1,2,3-Trifluoro-4-nitrobenzene

17700-09-3

771-69-7

General procedure for the synthesis of 2,3,4-trifluoronitrobenzene from 2,3,4-trichloronitrobenzene: (2) 240 g of DMSO and 120 g of 2,3,4-trichloronitrobenzene were added to an anhydrous reaction flask with stirring turned on, and the temperature was raised to 75-80 °C under reduced pressure with continuous stirring for 2 hours. Subsequently, 76.8 g of KF and 12 g of TBAB were added to the reaction system and dehydrated under reduced pressure at 75-80 °C for 2 h until no droplets of water fell from the distillation head. (3) The reaction system was slowly warmed up to 180 °C to start the reaction. The reaction process was monitored by gas chromatography (GC), and the reaction was completed when the content of both 2-fluoro-3,4-dichloronitrobenzene and 2,3-dichloro-4-fluoronitrobenzene decreased to less than 0.2% after 10 h. The reaction was completed when the content of 2-fluoro-3,4-dichloronitrobenzene and 2,3-dichloro-4-fluoronitrobenzene dropped below 0.2%. The reaction mixture was cooled to 70-75 °C, filtered, and the filtrate was vacuum distilled and reintroduced into the anhydrous reaction unit. 46 g of KF and 12 g of TBAF were added and dehydrated under reduced pressure at 75-80 °C for 2 h until no water droplets appeared in the distillation head. The reaction temperature was set to 120 °C and ultrasonic power to 20 kHz and the reaction was continued. The reaction was monitored by GC and completed after 2 hours. The reaction mixture was cooled to 70-75°C and filtered and the filtrate was distilled to separate DMSO from the product. The final yield of 2,3,4-trifluoronitrobenzene was 99.7%.