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A kind of method that reclaims nitrobenzene from nitrobenzene tar

A technology for nitrobenzene tar and nitrobenzene, which is applied in the field of nitrobenzene recovery, can solve the problems of high cumulative content, does not involve a method for recycling nitrobenzene tar, etc., and achieves the effects of simple recovery process and strong operability

Active Publication Date: 2020-11-10
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The above-mentioned patents all mention the method of reducing the content of phenoxide and sodium salt in crude nitrobenzene, but it is limited to the treatment of crude nitrobenzene, and does not involve the recovery and utilization method of nitrobenzene tar, and phenoxide and sodium salt are in the nitrobenzene The accumulated content in benzene tar is high, and there are many high boiling substances such as dinitrogen, so it cannot be recycled according to the crude nitrobenzene treatment process

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Nitrobenzene tar and 0.05% NaOH solution are mixed with a static mixer at a volume ratio of 1:1 for alkali washing. The temperature of the alkali wash is 20°C. After the alkali wash, the oil and water are separated, and the water phase and the oil phase are separated. The oil phase and the water are separated by The volume ratio is 1:1, and the static mixer is used to mix and wash with water. The washing temperature is 20°C. After washing, the oil and water are separated to separate the water phase and the oil phase. The specific surface area of ​​the oil phase is 600m 2 / g of spherical silica gel adsorbent to adsorb and remove trace moisture, and the oil phase after adsorption and separation is subjected to intermittent rectification to recover nitrobenzene.

[0021] The content of nitrophenol and its sodium salt in the oil phase after adsorption separation was 9.3 mg / kg, and the recovery rate of nitrobenzene was 95.5%.

Embodiment 2

[0023] Nitrobenzene tar and 1% NaOH solution are mixed with a static mixer at a volume ratio of 1:1 for alkali washing. The temperature of the alkali wash is 80°C. After the alkali wash, the oil and water are separated to separate the water phase and the oil phase. The volume ratio is 1:1, and the static mixer is mixed and washed with water. The washing temperature is 80°C. After washing, the oil and water are separated to separate the water phase and the oil phase. The oil phase is subjected to batch distillation to recover nitrobenzene.

[0024] The content of nitrophenol and its sodium salt in the oil phase after adsorption separation was 5.1 mg / kg, and the recovery rate of nitrobenzene was 97.2%.

Embodiment 3

[0026] Nitrobenzene tar and 10% NaOH solution are stirred and mixed in a kettle for alkali washing at a volume ratio of 10:1. The temperature of the alkali washing is 65°C. After the alkali washing, the oil and water are separated to separate the water phase and the oil phase. The oil phase and the water are separated according to the The volume ratio is 1:1, and the washing temperature is 65 ℃ by mixing and washing in a kettle. After washing, the oil and water are separated to separate the water phase and the oil phase. The specific surface area of ​​the oil phase is 600m 2 / g of spherical silica gel adsorbent to adsorb and remove trace moisture, and the oil phase after adsorption and separation is subjected to continuous rectification to recover nitrobenzene.

[0027] The content of nitrophenol and its sodium salt in the oil phase after adsorption separation was 7.7mg / kg, and the recovery rate of nitrobenzene was 96.3%.

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Abstract

The invention discloses a method for recycling nitrobenzene from nitrobenzene tar. The method comprises the following steps: performing alkali wash, water wash and adsorption separation, so that the contents of nitrophenol and sodium salt in the nitrobenzene tar are reduced to below 10mg / kg; and then, performing rectification and recycling on the nitrobenzene. The method has the characteristics ofbeing mature in treatment technology, being safe and reliable and being high in recovery rate of the nitrobenzene, and therefore, the method has good economic benefits and social benefits.

Description

technical field [0001] The invention relates to a method for recycling nitrobenzene tar, in particular to a method for firstly reducing the content of nitrophenol and its phenoxide through alkali washing, water washing and adsorption separation, and then recovering nitrobenzene from the nitrobenzene tar. Background technique [0002] Nitrobenzene is an important chemical raw material and intermediate, mainly used in the production of aniline and dyes, and also used in various industries such as pharmaceuticals, pesticides and dye intermediates. [0003] At present, the industrial nitrobenzene production process mainly includes unit processes such as benzene nitration, neutralization and water washing, and rectification. The risk of explosion is very high, and it is easy to accumulate in the heated parts such as the rectification tower and reboiler. During production, measures such as regular cleaning of the reboiler and extraction of the distillation tower residue are taken ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C201/16C07C205/06
CPCC07C201/16C07C205/06
Inventor 杨忠林金汉强丁红霞赵思远季峰崎孙盛凯
Owner CHINA PETROLEUM & CHEM CORP