Azobisisobutyronitrile → 1-Chloro-4-(trifluoromethyl)benzene

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Reaction Steps

The solution is heated to 60°-70° C. with stirring, using a magnetic stirring bar. Bromine, 32 g (0.2 mole), is added dropwise sub-surface. The reddish color dissipates quickly and a gas evolution occurs. A catalytic amount of radical initiator such as azodiisobutyronitrile may be added intermittently to promote the reaction. When the color begins to sustain, the pot temperature is raised to 90°-100° C. The remaining bromine is added in the same fashion. The pot temperature can be raised to 110°-120° C. for 2-4 hours. During this period, an additional amount of bromine such as 1-2 g may be added to complete the conversion of (I). 4-chlorobenzotrifluoride can be obtained in a good yield by fractional distillation of the mixture.

Provenance & Evidence