WASHING METHOD OF DINITROTOLUENE Russian patent published in 2017 - IPC C07C201/16 C07C205/06 

FIELD: chemistry.

SUBSTANCE: way of washing includes two stages (WS-I), and (WS-II). In the first stage of washing (WS-I), done in counter-current, crude mixture during washing, comprising at least two stages of extraction, extracted with acid leaching I containing nitric acid, oxides of nitrogen and sulphuric acid, at the last stage of extraction (WS-I-n) first stage washing (WS-I) serves fresh water or washing acid with the General content of acids from 0.2 to 1.5 wt %, and the centrality of first stage extraction (the WS-I-1) first stage washing (WS-I) rising acid has the general content of acids from 20 up to 40 wt %, and get pre washed wet mixture. In the second stage of washing (WS-II), held in counter-current, previously washed crude mixture containing dinitrotoluene, washing process, including at least two stages of extraction, extracted with acid leaching II. At the last stage of extraction (WS-II-m) second stage washing (WS-II) serves fresh water, and the centrality of first stage extraction (WS-II-1) second stage washing (WS-II) rising acid has a pH value less than or equal to 4. Receiving contains a mixture of dinitrotoluene, mostly free of nitric acid, sulfuric acid and nitrogen oxides, which, with a maximum content of 300 ppm of nitric acid and nitrogen oxides and 3 ppm sulphate are selected from the last stage of extraction (WS-II-m) second stage washing (WS-II).

EFFECT: enables to dump the sewage water from washing processes on biological purification stage without costly intermediate processing to separate or decomposition of nitrocresols and nitrobenzoic acids.

15 cl, 2 dwg, 2 ex