Bayer Aktiengesellschaft

Ineos Abs Limited

Wolfgang Dietz

Gunter Lailach

Ulrich Jansen

Rudolf Gerken

Karl-Heinz Schultz

Walter Bockmann

Peter Clasen

Wolfgang Larbig

Rudolf Hornung

A process for heating up moist gases containing hydrogen halides comprising removing the hydrogen halides from the gases by partial condensation of the water vapor, separating out the condensate and heating up the resultant gas in indirect or recuperative heat exchangers.

Process for heating up moist gases containing hydrogen halides

In the production of nitrobenzene by subjecting benzene to nitration with a mixture of nitric acid and sulfuric acid, separating off the nitrobenzene formed, concentrating the sulfuric acid by evaporation and returning the concentrated sulfuric acid to the bezene nitration stage, the improvement which comprises concentrating sulfuric acid to a concentration of from 75 to 92% by evaporation in vacuo at temperatures in the range from 130.degree. to 195.degree. C. Thereby the energy per kg of water evaporated is drastically reduced compared to processes wherein the sulfuric acid is concentrated to a higher level, without a corresponding loss in efficiency or capacity.

Process for the production of nitrobenzene

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Krefeld, Germany

Wolfgang Dietz