Pub Date : 1998-11-01DOI: 10.1080/01614949808007114
G. Mestl, T. K. Srinivasan
Abstract Oxides of the group VIb metals (Cr, Mo, W) and oxides of vanadium, rhenium, and niobium supported on a second high-surface-area metal oxide such as Al2O3, TiO2, Si02, ZrO2, and so forth are recognized as industrially important catalysts or catalyst precursors for various reactions [1–11], These materials frequently have been described as so-called monolayer catalysts based on a structural model which assumed spreading of the active oxide over the support surface. These catalysts have been investigated by a variety of techniques, conventional bulk sampling techniques as well as by surface-sensitive electron and ion spectroscopies, in an attempt to elucidate the nature of the catalyst surface species, and to study the coordination environment of the active metal center(s). Electronic spectroscopy gives rise to broad bands and the spectra are less informative than vibrational spectra. In addition, although techniques such as Auger electron spectroscopy (AES) and x-ray photoelectron spectroscopy (XPS...
{"title":"Raman Spectroscopy of Monolayer-Type Catalysts: Supported Molybdenum Oxides","authors":"G. Mestl, T. K. Srinivasan","doi":"10.1080/01614949808007114","DOIUrl":"https://doi.org/10.1080/01614949808007114","url":null,"abstract":"Abstract Oxides of the group VIb metals (Cr, Mo, W) and oxides of vanadium, rhenium, and niobium supported on a second high-surface-area metal oxide such as Al2O3, TiO2, Si02, ZrO2, and so forth are recognized as industrially important catalysts or catalyst precursors for various reactions [1–11], These materials frequently have been described as so-called monolayer catalysts based on a structural model which assumed spreading of the active oxide over the support surface. These catalysts have been investigated by a variety of techniques, conventional bulk sampling techniques as well as by surface-sensitive electron and ion spectroscopies, in an attempt to elucidate the nature of the catalyst surface species, and to study the coordination environment of the active metal center(s). Electronic spectroscopy gives rise to broad bands and the spectra are less informative than vibrational spectra. In addition, although techniques such as Auger electron spectroscopy (AES) and x-ray photoelectron spectroscopy (XPS...","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":"168 1","pages":"451-570"},"PeriodicalIF":10.9,"publicationDate":"1998-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73080254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-11-01DOI: 10.1080/01614949808007113
A. Pieplu, Odette Saur, J. Lavalley, O. Legendre, C. Nedez
Abstract This review article deals with the development of sulfur recovery from the Claus process to H2S selective oxidation. Governments are constantly tightening regulations to limit the emission of sulfur compounds into the air. This makes it necessary to constantly enhance the level of sulfur recovery from natural, refinery, or coal gasification geses, and many improvements in the Claus process have been introduced to this end. In this review, emphasis has been put on the mechanism of reactions occurring in most of the sulfur recovery units, reactions between H2S and SO2 or O2 and side reactions such as hydrolysis of COS and CS2 or sulfation of the catalyst.
{"title":"Claus catalysis and H2S selective oxidation","authors":"A. Pieplu, Odette Saur, J. Lavalley, O. Legendre, C. Nedez","doi":"10.1080/01614949808007113","DOIUrl":"https://doi.org/10.1080/01614949808007113","url":null,"abstract":"Abstract This review article deals with the development of sulfur recovery from the Claus process to H2S selective oxidation. Governments are constantly tightening regulations to limit the emission of sulfur compounds into the air. This makes it necessary to constantly enhance the level of sulfur recovery from natural, refinery, or coal gasification geses, and many improvements in the Claus process have been introduced to this end. In this review, emphasis has been put on the mechanism of reactions occurring in most of the sulfur recovery units, reactions between H2S and SO2 or O2 and side reactions such as hydrolysis of COS and CS2 or sulfation of the catalyst.","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":"14 1","pages":"409-450"},"PeriodicalIF":10.9,"publicationDate":"1998-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72998059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-08-01DOI: 10.1080/01614949808007111
S. Biz, M. Occelli
Abstract Catalysis and heterogeneous catalysts are essential to our present technology for the production and consumption of fuels, the manufacture and processing of chemical feedstocks and plastics [1,2]. It had been estimated that the introduction of this technology has permitted savings of more than 400 million barrels of oil each year [l]. Today, worldwide catalysts sales exceed $5.9 billion per year, and it has been estimated that catalysts generate fuels and chemicals worth $2.4 trillion annually, equivalent to half the U.S. Gross National Product [1,2].
{"title":"Synthesis and Characterization of Mesostructured Materials","authors":"S. Biz, M. Occelli","doi":"10.1080/01614949808007111","DOIUrl":"https://doi.org/10.1080/01614949808007111","url":null,"abstract":"Abstract Catalysis and heterogeneous catalysts are essential to our present technology for the production and consumption of fuels, the manufacture and processing of chemical feedstocks and plastics [1,2]. It had been estimated that the introduction of this technology has permitted savings of more than 400 million barrels of oil each year [l]. Today, worldwide catalysts sales exceed $5.9 billion per year, and it has been estimated that catalysts generate fuels and chemicals worth $2.4 trillion annually, equivalent to half the U.S. Gross National Product [1,2].","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":"25 1","pages":"329-407"},"PeriodicalIF":10.9,"publicationDate":"1998-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87052264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-08-01DOI: 10.1080/01614949808007110
B. Wojciechowski
Abstract Catalytic cracking has reached technological maturity without the benefit of a fundamental understanding and quantification of its elementary processes. Without this understanding, advances in this field have become increasingly rare and will be even more difficult to achieve in the future. This article offers a basis for the development of a fundamental understanding of catalytic cracking. It ties together all of the principal phenomena in catalytic cracking and lays a foundation for their quantification on the basis of the following postulates. 1. All important processes involved in the suite of reactions which fall under the generic name of “catalytic cracking” proceed via the mediation of surface-resident ions. 2. These ions undergo only two types of reactions and produce all the major gas-phase products: (a) Bimolecular disproportionations with neutral gas-phase molecules, or with neutral portions of neighboring carbenium ions, via the formation of pentacoordinated carbonium ion intermediate...
{"title":"The Reaction Mechanism of Catalytic Cracking: Quantifying Activity, Selectivity, and Catalyst Decay","authors":"B. Wojciechowski","doi":"10.1080/01614949808007110","DOIUrl":"https://doi.org/10.1080/01614949808007110","url":null,"abstract":"Abstract Catalytic cracking has reached technological maturity without the benefit of a fundamental understanding and quantification of its elementary processes. Without this understanding, advances in this field have become increasingly rare and will be even more difficult to achieve in the future. This article offers a basis for the development of a fundamental understanding of catalytic cracking. It ties together all of the principal phenomena in catalytic cracking and lays a foundation for their quantification on the basis of the following postulates. 1. All important processes involved in the suite of reactions which fall under the generic name of “catalytic cracking” proceed via the mediation of surface-resident ions. 2. These ions undergo only two types of reactions and produce all the major gas-phase products: (a) Bimolecular disproportionations with neutral gas-phase molecules, or with neutral portions of neighboring carbenium ions, via the formation of pentacoordinated carbonium ion intermediate...","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":"58 1","pages":"209-328"},"PeriodicalIF":10.9,"publicationDate":"1998-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87490384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-02-01DOI: 10.1080/01614949808007106
P. Gallezot, D. Richard
Abstract The synthesis of a large number of fine chemicals, particularly in the field of flavor and fragrance chemistry [1,2] and pharmaceuticals [3], involves the selective hydrogenation of unsaturated carbonyl intermediates as a critical step. The hydrogenation of α,β-unsaturated carbonyls into saturated carbonyls is comparatively easy to achieve because thermodynamics favor the hydro-genation of the C═C bonds; therefore, research efforts were more directed at improving the selectivity to unsaturated alcohols. When a substituent is present on the carbon atom of the carbonyl group (i.e. with ketones), there is no chance to hydrogenate selectively the C═O bond, and saturated ketones are obtained with a high yield. This review is thus mostly restricted to the hydrogenation of α, β-unsaturated aldehydes into the corresponding unsaturated alcohols.
{"title":"Selective Hydrogenation of a,-Unsaturated Aldehydes","authors":"P. Gallezot, D. Richard","doi":"10.1080/01614949808007106","DOIUrl":"https://doi.org/10.1080/01614949808007106","url":null,"abstract":"Abstract The synthesis of a large number of fine chemicals, particularly in the field of flavor and fragrance chemistry [1,2] and pharmaceuticals [3], involves the selective hydrogenation of unsaturated carbonyl intermediates as a critical step. The hydrogenation of α,β-unsaturated carbonyls into saturated carbonyls is comparatively easy to achieve because thermodynamics favor the hydro-genation of the C═C bonds; therefore, research efforts were more directed at improving the selectivity to unsaturated alcohols. When a substituent is present on the carbon atom of the carbonyl group (i.e. with ketones), there is no chance to hydrogenate selectively the C═O bond, and saturated ketones are obtained with a high yield. This review is thus mostly restricted to the hydrogenation of α, β-unsaturated aldehydes into the corresponding unsaturated alcohols.","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":"50 1","pages":""},"PeriodicalIF":10.9,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73782554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-02-01DOI: 10.1080/01614949808007105
W. Cheng, G. Kim, A. W. Peters, X. Zhao, K. Rajagopalan, M. Ziebarth, C. Pereira
The fluid catalytic cracking (FCC) process converts heavy oil into voluable fuel products and petrochemical feedstocks. Environmental regulations are a key driving force for reducing FCC process ai...
{"title":"Environmental Fluid Catalytic Cracking Technology","authors":"W. Cheng, G. Kim, A. W. Peters, X. Zhao, K. Rajagopalan, M. Ziebarth, C. Pereira","doi":"10.1080/01614949808007105","DOIUrl":"https://doi.org/10.1080/01614949808007105","url":null,"abstract":"The fluid catalytic cracking (FCC) process converts heavy oil into voluable fuel products and petrochemical feedstocks. Environmental regulations are a key driving force for reducing FCC process ai...","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":"21 1","pages":"39-79"},"PeriodicalIF":10.9,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79336507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-02-01DOI: 10.1080/01614949808007108
G. Centi, S. Perathoner
Abstract Heterogeneous catalysis plays a central role in most chemical reactions of industrial importance [1], but new advanced catalysts (superselective, able to transform new feedstocks and to synthesize new products, etc.) are required to comply with the future energy, safety, health, and environmental needs of the chemical industry [2]. The design of these new catalytic materials requires further understanding of the surface processes determining the catalytic transformations [3].
{"title":"The Role of Ammonia Adspecies on the Pathways of Catalytic Transformation at Mixed Metal Oxide Surfaces","authors":"G. Centi, S. Perathoner","doi":"10.1080/01614949808007108","DOIUrl":"https://doi.org/10.1080/01614949808007108","url":null,"abstract":"Abstract Heterogeneous catalysis plays a central role in most chemical reactions of industrial importance [1], but new advanced catalysts (superselective, able to transform new feedstocks and to synthesize new products, etc.) are required to comply with the future energy, safety, health, and environmental needs of the chemical industry [2]. The design of these new catalytic materials requires further understanding of the surface processes determining the catalytic transformations [3].","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":"72 1","pages":"175-208"},"PeriodicalIF":10.9,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81286797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-02-01DOI: 10.1080/01614949808007107
M. Bonn, H. Bakker, K. Domen, C. Hirose, A. Kleyn, R. V. van Santen
Abstract The application of (picosecond) nonlinear infrared spectroscopy to investigate zeolite catalysts and adsorbates is reviewed. In these time-resolved experiments, one specific vibration in the zeolite system (i.e., a zeolite or adsorbate vibration) is selectively excited with an ultrashort (tunable) mid-infrared pulse. The effect of this excitation and the subsequent energy relaxation can be monitored real time, providing information on the structure of the bare zeolite and adsorption complexes. More importantly, with this technique the picosecond energy flow at the catalytic site and the dynamics of the catalyst-adsorbate interaction can be investigated: Short-lived transient species (e.g., reaction intermediates) are observed and the picosecond relaxation rates and pathways at the catalytic site render insights into the dynamics of the interaction between the zeolite catalyst and its adsorbates at a molecular level. This illustrates the potential of time-resolved infrared spectroscopy in the inve...
{"title":"Dynamical studies of zeolitic protons and adsorbates by picosecond infrared spectroscopy","authors":"M. Bonn, H. Bakker, K. Domen, C. Hirose, A. Kleyn, R. V. van Santen","doi":"10.1080/01614949808007107","DOIUrl":"https://doi.org/10.1080/01614949808007107","url":null,"abstract":"Abstract The application of (picosecond) nonlinear infrared spectroscopy to investigate zeolite catalysts and adsorbates is reviewed. In these time-resolved experiments, one specific vibration in the zeolite system (i.e., a zeolite or adsorbate vibration) is selectively excited with an ultrashort (tunable) mid-infrared pulse. The effect of this excitation and the subsequent energy relaxation can be monitored real time, providing information on the structure of the bare zeolite and adsorption complexes. More importantly, with this technique the picosecond energy flow at the catalytic site and the dynamics of the catalyst-adsorbate interaction can be investigated: Short-lived transient species (e.g., reaction intermediates) are observed and the picosecond relaxation rates and pathways at the catalytic site render insights into the dynamics of the interaction between the zeolite catalyst and its adsorbates at a molecular level. This illustrates the potential of time-resolved infrared spectroscopy in the inve...","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":"44 1","pages":"127-173"},"PeriodicalIF":10.9,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83018956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-02-01DOI: 10.1080/01614949808007104
J. Millet
Abstract This review presents the iron phosphorus oxides used as catalysts for isobutyric acid oxidative dehydrogenation. Research on this catalytic system has been developed in the last decade and many publications have been devoted to this reaction, as it can be a step in a new process of production of methyl methacrylate. We emphasize particularly the nature of the active phase, the active centers, and the role of water and promoters. The mechanistic aspects of the reaction, which corresponds to an extension of the Mars and van Krevelen mechanism with a special role of water partial pressure, are discussed.
{"title":"FePO Catalysts for the Selective Oxidative Dehydrogenation of Isobutyric Acid into Methacrylic Acid","authors":"J. Millet","doi":"10.1080/01614949808007104","DOIUrl":"https://doi.org/10.1080/01614949808007104","url":null,"abstract":"Abstract This review presents the iron phosphorus oxides used as catalysts for isobutyric acid oxidative dehydrogenation. Research on this catalytic system has been developed in the last decade and many publications have been devoted to this reaction, as it can be a step in a new process of production of methyl methacrylate. We emphasize particularly the nature of the active phase, the active centers, and the role of water and promoters. The mechanistic aspects of the reaction, which corresponds to an extension of the Mars and van Krevelen mechanism with a special role of water partial pressure, are discussed.","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":"141 1","pages":"1-38"},"PeriodicalIF":10.9,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80053193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-11-01DOI: 10.1080/01614949708007100
M. Hunger
Abstract Nearly all atoms contributing to the local structure of Br⊘nsted acid sites in zeolites exhibit isotopes accessible for multinuclear solid-state nuclear magnetic resonance (NMR) investigations. Therefore, in the last 15 years, NMR spectroscopy has found numerous applications for the determination of the types of hydroxyl proton in zeolites, of their concentration, accessibility, and mobility, and for the characterization of their acid strength and local structure. It allows the study of the role of hydroxyl groups in the formation of adsorbate complexes and in heterogeneously catalyzed reactions. Meanwhile, NMR spectroscopy belongs to the most powerful techniques for the characterization of Br⊘nsted acid sites in zeolites and related materials. The basis of this success is the invention of new sample preparation techniques, external magnetic fields with high-flux densities, effective line-narrowing methods, and new two-dimensional experiments, making the detection of highly resolved solid-state N...
{"title":"Br⊘nsted Acid Sites in Zeolites Characterized by Multinuclear Solid-State NMR Spectroscopy","authors":"M. Hunger","doi":"10.1080/01614949708007100","DOIUrl":"https://doi.org/10.1080/01614949708007100","url":null,"abstract":"Abstract Nearly all atoms contributing to the local structure of Br⊘nsted acid sites in zeolites exhibit isotopes accessible for multinuclear solid-state nuclear magnetic resonance (NMR) investigations. Therefore, in the last 15 years, NMR spectroscopy has found numerous applications for the determination of the types of hydroxyl proton in zeolites, of their concentration, accessibility, and mobility, and for the characterization of their acid strength and local structure. It allows the study of the role of hydroxyl groups in the formation of adsorbate complexes and in heterogeneously catalyzed reactions. Meanwhile, NMR spectroscopy belongs to the most powerful techniques for the characterization of Br⊘nsted acid sites in zeolites and related materials. The basis of this success is the invention of new sample preparation techniques, external magnetic fields with high-flux densities, effective line-narrowing methods, and new two-dimensional experiments, making the detection of highly resolved solid-state N...","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":"25 1","pages":"345-393"},"PeriodicalIF":10.9,"publicationDate":"1997-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85675304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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