The preparation of 3,4-Difluorobenzonitrile is as follows:To the dry reactor was added 289.6 kg (1.843 kmoles) of 3,4-difluorobenzamide and 800 kg of dichloroethane solution, 241.2 kg (2.02 kmoles) of dichlorosulfoxide and catalyst DMF I.5 And the reaction was carried out at 50 ° C for 5 hours with stirring. After the reaction was complete, the reaction solution was poured into ice water with stirring and the mixture was separated to obtain a crude product having a qualitative content of 96% of 3,4-difluorobenzonitrile 259.1 kg (1.788 kmoles) in 97% yield. The crude product was distilled to give a qualitative content of 99% of 3,4,8-difluorobenzonitrile 248.6 kg (1.77 kmoles) and a distillation yield of 99%.
