Reaction #2186179

Reaction equation

sulfuric acid

3-chloro-2-fluoroaniline

sulfuric acid

sodium nitrite

→

3-chloro-2-fluorophenol

Yield 40.9%

Solvents

toluene

Conditions

Workup

1. 1
   TemperatureThereafter, the mixture was cooled to −10° C.
2. 2
   workup.WAITover 90 minutes in a temperature range of −10 to −5° C.
3. 3
   workup.STIRRINGby stirring for 30 minutes in that temperature range
4. 4
   OtherThe resulting reaction mixture
5. 5
   workup.ADDITIONwas added to another reactor
6. 6
   workup.WAITover 6 hours in a temperature range of 80 to 85° C.
7. 7
   workup.STIRRINGby stirring for 30 minutes in that temperature range
8. 8
   OtherThe resulting reaction mixture
9. 9
   Temperaturewas cooled to a temperature range of 70 to 75° C.
10. 10
    workup.WAITleft at rest
11. 11
    Otherto separate into two layers, i.e.
12. 12
    Otheran organic layer and an aqueous layer, and the organic layer was collected
13. 13
    TemperatureThe aqueous layer was cooled to 20° C.
14. 14
    Filtrationcopper sulfate was filtered off
15. 15
    Extractionby extracting with 1,200 mL toluene twice
16. 16
    OtherThe organic layer obtained by extraction
17. 17
    Washwas washed with 700 mL of water
18. 18
    workup.DISTILLATIONsubjected to fractional distillation

Procedure

728 g of 3-chloro-2-fluoroaniline was added to a reactor having 6,860 g of 30.6% sulfuric acid placed therein, followed by stirring for 30 minutes at 80° C. Thereafter, the mixture was cooled to −10° C., and 952 g of a 37.0% sodium nitrite aqueous solution was added dropwise thereto over 90 minutes in a temperature range of −10 to −5° C., followed by stirring for 30 minutes in that temperature range. The resulting reaction mixture was added to another reactor having 4,100 g of 51.2% sulfuric acid, 1,500 g of copper sulfate and 3,000 mL of toluene placed therein over 6 hours in a temperature range of 80 to 85° C., followed by stirring for 30 minutes in that temperature range. The resulting reaction mixture was cooled to a temperature range of 70 to 75° C. and left at rest to separate into two layers, i.e., an organic layer and an aqueous layer, and the organic layer was collected. The aqueous layer was cooled to 20° C., and copper sulfate was filtered off, followed by extracting with 1,200 mL toluene twice. The organic layer obtained by extraction was washed with 700 mL of water and subjected to fractional distillation to obtain 300 g of 3-chloro-2-fluorophenol (b5). The compound had a boiling point of 60 to 62° C./1 mmHg.

Source