Sulfuric Acid → 1,3-Difluorobenzene

Participants

Reaction Steps

2,4 Difluoroaniline sulfate was prepared by mixing 62.6 g (2.5 molar proportions) of 98% sulphuric acid with 32.3 g (0.25 mole) of 2,4-difluoroaniline in a three neck flask. 66 g (2.0 molar proportions) of 50% H3PO2 aqueous solution were added and the slurry was allowed to warm to 50° C.±5° C. Then 18.3 g (1.1 molar proportion) of sodium nitrite dissolved into 30 g of water were added drop by drop, while the temperature was kept at 50° C.±5° C. After 1 hour 30 minutes for the complete addition, only 3.2 liter of gas had been evolved (Theory [~6.3 l). The reaction mixture was worked up as in Example 1 (decantation, extraction, distillation). Only 7.7 g of 1,3-difluorobenzene (yield=27%) were obtained.

Provenance & Evidence