Pub Date : 1996-05-01DOI: 10.1080/01614949608006457
P. T. Vasudevan, J. Fierro
Introduction The increasing importance of hydrodesulfurization (HDS) in petroleum processing in order to produce clean-burning fuels has led to a surge of research on the chemistry and engineering of HDS. Most of the earlier works are focused on catalyst characterization by physical methods; on low-pressure reaction studies of compounds like thiophene having relatively high reactivities; on process development; or on CoMo, NiMo, or NiW catalysts supported on alumina, often doped by fluorine or phosphorus. Almost all the reviews have concentrated on alumina-supported CoMo, NiMo, and NiW sulfide catalysts for hydrotreating. Even reviews that are not limited to the above catalytic systems essentially deal with studies of simple compounds like thiophene.
{"title":"A review of deep hydrodesulfurization catalysis","authors":"P. T. Vasudevan, J. Fierro","doi":"10.1080/01614949608006457","DOIUrl":"https://doi.org/10.1080/01614949608006457","url":null,"abstract":"Introduction The increasing importance of hydrodesulfurization (HDS) in petroleum processing in order to produce clean-burning fuels has led to a surge of research on the chemistry and engineering of HDS. Most of the earlier works are focused on catalyst characterization by physical methods; on low-pressure reaction studies of compounds like thiophene having relatively high reactivities; on process development; or on CoMo, NiMo, or NiW catalysts supported on alumina, often doped by fluorine or phosphorus. Almost all the reviews have concentrated on alumina-supported CoMo, NiMo, and NiW sulfide catalysts for hydrotreating. Even reviews that are not limited to the above catalytic systems essentially deal with studies of simple compounds like thiophene.","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":"88204556","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: 10.1080/01614949608006459
L. Guczi, V. Santen, K. Sharma
Introduction Methane is the main component of natural gas and its utilization amounts to ca. 1.7 × 109 tons of oil equivalent per year [1]. Since the present reserve of methane is located in remote places, its transportation is a major problem. Methane coupling to form C2+ hydrocarbons is, therefore, of a primary importance because before transportation methane should be converted into hydrocarbons with higher boiling points, such as ethane, propane, etc. The catalytic conversion of methane can be carried out in several ways which have excellently been reviewed in Refs. 1 and 2. Basically, three routes exist: (i) the indirect route in which methane is first converted into syngas in presence of water (steam reforming), CO2 (carbon dioxide reforming), or oxygen (partial oxidation) and the resultant syngas can be utilized in the traditional way; (ii) direct coupling in the presence of oxygen (oxidative coupling of methane, OCM) or hydrogen (two-step polymerization); and (iii) direct conversion in the presenc...
{"title":"Low-temperature coupling of methane","authors":"L. Guczi, V. Santen, K. Sharma","doi":"10.1080/01614949608006459","DOIUrl":"https://doi.org/10.1080/01614949608006459","url":null,"abstract":"Introduction Methane is the main component of natural gas and its utilization amounts to ca. 1.7 × 109 tons of oil equivalent per year [1]. Since the present reserve of methane is located in remote places, its transportation is a major problem. Methane coupling to form C2+ hydrocarbons is, therefore, of a primary importance because before transportation methane should be converted into hydrocarbons with higher boiling points, such as ethane, propane, etc. The catalytic conversion of methane can be carried out in several ways which have excellently been reviewed in Refs. 1 and 2. Basically, three routes exist: (i) the indirect route in which methane is first converted into syngas in presence of water (steam reforming), CO2 (carbon dioxide reforming), or oxygen (partial oxidation) and the resultant syngas can be utilized in the traditional way; (ii) direct coupling in the presence of oxygen (oxidative coupling of methane, OCM) or hydrogen (two-step polymerization); and (iii) direct conversion in the presenc...","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":"80386004","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 : 1996-02-01DOI: 10.1080/01614949608006453
Y. Matros, G. Bunimovich
Introduction Transition from the usual steady-state mode of continuous processes toward forced unsteady-state conditions (FUSC) has been discussed in chemical engineering literature since the beginning of the 1960s [1-12]. FUSC can be created by periodic variations of temperature, composition, or other parameters to the inlet of a chemical unit.
{"title":"Reverse-Flow Operation in Fixed Bed Catalytic Reactors","authors":"Y. Matros, G. Bunimovich","doi":"10.1080/01614949608006453","DOIUrl":"https://doi.org/10.1080/01614949608006453","url":null,"abstract":"Introduction Transition from the usual steady-state mode of continuous processes toward forced unsteady-state conditions (FUSC) has been discussed in chemical engineering literature since the beginning of the 1960s [1-12]. FUSC can be created by periodic variations of temperature, composition, or other parameters to the inlet of a chemical unit.","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":null,"pages":null},"PeriodicalIF":10.9,"publicationDate":"1996-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86341605","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 : 1996-02-01DOI: 10.1080/01614949608006455
K. A. Cumming, B. Wojciechowski
Introduction Understanding of the process of hydrogen redistribution in catalytic cracking has long been recognized as essential to understanding of the coking processes responsible for catalyst decay. Hydrogen redistribution is also thought to be behind the puzzling excess of paraffins over olefins that has been noted by several authors [1-3], and to hold the key to determining the selectivity of cracking reactions. If the transfer of hydrogen during catalytic cracking can be understood and quantified, much of the detail of the overall process should become clear.
{"title":"Hydrogen Transfer, Coke Formation, and Catalyst Decay and Their Role in the Chain Mechanism of Catalytic Cracking","authors":"K. A. Cumming, B. Wojciechowski","doi":"10.1080/01614949608006455","DOIUrl":"https://doi.org/10.1080/01614949608006455","url":null,"abstract":"Introduction Understanding of the process of hydrogen redistribution in catalytic cracking has long been recognized as essential to understanding of the coking processes responsible for catalyst decay. Hydrogen redistribution is also thought to be behind the puzzling excess of paraffins over olefins that has been noted by several authors [1-3], and to hold the key to determining the selectivity of cracking reactions. If the transfer of hydrogen during catalytic cracking can be understood and quantified, much of the detail of the overall process should become clear.","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":null,"pages":null},"PeriodicalIF":10.9,"publicationDate":"1996-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87266504","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 : 1996-02-01DOI: 10.1080/01614949608006454
B. Delmon, G. Froment
Introduction Evidence has accumulated in the last 20 years that spillover processes play a crucial role in many catalytic phenomena. Four symposia have highlighted the advances of knowledge in this area, and the progressive recognition that the phenomena have extremely important consequences (Delmon et al., 1973; Inui et al., 1993; Pajonk et al., 1983; Steinberg, 1989). In spite of this, very few kinetic models incorporating spillover have been presented. Little attention, if any, is given to these phenomena in the design of processes or in the definition of operating conditions. ∗Review based on a lecture presented at the 13th Colloquim on Chemical Reaction Engineering (13 CCRE), held in Windsor Castle, U.K., and jointly organized by the Working Parties “Chemical Reaction Engineering” and “Chemical Engineering in the Applications of Catalysis” of the European Federation of Chemical Engineering.
在过去20年中积累的证据表明，溢出过程在许多催化现象中起着至关重要的作用。四次专题讨论会强调了这一领域知识的进步，并逐渐认识到这些现象具有极其重要的后果(Delmon et al.， 1973;Inui等人，1993年;Pajonk et al.， 1983;斯坦伯格,1989)。尽管如此，很少有包含溢出的动力学模型被提出。在工艺设计或操作条件的定义中，很少注意到这些现象。*基于在英国温莎城堡举行的第13届化学反应工程研讨会(13 CCRE)上的演讲，该研讨会由欧洲化学工程联合会“化学反应工程”和“化学工程在催化应用中的应用”工作组联合组织。
{"title":"Remote control of catalytic sites by spillover species: A chemical reaction engineering approach","authors":"B. Delmon, G. Froment","doi":"10.1080/01614949608006454","DOIUrl":"https://doi.org/10.1080/01614949608006454","url":null,"abstract":"Introduction Evidence has accumulated in the last 20 years that spillover processes play a crucial role in many catalytic phenomena. Four symposia have highlighted the advances of knowledge in this area, and the progressive recognition that the phenomena have extremely important consequences (Delmon et al., 1973; Inui et al., 1993; Pajonk et al., 1983; Steinberg, 1989). In spite of this, very few kinetic models incorporating spillover have been presented. Little attention, if any, is given to these phenomena in the design of processes or in the definition of operating conditions. ∗Review based on a lecture presented at the 13th Colloquim on Chemical Reaction Engineering (13 CCRE), held in Windsor Castle, U.K., and jointly organized by the Working Parties “Chemical Reaction Engineering” and “Chemical Engineering in the Applications of Catalysis” of the European Federation of Chemical Engineering.","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":null,"pages":null},"PeriodicalIF":10.9,"publicationDate":"1996-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74684648","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 : 1995-11-01DOI: 10.1080/01614949508006451
R. A. Santen, M. Neurock
Introduction A. General The heart of many commercial catalytic processes involves chemistry on transition metal particles and surfaces. The success in designing active surface ensembles, promoters, and selective poisons is inevitably tied to our knowledge of the fundamental principles which control transition metal surface chemistry. One extreme would be the rigorous description and energetic predictions for each elementary reaction step of an entire catalytic cycle from first-principle theoretical methods. While desirable, this has to date been an unattainable goal due to the limitations in both raw computer (CPU) requirements and the accuracy of the available computational methods. Recent advances in both quantum-chemical methods and computational resources, however, are driving this goal closer to reality. Theoretical treatments of adsorbate-surface interactions have rapidly advanced to the stage where detailed understandings of the governing structural and electronic features are readily available. In...
{"title":"Concepts in Theoretical Heterogeneous Catalytic Reactivity","authors":"R. A. Santen, M. Neurock","doi":"10.1080/01614949508006451","DOIUrl":"https://doi.org/10.1080/01614949508006451","url":null,"abstract":"Introduction A. General The heart of many commercial catalytic processes involves chemistry on transition metal particles and surfaces. The success in designing active surface ensembles, promoters, and selective poisons is inevitably tied to our knowledge of the fundamental principles which control transition metal surface chemistry. One extreme would be the rigorous description and energetic predictions for each elementary reaction step of an entire catalytic cycle from first-principle theoretical methods. While desirable, this has to date been an unattainable goal due to the limitations in both raw computer (CPU) requirements and the accuracy of the available computational methods. Recent advances in both quantum-chemical methods and computational resources, however, are driving this goal closer to reality. Theoretical treatments of adsorbate-surface interactions have rapidly advanced to the stage where detailed understandings of the governing structural and electronic features are readily available. In...","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":null,"pages":null},"PeriodicalIF":10.9,"publicationDate":"1995-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74079502","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 : 1995-11-01DOI: 10.1080/01614949508006450
M. Schneider, A. Baiker
Introduction Aerogels offer interesting opportunities for catalysis due to their unique morphological and chemical properties. These properties originate from their wet-chemical preparation by the solution-sol-gel (SSG) method and their subsequent liberation from the solvent via critical-point drying or supercritical (or hypercritical) drying (SCD). Due to the “structure-preserving” ability of SCD, the usually oxidic (or metallic) aerogels are solids of high porosity and specific surface area.
{"title":"Aerogels in catalysis","authors":"M. Schneider, A. Baiker","doi":"10.1080/01614949508006450","DOIUrl":"https://doi.org/10.1080/01614949508006450","url":null,"abstract":"Introduction Aerogels offer interesting opportunities for catalysis due to their unique morphological and chemical properties. These properties originate from their wet-chemical preparation by the solution-sol-gel (SSG) method and their subsequent liberation from the solvent via critical-point drying or supercritical (or hypercritical) drying (SCD). Due to the “structure-preserving” ability of SCD, the usually oxidic (or metallic) aerogels are solids of high porosity and specific surface area.","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":null,"pages":null},"PeriodicalIF":10.9,"publicationDate":"1995-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73324454","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 : 1995-11-01DOI: 10.1080/01614949508006452
L. Portela, B. Delmon, P. Grange
Introduction Regulations about maximum sulfur contents of oil fractions and consequent SO, emissions from their combustion are becoming increasingly more stringent. Simultaneously, the oil industry has to deal with oil chargesthat are heavier and have higher concentrations of sulfur-containing compounds, leading to more severe desulfurization conditions. Therefore, catalysts with higher performance in hydrodesulfurization (HDS) are sought in order to cope with these new needs. ∗ Present address: GRECAT—Dep. Eng. Quimica, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, P-1096 Lisboa Codex, Portugal.
{"title":"The Adsorption of Nitric Oxide on Supported Co-Mo Hydrodesulfurization Catalysts: A Review","authors":"L. Portela, B. Delmon, P. Grange","doi":"10.1080/01614949508006452","DOIUrl":"https://doi.org/10.1080/01614949508006452","url":null,"abstract":"Introduction Regulations about maximum sulfur contents of oil fractions and consequent SO, emissions from their combustion are becoming increasingly more stringent. Simultaneously, the oil industry has to deal with oil chargesthat are heavier and have higher concentrations of sulfur-containing compounds, leading to more severe desulfurization conditions. Therefore, catalysts with higher performance in hydrodesulfurization (HDS) are sought in order to cope with these new needs. ∗ Present address: GRECAT—Dep. Eng. Quimica, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, P-1096 Lisboa Codex, Portugal.","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":null,"pages":null},"PeriodicalIF":10.9,"publicationDate":"1995-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72688476","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 : 1995-08-01DOI: 10.1080/01614949508006446
A. N. Startsev
Introduction The mechanism of heterogeneous catalytic reactions is much more difficult to elucidate than that of homogeneous systems. Despite the facilities provided by physical methods for investigating the surface of solids, obtaining detailed information on the structure of the active component in real heterogeneous catalysts presents difficulties due to the nonuniform chemical composition of the surface species. Some of these surface species are totally inactive in catalysis, and others can catalyze the given chemical reaction by different pathways and according to different mechanisms. This results in a change of selectivity to the desired product and the appearance of intermediates and reaction by-products. Furthermore, the effect of the reaction medium on the catalyst gains importance during a catalytic process when, at high temperature and pressure, one type of surface species is transformed into another, thus changing the mechanism and direction of the catalyzed reaction. ∗ Telex: 133122 Sovet SU...
非均相催化反应的机理比均相催化反应的机理更难阐明。尽管物理方法为研究固体表面提供了便利，但由于表面物质的化学组成不均匀，获得实际非均相催化剂中活性成分结构的详细信息存在困难。这些表面物质有的完全不具有催化活性，有的则可以通过不同的途径，根据不同的机理催化给定的化学反应。这导致对期望产物的选择性改变以及中间产物和反应副产物的出现。此外，在高温高压催化过程中，当一种表面物质转化为另一种表面物质，从而改变催化反应的机理和方向时，反应介质对催化剂的影响就显得尤为重要。*电传:133122 Sovet SU…
{"title":"The Mechanism of HDS Catalysis","authors":"A. N. Startsev","doi":"10.1080/01614949508006446","DOIUrl":"https://doi.org/10.1080/01614949508006446","url":null,"abstract":"Introduction The mechanism of heterogeneous catalytic reactions is much more difficult to elucidate than that of homogeneous systems. Despite the facilities provided by physical methods for investigating the surface of solids, obtaining detailed information on the structure of the active component in real heterogeneous catalysts presents difficulties due to the nonuniform chemical composition of the surface species. Some of these surface species are totally inactive in catalysis, and others can catalyze the given chemical reaction by different pathways and according to different mechanisms. This results in a change of selectivity to the desired product and the appearance of intermediates and reaction by-products. Furthermore, the effect of the reaction medium on the catalyst gains importance during a catalytic process when, at high temperature and pressure, one type of surface species is transformed into another, thus changing the mechanism and direction of the catalyzed reaction. ∗ Telex: 133122 Sovet SU...","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":null,"pages":null},"PeriodicalIF":10.9,"publicationDate":"1995-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89428379","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 : 1995-08-01DOI: 10.1080/01614949508006448
Z. Sojka
Introduction The basic objective of mechanistic studies of real catalytic processes is to dissect the course of the reaction into individual steps; ascertain their sequence; and determine the stoichiometry, structure, and electronic states of active sites and intermediates. The electron paramagnetic resonance (EPR) technique is at present widely used to explore many of these principal aspects of heterogeneous catalysis and surface chemistry. The extreme sensitivity compared to the usual spectroscopic methods is perhaps its most acknowledged advantage and makes EPR best suited to investigate and characterize low-abundance active sites and intermediates appearing during catalytic reaction. Additional information can be drawn from the theoretical analysis of the experimental spin Hamiltonian parameters within the ligand field and from angular overlap or Newman's superposition models as well as by more sophisticated quantum chemical calculations. The purpose of this paper is to show how catalysis benefits fro...
{"title":"Molecular Aspects of Catalytic Reactivity. Application of EPR Spectroscopy to Stuies of the Mechanism of Heterogeneous Catalytic Reactions","authors":"Z. Sojka","doi":"10.1080/01614949508006448","DOIUrl":"https://doi.org/10.1080/01614949508006448","url":null,"abstract":"Introduction The basic objective of mechanistic studies of real catalytic processes is to dissect the course of the reaction into individual steps; ascertain their sequence; and determine the stoichiometry, structure, and electronic states of active sites and intermediates. The electron paramagnetic resonance (EPR) technique is at present widely used to explore many of these principal aspects of heterogeneous catalysis and surface chemistry. The extreme sensitivity compared to the usual spectroscopic methods is perhaps its most acknowledged advantage and makes EPR best suited to investigate and characterize low-abundance active sites and intermediates appearing during catalytic reaction. Additional information can be drawn from the theoretical analysis of the experimental spin Hamiltonian parameters within the ligand field and from angular overlap or Newman's superposition models as well as by more sophisticated quantum chemical calculations. The purpose of this paper is to show how catalysis benefits fro...","PeriodicalId":50986,"journal":{"name":"Catalysis Reviews-Science and Engineering","volume":null,"pages":null},"PeriodicalIF":10.9,"publicationDate":"1995-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78034093","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：