Sodium Chloride → Benzene, dichlorotrifluoro-

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Reaction Conditions

Reaction Steps

20 g (0.16 mol) of sodium sulfite and 40 g of sodium chloride are added to a solution of 82 g (0.2 mol) of copper sulfate pentahydrate to precipitate copper(I) chloride, which is dissolved in 100 ml of concentrated hydrochloric acid. 48.3 g (0.266 mol) of 2-chloro-3,4,5trifluoroaniline/5-chloro-2,3,4-trifluoroaniline (ratio 78:22 according to NMR) are added to this solution with stirring. The mixture is cooled to 10° C., and a solution of 30 g (0.352 mol) of potassium nitrite in 60 g of water is added dropwise. During the addition, the temperature of the mixture is maintained below 20° C. After the end of the metered addition, stirring is continued for 1 hour and then the mixture is heated at 80° C. for 30 min, then cooled and rendered alkaline with sodium hydroxide solution. The mixture of products is prepurified by steam distillation. The oily phase which separates out in the distillate is separated off and subjected to fractional distillation (41 g). 32.3 g (0,161 mol, 60%) are obtained of a 75:25 mixture of 1,2-dichloro-3,4,5-trifluorobenzene and 1,5-dichloro-2,3,4-trifluorobenzene.

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