Study On Synthesis And Quality Control Of Carfentrazone-Ethyl

Carfentrazone-ethyl,a triazolinone herbicide developed by FMC,launched in1997.With protoporphyrin oxidase as the target,it can be used to control weeds in wheat,rice,corn and other crops,with the characteristics of high efficiency,safety and low resistance.Currently,there are some issues in its synthesis process such as unsafe reagents used,high production cost,complicated operation,low yield and quality.In this paper,the synthesis technology and quality control of carfentrazone-ethyl were studied,so as to further simplify the process,reduce the cost and improve the quality to adapt to production.The main research contents are as follows:Using o-fluoroaniline as the starting material,the target product was obtained through the steps of amino protection,chlorination,amide deprotection,diazotization,reduction,acidification,triazolinone formation,difluoromethylation,nitration,reduction,Meerwein arylation and esterification.The process of key intermediate triazolinone,was optimized and scaled up in pilot plant.The purity of carfentrazone-ethyl was 98% and the total yield was 40% after optimizing the reaction solvent,molar ratio,reaction time and reaction temperature,etc.Based on carfentrazone-ethyl synthesis route,its product specification was established,including assay content,moisture,p H,solvent residue and related impurities.High performance liquid chromatography(HPLC)method was developed to determine the related substances of carfentrazone-ethyl,and headspace gas chromatography(HS-GC)was developed to determine the solvent residue.Both HPLC and HS-GC methods have been validated.The validation results show that HPLC and HS-GC methods have good repeatability and robastiness,good linearity and specificity.Both methods can be accurately applied to the detection of related substances and solvent residues in carfentrazone-ethyl.