Ammonia → 3,5-Difluoroaniline

Participants

Reaction Conditions

Reaction Steps

A 600 ml Hastelloy pressure reactor (Parr Instrument Co., Moline, Ill.) equipped with the standard stirrer, thermowell, and valves was used. The reactor was charged with 0.833 moles of 1,3,5-trifluorobenzene (110 g), 4.6 moles of 29% ammonia in water (270 g), and 0.44 moles of magnesium oxide (17.8 g). The reactor was purged with argon, and heated to 225° C. until the maximum pressure (about 1400 psig) was reached. As the reaction proceeded, the pressure dropped at a rate of about 20 lbs./hour for about 6 hours. The reactor was then cooled and the contents allowed to settle. The oils were drained from the reactor bottom until salts/water are observed. The salts float on the oils and settle slowly in the aqueous ammonia. The aqueous salts were extracted 2 or 3 times with MTBE. The MTBE was combined with the oils and charged to a distillation column packed with stainless steel packing (ProPak). The salts were centrifuged, washed with water, and discarded. The product was isolated by distilling MTBE at atm. Pressure, then distilling DFA at 20 to 50 mm.

Provenance & Evidence