Design of a capacity-enhanced single-mode reactor for microwave chemistry researches

With the development of microwave chemistry researches at higher ISM frequencies, reactors that can guarantee a high reproducibility of microwave-assisted reaction, a uniform microwave heating area and a more extensive processing volume become an urgent need. This paper proposes a new type of capacity-enhanced single-mode reactor and its design method for microwave chemistry research at the frequency of 5.8 GHz. The proposed reactor is constructed based on a size-enlarged rectangular waveguide, which can contain a larger volume of reactants. However, the higher-order propagating electromagnetic modes of the microwave in the proposed reactor were restrained and only left the first-order TE₁₀ mode. The heating uniformity thereby can be ensured by the restraint of higher-order modes. The single-mode microwave heating in our proposed reactors can also better guarantee the reproducibility of microwave-assisted reactions, compared with the multi-mode cavity microwave reactors, especially those with rotation elements. A set of full-wave numerical simulations are conducted to optimize the reactor and illustrate the design principles. Finally, a reactor is chosen and fabricated as an example to validate the design method and the numerical calculations. Experiments are implemented to prove the heating uniformity and the effective restraint of higher-order electromagnetic modes. The capacity-enhanced single-mode reactor and its design method can be extended to other ISM frequencies. 5.8 GHz is chosen because it has a much shorter wavelength and is more needed to increase the processing volume.