2,5-二氯硝基苯微波促进氟化反应的研究

Fluorination of 2,5-dichloronitrobenzene under Microwave Radiation

该文讨论了微波作用下 2 ,5-二氯硝基苯的卤素交换氟化反应 ,以二甲基亚砜 (DMSO)作溶剂 ,氟化钾作氟化剂 ,微波功率 2 2 5W时 ,反应 1h ,2 ,5-二氯硝基苯的转化率为 97 6 % ,5-氯 - 2 -氟硝基苯的收率为 54.4 %。相同条件下 ,不用微波照射 ,得到相近收率需要反应 1 0h。实验还发现 ,微波照射下 2 ,5-二氯硝基苯的卤素交换氟化反应存在明显的脱硝基氟化副反应。在适当的条件下脱硝基氟化副产物的量可占产物的 35.1 %。

The halogen exchange fluorination of 2,5-dichloronitrobenzen with potassium fluoride under microwave radiation in dimethyl sulfoxide(DMSO) and in the presence of a phase transfer catalyst was discussed. After 1 hour reaction, the conversion of the reactant 2,5-dichloronitrobenzen and the yield of the product 5-chloro-2-fluoronitrobenzene are 97.6 % and 54.4 % respectively. Without microwave radiation, it takes 10 hours to achieve a similar conversion and yield. There exists an obvious side reaction, the denitrofluorination,along with the halogen exchange fluorination under microwave radiation. The content of the by product of denitrofluorination can amount to 35.1 % of all products under proper conditions. The results have been analyzed and discussed.