阅读说明：本技术 邻甲苯胺采用微通道反应器进行硝化的方法 (Method for nitrifying o-toluidine by adopting microchannel reactor ) 是由 袁顺福 范洪振 袁郡 范琳 许薇 于 2020-11-26 设计创作，主要内容包括：本发明提供一种邻甲苯胺采用微通道反应器进行硝化的方法,包括如下步骤：(1)将乙酸酐和冰乙酸配制成混酸；(2)将邻甲苯胺和混酸分别通过平流泵输入到微通道反应器中的预加热器进行预热；(3)经预热的邻甲苯胺和混酸同时进入到微通道反应器中的反应通道进行反应,所述的反应时间为120～150s,反应温度为90～160℃；反应物流出反应通道,进入到反应产物收集容器中。流入到收集容器的反应物先冷却到60～90℃,再加入有机溶剂,搅拌均匀后,静置分层,上层为有机层,下层为无机层,分别输送至有机收集容器和无机收集容器中。采用本发明的技术方案,在微通道反应器中进行邻甲苯胺的硝化反应,可以使混酸再生,从而达到冰乙酸再利用的目的,减少对环境的污染。(The invention provides a method for nitrating o-toluidine by adopting a microchannel reactor, which comprises the following steps: (1) preparing acetic anhydride and glacial acetic acid into mixed acid; (2) respectively inputting o-toluidine and mixed acid into a preheater in a microchannel reactor through an advection pump for preheating; (3) the preheated o-toluidine and the mixed acid simultaneously enter a reaction channel in a microchannel reactor for reaction, the reaction time is 120-150 s, and the reaction temperature is 90-160 ℃; the reactants flow out of the reaction channel into a reaction product collection vessel. And cooling the reactant flowing into the collection container to 60-90 ℃, adding an organic solvent, uniformly stirring, standing for layering, wherein the upper layer is an organic layer, the lower layer is an inorganic layer, and conveying the reactant into the organic collection container and the inorganic collection container respectively. By adopting the technical scheme of the invention, the nitration reaction of the o-toluidine is carried out in the microchannel reactor, so that the mixed acid can be regenerated, the aim of recycling the glacial acetic acid is fulfilled, and the pollution to the environment is reduced.)

1. The method for nitrating the o-toluidine by adopting a microchannel reactor is characterized by comprising the following steps: the method comprises the following steps:

(1) preparing acetic anhydride and glacial acetic acid into mixed acid, wherein the mass ratio of the acetic anhydride to the glacial acetic acid in the mixed acid is 1: 3-5;

(2) respectively inputting o-toluidine and mixed acid into a preheater in a microchannel reactor through an advection pump for preheating, wherein the mass ratio of the o-toluidine to acetic anhydride in the mixed acid is 1: 2-2.5;

(3) the preheated o-toluidine and the mixed acid simultaneously enter a reaction channel in a microchannel reactor for reaction, the reaction time is 120-150 s, and the reaction temperature is 90-160 ℃; the reactant flows out of the reaction channel and enters a reaction product collecting container;

and cooling the reactant flowing into the collection container to 60-90 ℃, adding an organic solvent, uniformly stirring, standing for layering, wherein the upper layer is an organic layer, the lower layer is an inorganic layer, and conveying the reactant into the organic collection container and the inorganic collection container respectively.

2. The method for nitration of o-toluidine according to claim 1 using a microchannel reactor, wherein: the mass ratio of acetic anhydride to glacial acetic acid in the mixed acid in the step (1) is 1: 3.4-4.6.

3. The method for nitration of o-toluidine according to claim 1 using a microchannel reactor, wherein: the heat exchange medium adopted by the preheater in the step (2) is heat conduction oil.

4. The method for nitration of o-toluidine according to claim 3 wherein: the preheating temperature is 80-90 ℃.

5. The method for nitration of o-toluidine according to claim 1 using a microchannel reactor, wherein: in the step (3), the flow rate of o-toluidine is 1-2 mL/min; the flow rate of the mixed acid is 2-4 mL/min.

Technical Field

The invention belongs to the technical field of chemical intermediate preparation, and particularly relates to a method for nitrifying o-toluidine by adopting a microchannel reactor.

Background

The p-nitro-o-toluidine is mainly used as an ice dyeing dye, can also be used for synthesizing a pigment, and is also an important raw material of veterinary drug substance toltrazuril. The traditional synthesis method has the problems of complex equipment, low safety and large sewage treatment capacity, and particularly has large acid discharge amount in sewage. Continuous flow microreaction technology has gained general attention from the advent of its outstanding advantages of rapid mass and heat transfer rates, rapid reaction rates, continuous reaction, small equipment footprint, easy automation, and the like. Particularly, in recent years, the pursuit of intrinsic safety of chemical production, the research and development of the micro-reverse technology for dangerous processes such as nitration, hydrogenation, chlorination and the like are more important to manufacturers.

Disclosure of Invention

Aiming at the technical problems, the invention provides a method for nitrating o-toluidine by adopting a microchannel reactor, which reduces the amount of acetic anhydride and glacial acetic acid used and reduces the amount of acid as much as possible, thereby reducing the discharge and treatment of waste acid.

The purpose of the invention is realized by the following technical scheme:

the method for nitrating the o-toluidine by adopting the microchannel reactor comprises the following steps:

(1) preparing acetic anhydride and glacial acetic acid into mixed acid, wherein the mass ratio of the acetic anhydride to the glacial acetic acid in the mixed acid is 1: 3-5;

(2) respectively inputting o-toluidine and mixed acid into a preheater in a microchannel reactor through an advection pump for preheating, wherein the mass ratio of the o-toluidine to acetic anhydride in the mixed acid is 1: 2-2.5;

(3) the preheated o-toluidine and the mixed acid simultaneously enter a reaction channel in a microchannel reactor for reaction, the reaction time is 120-150 s, and the reaction temperature is 90-160 ℃; the reaction material flows out of the reaction channel and enters a reaction product collecting container, wherein the flow rate of o-toluidine is 1-2 mL/min; the flow rate of the mixed acid is 2-4 mL/min;

and cooling the reactant flowing into the collection container to 60-90 ℃, adding an organic solvent, uniformly stirring, standing for layering, wherein the upper layer is an organic layer, the lower layer is an inorganic layer, and conveying the reactant into the organic collection container and the inorganic collection container respectively.

The mass ratio of acetic anhydride to glacial acetic acid in the mixed acid is preferably 1: 3.4-4.6.

The heat exchange medium adopted by the preheater is heat conduction oil.

The preheating temperature is 80-90 ℃.

The invention has the beneficial effects that:

by adopting the technical scheme of the invention, the nitration reaction of the o-toluidine is carried out in the microchannel reactor, so that the mixed acid can be regenerated, the aim of recycling the glacial acetic acid is fulfilled, and the pollution to the environment is reduced.

Detailed Description

In order to more clearly illustrate the invention, the invention is further described below in connection with preferred embodiments. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and is not to be taken as limiting the scope of the invention.

Example 1

The method for nitrating the o-toluidine by adopting the microchannel reactor comprises the following steps:

(1) preparing acetic anhydride and glacial acetic acid into mixed acid, wherein the mass ratio of the acetic anhydride to the glacial acetic acid in the mixed acid is 1: 3.4;

(2) respectively inputting o-toluidine and mixed acid into a preheater in a microchannel reactor through an advection pump for preheating, wherein the mass ratio of the o-toluidine to acetic anhydride in the mixed acid is 1: 2.3; the heat exchange medium adopted by the preheater is heat conduction oil. The preheating temperature was 82 ℃.

(3) Simultaneously feeding the preheated o-toluidine and mixed acid into a reaction channel in a microchannel reactor for reaction, wherein the reaction time is 130s, and the reaction temperature is 150 ℃; the reactant flows out of the reaction channel and enters a reaction product collecting container, wherein the flow rate of o-toluidine is 1.3 mL/min; the flow rate of the mixed acid is 3.4 mL/min;

and cooling the reactant flowing into the collection container to 75 ℃, adding an organic solvent, uniformly stirring, standing for layering, wherein the upper layer is an organic layer, and the lower layer is an inorganic layer, and conveying the reactant into the organic collection container and the inorganic collection container respectively.

Example 2

The method for nitrating the o-toluidine by adopting the microchannel reactor comprises the following steps:

(1) preparing acetic anhydride and glacial acetic acid into mixed acid, wherein the mass ratio of the acetic anhydride to the glacial acetic acid in the mixed acid is 1: 4.5;

(2) respectively inputting o-toluidine and mixed acid into a preheater in a microchannel reactor through an advection pump for preheating, wherein the mass ratio of the o-toluidine to acetic anhydride in the mixed acid is 1: 2.4; the heat exchange medium adopted by the preheater is heat conduction oil. The preheating temperature is 90 ℃.

(3) Simultaneously feeding the preheated o-toluidine and mixed acid into a reaction channel in a microchannel reactor for reaction, wherein the reaction time is 150s, and the reaction temperature is 90 ℃; the reactant flows out of the reaction channel and enters a reaction product collecting container, wherein the flow rate of o-toluidine is 1.3 mL/min; the flow rate of the mixed acid is 3.7 mL/min;

and cooling the reactant flowing into the collection container to 65 ℃, adding an organic solvent, uniformly stirring, standing for layering, wherein the upper layer is an organic layer, and the lower layer is an inorganic layer, and conveying the reactant into the organic collection container and the inorganic collection container respectively.

Example 3

The method for nitrating the o-toluidine by adopting the microchannel reactor comprises the following steps:

(1) preparing acetic anhydride and glacial acetic acid into mixed acid, wherein the mass ratio of the acetic anhydride to the glacial acetic acid in the mixed acid is 1: 4.3;

(2) respectively inputting o-toluidine and mixed acid into a preheater in a microchannel reactor through an advection pump for preheating, wherein the mass ratio of the o-toluidine to acetic anhydride in the mixed acid is 1: 2.5; the heat exchange medium adopted by the preheater is heat conduction oil. The preheating temperature was 85 ℃.

(3) Simultaneously feeding the preheated o-toluidine and mixed acid into a reaction channel in a microchannel reactor for reaction, wherein the reaction time is 140s, and the reaction temperature is 120 ℃; the reactant flows out of the reaction channel and enters a reaction product collecting container, wherein the flow rate of o-toluidine is 2 mL/min; the flow rate of the mixed acid is 2 mL/min;

and cooling the reactant flowing into the collection container to 75 ℃, adding an organic solvent, uniformly stirring, standing for layering, wherein the upper layer is an organic layer, and the lower layer is an inorganic layer, and conveying the reactant into the organic collection container and the inorganic collection container respectively.

It should be understood that the detailed description of the present invention is only for illustrating the present invention and is not limited by the technical solutions described in the embodiments of the present invention, and those skilled in the art should understand that the present invention can be modified or substituted equally to achieve the same technical effects; as long as the use requirements are met, the method is within the protection scope of the invention.