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Terlingen B, Bos JW, Ahr M, Monai M, van Lare C, Weckhuysen BM. Europium–Magnesium–Aluminum-Based Mixed-Metal Oxides as Highly Active Methane Oxychlorination Catalysts. ACS Catal 2023; 13:5147-5158. [PMID: 37123594 PMCID: PMC10127201 DOI: 10.1021/acscatal.2c06344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 03/18/2023] [Indexed: 04/03/2023]
Abstract
Methane oxychlorination (MOC) is a promising reaction for the production of liquefied methane derivatives. Even though catalyst design is still in its early stages, the general trend is that benchmark catalyst materials have a redox-active site, with, e.g., Cu2+, Ce4+, and Pd2+ as prominent showcase examples. However, with the identification of nonreducible LaOCl moiety as an active center for MOC, it was demonstrated that a redox-active couple is not a requirement to establish a high activity. In this work, we show that Mg2+-Al3+-based mixed-metal oxide (MMO) materials are highly active and stable MOC catalysts. The synergistic interaction between Mg2+ and Al3+ could be exploited due to the fact that a homogeneous distribution of the chemical elements was achieved. This interaction was found to be crucial for the unexpectedly high MOC activity, as reference MgO and γ-Al2O3 materials did not show any significant activity. Operando Raman spectroscopy revealed that Mg2+ acted as a chlorine buffer and subsequently as a chlorinating agent for Al3+, which was the active metal center in the methane activation step. The addition of the redox-active Eu3+ to the nonreducible Mg2+-Al3+ MMO catalyst enabled further tuning of the catalytic performance and made the EuMg3Al MMO catalyst one of the most active MOC catalyst materials reported so far. Combined operando Raman/luminescence spectroscopy revealed that the chlorination behavior of Mg2+ and Eu3+ was correlated, suggesting that Mg2+ also acted as a chlorinating agent for Eu3+. These results indicate that both redox activity and synergistic effects between Eu, Mg, and Al are required to obtain high catalytic performance. The importance of elemental synergy and redox properties is expected to be translatable to the oxychlorination of other hydrocarbons, such as light alkanes, due to large similarities in catalytic chemistry.
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Terlingen B, Arens T, van Swieten TP, Rabouw FT, Prins T, de Beer MM, Meijerink A, Ahr M, Hutter EM, van Lare C, Weckhuysen BM. Bifunctional Europium for Operando Catalyst Thermometry in an Exothermic Chemical Reaction. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202211991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Bas Terlingen
- Utrecht University: Universiteit Utrecht Chemistry NETHERLANDS
| | - Tjom Arens
- Utrecht University: Universiteit Utrecht Chemistry NETHERLANDS
| | | | | | - Tim Prins
- Utrecht University: Universiteit Utrecht Chemistry NETHERLANDS
| | | | | | - Mathieu Ahr
- Nobian Chemistry Zutphenseweg 10 Deventer NETHERLANDS
| | - Eline M. Hutter
- Utrecht University: Universiteit Utrecht Chemistry NETHERLANDS
| | | | - Bert Marc Weckhuysen
- Utrecht University Dept. of Inorganic Chemistry and Catalysis Universiteitsweg 99 3584 CG Utrecht NETHERLANDS
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Zhou E, Chourreu P, Lefèvre N, Ahr M, Rousseau L, Herrero C, Gayon E, Cahiez G, Lefèvre G. Mechanistic Facets of the Competition between Cross-Coupling and Homocoupling in Supporting Ligand-Free Iron-Mediated Aryl–Aryl Bond Formations. ACS Org Inorg Au 2022; 2:359-369. [PMID: 35942278 PMCID: PMC9354087 DOI: 10.1021/acsorginorgau.2c00002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
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In the context of
cross-coupling chemistry, the competition between
the cross-coupling path itself and the oxidative homocoupling of the
nucleophile is a classic issue. In that case, the electrophilic partner
acts as a sacrificial oxidant. We investigate in this report the factors
governing the cross- versus homocoupling distribution using aryl nucleophiles
ArMgBr and (hetero)aryl electrophiles Ar′Cl in the presence
of an iron catalyst. When electron-deficient electrophiles are used,
a key transient heteroleptic [Ar2Ar′FeII]− complex is formed. DFT calculations show that
an asynchronous two-electron reductive elimination follows, which
governs the selective evolution of the system toward either a cross-
or homocoupling product. Proficiency of the cross-coupling reductive
elimination strongly depends on both π-accepting and σ-donating
effects of the FeII-ligated Ar′ ring. The reactivity
trends discussed in this article rely on two-electron elementary steps,
which are in contrast with the usually described tendencies in iron-mediated
oxidative homocouplings which involve single-electron transfers. The
results are probed by paramagnetic 1H NMR spectroscopy,
experimental kinetics data, and DFT calculations.
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Affiliation(s)
- Edouard Zhou
- Institut de Recherche de Chimie Paris, CNRS UMR8247, Chimie ParisTech, PSL Research University, 11 rue Pierre et Marie Curie, 75005 Paris, France
- M2i Development, Bâtiment ChemStart’Up, 64170 Lacq, France
| | - Pablo Chourreu
- Chimie ParisTech, PSL University, CNRS, Institute of Chemistry for Life and Health Sciences, CSB2D, 75005 Paris, France
- M2i Development, Bâtiment ChemStart’Up, 64170 Lacq, France
| | - Nicolas Lefèvre
- Institut de Recherche de Chimie Paris, CNRS UMR8247, Chimie ParisTech, PSL Research University, 11 rue Pierre et Marie Curie, 75005 Paris, France
| | - Mathieu Ahr
- Institut de Recherche de Chimie Paris, CNRS UMR8247, Chimie ParisTech, PSL Research University, 11 rue Pierre et Marie Curie, 75005 Paris, France
| | - Lidie Rousseau
- Chimie ParisTech, PSL University, CNRS, Institute of Chemistry for Life and Health Sciences, CSB2D, 75005 Paris, France
- Université Paris-Saclay, CEA, CNRS, NIMBE, 91191 Gif-sur-Yvette Cedex, France
| | - Christian Herrero
- Institut de Chimie Moléculaire et des Matériaux d’Orsay (UMR 8182) Université Paris Sud, Université Paris Saclay 91405 Orsay Cedex, France
| | - Eric Gayon
- M2i Development, Bâtiment ChemStart’Up, 64170 Lacq, France
| | - Gérard Cahiez
- Institut de Recherche de Chimie Paris, CNRS UMR8247, Chimie ParisTech, PSL Research University, 11 rue Pierre et Marie Curie, 75005 Paris, France
| | - Guillaume Lefèvre
- Chimie ParisTech, PSL University, CNRS, Institute of Chemistry for Life and Health Sciences, CSB2D, 75005 Paris, France
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Terlingen B, Oord R, Ahr M, Hutter EM, van Lare C, Weckhuysen BM. Favoring the Methane Oxychlorination Reaction over EuOCl by Synergistic Effects with Lanthanum. ACS Catal 2022; 12:5698-5710. [PMID: 35557710 PMCID: PMC9087184 DOI: 10.1021/acscatal.2c00777] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 04/18/2022] [Indexed: 11/30/2022]
Abstract
The direct conversion of CH4 into fuels and chemicals produces less waste, requires smaller capital investments, and has improved energy efficiency compared to multistep processes. While the methane oxychlorination (MOC) reaction has been given little attention, it offers the potential to achieve high CH4 conversion levels at high selectivities. In a continuing effort to design commercially interesting MOC catalysts, we have improved the catalyst design of EuOCl by the partial replacement of Eu3+ by La3+. A set of catalytic solid solutions of La3+ and Eu3+ (i.e., La x Eu1-x OCl, where x = 0, 0.25, 0.50, 0.75, and 1) were synthesized and tested in the MOC reaction. The La3+-Eu3+ catalysts exhibit an increased CH3Cl selectivity (i.e., 54-66 vs 41-52%), a lower CH2Cl2 selectivity (i.e., 8-24 vs 18-34%), and a comparable CO selectivity (i.e., 11-28 vs 14-28%) compared to EuOCl under the same reaction conditions and varying HCl concentrations in the feed. The La3+-Eu3+ catalysts possessed a higher CH4 conversion rate than when the individual activities of LaOCl and EuOCl are summed with a similar La3+/Eu3+ ratio (i.e., the linear combination). In the solid solution, La3+ is readily chlorinated and acts as a chlorine buffer that can transfer chlorine to the active Eu3+ phase, thereby enhancing the activity. The improved catalyst design enhances the CH3Cl yield and selectivity and reduces the catalyst cost and the separation cost of the unreacted HCl. These results showcase that, by matching intrinsic material properties, catalyst design can be altered to overcome reaction bottlenecks.
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Affiliation(s)
- Bas Terlingen
- Inorganic
Chemistry and Catalysis Group, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Ramon Oord
- Inorganic
Chemistry and Catalysis Group, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Mathieu Ahr
- Nobian, Zutphenseweg
10, 7418 AJ Deventer, The Netherlands
| | - Eline M. Hutter
- Inorganic
Chemistry and Catalysis Group, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Coert van Lare
- Nobian, Zutphenseweg
10, 7418 AJ Deventer, The Netherlands
| | - Bert M. Weckhuysen
- Inorganic
Chemistry and Catalysis Group, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
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Terlingen B, Oord R, Ahr M, Hutter E, van Lare C, Weckhuysen BM. Mechanistic Insights into the Lanthanide-Catalyzed Oxychlorination of Methane as Revealed by Operando Spectroscopy. ACS Catal 2021; 11:10574-10588. [PMID: 34484853 PMCID: PMC8411843 DOI: 10.1021/acscatal.1c00393] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 07/17/2021] [Indexed: 11/30/2022]
Abstract
Commercialization of CH4 valorization processes is currently hampered by the lack of suitable catalysts, which should be active, selective, and stable. CH4 oxychlorination is one of the promising routes to directly functionalize CH4, and lanthanide-based catalysts show great potential for this reaction, although relatively little is known about their functioning. In this work, a set of lanthanide oxychlorides (i.e., LnOCl with Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, and Ho) and Er- and Yb-based catalysts were synthesized, characterized, and tested. All lanthanide-based catalysts can directly activate CH4 into chloromethanes, but their catalytic properties differ significantly. EuOCl shows the most promising catalytic activity and selectivity, as very high conversion levels (>30%) and chloromethane selectivity values (>50%) can be reached at moderate reaction temperatures (∼425 °C). Operando Raman spectroscopy revealed that the chlorination of the EuOCl catalyst surface is rate-limiting; hence, increasing the HCl concentration improves the catalytic performance. The CO selectivity could be suppressed from 30 to 15%, while the CH4 conversion more than doubled from 11 to 24%, solely by increasing the HCl concentration from 10 to 60% at 450 °C. Even though more catalysts reported in this study and in the literature show a negative correlation between the S CO and HCl concentration, this effect was never as substantial as observed for EuOCl. EuOCl has promising properties to bring the oxychlorination one step closer to an economically viable CH4 valorization process.
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Affiliation(s)
- Bas Terlingen
- Inorganic Chemistry and Catalysis Group, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Ramon Oord
- Inorganic Chemistry and Catalysis Group, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Mathieu Ahr
- Nobian, Zutphenseweg 10, 7418 AJ Deventer, The Netherlands
| | - Eline Hutter
- Inorganic Chemistry and Catalysis Group, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Coert van Lare
- Nobian, Zutphenseweg 10, 7418 AJ Deventer, The Netherlands
| | - Bert M. Weckhuysen
- Inorganic Chemistry and Catalysis Group, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
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Ahr M, Thieuleux C, Copéret C, Fenet B, Basset JM. Noels’vs. Grubbs’ Catalysts: Evidence for One Unique Active Species for Two Different Systems! Adv Synth Catal 2007. [DOI: 10.1002/adsc.200700149] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Abstract
Iron-catalyzed homo-coupling of simple and functionalized arylmagnesium reagents is described. The reaction is highly chemoselective (CN, COOEt and NO(2) groups are tolerated). The procedure was used to perform intramolecular couplings. This cyclization reaction is the key step of the total synthesis of the N-methylcrinasiadine.
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Affiliation(s)
- Gérard Cahiez
- Laboratoire de Synthèse Organique Sélective et de Chimie Organométallique (SOSCO), UMR 8123 CNRS-UCP-ESCOM, Cergy-Pontoise, France.
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Wörz R, Blankenhorn B, Ahr M. [The problem of pain in a German nursing home]. MMW Fortschr Med 2005; 147:40-1, 43. [PMID: 15884502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The experience of, and reaction to, pain by the inhabitants of a nursing home (n = 148) were evaluated. They were invited to score their pain status with the aid of a verbal scale, and/or the nursing staff were asked to estimate it on the basis of a numerical rating scale. The regular and as-required prescription of painkillers was also recorded. Acute attacks of pain were symptoms of sometimes life-threatening diseases, and were scored at the highest level of severity. Patients suffering from chronic pain were most often treated with opioid analgesics. Recurrent attacks of pain were preferentially treated with NSAIDs or metamizol. Pain experienced only during nursing measures or while taking exercise was treated too infrequently. When appropriately trained, the nursing staff are well prepared to establish and document the painful situation, and to rapidly identify new pain syndromes. Regular evaluation should be a standard practice of nursing care.
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Affiliation(s)
- R Wörz
- Schmerzzentrum, Bad Schönborn
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Ahr M, Biehl M. Singularity spectra of rough growing surfaces from wavelet analysis. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 2000; 62:1773-1777. [PMID: 11088639 DOI: 10.1103/physreve.62.1773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2000] [Indexed: 05/23/2023]
Abstract
We apply the wavelet transform modulus maxima method [A. Arneodo, N. Decoster, and S. G. Roux, Phys. Rev. Lett. 83, 1255 (1999)] to the analysis of simulated surfaces grown by molecular-beam epitaxy. In contrast to the structure function approach commonly used in the literature, this method permits an investigation of the complete singularity spectrum. We focus on a kinetic Monte Carlo model with Arrhenius dynamics, which in particular takes into consideration the process of thermally activated desorption of particles. We find a wide spectrum of Holder exponents, which reflects the multiaffine surface morphology. Although our choice of parameters yields small desorption rates (<3%), we observe a dramatic change in the singularity spectrum, which is shifted toward smaller Holder exponents. Our results offer a mathematical foundation of anomalous scaling: We identify the global exponent alpha(g) with the Holder exponent that maximizes the singularity spectrum.
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Affiliation(s)
- M Ahr
- Institut fur Theoretische Physik, Julius-Maximilians-Universitat Wurzburg, Am Hubland, 97074 Wurzburg, Germany
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