Study On The Formulation And Physical Stability Of Chlorfenapyr 10% EW

The chlorfenapyr is a chemical with the structure of trifluoromethyl -pyrrole, which is produced by the company of American Cyanamid Company. It can control many kinds of resistant pest, such as P. xylostella, M. brassicae and B. brassicae, especially for the S. exigua and P. xylostella. So far some kinds of chlorfenapyr formulation have been reported, e.g. SC, WP, ME and so on. The formulation of chlorfenapyr EW has never been reported. Emulsion in water (EW) is the trend of the pesticide formulation development, so it has a good prospect. Chlorfenapyr is able to form EW because it has little solvency in water and good solvency in toluene and xylene property.Through the screening and assembling of solvent, and surfactant, the optimum formulation of 10% chlorfenapy EW was developed as following by the phase transfer-method. The optimum solvent is 22.8% toluene. The proportion of the mixture of surfactant, EL-40, S-80, and 500~#, is 16:3:1, which totally occupied 10% weight of the formulation. The other component was distilled water, which is 56.7% of the formulation. Made by the above formulation, the indexes of the chlorfenapyr EW is up to grade. The formulation had been stored at normal temperature, or 54℃±2℃for 80 days without oil-separation and creaming phenomenon. The viscosity of the formulation is low, which makes it easier to pour out and sub-package.After the formulation was developed, the effect of different factors to the stability of the chlorfenapyr EW was studied, such as the structure and dosage of emulsifier, thicker, co-emulsifier, inorganic-salt and product process, et al. The relations between the factors and the stability of EW system were studied through the method of combining the apparent phenomenons and the microcosmic analysis. The key factor is emulsifier. The situations of forming well stable EW system are as following. Firstly it is to select suitable kind and dosage of emulsifier which can form hard film. Secondly it is to select density of oil phase in order to anti-creaming. Thirdly, appropriate viscosity of system is made by selecting fit proportion of oil phase weight. Finally, it is to input enough energy which could separate the disperse phase into little droplets. The salt always reduce the stability of the system. The view is proved by the optimum formulation of 10% chlorfenapyr EW.In the end, the analysis method of HPLC for chlorfenapyr content is developed, which could offer reference for the quality control in the industry production.