Apparatus for carrying out the method and method for working up mixed acids and wastewater from the nitration of aromatics

摘要

A method for working up mixed acids and wastewater from the nitration of aromatics, wherein the contained nitric acid is converted by reaction with aromatics under adiabatic conditions, comprising: a. at least one waste stream component is provided selected from spent acid (mixed acid) from the nitration, acid wash water from the work-up of crude nitroaromatics and dilute nitric acid from the nitration procedure in the exhaust gas treatment; b. this at least one waste stream component is mixed with re-concentrated sulfuric acid; c. aromatics are introduced into the mixture in a stoichiometric excess with respect to nitric acid, d. The reaction mixture obtained is transformed in a reactor operated adiabatic, e. The organic phase obtained in the separator is separated from the sulfuric acid phase, f. The sulfuric acid phase is concentrated in vacuo, g. At least one partial stream of re-concentrated sulfuric acid is applied from step g) to step b).