Magnetic resonance imaging was used for two-dimensional temperature visualization of chemical wavespropagation in the autocatalytic exothermal reaction of thiosulfate oxidation by chlorite. The technique presentedis based on the temperature dependence of the water chemical shift. Temperature maps were acquired byemploying the TurboFLASH imaging method. The results obtained allow one to judge about directions ofbuoyancy flows. Two types of convection critical modes in a vertical tube during the wave propagation weredetected.