This critical review examines recent scientific and patent literature in the application of microwave reactors for catalytic transformation of biomass and biomass-derived molecules with a particular emphasis on heterogeneous catalysis. Several recent reports highlight dramatic reductions in reaction time and even superior selectivity when microwaves are used. However, there are still many controversies and unexplained effects in this area that deserve attention. We critically review the available sources attempting to establish trends and elucidate the actual status of this area of research. Additionally, where possible, we discuss the potential for scale-up and commercial utilisation of microwaves and impediments that currently hold back their implementation. This critical review also aims at highlighting the opportunity of combining catalysis with microwave technology for biomass conversion but also to stimulate the reader to generate future understanding on the influence of the microwaves in catalytic processes in general.

Green, inexpensive, and robust copper‐based heterogeneous catalysts achieve 100 % conversion and 99 % selectivity in the conversion of furfural to furfuryl alcohol when using cyclopentyl‐methyl ether as green solvent and microwave reactors at low H₂ pressures and mild temperatures. The utilization of pressurized microwave reactors produces a 3–4 fold increase in conversion and an unexpected enhancement in selectivity as compared to the reaction carried out at the same conditions using conventional autoclave reactors. The enhancement in catalytic rate produced by microwave irradiation is temperature dependent. This work highlights that using microwave irradiation in the catalytic hydrogenation of biomass‐derived compounds is a very strong tool for biomass upgrade that offers immense potential in a large number of transformations where it could be a determining factor for commercial exploitation.