Example 5: Synthesis of 3,4-difluorobenzoic acid. In a 100 mL jacketed reactor, 200 mL of acetic acid, 0.05 g of manganese(II) acetate, 1.91 g of sulfuric acid, and 14.1 g of 3,4-difluorotoluene were added sequentially. The reaction mixture was cooled to 16°C, followed by the slow passage of 4.0 g of ozone over 60 min. Upon completion of the ozonolysis reaction, the reaction system was purged with nitrogen to remove residual ozone. HPLC or GC analysis of the reaction mixture showed that the residue of 3,4-difluorotoluene was <0.1%; the yield of 3,4-difluorobenzoic acid was 98%.
