Patent ID: 9284255
Filing Date: 2016-03-15
CPC Classification: C07C

Claim Text:
1. A continuous adiabatic process for the preparation of nitrobenzene by the nitration of benzene in a nitration unit, comprising: a) reacting a benzene-containing stream (a.1), comprising at least 90 wt % of benzene, based on the total weight of (a.1), in a reactor with a mixture of sulfuric acid (a.2) and nitric acid (a.3) under adiabatic conditions, the benzene being used in a stoichiometric excess, based on nitric acid (a.3), b) separating the process product obtained in step a) in a phase separation apparatus into an aqueous phase (b.1) comprising sulfuric acid and an organic phase (b.2) comprising nitrobenzene, c) concentrating the aqueous phase (b.1) obtained in step b) by evaporation of the water to give an aqueous phase (c.1) having a higher sulfuric acid concentration than (b.1), and recycling all or part of the phase (c.1) into step a) and using the phase (c.1) as a component of (a.2), and d) working up the organic phase (b.2) obtained in step b) to pure nitrobenzene (d.1) to give a benzene-containing stream (d.2), all or part of which is used as a component of (a.1) in the nitration unit of step a), wherein aliphatic organic compounds are specifically removed from the process at at least one point so that only such a benzene-containing stream (a.1) having a content of aliphatic organic compounds of less than 1.5 wt %, based on the total weight of (a.1), is fed into the reactor.