- Environment-friendly preparation method of 2-chloro-4-nitro-6-bromoaniline
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A preparation method of 2-chloro-4-nitro-6-bromoaniline comprises the following steps: (a) carrying out mixed acid nitration on o-dichlorobenzene, and continuing to apply the generated waste acid to anext nitration reaction; (b) purifying the obtained nitration product in an alcohol solvent to obtain 3,4-dichloronitrobenzene, and continuously applying the recovered alcohol solvent to a next purification process; (c) carrying out ammonolysis on the 3,4-dichloronitrobenzene in a water phase by adopting a specific catalyst to prepare o-chloro-p-nitroaniline, and continuously applying the recycled liquid ammonia to a next ammonolysis reaction; and (d) brominating o-chloro-p-nitroaniline in a hydrogen bromide and oxidant system, and recycling brominated waste acid liquid and bromine for a nextbromination reaction. The product obtained by the method is good in yield, high in purity and high in quality; and two waste acids and bromine in the product are recycled, so that the amount of wastewater is reduced. Compared with traditional processes, the method has obvious quality and environmental protection advantages, and has high production safety.
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- Method for synthesizing monobrominated aniline compound
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The invention discloses a method for synthesizing a monobrominated aniline compound. The method comprises the following steps: by taking an aniline compound as a raw material, and taking zinc aluminum hydrotalcite ZnAl-BrO3-LDHs with a bromate inserted layer and an alkali metal bromide as bromine sources in a mixed solvent of water and an organic solvent, reacting for 1-3h at 10-50 DEG C; after ending the reaction, extracting a reaction mixed solution A by using dichloromethane; adding a column chromatography silica gel into dichloromethane phase; removing the solvent in the manner of reduced pressure distillation; and acquiring a mono-bromination objective product in the manner of column chromatography separation by using an eluent composed of petroleum ether and ethyl acetate at the ratio of 10:1. The invention realizes a high-selectivity oxidative bromination method by adopting an aniline compound under the effects of ZnAl-BrO3-LDHs and potassium bromide; the monobrominated aniline compound is prepared; the reaction popularity is high and the raw material is low in cost and is easily acquired; the reaction condition is mild; the reaction yield is high; the atom utilization ratio is high; and the chemical selectivity is excellent and the environment is protected.
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Paragraph 0060; 0061; 0061; 0062
(2017/09/26)
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- Sodium lauryl sulfate-catalyzed oxidative chlorination of aromatic compounds
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Chlorination of commercially important aromatic compounds using sodium chloride as chlorine source and sodium periodate as oxidant in acidic medium catalyzed by sodium lauryl sulfate (SLS) led to the chloro-substituted aromatics in good yields and purity. Addition of sodium lauryl sulfate led to increased chlorination rate, better yield, excellent purity, and better quality of end product. The advantages of the present method are greater yield, excellent purity, and shorter reaction time at room temperature. Also dichlorinated product can be obtained by increasing the amount of sodium chloride and sodium periodate at slightly higher temperature (40C).
- Mahajan, Tanu,Kumar, Lalit,Dwivedi, K.,Agarwal, D. D.
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p. 3655 - 3663,9
(2020/08/31)
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