Liquid phase hydrogenation of p-nitrotoluene in microchannel reactors

Födisch, Ringo; Hönicke, Dieter; Xu, Yunhua; Platzer, Bernd

doi:10.1007/978-3-642-56763-6_48

Cited by 15 publications

(36 citation statements)

References 5 publications

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“…[18] Anodically oxidized aluminum platelets with palladium deposits [19] and packed-bed microreactors with 2 % Pd/zeolite (inner channel diameter of 775 mm) have been also successfully demonstrated for hydrogenations. [20] A variety of catalyst-coated microreactors made from either glass, [21] stainless steel, [22] silicon (Figure 2 c and d), [23][24][25] or oxidized aluminum [26] wafers have also been used prominently in flow hydrogenation chemistry, in addition to titania and silica thinfilm reactors with embedded nanostructured mono or bimetallic catalysts.…”

Section: Custom-design Reactors For Flow Hydrogenationmentioning

confidence: 99%

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Heterogeneous Catalytic Hydrogenation Reactions in Continuous‐Flow Reactors

2011

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Microreactor technology and continuous flow processing in general are key features in making organic synthesis both more economical and environmentally friendly. Heterogeneous catalytic hydrogenation reactions under continuous flow conditions offer significant benefits compared to batch processes which are related to the unique gas-liquid-solid triphasic reaction conditions present in these transformations. In this review article recent developments in continuous flow heterogeneous catalytic hydrogenation reactions using molecular hydrogen are summarized. Available flow hydrogenation techniques, reactors, commonly used catalysts and examples of synthetic applications with an emphasis on laboratory-scale flow hydrogenation reactions are presented.

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Section: Custom-design Reactors For Flow Hydrogenationmentioning

confidence: 99%

“…[17, 19,20,91,92] The effects of the exact processing conditions including hydrogen pressure and concentration, temperature as well as residence time on conversion, yield and selectivity have been studied in great detail. Partial hydrogenations can yield phenylhydroxylamines.…”

Section: Nitro Group Reductionsmentioning

confidence: 99%

Heterogeneous Catalytic Hydrogenation Reactions in Continuous‐Flow Reactors

2011

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“…The prepared Pd-containing microstructured wafers were used for the liquid phase hydrogenation of p-nitrotoluene to ptoluidine [18].…”

Section: Distribution Of Catalytic Active Components In Microchannel mentioning

confidence: 99%

Consideration of the Effect of Irregular Catalytic Active Component Distributions in Mesopores – Extension of a Model for Wall Catalyzed Reactions in Microchannel Reactors

Platzer¹,

Roßmann

et al. 2003

Chem Eng & Technol

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Dedicated to Prof. Dr. Jens Weitkamp on the occasion of his 60 th birthdayData available from the literature and experimental results have shown that the distribution of the catalytic active components can be irregular already for fresh catalysts. The determination of the local concentrations of the catalytic active components using wavelength dispersive X-ray spectroscopy confirms this for microstructured wafers used in microchannel reactors. Considering this nonuniform distribution, the used model gives the relation between the local concentration profiles of the reactants inside the pores and the product yield in the entire pore. These results were used in an equation for the diffusion flux at the pore mouth, which is useful for a microchannel model developed in a recent paper [1]. The theoretical considerations deal with cylindrical pores with known reactant concentrations at the pore mouth and known distribution of the catalytic active component within the pore. Beside numerical results, some analytical solutions with low mathematical expense, applicable to special cases, are discussed. The nonconsideration of the irregular distribution of the catalytic active component can be the reason for difficulties during the extrapolation of experimental results to slightly different conditions and can have a great influence on the reaction results. The regarded examples are typical of wall-catalyzed reactions in microchannel reactors with mesopores.

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“…Nitro aromatics owe their great importance in organic synthesis for being intermediates for the generation of the respective anilines by hydrogenation [17,61]. For instance, pharmaceuticals are produced via that route [61].…”

Section: Drivers For Performing Nitro Group Hydrogenation In Micro Rementioning

confidence: 99%

“…The reaction rates cannot be set as high as intrinsically possible by the kinetics, because otherwise heat removal due to the large reaction enthalpies (500-550 kJ mol −1 ) will become a major problem [17,60,61]. For this reason, the hydrogen supply is restricted, thereby controlling the reaction rate.…”

Section: Drivers For Performing Nitro Group Hydrogenation In Micro Rementioning

confidence: 99%