反应详情

32 g of 20% hydrogen peroxide solution are added dropwise over 30 min to a solution of 37.8 g (0.15 mol) of 2-chloro-4,5-difluorobenzophenone in 400 g of 100% sulfuric acid in such a way that the temperature remains below 35° C. The reaction is complete after 7 h. The reaction mixture is then poured on to 1200 g of ice. Extraction of the mother liquor with methyl tert-butyl ether, isolation of the crude product from the extract and crystallization from water gives 17.0 g (0.0883 mol, 88%) of colorless 2-chloro-4,5-difluorobenzoic acid melting at 104.4°-105.8° C.

1. customremains below 35° C
2. extractionExtraction of the mother liquor with methyl tert-butyl ether, isolation of the crude product from the
3. extractionextract
4. customcrystallization from water