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Lewis RJ, Hutchings GJ. Selective Oxidation Using In Situ-Generated Hydrogen Peroxide. Acc Chem Res 2024; 57:106-119. [PMID: 38116936 PMCID: PMC10765371 DOI: 10.1021/acs.accounts.3c00581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 12/04/2023] [Accepted: 12/04/2023] [Indexed: 12/21/2023]
Abstract
ConspectusHydrogen peroxide (H2O2) for industrial applications is manufactured through an indirect process that relies on the sequential reduction and reoxidation of quinone carriers. While highly effective, production is typically centralized and entails numerous energy-intensive concentration steps. Furthermore, the overhydrogenation of the quinone necessitates periodic replacement, leading to incomplete atom efficiency. These factors, in addition to the presence of propriety stabilizing agents and concerns associated with their separation from product streams, have driven interest in alternative technologies for chemical upgrading. The decoupling of oxidative transformations from commercially synthesized H2O2 may offer significant economic savings and a reduction in greenhouse gas emissions for several industrially relevant processes. Indeed, the production and utilization of the oxidant in situ, from the elements, would represent a positive step toward a more sustainable chemical synthesis sector, offering the potential for total atom efficiency, while avoiding the drawbacks associated with current industrial routes, which are inherently linked to commercial H2O2 production. Such interest is perhaps now more pertinent than ever given the rapidly improving viability of green hydrogen production.The application of in situ-generated H2O2 has been a long-standing goal in feedstock valorization, with perhaps the most significant interest placed on propylene epoxidation. Until very recently a viable in situ alternative to current industrial oxidative processes has been lacking, with prior approaches typically hindered by low rates of conversion or poor selectivity toward desired products, often resulting from competitive hydrogenation reactions. Based on over 20 years of research, which has led to the development of catalysts for the direct synthesis of H2O2 that offer high synthesis rates and >99% H2 utilization, we have recently turned our attention to a range of oxidative transformations where H2O2 is generated and utilized in situ. Indeed, we have recently demonstrated that it is possible to rival state-of-the-art industrial processes through in situ H2O2 synthesis, establishing the potential for significant process intensification and considerable decarbonization of the chemical synthesis sector.We have further established the potential of an in situ route to both bulk and fine chemical synthesis through a chemo-catalytic/enzymatic one-pot approach, where H2O2 is synthesized over heterogeneous surfaces and subsequently utilized by a class of unspecific peroxygenase enzymes for C-H bond functionalization. Strikingly, through careful control of the chemo-catalyst, it is possible to ensure that competitive, nonenzymatic pathways are inhibited while also avoiding the regiospecific and selectivity concerns associated with current energy-intensive industrial processes, with further cost savings associated with the operation of the chemo-enzymatic approach at near-ambient temperatures and pressures. Beyond traditional applications of chemo-catalysis, the efficacy of in situ-generated H2O2 (and associated oxygen-based radical species) for the remediation of environmental pollutants has also been a major interest of our laboratory, with such technology offering considerable improvements over conventional disinfection processes.We hope that this Account, which highlights the key contributions of our laboratory to the field over recent years, demonstrates the chemistries that may be unlocked and improved upon via in situ H2O2 synthesis and it inspires broader interest from the scientific community.
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Affiliation(s)
- Richard J. Lewis
- Max Planck−Cardiff Centre on
the Fundamentals of Heterogeneous Catalysis FUNCAT, Cardiff Catalysis
Institute, School of Chemistry, Cardiff
University, Cardiff, CF24 4HQ, United Kingdom
| | - Graham J. Hutchings
- Max Planck−Cardiff Centre on
the Fundamentals of Heterogeneous Catalysis FUNCAT, Cardiff Catalysis
Institute, School of Chemistry, Cardiff
University, Cardiff, CF24 4HQ, United Kingdom
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Dummer NF, Willock DJ, He Q, Howard MJ, Lewis RJ, Qi G, Taylor SH, Xu J, Bethell D, Kiely CJ, Hutchings GJ. Methane Oxidation to Methanol. Chem Rev 2022; 123:6359-6411. [PMID: 36459432 PMCID: PMC10176486 DOI: 10.1021/acs.chemrev.2c00439] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The direct transformation of methane to methanol remains a significant challenge for operation at a larger scale. Central to this challenge is the low reactivity of methane at conditions that can facilitate product recovery. This review discusses the issue through examination of several promising routes to methanol and an evaluation of performance targets that are required to develop the process at scale. We explore the methods currently used, the emergence of active heterogeneous catalysts and their design and reaction mechanisms and provide a critical perspective on future operation. Initial experiments are discussed where identification of gas phase radical chemistry limited further development by this approach. Subsequently, a new class of catalytic materials based on natural systems such as iron or copper containing zeolites were explored at milder conditions. The key issues of these technologies are low methane conversion and often significant overoxidation of products. Despite this, interest remains high in this reaction and the wider appeal of an effective route to key products from C-H activation, particularly with the need to transition to net carbon zero with new routes from renewable methane sources is exciting.
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Affiliation(s)
- Nicholas F. Dummer
- Max Planck−Cardiff Centre on the Fundamentals of Heterogeneous Catalysis FUNCAT, Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, CardiffCF10 3AT, United Kingdom
| | - David J. Willock
- Max Planck−Cardiff Centre on the Fundamentals of Heterogeneous Catalysis FUNCAT, Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, CardiffCF10 3AT, United Kingdom
| | - Qian He
- Department of Materials Science and Engineering, National University of Singapore, Singapore117575, Singapore
| | - Mark J. Howard
- Max Planck−Cardiff Centre on the Fundamentals of Heterogeneous Catalysis FUNCAT, Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, CardiffCF10 3AT, United Kingdom
| | - Richard J. Lewis
- Max Planck−Cardiff Centre on the Fundamentals of Heterogeneous Catalysis FUNCAT, Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, CardiffCF10 3AT, United Kingdom
| | - Guodong Qi
- National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan430071, P. R. China
- University of Chinese Academy of Sciences, Beijing100049, P. R. China
| | - Stuart H. Taylor
- Max Planck−Cardiff Centre on the Fundamentals of Heterogeneous Catalysis FUNCAT, Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, CardiffCF10 3AT, United Kingdom
| | - Jun Xu
- National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan430071, P. R. China
- University of Chinese Academy of Sciences, Beijing100049, P. R. China
| | - Don Bethell
- Department of Chemistry, University of Liverpool, Crown Street, LiverpoolL69 7ZD, United Kingdom
| | - Christopher J. Kiely
- Department of Materials Science and Engineering, Lehigh University, 5 East Packer Avenue, Bethlehem, Pennsylvania18015, United States
| | - Graham J. Hutchings
- Max Planck−Cardiff Centre on the Fundamentals of Heterogeneous Catalysis FUNCAT, Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, CardiffCF10 3AT, United Kingdom
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Effects of Cu Species on Liquid-Phase Partial Oxidation of Methane with H2O2 over Cu-Fe/ZSM-5 Catalysts. Catalysts 2022. [DOI: 10.3390/catal12101224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In this study, a Cu-promoted Fe/ZSM-5 catalyst was examined to reveal the effects of Cu species in selective oxidation of methane into methane oxygenates using H2O2 in water. Cu/ZSM-5, Cu-Fe/ZSM-5, and Fe/ZSM-5 catalysts were prepared using wet impregnation, solid-state ion exchange, and ion-exchange methods. Various techniques, including nitrogen physisorption, temperature-programmed reduction with H2, UV-vis spectroscopy, and FT-IR spectroscopy after NO adsorption, were utilized to characterize the catalysts. The promotional effect of Cu on the Cu-Fe/ZSM-5 catalyst in terms of methanol selectivity was confirmed. The preparation method has a considerable influence on the catalyst performance, and the ion-exchange method is the most effective. However, leaching of the Cu species was observed during this reaction, which can affect the quantification of formic acid by 1H-NMR. The homogeneous Cu species increase hydrogen peroxide decomposition and CO2 selectivity, which is undesirable for this reaction.
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Álvarez M, Marín P, Ordóñez S. Upgrading of methane emissions via chemical looping over copper-zeolites: Experiments and modelling. Chem Eng Sci 2022. [DOI: 10.1016/j.ces.2022.117818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Álvarez M, Marín P, Ordóñez S. Harnessing of Diluted Methane Emissions by Direct Partial Oxidation of Methane to Methanol over Cu/Mordenite. Ind Eng Chem Res 2021; 60:9409-9417. [PMID: 35273425 PMCID: PMC8900128 DOI: 10.1021/acs.iecr.1c01069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/11/2021] [Accepted: 06/13/2021] [Indexed: 11/28/2022]
Abstract
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The upgrading of diluted methane
emissions into valuable products
can be accomplished at low temperatures (200 °C) by the direct
partial oxidation of methanol over copper-exchanged zeolite catalysts.
The reaction has been studied in a continuous fixed-bed reactor loaded
with a Cu–mordenite catalyst, according to a three-step cyclic
process: adsorption of methane, desorption of methanol, and reactivation
of the catalyst. The purpose of the work is the use of methane emissions
as feedstocks, which is challenging due to their low methane concentration
and the presence of oxygen. Methane concentration had a marked influence
on methane adsorption and methanol production (decreased from 164
μmol/g Cu for pure methane to 19 μmol/g Cu for 5% methane).
The presence of oxygen, even in low concentrations (2.5%), reduced
methane adsorption drastically. However, methanol production was only
affected slightly (average decrease of 9%), concluding that methane
adsorbed on the active centers yielding methanol is not influenced
by oxygen.
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Affiliation(s)
- Mauro Álvarez
- Catalysis, Reactors and Control Research Group (CRC), Department of Chemical and Environmental Engineering, University of Oviedo, Faculty of Chemistry, Julián Clavería 8, 33006 Oviedo, Spain
| | - Pablo Marín
- Catalysis, Reactors and Control Research Group (CRC), Department of Chemical and Environmental Engineering, University of Oviedo, Faculty of Chemistry, Julián Clavería 8, 33006 Oviedo, Spain
| | - Salvador Ordóñez
- Catalysis, Reactors and Control Research Group (CRC), Department of Chemical and Environmental Engineering, University of Oviedo, Faculty of Chemistry, Julián Clavería 8, 33006 Oviedo, Spain
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