Study On The Hydrolysis And Photolysis Of Buprofezin

Buprofezin, chemical name:2-tert butyl imino-3-isopropyl-5-phenyl-3,4,5,6-tetrahydro-2H-1,3,5-thiadiazine-4-ketone, which is a new kind of selective pesticides developed by Japan pesticides kabuskikikaisha.Very little comprehensive research on the behavior of Buprofezin in the environment has not beenstudied,although it is an efficient, harmfulless pesticide and it is applied widely. In order to provide thetheory evidence for migration and transformation of Buprofezin in the environment, we investigated thehydrolysis and photolysis of Buprofezin.The results showed that hydrolysis of Buprofezin follows first-order reaction.In the hydrolysisexperiments, we investigated the impacts of different temperatures(50℃、60℃、70℃、80℃、90℃) anddifferent pH values (2、3、4、5、7、9) on the hydrolysis of Buprofezin. The results showed, hydrolysis rateis the fastest in the buffer solution of pH4, and hydrolysis rate decreases gradually with the increase ordecrease of pH value in the same temperature environment. With increasing temperature, the hydrolysisrate gradually accelerated in the same pH value. In addition, the entropy of activation of hydrolysisdecreases with increasing temperature, showing a significant correlation.The results showed that the photolysis reaction of Buprofezin is in line with the order kineticsin four organic solvents and aqueous solution. The photolysis rate of Buprofezin in four organicsolvents followed the sequence: n-hexane＞ethanol＞methanol＞acetone, the photolysis half1ife ofBuprofezin in n-hexane, ethanol, methanol, acetone was6.754h、8.535h、8.684h、41.01h respectively. Inbuffer solutions, the photolysis rate decreases gradually with the increase of pH values. The photolysis half 1ife in pH6、pH7、pH8、pH9was1.97h、2.12h、2.24h、2.33h respectively. The nitrate have optical quenchingeffect on the photolysis of Buprofezin.With the concentration of nitrate increases, optical quenching effectincreased. The optical quenching rate was0.03%、0.44%、9.74%when the nitrate concentration was0.1mg/l、1mg/l、10mg/l respectively. Werther the ferric ion or humic acids have a siginificant opticalquenching effect on the photolysis of Buprofezin, and the optical quenching effect increased with theadded concentration increases. When their concentration was0.5mg/l, the optical quenching rate was42.77%and13.3%respectively. Besides, the results showed that three surfactants have optical quenchingeffect on the photolysis of Buprofezin also. In comparison, the optical quenching effect of CTAB and SDSis stronger than TBAB on Buprofezin photolysis.Finally, the photolysis products of Buprofezin were analysed by using high performance liquidchromatography and mass spectrometry techniques.