Investigation of the Belousov–Zhabotinsky reaction by thermal lensing

Thermal lensing is used for monitoring the course of unstirred Belousov–Zhabotinsky reaction (a bromate oscillator) based on malonic acid as an organic substrate in 1.5 M sulfuric acid with a mixture of free Fe(II) and its chelate with 1,10-phenanthroline as a catalyst and a photometric indicator of the reaction process. The dependences of the oscillation period and oscillation lifetime on the component concentrations are found. The sensitivity of thermal lensing in determining reaction components was compared to spectrophotometry and potentiometry by the model determination of bromide ions by its inhibition effect on the reaction kinetics.