Yield:327-92-4 94%

Reaction Conditions:

with sulfuric acid;nitric acid at 20 - 50; for 1 h;Large scale;

Steps:

1.1 (1) Nitration reaction
42.5 kg of fuming nitric acid and 280 kg of concentrated sulfuric acid were injected into the reaction kettle at a temperature of 20 to 30 ° C,Then, 100 kg of 2,4-difluoronitrobenzene was added dropwise under stirring,Dropping process to control the reaction temperature of 20 ~ 45 ,After the dropping was completed, the temperature was raised to 50 ° C,And reacted for at least 1 h,Then, 0.5 mL of the stirring solution,0.5 mL of dichloroethane was added,Take the upper organic phase,Washed,And then the mass content of 2,4-difluoronitrobenzene was detected under the condition of liquid phase analysis,When the mass content of 2,4-difluoronitrobenzene is less than 0.2%200 kg of 1,2-dichloroethane was added to the reaction kettle to extract,The obtained upper layer is a concentrated solution containing 1,2-dichloroethane containing 1,5-difluoro-2,4-dinitrobenzene, and the lower concentrated sulfuric acid phase is returned to the reaction kettle,100 kg of 1,2-dichloroethane,Extraction stratification,A dilute solution of 1,2-dichloroethane containing 1,5-difluoro-2,4-dinitrobenzene was again obtained,The resulting 1,2-dichloroethane containing 1,5-difluoro-2,4-dinitrobenzene was twice obtainedThe solution is stirred and mixed uniformly,A total of 422.5 kg of a 1, 2-dichloroethane solution of 1,5-difluoro-2,4-dinitrobenzene was obtained.among them,The content of 1,5-difluoro-2,4-dinitrobenzene was 28.7%Yield 94%

References:

Sichuan Yijie Technology Co., Ltd.;Tang, Youcheng;Tan, Pan CN105837563, 2016, A Location in patent:Paragraph 0041; 0045; 0046

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