The Synthesis Study Of The Cornfield Herbicide Of Mesotrione

Mesotrione is developed by the company of Syngenta as a new type of cornfield herbicide.4-toluene sulfonyl chloride is used as the raw materials in this study, Which will be subjected to reduction,sulfonylation reaction,nitration reaction,oxidation reaction,chlorination reaction,condensation reaction and rearrangement reaction before the synthesis of mesotrione.Focus on each step with single factor experiment mehod separately,getting the optimum conditions for each reaction step eventually.The results are as follows:The appropriate conditions of synthesizing 4-Methyl sulfonyl toluene:the molar ratio of the materials:n(4-toluene sulfonyl chloride):n(sodium sulfite):n(sodium chloroacetate)=1:1.2:1.2,the pH of reduction reaction liquid is 8,the temperature of reduction reaction is 80 ℃,the time of reduction reaction is 4h,the temperature of sulfonylation reaction is 105℃,the time of sulfonylation reaction is 20h,the yield of product is 90%.The appropriate conditions of synthesizing 2-Nitro-4-methylsulfonyl toluene:the molar ratio of the materials:n(4-Methyl sulfonyl toluene):n(nitric acid)=1:1.3,mixed acid n(nitric acid):n(sulfuric acid)=1:2.3,the temperature of nitration reaction is -5～ 0℃, the time of nitration reaction is 4h,the yield of product is 98%.The appropriate conditions of synthesizing 2-Nitro-4-methylsulfonylbenzoic acid:homemade copper-based catalyst,the mass ratio of materials:m(2-Nitro-4-methylsulfonyl toLuene):m(sodium percarbonate)=1:2.26,the temperature of the reaction is 70℃, the time of the reaction is 3.5h,theyield of product is 88.3%.The conditions of synthesizing 2-Nitro-4-methylsulfonylbenzoychloride::n(2-Nitro-4-methylsulfonylbenzoic acid):n(thionyl chloride)=1:17,the temperature of the reaction is 80℃,the time of the reaction is 5h,the yield of product is 97%.The appropriate conditions of synthesizing mesotrione:the solvent is dichloroethane,the scavenger is trimethylamine,the time of condensation reaction is lh,the time of rearrangement time is lh,the temperature of rearrangement reaction is 50℃, the yield of product is 78%.The synthetic route of mesotrione:raw materials are cheap,the operation is simple,the reaction condition is mild,the yield of product is high.In addition,this study makes the waste acid solution after the nitration and oxidation as a raw material for preparing calcium sulphate gypsum whisker,the calcium sulphate gypsum whisher is crystal shape neat,the diameter of it is3-5um,the ratio of length to diameter is more than 20,the whiteness of it is 95%.