3,4-二氯三氟甲苯的合成工艺研究

Study on Synthesis Process of 3,4- Dichlorobenzotrifluoride

介绍了一种3,4-二氯三氟甲苯的制备方法,以对氯甲苯为原料,经侧链光氯化、常温常压下进行氟化、苯环氯化反应得到目标产品。并考察了反应温度、催化剂用量、物料配比、加料顺序等因素对实验的影响。结果表明反应温度为140~150℃,氯气输出压力为0.15 MPa条件下氯化,n（对氯三氯甲苯）∶n（氢氟酸）=1∶4.5（物质的量比）,20℃温度下氟化,温度为50~60℃条件下苯环氯化,反应收率最高。利用气相色谱对产物进行表征,发现3,4-二氯三氟甲苯的纯度可达99.5%以上。

A new synthetic process of the 3,4 - dichlorobenzotrifluoride is introduced. The final products is obtained using 4 - chlorotoluene as materials by potochlorination in the side chain,fluorination under normal pressure and temperature,chlorination of benzene ring. The different reaction temperature,catalyst dosage,mole ratio and different charging sequence effects on the experiment are examined. The experi mental result indicates that when reaction temperature is 1 4 0 ~ 1 5 0 ℃ ,chlorine gas output pressure is 0. 15 MPa to potochlorinate,when n（4 - chlorobenzotrichloride）： n（hydrofluoric acid）= 1 ： 4. 5,reac-tion temperature is 20 ℃ to fluorinate,when reaction temperature is 50 ~ 60℃ to chlorinate of benzene ring,the best reaction yield is obtained. The product is characterized by GC resulting that the content can reach more than 99. 5% .