Synthesis Of Four Kinds Of Diphenylether Herbicides With-CF₃

Acifluorfen, Fomesafen, Lactuofen, Fluorofen- ethyl belong to diphenyl ethers herbicides.They are used in controlling or killing broadleaf in post-emergency for cereal crops. They have high activity, broad spectrum in controlling grasses, low toxicity. So, they are used widespread in our country north area. The four herbicides were first manufactured by Rhom & Hass Co. in American and ICI Co. in ENGLAND.This paper has selected synthetic rout, tried to find out optimum reacting conditions, confirmed the chemical structure of products, established analytical methods of intermediates and products in the basis of patents. And provided with basic data for technological scale. Effective tests and toxicity test of Acifluorfen and Fomesafen have been evaluated.The four herbicides have similar chemical structure, their main structure is 5-[2-chloro-4-(trifluoromethyl)phenoxyl]-2-nitro benzoic acid. The selection of synthesis rout have been comprehensively depended upon materials, practical probability of technological process, costs, purity of products, reacting conditions, eflPects on environment, etc. It has been confirmed that 3.4-dichlorotrifluomethylbenzene and m-hydroxyl benzoic acid are starting materials.The intermediate of 3-[2-chloro-4-(trifluoromethyl)phenolxyl] benzoic acid has been first prepared. Aciflurofen has been synthesized by nitrating reaction with intermediate. Fomesafen has been synthesized by reacting Acifluorfen with methanesulphonamide, Lactofen and Fluorofen-ethyl have been respectively prepared by reacting Acifluorfen with 2-chloropropanoate ethyl or chloroacetic ether.The optimum technological conditions, such as reactant proportion, solvent, catalyst, reacting temperature, reacting times, etc., have been obtained.Analytical method of intermediates and products has been established, quantitative analysis and qualitative analysis have been conducted by HPLC. Thechemical structure of products have been confirmed by IR, LC-MS, !H-NMR, 13C-NMR, 19F-NMR, etc.Effective tests and toxicity test of Acifluorfen and Fomesafen have been evaluated. Effective tests of 21.4% SL Acifluorfen and 25% SL Fomesafen were similar to BLAZER of Rhom & Hass Co. and FLEX of ICI Co. The toxicity of Acifluorfen and Fomesafen prepared were lowly poisonous matters according to pesticide classified standard of acute toxicity in our country.Compared with patent, synthesis method were correct, technological process were advanced. The yield and purity of Acifluorfen, Fomesafen, Lactuofen, Fluorofen - ethyl were respectively 83.5%, 84.2%;85.6%, 97.0%; 82.6%, 75.0%; 90.5%, 80.5%. It came up to patent level, evenly surpassed.