Continuous process for the manufacture of nitrobenzene
View Patent ↗The invention relates to a continuous process for the manufacture of nitrobenzene. This process comprises the nitration of benzene with nitrating acid that contains at least 3.0 wt. % of nitric acid and at least 67.0 wt. % of sulfuric acid, in a reaction space in which the start temperature of the reaction is above 100.0° C. but below 102.0° C. In addition, this process requires that the benzene and the nitrating acid are dispersed in one another several times.
1. A continuous process for the manufacture of nitrobenzene comprising
(1) nitrating benzene with a nitrating acid in a reaction space in which said benzene and said nitrating acid are dispersed in one another several times, wherein:
a) said nitrating acid contains at least 3.0 wt. %, based on 100 wt. % of said nitrating acid, of nitric acid and at least 67.0 wt. % of sulfuric acid, based on 100 wt.% of said nitrating acid;
b) the starting temperature of the reaction is above 100.0° C. but below 102.0° C.;
c) the emulsion of said nitrating acid and said benzene which is obtained after the first dispersion is redispersed at least 4 times before the nitric acid conversion is 60%;
and
d) at least 60% of said nitric acid used is converted within the first 13 vol. % of the reaction space in the direction of flow of the reactants after the first dispersion.
2. The process of claim 1 , wherein said nitration is carried out without heating or cooling.
3. The process of claim 1 , wherein said nitration is cooled in the region of the first 20 vol. % of the reaction space in the direction of flow of the reactants.
4. The process of claim 1 , wherein said nitration is cooled in the region of the first 15 vol. % of the reaction space in the direction of flow of the reactants.
5. The process of claim 1 , wherein the resultant nitrobenzene is produced with a space-time yield of more than 5 tons per cubic meter of reaction space per hour.