3,4-Difluorobenzonitrile has been prepared by a halogen- exchange reaction between 3,4-dichlorobenzonitrile and spray- dried potassium fluoride in the presence of tetraphenylphosphonium bromide in refluxing 1,3-dimethylimidazolidine-2- one. In the fluorination reaction, 4-chloro-3-fluorobenzonitrile seems to be a key intermediate.

中文翻译：

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卤素交换氟化法合成3,4-二氟苄腈和单氟苄腈

在回流的1，3-二甲基咪唑烷-2-1中，在四苯基tetra溴化物的存在下，通过3，4-二氯苄腈与喷雾干燥的氟化钾之间的卤素交换反应，制备了3，4-二氟苄腈。在氟化反应中，4-氯-3-氟苄腈似乎是关键的中间体。