged. Repsol is thanked for financial support and permission to publish these results.Peer Reviewe

Síntesis de la zeolita beta en su forma nanocristalina, procedimiento de síntesis y su uso en aplicaciones catalíticas

Síntesis de la zeolita beta en su forma nanocristalina, procedimiento de síntesis y su uso en aplicaciones catalíticas. La presente invención se refiere a un nuevo proceso de síntesis de un material cristalino que presenta la estructura zeolítica Beta en su forma nanocristalina, y que puede comprender, al menos, los siguientes pasos: i) Preparación de una mezcla que comprenda al menos una fuente de agua, al menos una fuente de un elemento tetravalente Y, al menos una fuente de un elemento trivalente X, al menos una fuente de un catión alcalino o alcalinotérreo (A), y al menos una molécula orgánica seleccionada entre un amonio cuaternario monocíclico R1R2CycloN+, y un amonio cuaternario sustituido con un grupo cicloalquílico R3R4R5R6N+. La composición molar de la mezcla es: n X2O3 : YO2 : a A : m ADEO1 : z H2; ii) Cristalización de dicha mezcla; y iii) Recuperación del material cristalino. [ES]The present invention relates to a new process for synthesising a crystalline material comprising the structure Beta zeolite in nanocrystalline form, and which can comprise at least the following steps: (i) preparing a mixture comprising at least one source of water, at least one source of a tetravalent element Y, at least one source of a trivalent element X, at least one source of an alkali cation or alkaline earth metal cation (A), and at least one organic molecule selected from a monocyclic quaternary ammonium R1R2CycloN+, and a quaternary ammonium substituted with a cycloalkyl group R3R4R5R6N+, the molar composition of the mixture being n X2O3 : YO2 : a A : m ADEO1 : z H2O; (ii) crystallising the mixture; and (iii) recovering the crystalline material. [EN]Peer reviewedUniversitat Politècnica de València, Consejo Superior de Investigaciones Científicas (España)A1 Solicitud de patente con informe sobre el estado de la técnic

Synthesis of nanocrystalline beta zeolite, synthesis method and use thereof in catalytic applications

The present invention relates to a new process for synthesising a crystalline material comprising structure Beta zeolite in nanocrystalline form, and which can comprise at least the following steps: (i) preparing a mixture comprising at least one source of water, at least one source of a tetravalent element Y, at least one source of a trivalent element X, at least one source of an alkali cation or alkaline earth metal cation (A), and at least one organic molecule selected from a monocyclic quaternary ammonium R1R2CycloN+, and a quaternary ammonium substituted with a cycloalkyl group R3R4R5R6N+. The molar composition of the mixture is: n X2O3:YO2:a A:m OSDA1:z H2O; ii) crystallising the mixture; and iii) recovering the crystalline materialPeer reviewedUniversitat Politècnica de València, Consejo Superior de Investigaciones Científicas (España)A1 Solicitud de patente con informe sobre el estado de la técnic

Synthesis of nanocrystalline beta zeolite, synthesis method and use thereof in catalytic applications

The present invention relates to a new process for synthesising a crystalline material comprising structure Beta zeolite in nanocrystalline form, and which can comprise at least the following steps: (i) preparing a mixture comprising at least one source of water, at least one source of a tetravalent element Y, at least one source of a trivalent element X, at least one source of an alkali cation or alkaline earth metal cation (A), and at least one organic molecule selected from a monocyclic quaternary ammonium R1R2CycloN+, and a quaternary ammonium substituted with a cycloalkyl group R3R4R5R6N+. The molar composition of the mixture is: n X2O3 : YO2 : a A : m OSDA1 : z H2O; ii) crystallising the mixture; and iii) recovering the crystalline materialPeer reviewedUniversitat Politècnica de València, Consejo Superior de Investigaciones Científicas (España)A1 Solicitud de patente con informe sobre el estado de la técnic

Síntesis de la zeolita beta en su forma nanocristalina, procedimiento de síntesis y su uso en aplicaciones catalíticas

The present invention relates to a new process for synthesising a crystalline material comprising the structure Beta zeolite in nanocrystalline form, and which can comprise at least the following steps: (i) preparing a mixture comprising at least one source of water, at least one source of a tetravalent element Y, at least one source of a trivalent element X, at least one source of an alkali cation or alkaline earth metal cation (A), and at least one organic molecule selected from a monocyclic quaternary ammonium R1R2CycloN+, and a quaternary ammonium substituted with a cycloalkyl group R3R4R5R6N+, the molar composition of the mixture being n X2O3 : YO2 : a A : m ADEO1 : z H2O; (ii) crystallising the mixture; and (iii) recovering the crystalline material. [EN]La presente invención se refiere a un nuevo proceso de síntesis de un material cristalino que presenta la estructura zeoiítica Beta en su forma nanocristalina, y que puede comprender, al menos, los siguientes pasos: i) Preparación de una mezcla que comprenda al menos una fuente de agua, ai menos una fuente de un elemento tetravalente Y, al menos una fuente de un elemento trivalente X, ai menos una fuente de un catión alcalino o alcalinotérreo (A), y al menos una molécula orgánica seleccionada entre un amonio cuaternario monocíclico R1R2CycloN+, y un amonio cuaternario sustituido con un grupo cicloalquílico R3R4R5R6N+. La composición molar de la mezcla es: n X2O3 : YO2 : a A : m ADEO1 : z H2O; ii) Cristalización de dicha mezcla: y iii) Recuperación del material cristalino. [ES]Peer reviewedUniversitat Politècnica de València, Consejo Superior de Investigaciones Científicas (España)A1 Solicitud de patente con informe sobre el estado de la técnic

ITQ-39 zeolite, an efficient catalyst for the conversion of low value naphtha fractions into diesel fuel: The role of pore size on molecular diffusion and reactivity

[EN] ITQ-39, a multipore zeolite with interconnected 12- and 10-ring channel systems, effectively catalyzes the alkylation of two low value naphtha fractions for the production of diesel range alkylaromatics. A catalytic and molecular dynamics study allows us to conclude that its higher selectivity to the desired diesel fraction and, especially, its longer catalyst life as compared to beta or MCM-22, conventionally used as heterogeneous alkylation catalysts, are due to the combined contribution of its small nano-sized crystallites, moderate Bronsted acidity and unique framework topology. The small diffusion coefficients obtained for alkylaromatics on ITQ-39 as compared to those corresponding to the large pore beta zeolite evidence the significant diffusional problems of most of the reactants and products through the channels of the ITQ-39 structure. Thus, alkylation reactions on this zeolite seem to occur mainly on the most external acid sites (external surface, pore mouths), whereas the zeolite structure contributes positively by preventing undesired reactions to occur, which would result in lower selectivity to the monoalkylated products and in a faster catalyst deactivation.Financial support by the Spanish Government-MINECO through "Severo Ochoa" (SEV 2012-0267), Consolider Ingenio 2010-Multicat, MAT2012-37160 and MAT2012-31657, by the European Union through ERC-AdG-2014-671093 - SynCatMatch and by the Generalitat Valenciana through the Prometeo program (PROME-TEOII/2013/011) is acknowledged. Repsol is thanked for financial support and permission to publish these results. G.S. thanks ASIC-UPV for computing time. The Electron Microscopy Service of the UPV is acknowledged for their help in samples characterization.Martínez Armero, ME.; Moliner Marin, M.; Sastre Navarro, GI.; Rey Garcia, F.; Martínez, C.; Corma Canós, A. (2016). ITQ-39 zeolite, an efficient catalyst for the conversion of low value naphtha fractions into diesel fuel: The role of pore size on molecular diffusion and reactivity. Journal of Catalysis. 333:127-138. https://doi.org/10.1016/j.jcat.2015.10.02412713833

Prosthetic Valve Candida spp. Endocarditis: New Insights Into Long-term Prognosis—The ESCAPE Study

International audienceBackground: Prosthetic valve endocarditis caused by Candida spp. (PVE-C) is rare and devastating, with international guidelines based on expert recommendations supporting the combination of surgery and subsequent azole treatment.Methods: We retrospectively analyzed PVE-C cases collected in Spain and France between 2001 and 2015, with a focus on management and outcome.Results: Forty-six cases were followed up for a median of 9 months. Twenty-two patients (48%) had a history of endocarditis, 30 cases (65%) were nosocomial or healthcare related, and 9 (20%) patients were intravenous drug users. "Induction" therapy consisted mainly of liposomal amphotericin B (L-amB)-based (n = 21) or echinocandin-based therapy (n = 13). Overall, 19 patients (41%) were operated on. Patients <66 years old and without cardiac failure were more likely to undergo cardiac surgery (adjusted odds ratios [aORs], 6.80 [95% confidence interval [CI], 1.59-29.13] and 10.92 [1.15-104.06], respectively). Surgery was not associated with better survival rates at 6 months. Patients who received L-amB alone had a better 6-month survival rate than those who received an echinocandin alone (aOR, 13.52; 95% CI, 1.03-838.10). "Maintenance" fluconazole therapy, prescribed in 21 patients for a median duration of 13 months (range, 2-84 months), led to minor adverse effects.Conclusion: L-amB induction treatment improves survival in patients with PVE-C. Medical treatment followed by long-term maintenance fluconazole may be the best treatment option for frail patients