PROCESS FOR PURIFYING WASTEWATERS FROM THE WORKUP OF CRUDE AROMATIC NITRO COMPOUNDS

摘要

The invention relates to a process for purifying crude aromatic nitro compounds which originate from the nitration of aromatic compounds, comprising the following wash stages (a1) and (a2), where each of stages (a1) and (a2) may be performed once or more than once in succession: (a1) contacting the crude aromatic nitro compound (N1-in) with a first aqueous phase (W1-in) comprising at least one base (B) and then separating the phases to obtain an organic phase (N1-res)and an aqueous phase (W1-res); and then (a2) contacting the organic phase (N1-res) obtained in stage (a1) with a second aqueous phase (W2-in) and then separating the phases to obtain a purified organic phase (N2-res) and at least one aqueous phase (W2-res), the aqueous phase used (W2-in) having a pH of 6 to 9.