When the ultrasound irradiates into water, the hydric and hydroxyl radicals genrerated. It has been reported that many sonochemical reactions are attributed to these radicals. In order to apply sonochemical reaction effectively, the estimation of hydroxyl radical reaction rate is important. In this study, the generation rate of hydroxyl radical in water is simply modeled and the simulation of sonochemical reaction is done. By fitting simulation results into experimental data, the generation rate constant of hydroxyl radical from water is estimated. Methyl orange aqueous solution, which is decomposed by hydroxyl radical, is used as sample. From the results of analysis, the hydroxyl radical concentration in solution approaches a steady value in the early stage of reaction. The steady value of hydroxyl radical concentration depends upon methyl orange concentration. It is considered that the model must be taken into account the reation between hydrogen peroxide and solute.
