The Water Environment Of The New Pesticides And Toxic Fluoride Phosphate Chemical Behavior

Dufulin is a novel virus inhibitor which was developed and synthesized by the Center for Research and Development of Fine Chemicals of Guizhou University. Chemical behaviors and ecological effects of Dufulin in the environments were unknown.Therefore,study on a method for determination of Dufulin residues in water, hydrolysis and photolysis for its reasonably application.According to the physicochemical properties of Dufulin,a sensitive HPLC-DAD analytical method was developed for determination of Dufulin residues after extraction of the aqueous solution with dichloromethane under laboratory condition. The accuracy and sensitivity of the method meet the requirements of pesticide residues analysis.On this basis,the following chemistry behaviors of Dufulin were observed:(1) Hydrolysis rate of Dufulin is faster in basic solution than in acidic or neutral medium.Hydrolysis of Dufulin in the buffer solutions of pH 5,pH 7 and pH 9 increases with the increasing temperature,the activation energy(Ea) and activation enthalpy(△H) have no visible relation with the temperature.The negative activation entropy(△S) indicates that the degradation of Dufulin under water environment depends on various factors.Hydrolysis of Dufulin in natural waters such as pond water,Huaxi river water and distilled water increased with incubating time,the half-lives were found to be 12.58 d,14.68 d and 21.19 d respectively.(2) Under irradiation with UV light at 253.7 nm,rapid photodecomposition of Dufulin in aqueous solutions and organic solvents were observed.Photolytic decomposition rate followed the decreasing order in different solvents,pH and water respectively: n-hexane＞methanol＞acetone,pH 9＞pH 7＞pH 5 and pond water＞river water＞distilled water.The shapes,positions and intensity of UV absorbance bands of Dufulin were dependent on the nature of the solution.These results not only provided important guiding significance about reasonably application of Dufulin in the environment,but also provided a theoretical basis for evaluating its environmental safety.