| 摘要 |
The relative amounts of 5,6-dichloro-2-(trichloromethyl) pyridine and 3,6-dichloro-2-(trichloromethyl)pyridine obtained in the chlorination of 2-chloro-6-(trichloromethyl)pyridine in the liquid phase at temperatures of 160.degree.C to 220.degree.C and in the presence of a metal halide catalyst, such as ferric chloride, are controlled by regulating the amount of hydrogen chloride present in the system, adding hydrogen chloride to obtain a mixture enriched in 5,6-dichloro-2-(triohloromethyl) pyridine or removing hydrogen chloride, usually by passing excess chlorine or an inert gas through the system, to obtain a mixture enriched in 3,6-dichloro-2-(trichloromethyl)pyridine.
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