Reaktion #55090

Reaktionsgleichung

sodium chloroacetate

2,4-dichlorobenzylchloride

thiourea

NaOH

→

product

Ausbeute 88.7%

2,4-Dichlorobenzylthio-acetic acid

Ausbeute 88.7%

Lösungsmittel

water

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe mixture is heated to 50°-60° C.
2. 2
   TemperaturThe mixture is heated
3. 3
   Temperaturunder reflux
4. 4
   Temperaturboiling is maintained for 15 minutes
5. 5
   TemperaturThe mixture is cooled
6. 6
   TemperaturThe mixture is again heated
7. 7
   Temperaturunder reflux for 30 minutes
8. 8
   Temperaturcooled
9. 9
   Sonstigeat 60°-70° C
10. 10
    TemperaturThe whole is then heated
11. 11
    Temperaturunder reflux for 30 minutes
12. 12
    Temperaturcooled
13. 13
    Filtrationfiltered
14. 14
    Sonstigethe precipitate obtained
15. 15
    Filtrationis filtered off
16. 16
    workup.DISSOLUTIONredissolved cold in dilute sodium bicarbonate solution
17. 17
    Waschenthis solution is washed with methylene chloride
18. 18
    Filtrationfiltered

Vorschrift

15.2 g (0.2 mol) of thiourea in 100 ml of water are introduced into a 1 liter 3-necked flask. The mixture is heated to 50°-60° C. and 39.1 g (0.2 mol) of 2,4-dichlorobenzylchloride are introduced in a single operation. The mixture is heated under reflux and boiling is maintained for 15 minutes; the solution becomes limpid. The mixture is cooled and a solution of 32 g (0.8 mol) of NaOH in 50 ml of water is introduced dropwise at about 60° C. The mixture is again heated under reflux for 30 minutes, cooled and a solution of about 0.28 mol of sodium chloroacetate (obtained by neutralising 26.46 g of chloroacetic acid in 200 ml of water with 23.52 g of NaHCO3) is introduced, dropwise, at 60°-70° C. The whole is then heated under reflux for 30 minutes, cooled, filtered and acidified with 3 N HCl; the precipitate obtained is filtered off and redissolved cold in dilute sodium bicarbonate solution, and this solution is washed with methylene chloride, filtered and again acidified. 41.7 g (yield: 83 %) of product are thus collected. Instantaneous melting point: 72°-73° C.

Quelle