METHOD OF TWO-STAGE OBTAINING OF DINITROTOLUENE Russian patent published in 2008 - IPC C07C201/08 C07C205/06 

FIELD: chemistry.

SUBSTANCE: invention concerns obtaining dinitrotoluene by two-stage nitration of toluene, where: a) at the first stage toluene undergoes adiabatic reaction with nitrating acid, so that at least 90% is involved in the reaction and max. 70% of toluene transforms into dinitritoluene; then organic phase containing mononitrotoluene and water acid phase containing sulfuric acid are immediately separated, water acid phase is concentrated by instantaneous evaporation with pressure release, and the concentrated sulfuric acid obtained is recycled in the first stage reaction and/or in the second stage concentration; and b) at the second stage the organic phase containing mononitrotoluene left from the first stage undergoes complete isothermal reaction with a nitrating acid mix; then organic phase and water acid phase containing sulfuric acid are immediately separated, water acid phase is concentrated by evaporation in vacuum, and the concentrated sulfuric acid obtained is recycled in the first and/or second stage reaction.

EFFECT: improved method of obtaining dinitrotoluene.

3 dwg, 3 tbl, 3 ex