Microwave‐Assisted Chemoselective Hydrogenation Reactions Incorporating Hydrogen as Reducing Agent

Abstract

The use of modern microwave equipment affords an easy and safe handling in the laboratory routine. The described quartz reactor system was tested in different reaction types to show its versatile applications. Various liquid-phase hydrogenations were carried out successfully. The construction of the reactor allows the direct introduction of gases into the reaction mixture so that the reduction can be performed with gaseous hydrogen.

Gaseous Reactants in Microwave‐Assisted Synthesis

“…The glasses were decorated with different metal precursors using a wet impregnation methodology. Benzalacetophenone [14] and verbenone [15] were employed as substrates for the investigation of reaction parameters such as hydrogen pressure, reaction temperature, reaction time, and type of metal. Hydrogenation reactions were carried out in ethyl acetate as solvent using a microwave-autoclave system allowing a maximum operating pressure of 1.0 MPa H 2 [15].…”

“…Benzalacetophenone [14] and verbenone [15] were employed as substrates for the investigation of reaction parameters such as hydrogen pressure, reaction temperature, reaction time, and type of metal. Hydrogenation reactions were carried out in ethyl acetate as solvent using a microwave-autoclave system allowing a maximum operating pressure of 1.0 MPa H 2 [15]. Experiments with both substrates revealed that the conversion increases with increasing pressure, temperature, and reaction time [14,15].…”

“…Hydrogenation reactions were carried out in ethyl acetate as solvent using a microwave-autoclave system allowing a maximum operating pressure of 1.0 MPa H 2 [15]. Experiments with both substrates revealed that the conversion increases with increasing pressure, temperature, and reaction time [14,15]. Owing to the strained bicyclic ring system of verbenone, the effect is more pronounced for benzalacetophenone.…”

Room‐Temperature Hydrogenation of Citral Catalyzed by Palladium–Silver Nanocrystals Supported on SnO2

“…to citronellal over Pd catalysts through the tuning of the reaction conditions [12][13][14] and the selection of different supports, including Al 2 O 3 , zeolite, CaCO 3 , TiO 2 , and sepiolite. [15][16][17][18] However, the selectivities to the desired products over these catalysts are not promising, likely because of the poor selectivity of Pd for the hydrogenation of C=C and C=O.…”

Sonochemical preparation of alumina-spheres loaded with Pd nanoparticles for 2-butyne-1,4-diol semi-hydrogenation in a continuous flow microwave reactor

“…24 Catalytic hydrogenation under MW irradiation has been conducted safely and quickly in open vessels, 25 sealed reaction systems, 26 a quartz reactor and even under 2.5 MPa of hydrogen pressure.…”