Study On Synthesis Process Of Pyraclostrobin

The synthetic process of pyraclostrobin,one of methyl acrylate fungicides,was systematic optimized.Methyl acrylate fungicides have the advantage of highly efficient,low toxicity,environmentally friendly and so on.The research of optimum synthesis about pyraclostrobin is of great significance to expand our product range and optimize the product structure.In this paper,synthesis process of pyraclostrobin starting from p-chlorophenylhydrazine hydrochloride and o-nitrotoluene was optimized.The process possessing simple operation steps,short of the reaction cycle,good product quality,reduction of the "three wastes" emissions and achievement of the green chemical process requirements was determined.This research provides a basis for industrial production.The main research contents are as follows:(1)The key intermediate of 1-(4-chlorophenyl)pyrazolidin-3-ol was obtained by oxidation of 1-(4-chlorophenyl)-pyrazolidin-3-one which was prepared by the reaction of p-chlorophenylhydrazine hydrochloride with acrylate.The optimum process parameters were determined by exploration of temperature,the ratio of materials and the new reactor of Corning microchannel reactor.(2)O-nitrobenzyl bromide was prepared by the microchannel reaction of photoinduced bromination starting from o-nitrotoluene.The optimum process was determined by parameters adjustment.(3)The target product of pyraclostrobin was prepared by four steps reaction.The first one is the condensation reaction between 1-(4-chlorophenyl)pyrazolidin-3-ol and o-nitrobenzyl bromide.Secondly,the resulting intermediate was subjected to hydrogenation.And then,the hydrogenated productwas reacted with methyl chloroformate via acylation reaction.Finally,methylation reaction was preceded with dimethyl sulfate to obtain the target product.In this paper,The synthesis of target product and simplification of operation was achieved by parameters adjustment and process optimization.This synthetic process greatly reduced the raw materials cost.Meanwhile,It provides the basis for the future enlargement of the production..