Patent ID: 8729309
Filing Date: 2014-05-20
Classification: C07C

Abstract:
1. A process for continuously producing nitrobenzene comprising a) nitrating benzene with a mixture of nitric acid and sulfuric acid under adiabatic conditions to obtain a product; b) separating the product obtained in step a) by phase separation into an aqueous phase comprising sulfuric acid, nitrobenzene, and benzene, and an organic phase comprising nitrobenzene and benzene; c) transferring the aqueous phase obtained in step b) into an evaporator wherein the sulfuric acid is concentrated by pressure reduction, wherein a gaseous stream comprising water, nitrobenzene, and benzene is removed from the evaporator and then condensed, and wherein the resulting concentrated sulfuric acid is fed back into step a); d) separating via distillation from 20% by mass to 100% by mass of the benzene contained in the organic phase obtained in step b) by evaporating the benzene using the adiabatic heat of reaction obtained in step a), wherein a pre-purified nitrobenzene depleted of benzene is obtained; e) washing the pre-purified nitrobenzene obtained in step d) with at least one aqueous phase and subsequently separating the at least one aqueous phase from the nitrobenzene by phase separation to obtain purified nitrobenzene.