A Gold‐Immobilized Microchannel Flow Reactor for Oxidation of Alcohols with Molecular Oxygen

Abstract

Golden capillaries: A gold-immobilized capillary column reactor allows oxidation of alcohols to carbonyl compounds using molecular oxygen. These capillary columns (see picture) can be used for at least four days without loss of activity.

Mussel‐Inspired Immobilization of Catalysts for Microchemical Applications

“…including mesoporous structures [ 10,11 ] and immobilized catalysts on channel surfaces, [12][13][14][15] have been employed as the most popular methods. However, the packed-bed catalysts are hampered by fundamental problems such as pressure drop control, clogging of the fl ow by solid cocatalysts, or/and products (or reactants).…”

Continuous flow (micro-)reactors for heterogeneously catalyzed reactions: Main design and modelling issues

“…The authors observed catalyst deactivation operating with a microfixed bed, which was negligible when using wall coated channels. Very high yields (89-99%) of benzylic, allylic and aliphatic aldehydes from the corresponding alcohols was obtained over gold coated microreactor walls in a multiphase microreactor under mild conditions and very short residence time [86].…”

Multiphase Flow Systems for Selective Aerobic Oxidation of Alcohols Catalyzed by Bimetallic Nanoclusters

“…As for flow systems for aerobic oxidation of alcohols using heterogeneous catalysts, to the best of our knowledge, there are only a few reports of multiphase reactions in microreactor systems [3], capillary systems [4], and multichannel reactor systems [5], and only one report of a conventional packed flow system [6]. Moreover, there are several limitations in previous studies: immobilization of the catalyst was relatively difficult in the case of the microreactor, capillary, and multichannel systems [3][4][5].Selective oxidation of alcohols is one of the most important transformations in organic synthesis. This is because the resulting carbonyl compounds possess higher energy and reactivity, allowing many types of carbon-carbon and other bond-forming reactions [7,8].…”

“…While gas-solid, liquid-liquid, or liquid-solid biphasic conditions are common in flow systems, examples of gas-liquidsolid multiphase conditions are very rare. As for flow systems for aerobic oxidation of alcohols using heterogeneous catalysts, to the best of our knowledge, there are only a few reports of multiphase reactions in microreactor systems [3], capillary systems [4], and multichannel reactor systems [5], and only one report of a conventional packed flow system [6]. Moreover, there are several limitations in previous studies: immobilization of the catalyst was relatively difficult in the case of the microreactor, capillary, and multichannel systems [3][4][5].…”