Purification of meta-chloronitrobenzene

摘要

This invention relates to the treatment of an isomeric mixture of chloronitrobenzenes to provide a product higher in meta- chloronitrobenzene content, and lower in ortho-chloronitrobenzene and para-chloronitrobenzene content. In particular, a liquid mixtuure of ortho-, meta-, and para-chloronitrobenzene isomers containing a major amount of the meta isomer is solidified by dispersing the isomeric mixture in a partially miscible solvent at temperatures below the melting point of meta-chloronitrobenzene, the solvent and its temperature being selected so that the chloronitrobenzene isomers are sparingly soluble in the solvent. More particularly, a liquid isomeric mixture of ortho-, meta- and para-chloronitrobenzene containing a major amount of meta- chloronitrobenzene is dispersed in a lower alkylene glycol solvent that is at a temperature below the melting point of meta-chloronitrobenzene. A finely divided solid is collected, for example, by filtration, to provide a product enriched in meta-chloronitrobenzene.