Process Research Of Acifluorfen Synthesis

China is a large agricultural country. The discovery of Organic Chemistryherbicides and large-scale applications brings the gospel to the modernization ofagriculture. The use of herbicides, reduces the economic losses caused by the weeds,saves the manual labor, improves the weed control efficiency, and promotes the processof modernization of agriculture. The market prospects of herbicide will be bright in thefuture. Research and development of new herbicides is difficult, so most of ourproductions of herbicide are generic ones. Acifluorfen belongs to diphenyl ethersherbicides which is created by the American company in the seventies of the last century.It has high activity, broad spectrum in controlling grasses and low toxicity. It is still usedwidespread in our country now. So the process research of Acifluorfen synthesis hasbeen of great practical utility.First, in this paper,using DMSO as solvent, hydroxybenzoic acid and3,4-dichloro-benzotrifluoride as the raw material, etherified compounds3-[2-chloro-4-(trifluoromethyl) phenoxy] benzoic acid was synthesized,it will be as the raw materialfor the synthesis of Acifluorfen.For the first time in the case of not using acetic anhydride, Acifluorfen issynthesized by nitration reaction, using3-[2-chloro-4-(trifluoromethyl)phenoxy] benzoicacid as a precursor, choosing methylene chloride as a solvent, using nitric and sulfuricacid as nitrating agent. It is investigated the impact of factors on the reaction of thematerial ratio, reaction time, reaction temperature, the concentration of nitric acid andproportion of mixed acid. Nitration process is optimized by orthogonal experiment andthe result is as follows: reaction temperature is40℃, nitrate concentration is96%, thereaction time is4h, the reactants and the molar ratio of nitric acid is1:1.4, the molarratio of nitric acid and sulfuric acid is1:1.5.The impact of various factors on the reaction by Range analysis are as follows: mixed acid ratio> reaction temperature> nitrateconcentration> ingredients ratio> reaction time. Under optimum conditions, acifluorfenproduct yield reached98.40%and the purity is(HPLC)80.35%. The yield is not reducedcompared to industrial production of acetic anhydride which provide a reliable basis andhas a certain economic efficiency and practical value for industrial production.This paper, five byproducts of Acifluorfen were separated by columnchromatography and thin layer chromatography for the first time and by IR,1H-NMR,ESI-MS on their structural characterization, ultimately determine the structure whichfour byproducts II, III, IV and V.Their name followed by3-(2-chloro-4-(rifluoromethyl)-6-nitro-phenoxy)-2,4,6-trinitro-benzoic acid,3-(2-chloro-4-(trifluoromethyl) phenoxy)-2,4,6-trinitro-benzoic acid,3-(2-chloro-4-(trifluoromethyl)phenoxy)-4-nitro-benzoic acid,3-(2-chloro-4-(trifluoromethyl)phenoxy)-2-nitro-benzoicacid.Isolation and identification of the byproducts will provide direct reference forfurther explore the synthesis mechanism and the optimization of reaction conditions toAcifluorfenthe. It is the main innovation of the paper.