The invention relates to a continuously operating process for producing nitrobenzene, comprising the following steps: a) nitriding benzene in adiabatic conditions with sulfuric acid and nitric acid, using a stoichiometric excess of benzene in relation to the nitric acid, in multiple parallel reactors; b) first combining the raw process products of the nitridation from the parallel reactors to form a mixed flow in a device provided specifically for this purpose, then separating the mixed flow into a sulfuric acid phase and a nitrobenzene phase in a downstream phase separation apparatus; and c) processing the nitrobenzene phase, obtaining nitrobenzene. The invention also relates to a production plant suitable for carrying out the claimed process.

The invention relates to a continuously operating process for producing nitrobenzene, comprising the following steps: a) nitriding benzene in adiabatic conditions with sulfuric acid and nitric acid, using a stoichiometric excess of benzene in relation to the nitric acid, in multiple parallel reactors; b) first combining the raw process products of the nitridation from the parallel reactors to form a mixed flow in a device provided specifically for this purpose, then separating the mixed flow into a sulfuric acid phase and a nitrobenzene phase in a downstream phase separation apparatus; and c) processing the nitrobenzene phase, obtaining nitrobenzene. The invention also relates to a production plant suitable for carrying out the claimed process.

In a process for workup of mixed acid and wastewater from the nitration of aromatics in which the nitric acid present is converted by reaction with an aromatic under adiabatic conditions, a. at least one waste stream component selected from waste acid (mixed acid) generated in the nitration, acidic washing water from the workup of crude nitroaromatics and dilute nitric acid generated in an off-gas treatment in the course of the nitration is provided, b. the at least one waste stream component is mixed with re-concentrated sulfuric acid, c. an aromatic is added to the mixture in stoichiometric excess based on the nitric acid, d. the obtained reaction mixture is reacted in an adiabatically operated reactor, e. the obtained organic phase is separated from the sulfuric-acid-containing phase in a separator, f. the sulfuric-acid-containing phase is concentrated under vacuum and g. at least one substream of the re-concentrated sulfuric acid from step g) is employed in step b).

In a process for workup of mixed acid and wastewater from the nitration of aromatics in which the nitric acid present is converted by reaction with an aromatic under adiabatic conditions, a. at least one waste stream component selected from waste acid (mixed acid) generated in the nitration, acidic washing water from the workup of crude nitroaromatics and dilute nitric acid generated in an off-gas treatment in the course of the nitration is provided, b. the at least one waste stream component is mixed with re-concentrated sulfuric acid, c. an aromatic is added to the mixture in stoichiometric excess based on the nitric acid, d. the obtained reaction mixture is reacted in an adiabatically operated reactor, e. the obtained organic phase is separated from the sulfuric-acid-containing phase in a separator, f. the sulfuric-acid-containing phase is concentrated under vacuum and g. at least one substream of the re-concentrated sulfuric acid from step g) is employed in step b).

The present invention relates to zeolite adsorbents based on agglomerated crystals of zeolite X comprising barium, potassium, sodium and strontium. These adsorbents have applications in the separation of fractions of aromatic C8 isomers and in particular xylenes.

The present invention relates to a process for the continuous production of nitrobenzene by the nitration of benzene with nitric acid and sulphuric acid under adiabatic conditions, not the entire production plant being shut down during a production stop, but the production plant being entirely or at least partly operated in recirculation mode. The invention further relates to a plant for producing nitrobenzene and to a method for operating a plant for producing nitrobenzene.

The present invention relates to a process for the continuous production of nitrobenzene by the nitration of benzene with nitric acid and sulphuric acid under adiabatic conditions, not the entire production plant being shut down during a production stop, but the production plant being entirely or at least partly operated in recirculation mode. The invention further relates to a plant for producing nitrobenzene and to a method for operating a plant for producing nitrobenzene.

The present invention refers to a crystalline 2-fluoro-3-nitrotoluene compound of formula (I), and a process for the preparation thereof. Furthermore, the present invention relates to a process for the synthesis of a compound of formula (II) or salts thereof by means of the crystalline 2-fluoro-3-nitrotoluene.

##STR00001##

The present invention refers to a crystalline 2-fluoro-3-nitrotoluene compound of formula (I), and a process for the preparation thereof. Furthermore, the present invention relates to a process for the synthesis of a compound of formula (II) or salts thereof by means of the crystalline 2-fluoro-3-nitrotoluene.

##STR00001##

The present invention refers to a crystalline 2-fluoro-3-nitrotoluene compound of formula (I), and a process for the preparation thereof. Furthermore, the present invention relates to a process for the synthesis of a compound of formula (II) or salts thereof by means of the crystalline 2-fluoro-3-nitrotoluene.

##STR00001##