Abstract: A device for carrying out large-scale chemical reactions includes a microwave generator, a microwave application vessel containing a high-capacity reactor, and a cover, in which the vessel is a cylinder having longitudinal axis X, a microwave inlet in the vessel bottom wall, and an open upper end, in which the generator provides single-mode microwaves along axis X in the vessel, the size of the vessel being made to match the wavelength of the resonant mode of the microwaves along axis X, and in which the cover seals the upper opening of the vessel, and the cover has a conduit that connects the inside of the vessel to the environment so that the vessel is under atmospheric pressure.