阅读说明：本技术 一种新型的苯二胺连续生产方法 (Novel continuous production method of phenylenediamine ) 是由 李根荣 徐新连 于 2020-06-30 设计创作，主要内容包括：本发明涉及一种新型的苯二胺连续生产方法,包括硝化、氨解、还原、精馏等步骤。本发明减少了反应步骤,省去了中间体精制工序,从而简化了生产程序,降低了生产成本,大幅提高了工作效率,并减少了损耗,降低了精馏要求,使产品更容易分离,从而节约了能耗,最终以高收率获得高纯度的苯二胺产品。(The invention relates to a novel continuous production method of phenylenediamine, which comprises the steps of nitration, ammonolysis, reduction, rectification and the like. The invention reduces the reaction steps and omits the intermediate refining process, thereby simplifying the production procedure, reducing the production cost, greatly improving the working efficiency, reducing the loss, reducing the rectification requirement, leading the product to be easier to separate, saving the energy consumption and finally obtaining the high-purity phenylenediamine product with high yield.)

1. A continuous production method of phenylenediamine comprises the following steps:

(1) nitration;

(2) ammonolysis;

(3) reduction; and

(4) and (5) rectifying.

2. The process according to claim 1, wherein, in the step (1),

halogenobenzenes are used as starting material, preferably monohalogenobenzenes which may be fluorobenzene, chlorobenzene, bromobenzene, more preferably chlorobenzene, such as monochlorobenzene,

the nitrating agent is nitric acid or a mixed agent containing nitric acid, for example, a mixed acid of nitric acid with hydrochloric acid, sulfuric acid, phosphoric acid, preferably a mixed acid of nitric acid with sulfuric acid.

3. The production process according to claim 1, characterized in that in step (1), preferably an isothermal continuous nitration process is used, the molar ratio of chlorobenzene to nitric acid being between 1:1 and 1.20, and the nitration can be carried out at different temperatures, for example between 45 and 80 ℃, preferably between 50 and 75 ℃.

4. The process according to claim 1, wherein in step (1) nitrohalogenobenzenes or mixtures thereof are obtained after nitration, the unreacted starting materials being removed, preferably by distillation, and optionally recycled to the next nitration reaction.

5. The production process according to any one of claims 1 to 4, wherein in the step (2), mixed nitrohalogenobenzenes such as mixed nitrochlorobenzene are subjected to ammonolysis to produce mixed nitroanilides such as p-nitroaniline and o-nitroaniline using an aqueous ammonia concentration of 35 to 40% by mass and a mass ratio of the mixed nitrochlorobenzene to the aqueous ammonia of 1:2 to 5.

6. The production process according to claim 5, wherein in the step (2), after the ammonolysis reaction, the temperature is reduced, filtration is carried out, and then washing is carried out to obtain a nitroaniline mixture.

7. The process according to any one of claims 1 to 6, wherein in step (3), the nitroaniline mixture is reduced in an acidic medium in the presence of a catalyst, or reduced by hydrogenation, preferably under heating, to obtain a phenylenediamine mixture.

8. The production process according to claim 7, characterized in that, in step (3), the hydrogenation reduction, for example, is carried out in the presence of a hydrogenation catalyst, preferably raney nickel is used as the catalyst.

9. The production process according to claim 7 or 8, characterized in that, in the step (3), the hydrogenation reduction is carried out in the presence of a solvent selected from an alcohol solvent, an ether solvent, a ketone solvent or an ester solvent, preferably using an alcohol solvent such as methanol, ethanol, propanol or butanol.

10. Phenylenediamine produced by the production process according to one of claims 1 to 9.

Technical Field

The invention relates to a method for producing phenylenediamine, in particular to a novel method for continuously producing phenylenediamine, belonging to the field of fine chemical engineering.

Background

Aromatic diamines, in particular 1, 4-Phenylenediamine, p-Phenylenediamine and 1, 2-Phenylenediamine, o-Phenylenediamine, are intermediates having a wide range of applications. P-phenylenediamine (which has a melting point of about 140 ℃, such as a boiling point of about 267 ℃ in the range of 138 ℃ and 147 ℃) can be used for preparing azo dyes, high molecular polymers, and can also be used for producing fur dyeing agents, rubber anti-aging agents and photo developers. P-phenylenediamine is an extremely important dye intermediate, and is mainly used for aramid fiber, azo dyes, sulfur dyes and acid dyes. O-phenylenediamine (which has a melting point of about 103 deg.C, e.g., in the range of 102 deg.C and 104 deg.C, and a boiling point in the range of 252 deg.C and 258 deg.C, e.g., about 256 deg.C and 258 deg.C). The o-phenylenediamine is an intermediate of dyes, pesticides, auxiliaries, photosensitive materials and the like. It is itself the dye tare yellow brown M. The method is used for preparing polyamide, polyurethane, carbendazim, thiophanate, vat scarlet GG, leveling agent, anti-aging agent MB, and is also used for preparing developing agent, surfactant and the like.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a novel continuous production method of phenylenediamine, which comprises the steps of nitration, ammonolysis, reduction, post-treatment and the like. The invention reduces the reaction steps, omits the intermediate refining process, simplifies the production procedure, reduces the production cost, greatly improves the working efficiency, reduces the loss, reduces the rectification requirement, enables the product to be easier to separate, saves the energy consumption, and finally obtains the phenylenediamine product with high yield, thereby completing the invention.

The inventor continuously searches and repeatedly tries the original process, carries out a plurality of improvements and innovations, and provides a novel continuous production method of phenylenediamine, which comprises the steps of nitration, ammonolysis, reduction, rectification and the like.

In the nitration in the step (1), halogenobenzene is used as a raw material, preferably monohalogenated benzene, which can be fluorobenzene, chlorobenzene and bromobenzene, more preferably chlorobenzene, such as monochlorobenzene.

In step (1), the nitrating agent is nitric acid or a mixed reagent containing nitric acid, for example, a mixed acid of nitric acid and hydrochloric acid, sulfuric acid, phosphoric acid, preferably a mixed acid of nitric acid and sulfuric acid.

In the step (1), an isothermal continuous nitration method is preferably adopted, and the molar ratio of chlorobenzene to nitric acid is 1: 1-1.20. The nitration can be carried out at different temperatures, for example at from 45 to 80 ℃ and preferably from 50 to 75 ℃. Nitrohalogenobenzenes or mixtures thereof are obtained after nitration, the unreacted starting materials are removed, preferably by distillation, and optionally recycled for further nitration.

In the ammonolysis in step (2), mixed nitrohalobenzenes, such as mixed nitrochlorobenzene, are ammonolyzed to produce mixed nitroanilides, such as p-nitroaniline and o-nitroaniline. The mass concentration of the used ammonia water is 35-40%, and the mass ratio of the mixed nitrochlorobenzene to the ammonia water is 1: 2-5.

In the step (2), after the ammonolysis reaction, cooling, filtering and washing to obtain the nitroaniline mixture.

In the reduction reaction in the step (3), the nitroaniline mixture can be reduced in an acidic medium under the action of a catalyst, and can also be subjected to hydrogenation reduction, preferably under heating, so as to obtain the phenylenediamine mixture.

In step (3), the hydrogenation reduction, for example, is carried out in the presence of a hydrogenation catalyst, preferably raney nickel is used as the catalyst.

In the step (3), the hydrogenation reduction is carried out in the presence of a solvent selected from an alcohol solvent, an ether solvent, a ketone solvent or an ester solvent, preferably using an alcohol solvent such as methanol, ethanol, propanol or butanol.

In the rectification in the step (4), the mixture containing p-phenylenediamine and o-phenylenediamine is rectified.

By the above-described production process of the present invention, p-phenylenediamine and o-phenylenediamine, respectively, are obtained in higher purity and in higher yield

According to the invention, the reaction steps are reduced, and the intermediate refining process is omitted, so that the production process is simplified, the production cost is reduced, the working efficiency is greatly improved, the loss is reduced, the rectification requirement is reduced, the product is easier to separate, the energy consumption is saved, and the phenylenediamine product is obtained with high yield.

The present invention is described in detail below.

In the prior art, the prior art needs to separate one isomer in the process of crystallization after reduced pressure distillation, separate the other isomer by operations such as rectification crystallization and the like, then respectively carry out ammonolysis, and further respectively carry out steps such as filtration, drying, reduction and the like, thereby respectively obtaining different phenylenediamine isomers.

Therefore, the invention provides a novel continuous production method of phenylenediamine, which comprises the following steps:

and (1) nitration.

In the present invention, halogenobenzene is used as a raw material to prepare phenylenediamine, preferably monohalogenobenzene, which can be fluorobenzene, chlorobenzene, bromobenzene, more preferably chlorobenzene, such as monochlorobenzene.

The nitrating agent used in the present invention is one capable of making the halobenzene have a nitro group, and for this purpose, a common nitrating agent such as nitric acid or a mixed reagent containing nitric acid can be used, for example, a mixed acid of nitric acid and other strong acids, for example, a mixed acid of nitric acid and hydrochloric acid, sulfuric acid, phosphoric acid, preferably a mixed acid of nitric acid and sulfuric acid, wherein the nitric acid may be in slight excess, for example, the volume ratio of concentrated nitric acid to concentrated sulfuric acid is 1.1-1.5:1, preferably 1.2:1, and the concentrated sulfuric acid is added dropwise to the nitric acid during the preparation of the mixed acid.

According to the invention, the nitration is carried out by an isothermal continuous nitration process with said mixed acid para-halobenzenes, such as chlorobenzene, preferably in a molar ratio of chlorobenzene to nitric acid of 1:1 to 1.20, preferably 1:1.02 to 1.10, more preferably 1: 1.05.

In the present invention, the nitration reaction may be carried out in a nitration reactor, such as a nitration kettle, preferably, a plurality of nitration kettles, for example, 3, are used.

The nitration reaction of the present invention may be carried out at various temperatures, for example, at 45 to 80 ℃ and preferably at 50 to 75 ℃, and the temperature is preferably gradually increased in the continuously used nitration pots, for example, the reaction temperatures of the first to third nitration pots are 50 to 55 ℃, 60 to 65 ℃ and 70 to 75 ℃, respectively, and the reaction time is 30 to 60 minutes, preferably 40 minutes in each nitration pot.

After nitration, the nitrohalogenobenzenes or mixtures thereof are obtained, and the nitrated product is preferably subjected to the necessary work-up before further reaction, for example by distillation, to remove unreacted starting materials, which are optionally recycled to the next nitration reaction batch.

Drawings

FIG. 1 shows a hydrogen spectrum of o-phenylenediamine obtained in example 1;

FIG. 2 shows a carbon spectrum of o-phenylenediamine obtained in example 1;

FIG. 3 shows a hydrogen spectrum of p-phenylenediamine obtained in example 1;

FIG. 4 shows a carbon spectrum of p-phenylenediamine obtained in example 1.

Detailed Description

The invention is further explained or illustrated by the following examples. The examples provided should not be construed as limiting the scope of the invention.