Process for the production of nitrobenzene

US4772757A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Gunter Lailach · Krefeld, DE
• Rudolf Gerken · Krefeld, DE
• Karl-Heinz Schultz · Krefeld, DE
• Rudolf Hornung · Krefeld, DE
• Walter Bockmann · Krefeld, DE
• Wolfgang Larbig · Krefeld, DE
• Wolfgang Dietz · New Hope, US

Key dates

• Filing date: Oct 21, 1986
• Grant date: Sep 20, 1988
• Expiry date: Oct 21, 2006

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01B17/88
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

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.