Hydrogenation of Deactivated Carbonyls Over Platinum Group Metal Catalysts PDF Download

Author: Johanne Carmichael
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Paul Nels Rylander
Publisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 576

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Author: Paul Rylander
Publisher: Elsevier
ISBN: 0323145868
Category : Technology & Engineering
Languages : en
Pages : 565

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Catalytic Hydrogenation over Platinum Metals focuses on catalytic hydrogenation as an effective process in attaining controlled transformations of organic compounds. Composed of contributions of various authors, the book first provides information on catalysts, equipment, and conditions. Catalyst stability and reuse; types of catalyst; platinum metals; and synergism are covered. The text proceeds with discussions on hydrogenation reactors. Topics include atmospheric pressure reactors; low pressure reactors; microreactors; and high pressure reactors. The book also covers hydrogenation of carbon-carbon unsaturation. Catalytic metal; modified catalyst systems; stereochemistry; diacetylenes; and hydrogenolysis are discussed. The text also looks at the hydrogenation of aromatics, nitrogen and carbonyl compounds, and hydrogenolysis. Numerical representations and analysis, diagrams, and reactions of compounds when exposed to different laboratory conditions are considered. The selection is a great source of data for readers interested in studying the process of catalytic hydrogenation.

Author: L. Cervený
Publisher: Elsevier
ISBN: 0080960618
Category : Technology & Engineering
Languages : en
Pages : 705

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The collection of contributions in this volume presents the most up-to-date findings in catalytic hydrogenation. The individual chapters have been written by 36 top specialists each of whom has achieved a remarkable depth of coverage when dealing with his particular topic. In addition to detailed treatment of the most recent problems connected with catalytic hydrogenations, the book also contains a number of previously unpublished results obtained either by the authors themselves or within the organizations to which they are affiliated.Because of its topical and original character, the book provides a wealth of information which will be invaluable not only to researchers and technicians dealing with hydrogenation, but also to all those concerned with homogeneous and heterogeneous catalysis, organic technology, petrochemistry and chemical engineering.

Author: Marco Zimmer-De Iuliis
Publisher:
ISBN:
Category :
Languages : en
Pages : 356

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The results of kinetic isotope determination and computational studies on Noyori-type catalytic systems for the hydrogenation of ketones are presented. The catalysts examined include RuH2(NHCMe2 CMe2NH2)(R-binap) and RuH(NHCMe 2CMe2NH2)(PPh3)2. These complexes are active catalysts for ketone hydrogenation in benzene without addition of an external base. The kinetic isotope effect (KIE) for catalysis by RuH2(NHCMe2CMe2NH2)( R-binap) was determined to be 2.0 +/- (0.1). The calculated KIE for the model system RuH(NHCH2CH2NH2)(PH 3)2 was 1.3, which is smaller than the experimentally observed value but does not include tunneling effects.The complex OsH(NHCMe2CMe2NH2)(PPh 3)2 is known to display autocatalytic behaviour when it catalyzes the hydrogenation of acetophenone in benzene. Pseudo first-order reaction conditions are obtained via addition of the product alcohol at the beginning of each kinetic experiment. The KIE determined using various combinations of deuterium-labeled gas, alcohol and ketone was found to be 1.1 +/- (0.2). DFT calculations were used to explore the effect of the alcohol and the KIE. An induction period is observed at the start of the hydrogenation that is attributed to the formation of an alkoxide complex. A novel, diamine-orchestrated hydrogen-bonding network is proposed based on DFT calculations to explain how the alkoxide is converted back to the active catalyst.The tetradentate complexes trans-RuHCl[PPh2(ortho-C6 H4)CH2NHCH2)]2 and RuHCl[PPh 2(ortho-C6H4)CH2NHCMe2)]2 are known to be catalysts for the hydrogenation of acetophenone and benzonitrile in toluene when activated by KOtBu/KH. DFT studies were performed and a mechanism is proposed. The calculated rate limiting step for acetone hydrogenation was found to be heterolytic splitting of dihydrogen, which agrees well with experiment. The novel outer-sphere sequential hydrogenation of a C≡N triple bond and then a C=N double bond is proposed.A mechanism is proposed, which is supported by DFT studies, to explain the selectivity observed in the nucleophilic attack of amines or aziridines on palladium pi-prenyl phosphines complexes. Calculations on based on a palladium complex with two phosphorus donor ligands indicated that the observed selectivity would not be produced. Using two new model intermediates with either THF or aziridine substituted for a phosphine ligand trans to the unhindered side of the prenyl ligand did predict the experimentally observed selectivity.

Author: Robert L. Augustine
Publisher: CRC Press
ISBN: 1000105008
Category : Science
Languages : en
Pages : 668

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This work delineates the effect of different reaction variables on the outcome of heterogeneously catalyzed reactions, and explains how to optimize the product yield of specific compounds. Metal catalysis, simple and complex oxides, zeolites and clays are discussed, both as catalysts and as potential supports for catalytically active metals.

Author: Paul N. Rylander
Publisher: Elsevier
ISBN: 0323162614
Category : Science
Languages : en
Pages : 344

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Organic Chemistry, Volume 28: Organic Syntheses with Noble Metal Catalysts provides information pertinent to the catalysis by noble metals, which is presented in a form as to be of use to those interested in organic synthesis. This book discusses the mechanistic aspects of reactions. Organized into nine chapters, this volume begins with an overview of catalytic dehydrogenation over platinum metals, which provides a convenient method for synthesis of organic compounds. This text then examines the mechanisms and kinetics of homogeneous hydrogenation. Other chapters consider the oxidation of organic compounds in the presence of noble metal catalysts that may affect a variety of changes, including introduction of alcohol, epoxide, carbonyl, and halogen functions into the molecule. This book discusses as well the differences between osmium tetroxide and ruthenium tetroxide in their reactions with organic compounds. The final chapter deals with noble metal catalysts. This book is a valuable resource for synthetic organic chemists.

Author: Steven L Suib
Publisher: Newnes
ISBN: 0444538798
Category : Technology & Engineering
Languages : en
Pages : 413

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New and Future Developments in Catalysis is a package of books that compile the latest ideas concerning alternate and renewable energy sources and the role that catalysis plays in converting new renewable feedstock into biofuels and biochemicals. Both homogeneous and heterogeneous catalysts and catalytic processes will be discussed in a unified and comprehensive approach. There will be extensive cross-referencing within all volumes. This volume covers all the biomass sources and gives detailed and in-depth coverage of all current chemical/catalytic conversion processes of biomass into liquid hydrocarbons to be further used as a feedstock for the production of not only biofuels but a large array of chemicals. Offers an in-depth coverage of all catalytic topics of current interest and outlines the future challenges and research areas A clear and visual description of all parameters and conditions enables the reader to draw conclusions for a particular case Outline the catalytic processes applicable to energy generation and design of green processes

Author: Bo Wang
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Hydrogenation and dehydrogenation on Pd- and Pt- catalysts are encountered in many industrial hydrocarbon processes. The present work considers the development of catalysts and their kinetic modeling along a general and rigorous approach. The first part deals with the kinetics of selective hydrogenation, more particularly of the C3 cut of a thermal cracking unit for olefins production. The kinetics of the gas phase selective hydrogenation of methyl-acetylene (MA) and propadiene (PD) over a Pd/y-alumina catalyst were investigated in a fixed bed tubular reactor at temperatures 60 - 80 oC and a pressure of 20 bara. Hougen-Watson type kinetic equations were derived. The formation of higher oligomers slowly deactivated the catalyst. The effect of the deactivating agent on the rates of the main reactions as well as on the deactivating agent formation itself was expressed in terms of a deactivation function multiplying the corresponding rates at zero deactivation. Then, the kinetic model was plugged into the reactor model to simulate an industrial adiabatic reactor. In the second part the production of hydrogen from hydrocarbons was investigated. In both cyclohexane and decalin dehydrogenations, conversions higher than 98% could be obtained over Pd/y-alumina catalyst at temperature of 320 and 340 oC, respectively, with no apparent deactivation for 30 h and with co-feed of H2 in the feed. Except for H2 and trace amounts of side cracking products, less than 0.01%, benzene was the only dehydrogenated product in cyclohexane dehydrogenation. In the case of decalin dehydrogenation, partially dehydrogenated product, tetralin, was also formed with selectivity lower than 5%, depending on operating conditions. A rigorous Hougen-Watson type kinetic model was derived, which accounted for both the dehydrogenation of cis- and trans- decalin in the feed and also the isomerization of the two isomers. Jet A is the logic fuel in the battlefields. The dehydrogenation of Jet A can produce H2 for military fuel cell application. Although the H2 production is lower than that of steam/autothermal reforming, it eliminates the needs of high temperature and product separation operation.

Author: Hema Ramsurn
Publisher: Elsevier Inc. Chapters
ISBN: 0128081643
Category : Science
Languages : en
Pages : 42

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