Sonolytic Degradation of Phthalic Acid Esters in Aqueous Solutions. Acceleration of Hydrolysis by Sonochemical Action

Abstract

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.

Extraction and Pre-concentration of Phthalic Acid Esters from Aqueous Solutions using Agitation-assisted Dispersed Binary Solvents Microextraction

“…This failure could be attributed to the fact that esters hydrolyse easily even in water when subjected to heat, than any other cause such as loss in the method. The same loss in efficiency was reported using sonication-assisted extraction, 43 where the loss was attributed to the sonication energy enhancing the hydrolysis of these phthalic acid esters. Despite this setback with regards to the soil samples, RESEARCH ARTICLE M.J. George, O.R.…”

Effect of ultrasound on ester hydrolysis in aqueous ethanol

“…The hydrolysis of phthalic acid esters in an aqueous solution by sonochemical action was performed at an ultrasonic frequency of 200 kHz [15]. Moderate ultrasonic accelerations were found over the pH range between 4 and 13.…”

“…2-hydroxy-4-nitrophenyl acetate, Scheme 1) and pyrolytic products were found exclusively; hydrolysis, however, was extremely slow at this pH. Yim et al [15] studied the degradation of phthalic acid esters in aqueous solution under ultrasound at 200 kHz. Compared to hydrolysis, attack by OH radicals was found to predominate in the degradation of diethyl phthalate in the pH range 4-11.…”

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“…다양한 식물잎으로부터 원하는 성분을 높은 효율로 추출하기 위한 초음파 추출방법은 오래전부터 보고되 고 있다 (Vinatoru, 2001;Fred Schurig and Sole, 1967;Ovadia and Skauen, 1965;Thompson and Sutherland, 1955) Yim et al, 2002;Suslick, 1990;Suslick et al, 1986). …”