Application of green nitrating agent N2O5-HNO3 in 2,5-dichloronitrobenzene nitration reaction

The present invention discloses an application of a green nitrating agent N2O5-HNO3 in a 2,5-dichloronitrobenzene nitration reaction. The characteristics are that: N2O5-HNO3 is added to a kettle in a dropwise manner to carry out a nitration reaction, wherein the kettle is filled with para dichlorobenzene with a content more than 98%; after the reaction is completed, standing is performed for 1 hour to obtain a 2,5-dichloronitrobenzene crude product; a liquid alkali is adopted to carry out neutralization until the 2,5-dichloronitrobenzene is slightly alkaline; and finally washing with water, and separation are performed to obtain the pure 2,5-dichloronitrobenzene. Advantages of the application are that: the yield of the 2,5-dichloronitrobenzene prepared by the process of the present invention is 95.52%; the green nitrating agent N2O5-HNO3 does not require waste acid treatment, and is not subjected to oxidation and other side reactions, and the obtained product has high purity, wherein the content is more than or equal to 99.8%.