تفاعل #62801

معادلة التفاعل

nitric acid

sulphuric acid

2,4-dichloro-5-fluorobenzoic acid

→

2,4-dichloro-5-fluoro-3-nitrobenzoic acid

المذيبات

ظروف التفاعل

المعالجة

1. 1
   درجة الحرارةwhile cooling in ice
2. 2
   أخرىrises to 45°-50° C
3. 3
   درجة الحرارةThe mixture is then heated at 90°-100° C. for 3 hours
4. 4
   ترشيحthe precipitate is filtered off with suction
5. 5
   غسيلwashed with water
6. 6
   workup.DISSOLUTIONThe moist crude product was dissolved in 30 ml of hot methanol
7. 7
   workup.ADDITION150 ml of H2O are added to the solution
8. 8
   درجة الحرارةThe precipitate is cooled
9. 9
   ترشيحfiltered off with suction
10. 10
    غسيلwashed with CH3OH/H2O
11. 11
    أخرىdried in vacuo at 80° C

الإجراء التجريبي

40 ml of concentrated nitric acid are added dropwise to 34 ml of concentrated sulphuric acid, while cooling in ice and stirring. 20.9 g of 2,4-dichloro-5-fluorobenzoic acid are introduced in portions into this nitration mixture, during which the temperature rises to 45°-50° C. The mixture is then heated at 90°-100° C. for 3 hours, cooled to room temperature, and poured onto 350 ml of ice-water, and the precipitate is filtered off with suction and washed with water. The moist crude product was dissolved in 30 ml of hot methanol, and 150 ml of H2O are added to the solution. The precipitate is cooled, filtered off with suction, washed with CH3OH/H2O and dried in vacuo at 80° C. 21.2 g of crude 2,4-dichloro-5-fluoro-3-nitrobenzoic acid are obtained. It is sufficiently pure for the subsequent reactions. A sample recrystallized from toluene/petroleum ether provides crystals of melting point 192° C.

المصدر