تفاعل #56457
ord-90b6abbdc7c44f2195eb796835879a6d
معادلة التفاعل
الكواشف
ظروف التفاعل
المعالجة
- 1أخرىequipped with a magnetic stirrer, a condenser
- 2درجة الحرارةThe mixture is heated
- 3درجة الحرارةto reflux
- 4درجة الحرارةboiling is maintained for about 15 minutes
- 5درجة الحرارةThereafter the mixture is cooled
- 6درجة الحرارةThe whole is heated
- 7درجة الحرارةunder reflux for about 30 minutes
- 8درجة الحرارةcooled
- 9درجة الحرارةThereafter the whole is heated
- 10درجة الحرارةunder reflux for 30 minutes
- 11درجة الحرارةcooled
- 12أخرىthe oil obtained
- 13غسيلthe solution is washed with a dilute solution of sodium bicarbonate
- 14ترشيحfiltered over charcoal
- 15أخرىthus precipitates
- 16ترشيحis filtered off
الإجراء التجريبي
A solution of 15.2 g (0.2 mol) of thiourea in 100 ml of water is introduced into a 1 liter 3-necked flask equipped with a magnetic stirrer, a condenser and dropping funnel, and 28.9 g (0.2 mol) of p-fluorobenzylchloride are introduced, at 50°-60° C., in a single operation. The mixture is heated to reflux and boiling is maintained for about 15 minutes; the solution becomes limpid. Thereafter the mixture is cooled and a solution of 32 g (0.8 mol) of NaOH in water is added dropwise at about 60° C. The whole is heated under reflux for about 30 minutes and 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 sodium bicarbonate) is added dropwise at 60°-70° C. Thereafter the whole is heated under reflux for 30 minutes, and then cooled. The mixture is acidified with 3N HCl, the oil obtained is taken up in methylene chloride, the solution is washed with a dilute solution of sodium bicarbonate, filtered over charcoal and acidified once more with 3 N HCl and p-flourobenzylthioacetic acid thus precipitates and is filtered off. After recrystallisation from cyclohexane, 33.4 g (yield: 83%) of the said acid are collected. Instantaneous melting point: 68°-69° C.