Microreactor composed of plates and comprising a catalyst

A microreactor for performing heterogeneous catalytic reactions, having a multiplicity of chambers in vertical or horizontal and essentially parallel arrangement, each being equipped with at least one feed line and one discharge line, the feed lines being connected to at least one manifold and the discharges to at least one header, the chambers being formed by stacked plates or layers, and one part of the chambers representing reaction chambers and the other part of the chambers representing heat carrier chambers, the heat transport between reaction and heat carrier chambers taking place through at least one common chamber wall formed by a common plate, with spacers being arranged in all chambers, wherein catalyst material is applied at least in part to the internal walls of the reactor chambers, the hydraulic diameter, defined as the quotient of the four-fold area to the circumferential length of the cross section of free flow, in the reaction chambers is smaller than 4000 μm, and the ratio between the smallest perpendicular distance between two neighboring spacers to the slot height of the reaction chamber after coating with catalyst is smaller than 800, and greater than or equal to 10.