间-(三氟甲基)苯甲酸的合成

Synthesis of m-Trifluoromethylbenzoic Acid

以α,α,α 三氟甲苯(Ⅰ)为原料,合成了间 (三氟甲基)苯甲酸。Ⅰ与三聚甲醛及氯磺酸在n(Ⅰ)∶n(三聚甲醛)∶n(氯磺酸)=1∶1 4∶1 2,反应温度40～50℃下反应3h,制得间 (三氟甲基)氯化苄(Ⅱ),收率为60 3%。在引发剂存在下Ⅱ在65～70℃时通入干燥氯气,反应18h制得三氯产物,收率达92%。使其进一步水解得到产品间 (三氟甲基)苯甲酸,收率达到90%以上。

mTrifluoromethylbenzoic acid was prepared from α, α, αtrifluorotoluene(Ⅰ).Ⅰ with 80% H2SO4 reacted with trioxymethylene and chlorosulfonic acid in mole ratio n(Ⅰ)∶n(trioxymethylene)∶n(chlorosulfonic acid)=1∶14∶12 at 40-50 ℃ for 3 h to give 3trifluoromethylbenzyl chloride(Ⅱ) in 603% yield.Then the reaction of Ⅱ with dry chlorine gas and initiator at 65-70 ℃ for 18 h produced 1trichloromethyl3trifluoromethylbenzene in 92% yield.Subsequent hydrolysis produced mtrifluoromethylbenzoic acid in 90% yield and over.