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Mononitrotoluene (MNT)

MNT DNT umlauf reaktor circulation reactor

In industrial chemistry, Mononitrotoluene is mainly used in as a pre-product for polyurethanes, via the route Dinitrotoluene / TDA / TDI. Mononitrotoluene is obtained as a mixture of isomers by nitration of Toluene in MNT mixed acid. Besides of MNT, the obtained pure isomers, after isomer separation, serve as an important raw material for the dyeing industry and other related industries.

Meissner MNT plants are characterized by their circulation reactors which have been developed especially for nitration purposes, and which ensure a high degree of security due to their large cooling areas for a small reactor volume. The circulation pumps used in the reactors accomplish an optimum conversion of the reactants, in this way providing a constantly high quality of MNT.

For safety reasons, the separation of the mixture of MNT isomers from the spent acid is performed in dynamic separators, which are characterized by a short separation time (within the range of seconds) and a very small volume. The MNT isomer mixture is automatically conveyed to the washing section consisting of compact Meissner washing apparatuses performing the washing as well as the separation of the product from the washing medium.

Additionally to the MNT plant, Meissner as main contractor also offers the spent acid regeneration plant performing the recovery of concentrated Sulfuric Acid and Nitric Acid, as well as the respective plant for MNT isomer separation and an economical waste water purification plant for the removal of toxic nitrocresols, contained in the MNT waste water, in order to obtain a biologically degradable waste water.

Dinitrotoluene

DNT

The mixture of Dinitrotoluene isomers is a very valuable raw material for the plastics chemistry, which after hydrogenation (to TDA) and subsequent phosgenation (to TDI) is finally processed to polyurethane.

DNT plants by MEISSNER are characterized by their circulation reactors, which have been developed especially for nitration purposes, and which ensure a high degree of security due to their large cooling areas with small reactor volumes. The circulation pumps used in the reactors provide for an optimum conversion of the reactants and thus a DNT of uniformly high quality.

Thanks to the special design of the MEISSNER nitration reactors, MEISSNER is able to supply DNT plants with a capacity of up to 50 t of DNT/hour in one line.

In MEISSNER DNT plants, nitration is carried out in two steps. First, Toluene is nitrated to produce MNT, and then MNT is nitrated to produce DNT. After each nitration step the product is separated from the respective acid in dynamic separators and is then further processed. The raw DNT is automatically conveyed to the washing unit consisting of MEISSNER compact washing apparatus, which perform the product washing as well as the separation of the product from the respective washing medium.

MEISSNER DNT plants do not generate any acidic, nitrate-loaded waste water, since the Nitric Acid contained in the raw DNT is regenerated and re-used.

Additionally to the DNT plant, MEISSNER as main contractor also offers the spent acid regeneration plant performing the recovery of concentrated Sulphuric Acid with recovery of Nitric Acid and organics, as well as an economical waste water treatment plant for the disposal of toxic nitrocresols contained in the DNT waste water so that a biologically degradable waste water is obtained.

Mononitrobenzene

MNB

MNB NB rohr reaktor adiabatische nitrierung benzol tube reactor adiabatic nitration benzene

Mononitrobenzene, obtained from Benzene and Nitric Acid in the presence of Sulfuric Acid by the adiabatic process, is the starting material for Aniline, which is a valuable raw material for the plastics chemistry (MDI, polyurethane) and the dyeing chemistry (Aniline derivatives).

Adiabatic nitration MNB plants by MEISSNER are characterized by the application of tube reactors, which minimize the formation of by-products (Nitrophenols, Picric Acid and Dinitrobenzene) by optimum reactant intermixing and negligible back mixing inside the tube reactor. Due to the adiabatic technology, the reconcentration of the Sulfuric Acid accruing after separation of the MNB takes place directly in the plant.

The crude Mononitrobenzene is automatically fed to the washing section consisting of MEISSNER compact washers, which perform the product washing as well as the separation of the product from the respective washing medium.

In the subsequent stripping unit the residual Benzene still contained in the purified Mononitrobenzene is separated by means of steam and returned into the process.

Additionally to the MNB plant, MEISSNER as main contractor also offers the Aniline plant, as well as the economical waste water treatment plant for the disposal of toxic Nitrophenols and Picric Acid to obtain a biologically degradable waste water.

Mononitrochlorobenzene

MNCB

The mixture of Mononitrochlorobenzene isomers, obtained from Chlorobenzene and Nitric Acid in the presence of Sulphuric Acid by the adiabatic process, or from Chlorobenzene and the corresponding mixed acid by the conventional nitration process, serves for obtaining the separate isomers. These are mainly used as raw materials in the dyeing chemistry and the agricultural chemistry.

Adiabatic nitration MNCB plants by MEISSNER are characterized by the application of tube reactors, which minimize the formation of by-products by optimum reactant intermixing and negligible back mixing inside the tube reactor. Due to the adiabatic technology, the reconcentration of the Sulphuric Acid accruing after separation of the MNCB takes place directly in the plant.

The crude Mononitrochlorobenzene is automatically fed to the washing section consisting of MEISSNER compact washers, which perform the product washing as well as the separation of the product from the respective washing medium. In the subsequent stripping unit the Chlorobenzene contained in the purified MNCB is separated by means of steam and returned into the process.


MNCB plants by MEISSNER using the conventional nitration process are characterized by the application of circulation reactors which have been developed especially for nitration purposes, and which ensure a high degree of security due to their large cooling areas with a small reactor volume. The circulation pumps used in the reactors provide for an optimum conversion of the reactants and thus an MNCB of uniformly high quality.

For safety reasons, the separation of the MNCB isomer mixture from the spent acid is performed in dynamic separators featuring a short separation time (within the range of seconds) and a very small volume. The mixture of MNCB isomers is automatically fed to the washing section consisting of MEISSNER compact washers, which perform the product washing as well as the separation of the product from the washing medium.


Additionally to the MNCB plant, MEISSNER as main contractor also offers the spent acid regeneration plant for the recovery of concentrated Sulphuric Acid and Nitric Acid.

Other Nitroaromatics

nitro ethylbenzol xylol cumol dichlornitrobenzol dinitro benzol chlorbenzol nitro ethylbenzene xylene cumene dichloronitrobenzene dinitro benzene chlorobenzene

Throughout 70 years of process development in the field of Nitroaromatics, MEISSNER has also been developing and putting into practice the nitration technology for special aromatics.

This applies, for example, to the isomer mixtures of Nitroethylbenzene, Nitroxylene, Nitrocumene, Dichloronitrobenzene, Dinitrobenzene, Dinitrochlorobenzene, etc.

Aniline

nitro benzol nitro benzene

Aniline is an economically important intermediate for isocyanates, pharmaceuticals, dyeing agents and for rubber and agricultural chemicals.

Upon customer request, MEISSNER co-operates with Aniline licensors. Together with MEISSNER's MNB process, liquid-phase hydrogenation as well as gas phase hydrogenation to Aniline can be applied.

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