阅读说明：本技术 一种利用微反应器制备2,4-二硝基苯胺的方法 (Method for preparing 2, 4-dinitroaniline by using microreactor ) 是由 何强 张国富 周坤 许英彪 王康杨 胡才勇 谢学友 赵建坤 于 2020-06-15 设计创作，主要内容包括：本发明涉及2,4-二硝基苯胺制备技术领域,尤其是一种利用微反应器制备2,4-二硝基苯胺的方法,其步骤为：(1)准备设备,准备预热器、微反应器和两台色谱泵；(2)连接反应设备,将两台色谱泵分别与预热器和微反应器相连,然后预热器与微反应器相连,连接完成后将预热器与微反应器放入恒温油浴中；(3)反应材料的输送,将氨水以预设流速输送到预热器,将融化后的2,4-二硝基氯苯以预设流速输送到微反应器中与氨水混合反应得到2,4-二硝基苯胺；(4)根据步骤(3)在材料反应完成后,将多余的氨气通过氨气回收装置重新制成氨水回用,将反应产生的氯化铵与氢氧化钾反应生成的氨继续回用,本发明具有生产效率高、能耗低、经济环保、安全可靠的特点。(The invention relates to the technical field of preparation of 2, 4-dinitroaniline, in particular to a method for preparing 2, 4-dinitroaniline by using a microreactor, which comprises the following steps: (1) preparing equipment, namely preparing a preheater, a microreactor and two chromatographic pumps; (2) connecting reaction equipment, respectively connecting two chromatographic pumps with a preheater and a microreactor, then connecting the preheater with the microreactor, and putting the preheater and the microreactor into a constant-temperature oil bath after connection is finished; (3) conveying reaction materials, namely conveying ammonia water to a preheater at a preset flow rate, conveying the melted 2, 4-dinitrochlorobenzene to a microreactor at a preset flow rate, and mixing and reacting the melted 2, 4-dinitrochlorobenzene with the ammonia water to obtain 2, 4-dinitroaniline; (4) and (4) after the material reaction is finished according to the step (3), making redundant ammonia gas into ammonia water again for recycling through an ammonia gas recovery device, and continuously recycling ammonia generated by the reaction of the ammonium chloride and the potassium hydroxide.)

1. A method for preparing 2, 4-dinitroaniline by using a microreactor is characterized by comprising the following steps: the method comprises the following steps:

(1) preparing equipment, namely preparing a preheater, a microreactor and two chromatographic pumps;

(2) connecting reaction equipment, respectively connecting two chromatographic pumps with a preheater and a microreactor, then connecting the preheater with the microreactor, and putting the preheater and the microreactor into a constant-temperature oil bath after connection is finished;

(3) conveying the reaction material, conveying the ammonia water to a preheater at a preset flow rate,

conveying the melted 2, 4-dinitrochlorobenzene into a microreactor at a preset flow rate to be mixed with ammonia water and react for a preset time to obtain a product 2, 4-dinitroaniline;

(4) and (4) after the material reaction is finished according to the step (3), making redundant ammonia gas into ammonia water again for recycling through an ammonia gas recovery device, continuously recycling ammonia generated by the reaction of the ammonium chloride and the potassium hydroxide, taking the potassium chloride as a byproduct, and recycling reclaimed water into an ammonia gas absorption device to achieve zero discharge of wastewater.

2. The method of claim 1 for preparing 2, 4-dinitroaniline using a microreactor, wherein: the inner diameter of the preheater is 3-6 mm.

3. The method of claim 1 for preparing 2, 4-dinitroaniline using a microreactor, wherein: the inner diameter of the micro-channel of the micro-reactor is 2-7 mm.

4. The method of claim 1 for preparing 2, 4-dinitroaniline using a microreactor, wherein: and (4) conveying the ammonia water to a preheater at a preset flow rate according to the step (3), wherein the preset flow rate is 100 ml/min.

5. The method of claim 4 for preparing 2, 4-dinitroaniline using a microreactor, wherein: the molar ratio of the 2, 4-dinitrochlorobenzene to the ammonia is 1.0 (2-5).

6. The method of claim 1 for preparing 2, 4-dinitroaniline using a microreactor, wherein: according to the step (3), the residence time of the ammonia water in the preheater is 0.06-0.13s, and the residence time of the main reaction in the micro-channel of the microreactor is 11-36 s.

7. The method of claim 1 for preparing 2, 4-dinitroaniline using a microreactor, wherein: the concentration of the ammonia water in the step (3) is 25%.

8. The method of claim 1 for preparing 2, 4-dinitroaniline using a microreactor, wherein: according to the step (2), the temperature of the constant temperature reaction bath of the constant temperature oil bath is 200-220 ℃.

9. The method of claim 1 for preparing 2, 4-dinitroaniline using a microreactor, wherein: and (4) conveying the melted 2, 4-dinitrochlorobenzene in the step (3) into the microreactor at a preset flow rate to be mixed with ammonia water and react for a preset time, wherein the preset time is 28-16 s.

Technical Field

The invention relates to the technical field of preparation of 2, 4-dinitroaniline, in particular to a method for preparing 2, 4-dinitroaniline by using a microreactor.

Background

The reaction principle for preparing the 2, 4-dinitroaniline by using the 2, 4-dinitrochlorobenzene and ammonia water as reaction raw materials is that the 2, 4-dinitrochlorobenzene and the ammonia water generate bimolecular nucleophilic substitution reaction, firstly, ammonia molecules with unshared electron pairs attack carbon connected with chlorine atoms on an aromatic ring to obtain an intermediate product with polarity, and the intermediate product is quickly reacted and converted to generate the final product 2, 4-dinitroaniline.

At present, the existing and the prior reported production of the 2, 4-dinitroaniline is interrupted single-kettle production and continuous kettle production, and has low production efficiency, long reaction time, larger pollution and low safety of high-pressure exothermic reaction. Various reaction schemes have been designed for the requirement of the ammoniation reaction, for example, the patent name of the invention patent of the ammoniation reaction catalyst, which is published by the national institute of petrochemical engineering, the institute of petrochemical engineering, and the grant number is CN87105833.2 and is published by the national intellectual property office of the Chinese petrochemical industry, 03.15.1989, has the defects of the adopted technology and cannot solve the continuous production requirement. The invention patent of the patent number CN201410316049.8, which is announced by Henan Luo dye Co Ltd and is published by the Chinese intellectual property office in 07/04/2014, has the defects of long reaction time, low safety factor and the like, and can not achieve real green safe production.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a method for preparing 2, 4-dinitroaniline by using a microreactor, which solves the technical problems of low production efficiency, high pollution, high cost and low safety factor of the traditional kettle-type reaction.

In order to achieve the purpose, the invention provides the following technical scheme: a method for preparing 2, 4-dinitroaniline by using a microreactor comprises the following steps:

(1) preparing equipment, namely preparing a preheater, a microreactor and two chromatographic pumps;

(2) connecting reaction equipment, respectively connecting two chromatographic pumps with a preheater and a microreactor, then connecting the preheater with the microreactor, and putting the preheater and the microreactor into a constant-temperature oil bath after connection is finished;

(3) conveying the reaction material, conveying the ammonia water to a preheater at a preset flow rate,

conveying the melted 2, 4-dinitrochlorobenzene into a microreactor at a preset flow rate to be mixed with ammonia water and react for a preset time to obtain a product 2, 4-dinitroaniline;

(4) and (4) after the material reaction is finished according to the step (3), making redundant ammonia gas into ammonia water again for recycling through an ammonia gas recovery device, continuously recycling ammonia generated by the reaction of the ammonium chloride and the potassium hydroxide, taking the potassium chloride as a byproduct, and recycling reclaimed water into an ammonia gas absorption device to achieve zero discharge of wastewater.

Preferably, the inner diameter of the preheater is 3-6 mm.

Preferably, the micro-channel inner diameter of the micro-reactor is 2-7 mm.

Preferably, the ammonia water is delivered to the preheater at a preset flow rate according to the step (3), wherein the preset flow rate is 100 ml/min.

Preferably, the molar ratio of 2, 4-dinitrochlorobenzene to ammonia is 1.0 (2-5).

Preferably, according to step (3), the residence time of the aqueous ammonia in the preheater is between 0.06 and 0.13s, and the residence time of the main reaction in the microchannel of the microreactor is between 11 and 36 s.

Preferably, the concentration of the aqueous ammonia in the step (3) is 25%.

Preferably, according to step (2), the temperature of the constant temperature reaction bath of the constant temperature oil bath is 200-220 ℃.

Preferably, the 2, 4-dinitrochlorobenzene melted in the step (3) is conveyed into the microreactor at a preset flow rate to be mixed with ammonia water and react for a preset time, wherein the preset time is 28-16 s.

Compared with the prior art, the invention has the beneficial effects that: the process has the characteristics of high production efficiency, low energy consumption, economy, environmental protection, safety and reliability, and has the technical effects that; the reaction time is shortened by utilizing the efficient heat and mass transfer characteristics of the microreactor, and the possibility of explosion caused by sudden temperature rise in the traditional reaction process is avoided by utilizing the high-quality heat and mass transfer effects of the microreactor. The whole reaction process is continuous and automatic, manual operation is not needed, personal safety is guaranteed, and production cost is reduced.

The micro-reactor equipment is used for continuous feeding and discharging, the productivity is high, the equipment is fully utilized, and the utilization rate of the equipment is improved.

The common batch reaction method is adopted to prepare the 2, 4-dinitroaniline, the labor intensity is high, the safety is low, the temperature rise and the pressure rise are both dependent on manual work, the operations of feeding and discharging occupy a large amount of time, the common continuous reaction method needs a plurality of reaction kettles, the occupied area is large, and the reaction residence time is long.

Detailed Description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a technical scheme that: a method for preparing 2, 4-dinitroaniline by using a microreactor is characterized by comprising the following steps: the method comprises the following steps:

(1) preparing equipment, namely preparing a preheater, a microreactor and two chromatographic pumps;

(2) connecting reaction equipment, respectively connecting two chromatographic pumps with a preheater and a microreactor, then connecting the preheater with the microreactor, and putting the preheater and the microreactor into a constant-temperature oil bath after connection is finished;

(3) conveying the reaction material, conveying the ammonia water to a preheater at a preset flow rate,

conveying the melted 2, 4-dinitrochlorobenzene into a microreactor at a preset flow rate to be mixed with ammonia water and react for a preset time to obtain a product 2, 4-dinitroaniline;

(4) and (4) after the material reaction is finished according to the step (3), making redundant ammonia gas into ammonia water again for recycling through an ammonia gas recovery device, continuously recycling ammonia generated by the reaction of the ammonium chloride and the potassium hydroxide, taking the potassium chloride as a byproduct, and recycling reclaimed water into an ammonia gas absorption device to achieve zero discharge of wastewater.

The inner diameter of the preheater is 3-6 mm. The inner diameter of the micro-channel of the micro-reactor is 2-7 mm.

According to the step (2), the temperature of the constant temperature reaction bath of the constant temperature oil bath is 200-220 ℃.

And (4) conveying the ammonia water to a preheater at a preset flow rate according to the step (3), wherein the preset flow rate is 100 ml/min.

The concentration of the ammonia water in the step (3) is 25%. The molar ratio of the 2, 4-dinitrochlorobenzene to the ammonia is 1.0 (2-5).

According to the step (3), the residence time of the ammonia water in the preheater is 0.06-0.13s, and the residence time of the main reaction in the micro-channel of the microreactor is 11-36 s.

And (4) conveying the melted 2, 4-dinitrochlorobenzene in the step (3) into the microreactor at a preset flow rate to be mixed with ammonia water and react for a preset time, wherein the preset time is 28-16 s.

Through the technical scheme, the specific implementation process is as follows: