We discuss the possibility of designing a pressure-driven single-phase microreactor with characteristics similar to that in an ideal plug-flow reactor. We consider equations for the moments of the residence time distribution and investigate the behavior of the solution in long spatially-periodic channels. If the microreactor consists of a large number of folding flow elements, the chaotic advection plays a double role: it mixes the chemical species and suppresses the axial dispersion. It is shown using analytical estimates and numerical modeling that chemical reactions have different sensitivity to the axial dispersion and for some reactions the effect of dispersion can be successfully eliminated. (C) 2009 American Institute of Chemical Engineers AIChE J, 56: 1988-1994,2010