Study On The Synthesis Technology Of Pyraclostrobin

Strobilurin fungicide is a sort of fungicides with low toxicity,high efficiency and broad spectrum which is used as fungicide to treat the plant diseases caused by fungus.Because of its features of protection,cure,eradication,penetration,non-carcinogenesis and non-mutagenesis,Strobilurin fungicide is a new-type fungicide with greatly market potential.In this thesis,the synthesis processes of strobilurin fungicide pyraclostrobin was studied.The optimum operation conditions were obtained by cyclization,oxidation,bromination,condensation,reduction,acylation and methylation with 4-chlorophenylhydrazine hydrochloride and 2-methylnitrobenzene.And the properties of pyraclostrobin and intermediate compound were identified by FT-IR?1HNMR?MS et al,providing an experimental basis for industrial applications.The catalytic reduction of nitro group to hydroxylamine,including the factors such as reaction system,temperature and catalyst,was mainly studied in this thesis.The o-methylphenylhydroxyamine which was prepared by the reaction using active metal molybdenum as the catalyst,hydrazine hydrate as the hydrogen source,the tetrahydrofuran as the solvent,could used in the next acylation directly.And the reaction conditions were verified as follows:n(ortho-nitrotoluene):n(hydrazine hydrate)=1:1.5,reaction temperature was 20-30?,reaction time was 7-8h,the content was greater than 98.0%.The optimum operation conditions and the ideal erperimental data were obtained through single-factor experiment which includes the effects of ratio,solvent,catalyst,reaction temperature and reaction time.Finnlly,the total yield reached up to 65.6%counted by nitrotoluene,which improved the yield of pyraclostrobin nearly 20%compared with 47.8%reported in the literature.The route in this thesis has significant effect on the sustainable development because of its low emission,high security and relatively inexpensive cost.