Study On The Synthesis Of Bifenazat

As a new kind of acaricide technical,bifenazate is mainly used for prevention of Tetranychus urticae and Panonychus ulmi Koch.It is environment friendly and it has low toxicity to beneficial insects and predatory mite.It can be said that bifenazate fits well for comprehensive treatment of insects.In this paper,we chosed three different synthetic routes of bifenazate in the study of informed research.4-phenylphenol was used as the starting material in those routrs.Route A,bifenazate was synthesised by six steps,they were methylation,nitration and reduction,diazotization,reduction of diazonium salt and acylation in turn.The overall yield was 2.8%.We focused on the dosage effect of Phasetransfer catalyst TBAB in K2CO3/TBAB methylation system.Na2S-H2O and SnCl2-HCl-EtOH systems were also studied in this route.It was considered that Na2S-H2O system was more suitable for industrial production.Route B,bifenazate was produced by methylation,amination and selective decarboxylation in acidic condition.The total yield was 9.1%.We paid more attention to purification of our compounds.At the same time,we found that the yield of selective decarboxylation in acidic condition could get 17.6%at 40 centigrade.Route C,bifenazate was obtained by amination,selective decarboxylation under alkalinity condition and methylation.The total yield was 1.0%.The purification and the influence of DMC-K2CO3.DMC-K2CO3-TBAB and DMC-TBAB systems on the yield of methylation was investigated.Comparing the advantages and disadvantages of the above routes,it can be concluded that route B was more suitable for industy for lower cost,more simple craft,fewer steps and relatively higher yield.