Studing On The Influence Factors Of The Formation Process Of Beta-cyfluthrin And Cyhalothrin Microemulsion

Following the development of the pesticide production,the pressure of circumstance protection caused by pesticides is getting worse and worse. The pesticide agent producing is an effective approach to postpone this pressure, it is facing both a big opportunity and a great challenge. Agro-microemulsion developped quickly in the last few years because it can fit the need of water solution pesticide agent producing. However , the current research is mainly focused on simple formula screenning on the home and abroad. This thesis chose beta-cyfluthrin and Cyhalothrin as the research objects. On the base of the research we have done before, we did more research about the influence factors of agro-microemulsion's forming mechanisms. The following aspects were studied in this thesis :1. We have screened out better raw-pesticide solvent,surfactants and co-surfactant through complex mixed experiments.Then the formula and every composition content were determined by microemulsion index inspect. The best beta-cyfluthrin microemulsion formula is described as follows: The ratio of raw-pesticide and cyclohexanone is 1:2,their total content is 15%,the total content of 34# and 500# is 15% when their mixed ratio is 4:1,the content of co-surfactant(n-octanol)is 2%.2. A theoretical mathematical model was established about the conce- ntrations of mixed surfactants and n-octanol on the maximum amount of beta-cyfluthrin that could be added during the formation of a microemulsion at 25℃. Y=AXcXs+BXc+CXs+DA=0.0882,B=0.0812,C=0.1755,D=-0.3265,with an application range as follows: at 25℃, Xc (Cn-octanol) =0.5%～4%, Xs(Csurfactant) = 10%～17%.3. The maxium contents of beta-cyfluthrin were respectively mensurated at 20℃,25℃,30℃,35℃,40℃.The results show that the maxium contents of beta-cyfluthrin are increased with temperature rising at 20℃～40℃when the contents of mixed surfactant and co-surfactant are changeless.4. The differences of electric mechanism ,phase behavior and heigh temper- ature stability of Cyhalothrin microemulsion formed by polyoxyethylene sty- renyl ether and dodecyl benzenesulfonic salts combined with five coherer counter-ions were investigated. These two kinds of surfactants were mixed at the amount of substance 1 to 1. The results showed that K⁺ and Na⁺ were propitious to the formation of O/W microemulsion for their dodecyl benzenesulfonic salts'big solubility in water and their small hydrated radius which induced big bingding degrees of the counter-ions with the hydronium garret group. Li⁺ was better . Ca²⁺ and Mg²⁺, which dodecyl benzenesulfonic salts are yield lipophilic surfactants, were not propitious to the formation of O/W microemulsion .When the molar ratio of DBSK, DBSNa, DBSLi and NR601 is about 1:1, the high temperature decompose ratio is the lowest. When the molar ratio of DBSMg , DBSCa and NR600 is about 1:1.5, the high temperature decompose ratio is the lowest.5. Studied the interface nature of SDBS at 30±0.1℃by electric conductivity measurement and interface tension. The results show that the cmc of DBSK, DBSNa, DBSLi are much higher than DBSMg , DBSCa, and cmc(DBSK)< cmc(DBSNa)< cmc(DBSLi), cmc(DBSCa)