反应详情

温度

60 °C

Into a solution of 321 g. of 3-bromo benzaldehyde, 220 cm3 of 30% formaldehyde and 600 cm3. of methanol one-third of the solution of 300 g. of potassium hydroxide in 300 cm3. of water are dropped at 50° C. while stirring then the reaction mixture is stirred at this temperature for 1 hour. The temperature is raised to 60° C. and at this temperature the second third part of the base solution are dropped into the reaction mixture. After stirring the reaction mixture 1 hour at 60° C. the temperature is rised to 70° C. and at this temperature the last part of the base solution is dropped into the reaction mixture. The reaction mixture is stirred 1 hour at 70° C. then cooled to ambient temperature. The pH-value of the reaction mixture is adjusted with concentrated hydrochloric acid solution between 7.5 to 8 while maintaining the temperature at 40° C. From this reaction mixture 500 cm3. of methanol is distilled off, 500 cm3. of water are added to the residue then extracted twice with 150 cm3 of 1,2-dichloro ethane. From the united organic phase the water is removed by azeotropic distillation then 200 cm3. of acetic acid anhydride are dropped into the dichloro ethane solution while boiling and stirring. After boiling for 6 hours the reaction mixture is cooled, washed with 500 cm3. of water and 500 cm3. of 10% sodium hydrogen carbonate solution then evaporated. The residue is distilled in vacuo. 287.2 g. of 3-bromobenzyl acetate are obtained. Boiling point 123°-125° C./1200 Pa, nD24 : 1.5406, yield 72%.

1. stirringthe reaction mixture is stirred at this temperature for 1 hour
2. additionare dropped into the reaction mixture
3. stirringAfter stirring the reaction mixture 1 hour at 60° C. the temperature
4. customis rised to 70° C. and at this temperature
5. additionis dropped into the reaction mixture
6. stirringThe reaction mixture is stirred 1 hour at 70° C.
7. temperaturethen cooled to ambient temperature
8. temperaturewhile maintaining the temperature at 40° C
9. distillationof methanol is distilled off
10. additionof water are added to the residue
11. extractionthen extracted twice with 150 cm3 of 1,2-dichloro ethane
12. customFrom the united organic phase the water is removed by azeotropic distillation
13. additionof acetic acid anhydride are dropped into the dichloro ethane solution
14. stirringstirring
15. temperaturethe reaction mixture is cooled
16. washwashed with 500 cm3
17. customof 10% sodium hydrogen carbonate solution then evaporated
18. distillationThe residue is distilled in vacuo