Abstract
Peroxycitric acid (PCA) was successfully synthesized for the first time as an equilibrium mixture with citric acid and hydrogen peroxide using sulfuric acid (homogeneous) and Nafion (heterogeneous) catalysts. The formation of PCA in the equilibrium mixture was detected by the potentiometric measurement based on the triiodide/iodide redox couple potential buffer and the concentration of PCA was determined from the obtained potential change. The equilibrium % yield of PCA was found to largely depend on the concentration and the nature of catalysts. The peculiar roles of the heterogeneous and homogeneous catalysts in the formation of PCA were discussed briefly.