- Green synthesis method of 3,4,5-trifluorobromobenzene
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The invention discloses a green synthesis method of 3,4,5-trifluorobromobenzene. The green synthesis method comprises the following steps: adding 2,3,4-trifluoroaniline and water into a reactor, adding hydrobromic acid and hydrogen peroxide, and carrying out a hybrid reaction to obtain 2,3,4-trifluoro-6-bromoaniline after the reaction is ended; slowly adding a sulfuric acid solution of nitroso sulfuric acid into the prepared 2,3,4-trifluoro-6-bromoaniline, and carrying out a diazotization reaction to obtain a diazonium salt solution; and adding sodium hypophosphite and porous material-loaded copper oxide into the prepared diazonium salt solution as catalysts, conducting reacting, and sequentially carrying out distillation, alkali washing, water washing and reduced-pressure rectification on reaction liquid after the reaction is finished so as to obtain a target product. According to the method, nitrososulfuric acid replaces sodium nitrite to serve as a diazotization reagent, so no high-salt wastewater is discharged, production cost is reduced, and the method is more environmentally friendly; and hydrobromic acid serves as a bromine source, and hydrogen peroxide is added, so the utilization rate of bromine atoms is high, the adding amount of hydrobromic acid is reduced, and the amount of three wastes generated in implementation of the method is remarkably reduced.
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Paragraph 0026-0027; 0030-0031; 0034-0035; 0038-0039; 0042
(2021/04/10)
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- Preparation method of 3, 4, 5-trifluorobromobenzene
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The invention relates to a preparation method of 3, 4, 5-trifluorobromobenzene, belongs to the technical field of chemical synthesis, and solves the problem that a byproduct 3, 4, 5-trichloronitrobenzene generated in a process of preparing 3, 4-dichloronitrobenzene by introducing chlorine into parachloronitrobenzene cannot be effectively utilized. The method comprises the step of preparing 3, 4, 5-trifluorobromobenzene by taking 3, 4, 5-trichloronitrobenzene as a raw material. According to the technical scheme provided by the invention, the utilization rate of raw materials and the efficiencyof the process can be improved, and high-value utilization of byproducts is realized.
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