反应详情

温度

200 °C

134 g of dimeric p-isopropenyl phenol are dissolved under nitrogen in 150 g of acetic acid anhydride, followed by the addition of 0.5 g of concentrated sulphuric acid. The reaction begins with a slight heat effect under which the temperature of the reaction mixture rises to around 50° C and then falls again. When the reaction temperature has fallen to around 30° C, the reaction mixture is slowly heated until, finally, acetic acid distils off under normal pressure. The temperature is regulated in such a way that distillation is continuous. When no more acetic acid distils over, the remaining acetic acid and the excess acetic acid anhydride are distilled off in a water jet vacuum, after which the reaction mixture is cooled. Another 5 g of concentrated sulphuric acid are then added, followed by heating in a high vacuum until p-acetoxy-α-methyl styrene distils off. The temperature of the reaction mixture is regulated in such a way that the reaction mixture distils off continuously; it is in the range from 70° to 120° C and is ultimately increased to 200° C. The reaction product which has distilled over is then redistilled; 119 g (68% of the theoretical) of p-acetoxy-α-methyl styrene are obtained in the boiling range from 80° to 82° C/0.1 Torr.

1. customrises to around 50° C
2. customhas fallen to around 30° C
3. customdistils off under normal pressure
4. distillationthat distillation
5. customWhen no more acetic acid distils over, the remaining acetic acid
6. distillationthe excess acetic acid anhydride are distilled off in a water jet vacuum
7. temperatureafter which the reaction mixture is cooled
8. additionAnother 5 g of concentrated sulphuric acid are then added
9. temperatureby heating in a high vacuum until p-acetoxy-α-methyl styrene
10. customdistils off
11. customdistils off continuously
12. customis in the range from 70° to 120° C
13. distillationThe reaction product which has distilled
14. distillationover is then redistilled