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A kind of method that microchannel reactor synthesizes dinitrotoluene

A technology of microchannel reactor and dinitrotoluene, which is applied in the chemical industry, can solve the problems of aggravated temperature rise, equipment corrosion, high temperature, etc., and achieve the effects of short residence time, safe and reliable production, and low material inventory

Active Publication Date: 2021-08-10
SICHUAN GOLDEN ELEPHANT SINCERITY CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In addition, in the nitration reaction, if mixed acid is used as the nitrating agent, the combination of sulfuric acid and the water generated by the reaction will also release a large amount of heat, which intensifies the rising trend of temperature during the reaction process.
After the reaction, the concentration of the mixed acid decreases, and it needs to be concentrated before it can be returned to the system for reuse. Moreover, the temperature of the mixed acid concentration process is high, and the material corrodes the equipment seriously.

Method used

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  • A kind of method that microchannel reactor synthesizes dinitrotoluene
  • A kind of method that microchannel reactor synthesizes dinitrotoluene
  • A kind of method that microchannel reactor synthesizes dinitrotoluene

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Embodiment 1

[0022] Present embodiment provides a kind of method that microchannel reactor synthesizes dinitrotoluene, as figure 1 As shown, the specific steps are as follows:

[0023] (1) The metered mixed acid, NO 2 and toluene are respectively sent into the microchannel reactor for mixed reaction, the mixed acid is a mixture of concentrated nitric acid and concentrated sulfuric acid, the mass ratio of the two is 1:5, the mass concentration of concentrated nitric acid is 85%, the mass concentration of concentrated sulfuric acid is 98%, toluene and The molar ratio of concentrated nitric acid is 1:2, toluene and NO 2 The molar ratio is 1:1.08, the reaction temperature is 52°C, and the reaction time is 90s; the reaction equation is as follows:

[0024]

[0025] (2) After the reaction is over, gas-liquid separation is carried out first, and the nitrogen oxides in the gas phase are further oxidized and then returned to the system to participate in the reaction again; the liquid phase is ...

Embodiment 2

[0030] Present embodiment provides a kind of method that microchannel reactor synthesizes dinitrotoluene, as figure 1 As shown, the specific steps are as follows:

[0031] (1) The metered mixed acid, NO 2 and toluene into the microchannel reactor for mixed reaction, the mixed acid is a mixture of concentrated nitric acid and concentrated sulfuric acid, the mass ratio of the two is 1:7, the concentration of concentrated nitric acid is 88%, the concentration of concentrated sulfuric acid is 95%, the molar ratio of toluene to concentrated 1:3, toluene and NO 2 The molar ratio is 1:1.1, the reaction temperature is 55°C, and the reaction time is 70s; the reaction equation is as follows:

[0032]

[0033] (2) After the reaction is over, gas-liquid separation is carried out first, and the nitrogen oxides in the gas phase are further oxidized and then returned to the system to participate in the reaction again; the liquid phase is left to stand and stratified, the organic phase i...

Embodiment 3

[0038] Present embodiment provides a kind of method that microchannel reactor synthesizes dinitrotoluene, as figure 1 As shown, the specific steps are as follows:

[0039] (1) The metered mixed acid, NO 2 and toluene into the microchannel reactor for mixed reaction, the mixed acid is a mixture of concentrated nitric acid and concentrated sulfuric acid, the mass ratio of the two is 1:8, the concentration of concentrated nitric acid is 75%, the concentration of concentrated sulfuric acid is 92%, the molar ratio of toluene to concentrated nitric acid 1:5, toluene and NO 2 The molar ratio is 1:1.1, the reaction temperature is 63°C, and the reaction time is 150s; the reaction equation is as follows:

[0040]

[0041] (2) After the reaction is over, gas-liquid separation is carried out first, and the nitrogen oxides in the gas phase are further oxidized and then returned to the system to participate in the reaction again; the liquid phase is left to stand and stratified, the or...

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Abstract

The invention belongs to the field of chemical technology, in particular to a method for synthesizing dinitrotoluene with a microchannel reactor. In this method, the metered mixed acid, NO 2 The gas and toluene are sent to the microchannel reactor in proportion to fully mix and react. After the reaction, the gas-liquid separation is carried out first. The nitrogen oxides in the gas phase are further oxidized and then returned to the system to participate in the reaction again. The liquid phase is left to stand and separated, and the organic phase, Aqueous phase and NO 2 After being metered separately, it is sent to the secondary microchannel reactor for reaction again. The secondary reaction product is separated from gas and liquid again. The nitrogen oxides in the gas phase are further oxidized and then returned to the system to participate in the reaction again. Participating in the reaction, the organic phase is cooled, washed with alkali, dried and purified to obtain the dinitrotoluene product. The method uses concentrated sulfuric acid as catalyst, nitric acid and NO 2 As a nitrating agent, the mixed acid after the reaction does not need to be concentrated and can be recycled directly, which saves equipment investment and significantly reduces production energy consumption.

Description

technical field [0001] The invention belongs to the field of chemical industry, and specifically relates to a method for synthesizing dinitrotoluene with a microchannel reactor. Background technique [0002] Dinitrotoluene is a raw material for the preparation of toluene diisocyanate, and it can also be used to manufacture dye intermediates and explosives. It is an important organic chemical intermediate. Dinitrotoluene is usually produced by nitration of toluene, which is a widely used chemical reaction in organic chemical industry. [0003] At present, the equipment used in the nitration reaction is usually a tank reactor or an annular reactor. During continuous production, multiple reactors are required to be connected in series. Although this reaction method realizes the continuous feeding and discharging of materials, the materials in the reactor The residence time is uneven, the unnitrated and overnitrated substances in the production process are not easy to control, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C201/08C07C205/06
CPCC07C201/08C07C205/06
Inventor 唐印冯瑞雷林刘朝慧郭志刚李旭初
Owner SICHUAN GOLDEN ELEPHANT SINCERITY CHEM CO LTD