Method for the continuous production of nitrobenzene

US9227909B2 · kind B2 · utility

Assignee

• Covestro Deutschland AG · DE

Inventors

• Thomas Knauf · Dormagen, DE
• Jurgen Munnig · Kaarst, DE
• Joerg Schmiedler · Duisburg, DE

Key dates

• Filing date: Oct 4, 2013
• Grant date: Jan 5, 2016
• Expiry date: Dec 12, 2033

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C201/16
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The present invention relates to a method for producing nitrobenzene, in which the waste gas streams accruing in the process and containing benzene and (traces of) nitrobenzene, possibly low- and medium-boiling components, possibly non-condensable gases and possibly water, optionally after removal of nitrogen oxides, are scrubbed in an absorption column with nitrobenzene, which comprises only very small amounts (maximum 50 ppm) of benzene and is distributed by means of a liquid distributor at a rate of 50 to 200 drip points per square meter, preferably 60 to 120 drip points per square meter, wherein (i) a liquid stream containing benzene and nitrobenzene, possibly organic low- and medium-boiling components and additionally containing sulfuric acid if sulfuric acid is used as the scrubbing agent and (ii) waste gas depleted in benzene and possibly in organic low- and medium-boiling components are obtained. A waste gas purified by the method according to the invention is particularly suitable for burning in a thermal exhaust air treatment process.