Sonolytic degradation of phthalic acid esters in aqueous solutions. Acceleration of hydrolysis by sonochemical action

The degradation of phthalic acid esters in an aqueous solution by sonochemical action was performed at an ultrasonic frequency of 200 kHz. The sonochemical degradation of phthalic acid esters followed pseudo first-order kinetics. The OH radical reaction was found to be a predominant factor of the degradation of diethyl phthalate in the pH range 4-11. However, over pH 11, the degradation rate was accelerated with an increased pH due to the increased hydrolysis. From experiments involving stirring and ultrasonic irradiation, the accelerated degradation by hydrolysis in the presence of ultrasound was also established. The accelerated hydrolysis of phthalic acid esters by sonochemical action may be due to the existence of a sphere in which a temperature higher than that in the bulk solution is present.