Kinetics and mechanism of hydrolysis of phenylureas

Salvestrini, Stefano; Cerbo, Paola Di; Capasso, Sante

doi:10.1039/b205850b

Cited by 36 publications

(46 citation statements)

References 10 publications

(1 reference statement)

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“…Diuron is stable toward hydrolysis under neutral conditions but at lower and higher pH values the hydrolysis rate sharply increases (12,24). Enhanced NDMA formation at pH 4 may therefore be attributed to the greater availability of DMA un this condition.…”

Section: Resultsmentioning

confidence: 95%

NDMA Formation during Chlorination and Chloramination of Aqueous Diuron Solutions

Chen

Young

2008

Environ. Sci. Technol.

118

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Formation of the potent carcinogen N-nitrosodimethylamine (NDMA) during chlorine disinfection of water containing secondary amines is now generally acknowledged. The phenylurea herbicide diuron is one of the most widely used herbicides in California, has been frequently detected in California's water sources with a transient nature of appearance, and has a structure that suggests it might be an NDMA precursor. This study sought to quantify the potential for NDMA formation from aqueous diuron solutions under varied chlorine and chloramine conditions. NDMA formation was consistently observed even in the absence of added ammonia, which has usually been the source of the nitroso-nitrogen during chloramination of other precursors. It appears that both nitrogen atoms in NDMA are donated by diuron during chlorination in the absence of added ammonia. For a given chlorine and diuron dose, NDMA formation increased in the order OCl -

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Section: Resultsmentioning

confidence: 95%

NDMA Formation during Chlorination and Chloramination of Aqueous Diuron Solutions

Chen

Young

2008

Environ. Sci. Technol.

118

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“…Earlier reports [12,15,[17][18][19] have shown that hydrolysis of phenylureas involved formation of isocyanic acids or isocynanates which are subsequently hydrolyzed to corresponding amines and carbon dioxide (Figure 4).…”

Section: Conversion Behaviormentioning

confidence: 95%

“…[17][18][19] Thus, it is necessary to investigate the influence of the leaving group, the poly(oxyalkylene)-amines, on the conversion rate. Figure 7 shows the residual contents of four dye-polyether derivatives in aqueous solutions buffered at pH 7-9 after treated at 130 C for 60 minutes.…”

Section: Effect Of the Polyether Structure On Thementioning

confidence: 99%

pH-Sensitive Dye-Polyether Derivatives as Dispersants for Its Parent Dye. Part 1: Synthesis and Hydrolysis Behavior

Dong

2010

Journal of Dispersion Science and Technology

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A series of dye-polyether derivatives, supposedly to be used as dispersants for parent dye, were synthesized by grafting poly(oxyalkylene)-amines based on differing both molecular weights and degrees of hydrophilicity/hydrophobicity, onto C.I. disperse red 60 via a stable urea linkage. The structures of the dye-polyether derivatives were characterized by FTIR, 1 H NMR, and SEC. The influence of pH on the hydrolysis behaviors of the dye-polyether derivatives were studied in buffered aqueous solutions within the pH range of 4 to 10. The hydrolysis of dye-polyether derivatives was pH dependent and relatively faster in mild alkaline buffer solution than in acidic one. The influence of poly(oxyalkylene)-amine structure on the hydrolysis behavior was also investigated; it was found that the hydrolysis rate is affected little by the molecular weight and increases with the increasing hydrophilicity of the poly(oxyalkylene)-amine.

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“…− concentration, the hydrolysis proceeds through the fast reversible deprotonation of nitrogen (attached to phenyl group) followed by slow protonation of dimethyl amino nitrogen by water [7]. The reaction may be represented by Scheme 2.…”

Section: At High Ohmentioning

confidence: 99%

“…Isoproturon is hydrolyzed in the environment slowly with the half-life period of 30 days [4]. Isoproturon is hydrolyzed in both acidic and alkaline media [5][6][7][8]. During acidic hydrolysis, the reaction proceeds through the protonation of phenylurea followed by a rate-determining attack by water to yield isopropyl aniline, dimethyl amine, and CO 2 .…”

Section: Introductionmentioning

confidence: 99%

Kinetics of the alkaline hydrolysis of isoproturon in CTAB and NaLS micelles

Gangwar

Rafiquee

2006

Int J of Chemical Kinetics

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Kinetics of the alkaline hydrolysis of isoproturon has been studied in the absence and presence of cetyltrimethylammonium bromide (CTAB) and sodium lauryl sulfate (NaLS) micelles. CTAB micelles were found to enhance the rate of reaction, while NaLS micelles inhibited the reaction rate. The reaction obeyed first-order kinetics in [isoproturon] and was linearly dependent on [NaOH] at lower concentration. The rate of reaction became independent at higher [NaOH]. At lower [NaOH] the reaction proceeded via formation of hydroxide ion addition complex, while at higher [NaOH] the reaction occurred via deprotonation of NH , leading to the formation of isocyanate. The values of k w , k m , and K s were determined by considering the pseudophase ion exchange model. The activation parameters have also been reported. The effect of added salts (NaCl and KNO 3 ) on the reaction rate has also been studied.

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Kinetics and mechanism of hydrolysis of phenylureas

Cited by 36 publications

References 10 publications

NDMA Formation during Chlorination and Chloramination of Aqueous Diuron Solutions

NDMA Formation during Chlorination and Chloramination of Aqueous Diuron Solutions

pH-Sensitive Dye-Polyether Derivatives as Dispersants for Its Parent Dye. Part 1: Synthesis and Hydrolysis Behavior

Kinetics of the alkaline hydrolysis of isoproturon in CTAB and NaLS micelles

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