Removal of nitrocresols from dinitrotoluene waste streams using fentons reagent

摘要

This invention relates to a process for removing trinitrocresols and picric acid contaminants from a wastewater stream generated in the production of nitroaromatics, particularly dinitrotoluene, by the mixed acid technique. The process involves contacting the crude dinitrotoluene generated by the mixed acid technique with an alkaline medium to generate an alkaline wash water containing water soluble nitrocresols and picric acid therein. This wastewater then, is separated from the organic component or may be recycled for contact with further quantities of crude dinitrotoluene product from the reactor. When the concentration of the water soluble salts of trinitrocresols and picric acid is of sufficient concentration, the wash water is treated with aqueous acid in sufficient proportion to reduce the pH to a level from 3-4. After pH adjustment, the medium is contacted with hydrogen peroxide and a ferrous ion under conditions to effect oxidation of a substantial portion of the trinitrocresol to carboxylic acid, nitric acid and carbon dioxide.