Reaktion #62868

Reaktionsgleichung

3-fluoro-4-methyl-benzoic acid

nitric acid

→

2-nitro-4-methyl-5-fluoro-benzoic acid

Lösungsmittel

sulphuric acid

sulphuric acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONis added dropwise at 20°-25°
2. 2
   Temperaturwhile cooling with ice
3. 3
   workup.ADDITIONThe batch is then poured onto ice-water
4. 4
   Filtrationthe crystals are filtered off with suction
5. 5
   Waschenwashed thoroughly with water
6. 6
   SonstigeAfter drying
7. 7
   Sonstigerecrystallization from toluene, 48 g (74.3% of theory) of 2-nitro-4-methyl-5-fluorobenzoic acid
8. 8
   Sonstigeare obtained

Vorschrift

50 g of 3-fluoro-4-methyl-benzoic acid are initially introduced into 100 ml of concentrated sulphuric acid, and a mixture consisting of 26 g of 98% strength nitric acid and 40 g of concentrated sulphuric acid is added dropwise at 20°-25°, while cooling with ice. The mixture is subsequently stirred at room temperature for 1 hour. The batch is then poured onto ice-water and the crystals are filtered off with suction and washed thoroughly with water. After drying and recrystallization from toluene, 48 g (74.3% of theory) of 2-nitro-4-methyl-5-fluorobenzoic acid of melting point m.p.: 163°-5° C. are obtained.

Quelle