Method for manufacturing nitrobenzole

一种硝基苯、硝化酸的技术，应用在化学仪器和方法、硝基化合物制备、有机化合物的制备等方向，能够解决纯化粗制硝基苯、没有描述、没有揭示等问题

Active Publication Date: 2007-08-08
COVESTRO DEUTSCHLAND AG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, DE-A-2808225 does not disclose that crude nitrobenzene contaminated with benzene must be subjected to an acid wash followed by an alkaline wash followed by a neutral wash before electrophoresis destroys the dispersion
There is also no description in this document of separating water and benzene to obtain high-purity nitrobenzene after electrophoresis destroys the dispersion.
Moreover, the method disclosed in DE-A-2808225 cannot be converted to a method for purifying crude nitrobenzene by neutral washing after acid washing and alkaline washing, because in the stage before neutral washing, influence Important components of electrophoresis results such as sulfuric acid have been washed out of crude nitrobenzene

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Example 1 (comparative example)

[0029] Crude nitrobenzene obtained by the isothermal nitrobenzene process is first subjected to an acid wash and then to an alkaline treatment by adding a sodium hydroxide solution (50%) in a mixing vessel. Then, in the downstream separation vessel, due to the difference in density, the mixture is separated into an organic phase (crude nitrobenzene) and an aqueous phase (spent lye). The aqueous phase goes to a separate alkaline treatment. The remaining warmed crude nitrobenzene at 31° C. contained 95 ppm dinitrobenzene, 42 ppm nitrophenol and 100 ppm Monopol varnish with a benzene content of 4.8% by weight. The warm crude nitrobenzene is neutrally washed with a mixture of deionized water and steam condensate in a four-step countercurrent wash. For this purpose, 4 mixing vessels with downstream separation devices were used (mixer / settler technology). The crude nitrobenzene washed in this way finally passes from the last separation ve...

Embodiment 2

[0030] Example 2 (comparative example)

[0031] Firstly, the crude nitrobenzene obtained by the adiabatic nitrobenzene process is subjected to an acidic washing step and then alkalized by adding sodium hydroxide solution (50%) in a mixing vessel. Then, in the downstream separation vessel, due to the difference in density, the mixture is separated into an organic phase (crude nitrobenzene) and an aqueous phase (spent lye). The aqueous phase goes to a separate alkaline treatment. The remaining 40°C warm crude nitrobenzene contains 245ppm of dinitrobenzene and 53ppm of nitrophenol, and the benzene content is 7.5% by weight. The warm crude nitrobenzene is neutralized by a four-step countercurrent washing method. washing. For this purpose, 4 (only the first 3 are stirred) mixing vessels with downstream separation equipment (mixer / settler technology) are used. Starting from the second washing step, Monopol varnish was additionally used as separation aid (the amount used was 10 ...

Embodiment 3

[0032] Example 3 (according to the embodiment of the present invention)

[0033]First, the crude nitrobenzene obtained by the adiabatic nitrobenzene method is sent to an acid scrubber and then alkalized by adding sodium hydroxide solution (32%) in a static mixer. Then, in the downstream separation vessel, due to the difference in density, the mixture is separated into an organic phase (crude nitrobenzene) and an aqueous phase (spent lye). Warm crude nitrobenzene at 39°C containing 179 ppm of dinitrobenzene and 51 ppm of nitrophenol and having a benzene content of 6.8% by weight was washed in the first neutral wash step with the wash from the second neutral wash step Water is combined on the inlet side of a centrifugal pump operating at 2900 rpm. In this centrifugal pump, the first neutral washing step of crude nitrobenzene takes place. The resulting dispersion was disrupted in an electrophoresis unit operated at a DC voltage of 280 V and a current of 0.3 A and passed into ...

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Abstract

Preparation of nitrobenzene comprises reacting benzene with nitric acid to give nitrobenzene, washing the raw nitrobenzene in an acid, alkaline or neutral wash with water, and removing the raw nitrobenzene from water and benzene. Preparation of nitrobenzene comprises reacting benzene with nitric acid to give nitrobenzene, washing the raw nitrobenzene in an acid, alkaline or neutral wash with water, and removing the raw nitrobenzene from water and benzene, where the step of washing the nitrobenzene in neutral wash with water comprises mixing the raw nitrobenzene with water in a mixing medium and dispersing such that the organic phase essentially containing nitrobenzene is at least partially dispersed, supplying the dispersion to an electrophoresis-unit, in which the dispersion is applied by breaking an electric DC voltage and subsequently separating the aqueous and the organic phase.

Description

technical field [0001] The present invention relates to a continuous process for the treatment of crude nitrobenzene. In this process, crude nitrobenzene is washed successively in acidic, alkaline and neutral washes. In the neutral washing step, the nitrobenzene-containing organic phase was first dispersed, and then the dispersion was broken in an electrophoretic device, followed by separation of the aqueous and organic phases. Background technique [0002] The neutral washing of crude nitrobenzene in the prior art uses a mixing vessel or a static mixer to disperse the organic phase with washing water. The phase separation then takes place in a separation vessel (settler with or without coalescer) possibly under the action of a demulsifier (separation aid). [0003] Alkaline electrophoresis is described in DE-A-2808225. In this known method, an emulsion of nitrobenzene dispersed in spent sulfuric acid is produced batchwise by stirring or recirculation, and this emulsion i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C201/08C07C201/16C07C205/06
CPCC07C201/08C07C201/16C07C205/06C07C201/06
Inventor T·诺夫F·-U·冯杰伦J·希米德勒K·皮拉克兹克P·德里达
Owner COVESTRO DEUTSCHLAND AG
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