US EPA

4527512 

Journal Article 

Kinetic study of the degradation of ethiofencarb in aqueous solutions 

Sanz-Asensio, J; Plaza-Medina, M; Martinez-Soria, MT 

1997 

1 

Pesticide Science
ISSN: 0031-613X
EISSN: 1096-9063 

JOHN WILEY & SONS, LTD. 

50 

3 (July 1997) 

187-194 

10.1002/(SICI)1096-9063(199707)50:3<187::AID-PS580>3.0.CO;2-H 

WOS:A1997XK04400003 

A kinetic study of the hydrolysis of ethiofencarb ( alpha -ethylthio-o-tolyl methylcarbamate) in pure water and in aqueous solutions at pH 2, 6, 9 and 12 and at three different temperatures (4, 20 and 50( plus or minus 1) degree C) has been carried out using a gas chromatographic nitrogen-phosphorus detection method. The values of the first-order rate constants (k) for the degradation reaction were calculated. The values for k were found to be dependent on pH and temperature. No acid hydrolysis was observed in any case. Complete degradation of ethiofencarb was observed at pH 12 at all three temperatures; it was practically instantaneous at room temperature. Ethiofencarb was also completely degraded at pH 9 at 20 and 50 degree C, while in pure water (pH 6) degradation took place at 50 degree C but not at 20 degree C. Ethiofencarb was not degraded in pure water at lower temperatures and, due to the reversible nature of the reaction, at equilibrium about 80% of the pesticide remained undegraded at room temperature. 

decomposition; chemical reactions; hydrolysis; pesticides; kinetics; temperature; organic pesticides; degradation; water temperature