4-Nitrophthalic acid anhydride → 1,3-Isobenzofurandione, 5-fluoro-

Participants

Reaction Conditions

Reaction Steps

Into a reaction vessel were placed 290 grams (1.5 mol) 4-nitrophthalic anhydride and 91 grams (1.57 mol) of anhydrous potassium fluoride. The reaction vessel was closed and shaken to mix the reactants and was then attached to a distilling head, receiver, and nitrogen inlet. The mixture was heated, under a nitrogen blanket beginning at 100°C. while the temperature was raised to 230°C. over a 25 minute period and kept at a temperature of 230°-250°C. for about 4 hours. After 2 hours, the nitrogen line was replaced by a vacuum line and the system evacuated to about 160 mm. This resulted in the collection over the next 2 hours of 148.5 grams (60% yield) 4-fluorophthalic anhydride, which upon analysis indicated the material to be greater than 97% pure (melting point 72°-76°C.).

Provenance & Evidence