| abstract |
The invention relates to a process for removing nitrophenolic by-products contained in nitration waste water. The process involves extracting the nitrophenolic by-products from the waste water using a solvent, such as toluene, benzene, o-nitrobenzene or nitrobenzene, in the presence of an acid, such as sulfuric acid, phosphoric or hydrochloric acid, at an elevated temperature, for example 60.0 degree (s) C to 65.6 degree (s) C, and an acidic pH, for example 1.0 to 1.2, to subject the solution of nitrophenolic by-products in the resulting solvent to distillation to recover the solvent for reuse and to produce a residue containing the nitrophenolic by-products, and to incinerate this residue. The invention applies to the treatment of nitration wastewater with a view to their discharge. |