Pub Date : 1997-08-01DOI: 10.1080/01614949709353777
G. Vayssilov
Abstract The review presents a comparison and discussion of the substantial amount of information about the state and coordination of titanium ions in titanium silicalites. The results from structural characterization of titanium silicalites with spectral, electrochemical, and quantum-chemical methods with emphasis on location of the Ti ions in framework or extraframework positions, their coordination, and the relationship of some spectral features to concrete structures at the atomic level are summarized. The main methods for the determination of some specific characteristics of titanium silicalite samples are considered—presence of metal ion impurities, extraframework titania, acidity, hydrophobicity, diffusion, and other sterical restrictions. Speculations on how these properties influence the catalytic activities and selectivities of the samples are discussed. Some experimental results for interaction of molecules—solvents, water, and hydrogen peroxide—with titanium silicalites are also presented. The...
{"title":"Structural and Physicochemical Features of Titanium Silicalites","authors":"G. Vayssilov","doi":"10.1080/01614949709353777","DOIUrl":"https://doi.org/10.1080/01614949709353777","url":null,"abstract":"Abstract The review presents a comparison and discussion of the substantial amount of information about the state and coordination of titanium ions in titanium silicalites. The results from structural characterization of titanium silicalites with spectral, electrochemical, and quantum-chemical methods with emphasis on location of the Ti ions in framework or extraframework positions, their coordination, and the relationship of some spectral features to concrete structures at the atomic level are summarized. The main methods for the determination of some specific characteristics of titanium silicalite samples are considered—presence of metal ion impurities, extraframework titania, acidity, hydrophobicity, diffusion, and other sterical restrictions. Speculations on how these properties influence the catalytic activities and selectivities of the samples are discussed. Some experimental results for interaction of molecules—solvents, water, and hydrogen peroxide—with titanium silicalites are also presented. The...","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":null,"pages":null},"PeriodicalIF":10.9,"publicationDate":"1997-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87127876","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 : 1997-02-01DOI: 10.1080/01614949708006468
F. Ribeiro, A. E. S. V. Wittenau, C. H. Bartholomew, G. Somorjai
Abstract The combination of turnover rate measurements and surface science techniques allows a firm quantification of rates in heterogeneous catalysis by metals. There are many examples of reactions where the turnover rates from different laboratories are the same. However, there are still problems, as in the isomerization and hydrogenolysis of hydrocarbons over noble metals, where the turnovers rates from different laboratories differ by many orders of magnitude. An explanation for this discrepancy is discussed. Guidelines for experimental work in heterogeneous catalysis that will help to minimize this wide scatter of turnover rates in the future are presented. ∗Current address: Department of Chemical Engineering, Worcester Polytechnic Institute, Worcerster, MA 01609-2280.
{"title":"Reproducibility of Turnover Rates in Heterogeneous Metal Catalysis: Compilation of Data and Guidelines for Data Analysis","authors":"F. Ribeiro, A. E. S. V. Wittenau, C. H. Bartholomew, G. Somorjai","doi":"10.1080/01614949708006468","DOIUrl":"https://doi.org/10.1080/01614949708006468","url":null,"abstract":"Abstract The combination of turnover rate measurements and surface science techniques allows a firm quantification of rates in heterogeneous catalysis by metals. There are many examples of reactions where the turnover rates from different laboratories are the same. However, there are still problems, as in the isomerization and hydrogenolysis of hydrocarbons over noble metals, where the turnovers rates from different laboratories differ by many orders of magnitude. An explanation for this discrepancy is discussed. Guidelines for experimental work in heterogeneous catalysis that will help to minimize this wide scatter of turnover rates in the future are presented. ∗Current address: Department of Chemical Engineering, Worcester Polytechnic Institute, Worcerster, MA 01609-2280.","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":null,"pages":null},"PeriodicalIF":10.9,"publicationDate":"1997-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84534906","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 : 1997-02-01DOI: 10.1080/01614949708006467
P. Mériaudeau, C. Naccache
Abstract The direct catalytic conversion of alkanes into aromatics has found potentially important industrial applications. Initially only alkanes with 6 and more carbon atoms in the chain were concerned. Supported platinum catalysts were found active for the aromatization of alkanes; the drawbacks of these catalysts were their deactivation with time on stream and the existence of simultaneous parallel reactions. Much discussion has been published on the aromatization of C6+ alkanes. A bifunctional mechanism which involves both the metal and the acid sites of the support and a monofunctional mechanism involving only the metallic sites operate over, respectively, Pt supported on acidic support and Pt supported on nonacidic support. In the present review the mechanisms proposed for the aromatization of alkanes are described. Over monofunctional Pt catalysts two possible mechanisms prevail: 1,6 ring closure on the Pt surface involving primary and secondary C-H bond rupture, followed by dehydrogenation of the...
{"title":"Dehydrocyclization of Alkanes Over Zeolite-Supported Metal Catalysts: Monofunctional or Bifunctional Route","authors":"P. Mériaudeau, C. Naccache","doi":"10.1080/01614949708006467","DOIUrl":"https://doi.org/10.1080/01614949708006467","url":null,"abstract":"Abstract The direct catalytic conversion of alkanes into aromatics has found potentially important industrial applications. Initially only alkanes with 6 and more carbon atoms in the chain were concerned. Supported platinum catalysts were found active for the aromatization of alkanes; the drawbacks of these catalysts were their deactivation with time on stream and the existence of simultaneous parallel reactions. Much discussion has been published on the aromatization of C6+ alkanes. A bifunctional mechanism which involves both the metal and the acid sites of the support and a monofunctional mechanism involving only the metallic sites operate over, respectively, Pt supported on acidic support and Pt supported on nonacidic support. In the present review the mechanisms proposed for the aromatization of alkanes are described. Over monofunctional Pt catalysts two possible mechanisms prevail: 1,6 ring closure on the Pt surface involving primary and secondary C-H bond rupture, followed by dehydrogenation of the...","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":null,"pages":null},"PeriodicalIF":10.9,"publicationDate":"1997-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74923844","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 : 1997-01-01DOI: 10.1080/01614949708006469
PIETER L. J. Gunter, J. (Hans) Niemantsverdriet, FABIO H. Ribeiro, G. Somorjai
Abstract Nanoscale structural information underlies research aimed at fabricating catalysts in a more controlled way. Surface science methods can provide that information, but the complexity of heterogeneous systems in general hinders the application of these methods to their full potential. In the last decades, a solution to this problem has been found in the use of model systems, ranging from well-defined single crystals of the supported phase to films or particles of that phase on flat or spherical model supports. In this paper, we review the literature on the latter model systems, that is, particles on a model support. Attention is payed to both preparation and use of such model systems.
{"title":"Surface Science Approach to Modeling Supported Catalysts","authors":"PIETER L. J. Gunter, J. (Hans) Niemantsverdriet, FABIO H. Ribeiro, G. Somorjai","doi":"10.1080/01614949708006469","DOIUrl":"https://doi.org/10.1080/01614949708006469","url":null,"abstract":"Abstract Nanoscale structural information underlies research aimed at fabricating catalysts in a more controlled way. Surface science methods can provide that information, but the complexity of heterogeneous systems in general hinders the application of these methods to their full potential. In the last decades, a solution to this problem has been found in the use of model systems, ranging from well-defined single crystals of the supported phase to films or particles of that phase on flat or spherical model supports. In this paper, we review the literature on the latter model systems, that is, particles on a model support. Attention is payed to both preparation and use of such model systems.","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":null,"pages":null},"PeriodicalIF":10.9,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89237393","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 : 1996-11-01DOI: 10.1080/01614949608006465
D. Barthomeuf
Abstract The presence of basic centers in some oxides has been recognized for a long time as being important in catalysis [1-4]. Usually both basic and acid sites exist simultaneously. The two centers may work independently or in a concerted way. For instance, in alcohol transformation, dehydration is favored on acidic sites and dehydrogenation on basic centers [3,5]. A large variety of materials are cited as having basic character. They include single-metal oxides (MgO, CaO, ZnO), supported alkali metals (Na/MgO, K/K2CO3), mixed-metal oxides (MgO-A12O3, ZnO-SiO2, MgO-TiO2), zeolites (X and Y saturated with alkaline cations of low electronegativity), hydrotalcite-type anionic clays, asbestoslike materials, carbon-supported basic catalysts, and basic organic resins. ∗ Present address: 16 rue Francois Gillet, 69003 Lyon, France.
{"title":"Basic zeolites : Characterization and uses in adsorption and catalysis","authors":"D. Barthomeuf","doi":"10.1080/01614949608006465","DOIUrl":"https://doi.org/10.1080/01614949608006465","url":null,"abstract":"Abstract The presence of basic centers in some oxides has been recognized for a long time as being important in catalysis [1-4]. Usually both basic and acid sites exist simultaneously. The two centers may work independently or in a concerted way. For instance, in alcohol transformation, dehydration is favored on acidic sites and dehydrogenation on basic centers [3,5]. A large variety of materials are cited as having basic character. They include single-metal oxides (MgO, CaO, ZnO), supported alkali metals (Na/MgO, K/K2CO3), mixed-metal oxides (MgO-A12O3, ZnO-SiO2, MgO-TiO2), zeolites (X and Y saturated with alkaline cations of low electronegativity), hydrotalcite-type anionic clays, asbestoslike materials, carbon-supported basic catalysts, and basic organic resins. ∗ Present address: 16 rue Francois Gillet, 69003 Lyon, France.","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":null,"pages":null},"PeriodicalIF":10.9,"publicationDate":"1996-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78420107","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 : 1996-11-01DOI: 10.1080/01614949608006464
A. Trovarelli
Abstract Over the past several years, cerium oxide and CeO2-containing materials have come under intense scrutiny as catalysts and as structural and electronic promoters of heterogeneous catalytic reactions. Recent developments regarding the characterization of ceria and CeO2-containing catalysts are critically reviewed with a special focus towards catalyst interaction with small molecules such as hydrogen, carbon monoxide, oxygen, and nitric oxide. Relevant catalytic and technological applications such as the use of ceria in automotive exhaust emission control and in the formulation of SO x reduction catalysts is described. A survey of the use of CeO2-containing materials as oxidation and reduction catalysts is also presented.
{"title":"Catalytic Properties of Ceria and CeO2-Containing Materials","authors":"A. Trovarelli","doi":"10.1080/01614949608006464","DOIUrl":"https://doi.org/10.1080/01614949608006464","url":null,"abstract":"Abstract Over the past several years, cerium oxide and CeO2-containing materials have come under intense scrutiny as catalysts and as structural and electronic promoters of heterogeneous catalytic reactions. Recent developments regarding the characterization of ceria and CeO2-containing catalysts are critically reviewed with a special focus towards catalyst interaction with small molecules such as hydrogen, carbon monoxide, oxygen, and nitric oxide. Relevant catalytic and technological applications such as the use of ceria in automotive exhaust emission control and in the formulation of SO x reduction catalysts is described. A survey of the use of CeO2-containing materials as oxidation and reduction catalysts is also presented.","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":null,"pages":null},"PeriodicalIF":10.9,"publicationDate":"1996-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87546993","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 : 1996-11-01DOI: 10.1080/01614949608006463
S. Albonetti, F. Cavani, F. Trifiró
Abstract This review examines some aspects in the development of heterogenous catalysts for the oxyfunctionalization of light paraffins. Particular attention is devoted to the raction of paraffin oxydehydrogenation to olefins and of n-butane oxidation to maleic anhydride. Most catalyst compositions are based on vanadium oxide as the main component, and the peculiar properties of this element with respect to the catalytic performance are discussed. These properties are also examined in ligh of the stability of the product of partial oxidation towards consecutive unselective oxidation reactions, and with respect to the mechanism of paraffin activation.
{"title":"Key Aspects of Catalyst Design for the Selective Oxidation of Paraffins","authors":"S. Albonetti, F. Cavani, F. Trifiró","doi":"10.1080/01614949608006463","DOIUrl":"https://doi.org/10.1080/01614949608006463","url":null,"abstract":"Abstract This review examines some aspects in the development of heterogenous catalysts for the oxyfunctionalization of light paraffins. Particular attention is devoted to the raction of paraffin oxydehydrogenation to olefins and of n-butane oxidation to maleic anhydride. Most catalyst compositions are based on vanadium oxide as the main component, and the peculiar properties of this element with respect to the catalytic performance are discussed. These properties are also examined in ligh of the stability of the product of partial oxidation towards consecutive unselective oxidation reactions, and with respect to the mechanism of paraffin activation.","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":null,"pages":null},"PeriodicalIF":10.9,"publicationDate":"1996-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85692120","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 : 1996-08-01DOI: 10.1080/01614949608006461
G. Tembe, A. R. Bandyopadhyay, P. A. Ganeshpure, S. Satish
Abstract The review deals with the chemistry of dimerization of acrylic esters in the presence of various catalysts. The article covers literature from 1963 through early 1995. The dimerization reactions are divided into three categories depending on the type of catalyst used, namely, phosphine-catalyzed, metal-catalyzed, and miscellaneous catalysts. Phosphine catalyzed dimerization leads to branched or head—tail dimers. Metal catalyzed dimerization deals with the reactions that take place in the coordination sphere of the transition metals (Ni, Pd, Ru, and Rh) complexes and are aimed at linear or tail—tail dimers. The tail—tail dimers, dialkyl hexenedioates, have a commercial potential as precursors of adipic acid, which is a raw material in the manufacture of nylon-6,6. Various strategies involved in designing the transition metal catalysts for tail—tail dimerization are highlighted. A miscellaneous catalyst section deals with systems that are not covered under the above two categories. It describes cat...
{"title":"Catalytic Dimerization of Alkyl Acrylates","authors":"G. Tembe, A. R. Bandyopadhyay, P. A. Ganeshpure, S. Satish","doi":"10.1080/01614949608006461","DOIUrl":"https://doi.org/10.1080/01614949608006461","url":null,"abstract":"Abstract The review deals with the chemistry of dimerization of acrylic esters in the presence of various catalysts. The article covers literature from 1963 through early 1995. The dimerization reactions are divided into three categories depending on the type of catalyst used, namely, phosphine-catalyzed, metal-catalyzed, and miscellaneous catalysts. Phosphine catalyzed dimerization leads to branched or head—tail dimers. Metal catalyzed dimerization deals with the reactions that take place in the coordination sphere of the transition metals (Ni, Pd, Ru, and Rh) complexes and are aimed at linear or tail—tail dimers. The tail—tail dimers, dialkyl hexenedioates, have a commercial potential as precursors of adipic acid, which is a raw material in the manufacture of nylon-6,6. Various strategies involved in designing the transition metal catalysts for tail—tail dimerization are highlighted. A miscellaneous catalyst section deals with systems that are not covered under the above two categories. It describes cat...","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":null,"pages":null},"PeriodicalIF":10.9,"publicationDate":"1996-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79976736","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 : 1996-08-01DOI: 10.1080/01614949608006462
Xuemin Song, A. Sayari
Abstract This review article deals with recent progress in the preparation of sulfated zirconia (SZ)-bassed, strong solid-acid catalysts, the characterization of their physicochemical properties and the evaluation of their catalytic performance in various promising applications. Strong emphasis was put on discussion of controversial issues such as the strength of acid sites, the nature of active sites, the reaction mechanism, and the role and state of supported platinum. An important part of this work was devoted to recent catalytic applications.
{"title":"Sulfated Zirconia-Based Strong Solid-Acid Catalysts: Recent Progress","authors":"Xuemin Song, A. Sayari","doi":"10.1080/01614949608006462","DOIUrl":"https://doi.org/10.1080/01614949608006462","url":null,"abstract":"Abstract This review article deals with recent progress in the preparation of sulfated zirconia (SZ)-bassed, strong solid-acid catalysts, the characterization of their physicochemical properties and the evaluation of their catalytic performance in various promising applications. Strong emphasis was put on discussion of controversial issues such as the strength of acid sites, the nature of active sites, the reaction mechanism, and the role and state of supported platinum. An important part of this work was devoted to recent catalytic applications.","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":null,"pages":null},"PeriodicalIF":10.9,"publicationDate":"1996-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82685489","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 : 1996-05-01DOI: 10.1080/01614949608006458
In-Soo Park∗, D. Do, A. Rodrigues
Introduction There has been a vast amount of investigation in the field of experimental and theoretical treatments of the effective diffusivity in porous media for more than half of a century [1-4]. The effective diffusivity is required for several reasons [5]; for example, during catalyst formulation, active species can be laid down precisely or with specified concentration profiles on a porous matrix or support. In experimental work on heterogeneous reactions an effective diffusivity is needed to obtain the value of the Thiele modulus and hence to determine the intrinsic reaction kinetics. In reactor design the diffusivity is needed to evaluate the Thiele modulus, which can then be an aid in predicting reaction rates for heterogeneous systems. In addition, a simple and quick testing method could be used as a screening or quality control procedure during catalyst manufacture. ∗ On leave from the Department of Chemical Engineering, Kyungnam University, Masan 631-701, Korea.
{"title":"Measurement of the Effective Diffusivity in Porous Media by the Diffusion Cell Method","authors":"In-Soo Park∗, D. Do, A. Rodrigues","doi":"10.1080/01614949608006458","DOIUrl":"https://doi.org/10.1080/01614949608006458","url":null,"abstract":"Introduction There has been a vast amount of investigation in the field of experimental and theoretical treatments of the effective diffusivity in porous media for more than half of a century [1-4]. The effective diffusivity is required for several reasons [5]; for example, during catalyst formulation, active species can be laid down precisely or with specified concentration profiles on a porous matrix or support. In experimental work on heterogeneous reactions an effective diffusivity is needed to obtain the value of the Thiele modulus and hence to determine the intrinsic reaction kinetics. In reactor design the diffusivity is needed to evaluate the Thiele modulus, which can then be an aid in predicting reaction rates for heterogeneous systems. In addition, a simple and quick testing method could be used as a screening or quality control procedure during catalyst manufacture. ∗ On leave from the Department of Chemical Engineering, Kyungnam University, Masan 631-701, Korea.","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":null,"pages":null},"PeriodicalIF":10.9,"publicationDate":"1996-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84767284","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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