粗苯甲酸甲酯的精制

Refining of crude methyl benzoate

介绍用加介质减压精馏方法除掉与苯甲酸甲酯 (BE)伴生的杂质。用减压精馏可以除掉与BE沸点相差较大的组分。采用加H2 O2 和加NaHSO3反应萃取 2种方法除醛后 ,再加酸性介质减压精馏 ,可使提纯后的BE的质量分数达到 99%～ 99.9%。操作条件是精馏塔的压力为 1.3 3kPa ,温度为 90～ 95℃ ,塔顶温度为 65～ 68℃ ,理论塔板数为 5 4。

The methods of using adding medium and vacuum rectification to get rid of the impurity associated with methyl benzoate are introduced.The components which are more different from methyl benzoate in the temperature of boiling point are got rid of.By adding H 2O 2 and NaHSO 3,extraction reactions are proceeded,aldehyde is got rid of by the two methods,then acid medium is added to vacuum rectification.After refining,the mass fraction of methyl benzoate is 99%～99.9%.The operation condition is that the pressure of rectification tower is 1.33 kPa,the temperature is 90～95 ℃,the tempeture at the top of the tower is 65～68 ℃,the theoretical tower tray number is 54.