Реакция #55090

Уравнение реакции

sodium chloroacetate

2,4-dichlorobenzylchloride

thiourea

NaOH

→

product

Выход 88.7%

2,4-Dichlorobenzylthio-acetic acid

Выход 88.7%

Растворители

water

water

Условия реакции

Обработка

1. 1
   ТемператураThe mixture is heated to 50°-60° C.
2. 2
   ТемператураThe mixture is heated
3. 3
   Температураunder reflux
4. 4
   Температураboiling is maintained for 15 minutes
5. 5
   ТемператураThe mixture is cooled
6. 6
   ТемператураThe mixture is again heated
7. 7
   Температураunder reflux for 30 minutes
8. 8
   Температураcooled
9. 9
   Другоеat 60°-70° C
10. 10
    ТемператураThe whole is then heated
11. 11
    Температураunder reflux for 30 minutes
12. 12
    Температураcooled
13. 13
    Фильтрацияfiltered
14. 14
    Другоеthe precipitate obtained
15. 15
    Фильтрацияis filtered off
16. 16
    workup.DISSOLUTIONredissolved cold in dilute sodium bicarbonate solution
17. 17
    Промывкаthis solution is washed with methylene chloride
18. 18
    Фильтрацияfiltered

Методика

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.

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