Recovery of the nitration acid mixtures from nitration processes

A mixture and aromatic compound technology, applied in the field of nitric acid and nitrogen oxides, mixture of nitric acid and nitrogen oxides, removal and recovery of acid mixture for nitrification, sulfuric acid, can solve problems such as nitrate pollution

Active Publication Date: 2007-04-25
JOSEF MEISSNER
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0029] As a result, all known measures of the prior art only partially solve the problem of avoiding nitric acid losses during the nitrification process, and therefore the waste water of the DNT plant is still contaminated with nitrates

Method used

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  • Recovery of the nitration acid mixtures from nitration processes
  • Recovery of the nitration acid mixtures from nitration processes

Examples

Experimental program
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Effect test

Embodiment

[0081] Phase I - Cross Flow Extraction

[0082] In one stage, 3400 kg of crude DNT with a residual content of 1.85% sulfuric acid, 1.5% nitric acid and 0.85% nitrogen dioxide was used after the spent DNT acid had been separated off using a mixture of 55.6% sulfuric acid, 3.07% nitric acid and 3.52% nitrous gas (as HNO 2 ) to wash with the washing acid composed of DNT:washing acid volume ratio of 1:2.

[0083] At the same time, approximately 42 kg of water / hour was added continuously so that the acid extracted from the crude DNT did not change the concentration of the washing acid.

[0084] 98% sulfuric acid, about 6.7% nitric acid and about 13.5% nitrous gas (as HNO 2 ) are removed from the crude DNT in this washing stage.

[0085] After the phase separation wash emulsion, the wash acid is recycled to the wash and the excess wash acid is collected in a vessel and recycled therefrom to the nitration process either directly or together with the acid in wash stage II (cross-f...

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Abstract

Removing and recovering nitrating acid mixtures of nitric acid, sulphuric acid and oxides of nitrogen, from the nitrated crude products occurring in the nitration of nitratable aromatic compounds, after the nitrating acid has been separated off, by a multistage extraction process involves one stage of a cross-flow extraction and another stage of a countercurrent extraction. An independent claim is also included for production plant for nitrating nitratable aromatic compounds with subsequent purification of the nitrated products, including removal and recovery of nitrating acid mixtures of sulphuric acid, nitric acid and oxides of nitrogen, comprises: (a) a nitrating unit for nitrating nitratable aromatic compounds, having at least one appropriate reaction containers for carrying out the nitration reactions; and (b) arranged in the production line downstream of the nitrating unit, a unit for carrying out acidic scrubbing by units of extraction and is comprising a cross-flow extraction unit for carrying out acidic scrubbing of nitrated crude products by units of cross-flow extraction, and in the production line downstream of the cross-flow extraction unit, a countercurrent extraction unit for carrying out acidic scrubbing of the nitrated crude products, scrubbed beforehand by units of cross-flow extraction, by units of countercurrent extraction.

Description

technical field [0001] The present invention relates to the removal and recovery of nitrification acid mixtures, especially mixtures of sulfuric acid, nitric acid and nitrogen oxides, from a nitrification process. In particular, the present invention relates to a method for the removal and recovery of nitrating acid mixtures, especially mixtures of sulfuric acid, nitric acid and nitrogen oxides, which are present in nitrated aromatic compounds such as benzene after the nitrating acid has been separated off. , toluene, chlorobenzene, dichlorobenzene, mononitrobenzene, mononitrochlorobenzene, mononitrotoluene, dinitrotoluene, etc.) in the nitration crude product of the nitration process. According to a particular aspect, the invention relates to a method for the removal and recovery of nitration from crude dinitrotoluene (DNT) formed during the nitration of toluene or mononitrotoluene (MNT) after the acid for nitration has been separated off. Acid mixtures, especially sulfuric ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B17/94C01B21/46C01B21/20B01D11/04
CPCC07C201/16C07C205/12C07C205/06C07C201/06
Inventor H·赫尔曼J·格鲍尔P·科尼茨尼M·汉德尔
Owner JOSEF MEISSNER
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