| abstract |
The invention relates to a continuous adiabatic process for producing nitrobenzene by nitrating benzene with sulphuric acid mixtures and nitric acid mixtures using a stoichiometric excess of benzene, the content of organic compounds in the sulphuric acid cycle being maintained, at least during the starting of the production system, at a level lower than 1.0 mass % in relation to the total mass of the sulphuric acid cycle. This is achieved, preferably, either after the end or prior to the start of the production cycle, by starting the circulation of the sulfuric acid cycle at a higher temperature in order to separate the organic substances contained in the sulphuric acid and comprising, preferably nitrobenzene and traces of benzene, dinitrobenzene and nitrophenol, in an evaporation device for concentrating the sulphuric acid. |