Nitrobenzene production capacities

There has been a gradual increase in nitrobenzene production volume in the United States from 73,600 metric tons (kkg) in 1960 to 434,900 kkg in 1986. Based on increased production capacity and increased production of aniline (the major end-product of nitrobenzene) in 1987, it is likely that nitrobenzene production volume will continue to increase (Collins et al. 1982 Dunlap 1981 EPA 1985a SRI 1985, 1986, 1987, 1988 USITC 1987, 1988). 

Table 5.7 summarizes production capacities for the major nitrobenzene-producing countries. The largest manufacturers are J5ayer(West Germany), Du Pont, First Chemical and ICI/Rubicon Chemicals (USA). 

Continuous Multicomponent Distillation Column 501 Gas Separation by Membrane Permeation 475 Transport of Heavy Metals in Water and Sediment 565 Residence Time Distribution Studies 381 Nitrification in a Fluidised Bed Reactor 547 Conversion of Nitrobenzene to Aniline 329 Non-Ideal Stirred-Tank Reactor 374 Oscillating Tank Reactor Behaviour 290 Oxidation Reaction in an Aerated Tank 250 Classic Streeter-Phelps Oxygen Sag Curves 569 Auto-Refrigerated Reactor 295 Batch Reactor of Luyben 253 Reversible Reaction with Temperature Effects 305 Reversible Reaction with Variable Heat Capacities 299 Reaction with Integrated Extraction of Inhibitory Product 280... 

Nitrobenzene is used mainly as an intermediate in the production of aniline. It also forms the basis for the production of 3-chloronitrobenzene, m-nitrobenzene-sulfonic acid and p-aminophenol its earlier importance in the production of the dyestuff intermediate benzidine is insignificant today, due to the carcinogenicity of the latter. The industrial production of nitrobenzene is achieved by isothermal nitration of benzene. Mixed nitration acid, composed of 40% HNO3, 40% H2SO4 and 20% water, is used as the nitrating medium. Whereas the process was originally carried out batchwise, continuous operation predominates today in plants with a capacity up to 100,000 tpa. Stainless steel equipment is used, which is resistant to corrosion due to a passivation effect. 

Apart from gas-phase oxidation, liquid-phase oxidation with dichromate is an expedient process if the chromium-(III)-sulfate by-product can be used as a tanning agent. The largest anthraquinone plant Bayer/ Qsi Germany) with a capacity of 11,000 tpa applies this process. Batch oxidation is carried out with pulverized 94-95% anthracene in a stirred tank reactor with the addition of sodium dichromate and sulfuric add at 60 to 105 °C. The reaction takes between 25 and 30 hours. The yield of anthraquinone, which is produced in purities of around 95%, is over 90%. The purity can be increased to over 99% by recrystallization from nitrobenzene or cyclohexanol/cyclohexanone. 

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