Selective Hydrogenation of [Alpha], [Beta]-unsaturated Aldehydes Towards Clean Synthesis Over Noble Metal Catalysts in Mass Transfer Efficient Three Phase Reactors PDF Download
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![Selective Hydrogenation of [Alpha], [Beta]-unsaturated Aldehydes Towards Clean Synthesis Over Noble Metal Catalysts in Mass Transfer Efficient Three Phase Reactors PDF](https://books.google.com/books/content/images/frontcover/UGr-sgEACAAJ?fife=w150-h200)
Author: Lai Qi Zhang
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Languages : en
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![Selective Hydrogenation of [alpha], [beta][alpha, Beta]-unsaturated Aldehydes Towards Clean Synthesis Over Noble Metal Catalysts in Mass Transfer Efficient Three Phase Reactors PDF](https://books.google.com/books/content/images/frontcover/SkZ4nQAACAAJ?fife=w80-h100)
Author: Laiqi Zhang
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Languages : en
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The hydrodynamics and mass transfer characteristics of a concurrent downflow contactor (CDC) are studied in this work in order to investigate the viability of this bubble column as a catalytic reactor for the hydrogenation of?,?-unsaturated aldehydes. Oxygen/water was used as the system throughout. In order to obtain reproducible results, a very effective gas-liquid separation method was conceived and developed after much trial and error work. Shutdown and deadleg gas holdup measuring methods were compared and it was found that the shutdown method is more reliable than the deadleg method. The hydrogenation of cinnamaldehyde using both in-house-prepared and commercial palladium, platinum and ruthenium catalysts was carried out in stirred tank reactors and cocurrent downflow reactors in order to study the kinetics and mass transfer characteristics and the selectivity towards the corresponding desired product, hydrocinnamaldehyde or cinnamyl alcohol. When palladium catalysts were used the desired product was hydrocinnamaldehyde. The effects of homogenous reactions, type of solvent, catalyst loading, temperature, pressure, reactant concentration and the effects of promoter or poison on the selectivity towards hydrocinnamaldehyde were investigated systematically. Aldehyde acetals were produced in polar solvents, but not in non-polar solvents. Two methods can be used to obtain hydrocinnamaldehyde selectivity without reduction of the carbonyl double bond: (1) by using non-polar solvents such as toluene; (2) by incorporating poisons or promoters into the reactant solution or onto the surface of the catalysts. 97% selectivity to hydrocinnamaldehyde was achieved. The effects of the solvent, temperature, pressure, catalyst loading, promoters, and reactants concentration on the kinetics were studied and the following reaction kinetics are proposed for the hydrogenation of cinnamaldehyde over non-modified palladium/charcoal catalysts in propan-2-ol and in toluene: Ra = kC\(_{Cat}\)C\(_{H2}\)C\(0_{CAL}\) The apparent activation energy varies with themperature range in propan-2-ol and is 65\(\pm\)5 kJ.mol\({-1}\) in toluene.
![Selective Hydrogenation of Α,β[alpha,beta]-unsaturated Aldehydes Towards Clean Synthesis Over Noble Metal Catalysts in Mass Transfer Efficient Three Phase Reactors PDF](https://books.google.com/books/content/images/frontcover/ukTlvgEACAAJ?fife=w80-h100)
Author: Laiqi Zhang
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
The hydrodynamics and mass transfer characteristics of a concurrent downflow contactor (CDC) are studied in this work in order to investigate the viability of this bubble column as a catalytic reactor for the hydrogenation of ?,?-unsaturated aldehydes. Oxygen/water was used as the system throughout. In order to obtain reproducible results, a very effective gas-liquid separation method was conceived and developed after much trial and error work. Shutdown and deadleg gas holdup measuring methods were compared and it was found that the shutdown method is more reliable than the deadleg method. The hydrogenation of cinnamaldehyde using both in-house-prepared and commercial palladium, platinum and ruthenium catalysts was carried out in stirred tank reactors and cocurrent downflow reactors in order to study the kinetics and mass transfer characteristics and the selectivity towards the corresponding desired product, hydrocinnamaldehyde or cinnamyl alcohol. When palladium catalysts were used the desired product was hydrocinnamaldehyde. The effects of homogenous reactions, type of solvent, catalyst loading, temperature, pressure, reactant concentration and the effects of promoter or poison on the selectivity towards hydrocinnamaldehyde were investigated systematically. Aldehyde acetals were produced in polar solvents, but not in non-polar solvents. Two methods can be used to obtain hydrocinnamaldehyde selectivity without reduction of the carbonyl double bond: (1) by using non-polar solvents such as toluene; (2) by incorporating poisons or promoters into the reactant solution or onto the surface of the catalysts. 97% selectivity to hydrocinnamaldehyde was achieved. The effects of the solvent, temperature, pressure, catalyst loading, promoters, and reactants concentration on the kinetics were studied and the following reaction kinetics are proposed for the hydrogenation of cinnamaldehyde over non-modified palladium/charcoal catalysts in propan-2-ol and in toluene: Ra = kC\(-{Cat}\)C\(-{H2}\)C\( 0-{CAL}\) The apparent activation energy varies with themperature range in propan-2-ol and is 65\(\pm\)5 kJ.mol\( {-1}\) in toluene.
![Selective Hydrogenation of [alpha],[beta]-unsaturated Aldehydes Over Metal Catalysts PDF](https://books.google.com/books/content/images/frontcover/55sUMwEACAAJ?fife=w80-h100)
Author: Thomas Balder Ludwig Wolfgang Marinelli
Publisher:
ISBN: 9789090067216
Category :
Languages : en
Pages : 129
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![A Study of Selective Hydrogenation of [alpha], [beta]-unsaturated Aldehyde in Three Phase Reactors PDF](https://books.google.com/books/content/images/frontcover/w7n2HAAACAAJ?fife=w80-h100)
Author: Wanida Koo-Amornpattana
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Languages : en
Pages :
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Author: Wanida Koo-Amornpattana
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Category : Chemical engineering
Languages : en
Pages :
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![Selective Hydrogenation of [alpha]-[beta] Unsaturated Aldehydes Over Ir Catalysts PDF](https://books.google.com/books/content/images/frontcover/6CSG0AEACAAJ?fife=w80-h100)
Author: J. Gomez-Lopez
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ISBN:
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Languages : en
Pages : 0
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Author: S. David Jackson
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110543753
Category : Science
Languages : en
Pages : 326
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Book Description
This book gives a comprehensive overview of modern hydrogenation methods used in organic synthesis. In clearly structured chapters, the authors cover the catalysts, scope and limitations of their application, and the techniques for hydrogenation of carbon-carbon, carbon-heteroatom and heteroatom-heteroatom multiple bonds.
![Selective Hyddrogenation of [alpha],[beta]-unsaturated Aldehydes Over Metal Catalysts PDF](https://books.google.com/books/content/images/frontcover/vtDzPgAACAAJ?fife=w80-h100)
Author: Thomas Balder Ludwig Wolfgang Marinelli
Publisher:
ISBN:
Category :
Languages : en
Pages : 129
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![Adsorption and Selective Hydrogenation of Α,β [alpha,beta] Unsaturated Aldehydes on Pt(111) and Pt-Sn Model Catalysts PDF](https://books.google.com/books/content/images/frontcover/h_fWzQEACAAJ?fife=w80-h100)
Author: Jan Haubrich
Publisher:
ISBN:
Category :
Languages : en
Pages : 266
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Author: Evgenii Klabunovskii
Publisher: Springer Science & Business Media
ISBN: 1402042965
Category : Science
Languages : en
Pages : 314
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Book Description
Heterogeneous Enantioselective Hydrogenation: Theory and Practice reviews the development of enantioselective hydrogenation reaction catalysts. It looks at the first relatively ineffective catalysts right through to modern highly effective enantioselective catalytic systems, comparable in their efficiency to chiral metal complexes and enzymatic systems. The book begins with a summary of the first work on heterogeneous metal catalysts, which showed only the principal possibilities of enantioselective reactions. It then elaborates on metal catalysts which have enantioselectivities close to 100%. Finally, the practical utilization of chiral catalytic systems in processes of hydrogenation is described. The alpha- and beta-hydroxy carboxylic acid esters produced are precursors for manufacturing many synthones used for medicines as well as for monomers used for biodegradable polyesters, both of which have important practical applications. The volume summarizes more than 800 scientific papers in the field of enantioselective catalytic hydrogenation reactions, mainly those using heterogeneous metal catalysts. It provides detailed explanations of special techniques for the preparation of effective dissymmetric catalysts which provide highly efficient catalytic systems.
