阅读说明：本技术 2-氰基-4-硝基-6-溴苯胺重氮盐的合成方法 (Synthesis method of 2-cyano-4-nitro-6-bromoaniline diazonium salt ) 是由 冯彦博 唐智勇 李寒梅 徐斌 徐万福 陈晓栋 张宏伟 周贤宝 任星洋 于 2021-08-19 设计创作，主要内容包括：本发明涉及一种2-氰基-4-硝基-6-溴苯胺重氮盐的合成方法,包括以下步骤：(1)将2-氰基-4-硝基苯胺、硫酸和表面活性剂混合,得到混合液；(2)向步骤(1)得到的混合液中加入溴化试剂和氧化剂进行溴代反应,得到溴代混合物；(3)使步骤(2)得到的溴代混合物与重氮化试剂反应,得到2-氰基-4-硝基-6-溴苯胺重氮盐。本发明的合成方法溶剂用量少、能耗低、废水少且生产效率高,制得的2-氰基-4-硝基-6-溴苯胺重氮盐可用于分散蓝183：1等染料的合成。(The invention relates to a synthetic method of 2-cyano-4-nitro-6-bromoaniline diazonium salt, which comprises the following steps: (1) mixing 2-cyano-4-nitroaniline, sulfuric acid and a surfactant to obtain a mixed solution; (2) adding a brominating reagent and an oxidant into the mixed solution obtained in the step (1) to carry out bromination reaction to obtain a brominated mixture; (3) and (3) reacting the bromo mixture obtained in the step (2) with a diazotization reagent to obtain the 2-cyano-4-nitro-6-bromoaniline diazonium salt. The synthetic method has the advantages of less solvent consumption, low energy consumption, less wastewater and high production efficiency, and the prepared 2-cyano-4-nitro-6-bromoaniline diazonium salt can be used for dispersing blue 183: 1, and the like.)

1. The synthesis method of the 2-cyano-4-nitro-6-bromoaniline diazonium salt is characterized by comprising the following steps:

(1) mixing 2-cyano-4-nitroaniline, sulfuric acid and a surfactant to obtain a mixed solution;

(2) adding a brominating reagent and an oxidant into the mixed solution obtained in the step (1) to carry out bromination reaction to obtain a brominated mixture;

(3) and (3) reacting the bromo mixture obtained in the step (2) with a diazotization reagent to obtain the 2-cyano-4-nitro-6-bromoaniline diazonium salt.

2. The synthesis method according to claim 1, wherein the surfactant is a nonionic surfactant, preferably fatty alcohol polyoxyethylene ether or alkylphenol polyoxyethylene ether.

3. The synthesis method according to claim 1 or 2, wherein the surfactant is used in an amount of 0.1 to 1.0 wt% based on the 2-cyano-4-nitroaniline.

4. The synthesis method according to claim 1 or 2, wherein the content of the 2-cyano-4-nitroaniline in the mixed solution is 20 to 40 wt% based on the weight of the mixed solution.

5. The synthesis method according to claim 1 or 2, wherein the concentration of the sulfuric acid is 50-80%.

6. The synthesis method according to claim 1 or 2, characterized in that the brominating reagent is one or more selected from the group consisting of liquid bromine, hydrobromic acid, bromides of alkali metals, bromides of alkaline earth metals and ammonium bromide, preferably liquid bromine; the molar ratio of bromine element to 2-cyano-4-nitroaniline in the brominating reagent is (2.00-2.20): 1; the temperature of the bromination reaction is 20-40 ℃.

7. A synthesis process according to claim 1 or 2, characterized in that the oxidant is one or more selected from hypochlorous acid, chloric acid, hypochlorite, chlorate, sulfur trioxide, chlorine dioxide or hydrogen peroxide, preferably hydrogen peroxide; the molar ratio of the oxidant to the brominating agent is (0.95-2.10): 1.

8. A synthetic process according to claim 1 or 2, wherein the diazotising agent is selected from one or more of nitrosylsulfuric acid and nitrite, preferably nitrosylsulfuric acid; the temperature of the diazotization reaction is 0-10 ℃; the molar ratio of the diazotization reagent to the 2-cyano-4-nitroaniline is (1.00-1.06): 1.

9. An apparatus for carrying out the synthesis method of any one of claims 1 to 8, comprising, in order, a mixing unit, a bromination unit and a diazotization unit; wherein

The mixing unit is configured to mix 2-cyano-4-nitroaniline, sulfuric acid and a surfactant to obtain a mixed solution;

the bromination unit is configured to perform bromination reaction on the mixed solution, a bromination reagent and an oxidant to obtain a bromination mixture;

the diazotization unit is configured for subjecting the brominated mixture to a diazotization reaction with a diazotization reagent.

10. The apparatus according to claim 9, wherein the mixing unit and the bromination unit are equipped with spoilers inside the pipes.

Technical Field

The invention belongs to the field of organic synthesis, and particularly relates to a method for synthesizing 2-cyano-4-nitro-6-bromoaniline diazonium salt.

Background

2-cyano-4-nitro-6-bromoaniline is a synthetic azo disperse dye, such as disperse blue 183: 1, which is also an intermediate for the synthesis of heterocyclic compounds. Methods for the synthesis of 2-cyano-4-nitro-6-bromoaniline by bromination of 2-cyano-4-nitroaniline are known in the prior art.

Citation 1 discloses a method for brominating 2-cyano-4-nitroaniline with bromine using dilute hydrochloric acid as a solvent, in which Br "is oxidized by adding sodium hypochlorite, thereby improving the bromine utilization efficiency.

Citation 2 discloses a method for synthesizing 2-cyano-4-nitro-6-bromoaniline by brominating 2-cyano-4-nitroaniline with sulfuric acid as a solvent using hydrogen bromide and an oxidizing agent.

Citation 3 discloses a method for synthesizing 2-cyano-4-nitro-6-bromoaniline diazonium salt, which comprises the steps of brominating o-cyano-p-nitroaniline by using sulfuric acid as a solvent and a bromine compound and an oxidant, and directly reacting with a diazotization reagent after bromination.

Cited document 1: CN 1314343A;

cited document 2: CN 104341319A;

cited document 3: CN 101671272A.

Disclosure of Invention

Problems to be solved by the invention

The method in the cited document 1 uses dilute hydrochloric acid as a solvent, and the dried product of 2-cyano-4-nitro-6-bromoaniline is obtained by filtering and drying after bromination, so that the waste water amount is large and the method is not environment-friendly.

In the above-cited references 2 and 3 in which sulfuric acid is used as a solvent, there is a problem that the solubility of the material in sulfuric acid is poor, resulting in the slurry being heterogeneous and further causing fluctuations in continuous metering. In addition, the bromo-finished product is sticky, so that the reaction liquid generates sticky caking in the later reaction stage, the mass transfer efficiency of a reaction system is influenced, the consumption of sulfuric acid is increased, and the wastewater treatment cost is increased.

In addition, the methods of the above cited documents 1 to 3 are all batch processes.

Means for solving the problems

In view of the problems in the prior art, the inventors of the present invention found that, in the process of process exploration, the addition of a surfactant to a reaction system can improve the dissolution and dispersion of 2-cyano-4-nitroaniline in sulfuric acid and can also improve the rate of bromination reaction, thereby completing the present invention.

Specifically, the present invention solves the technical problems of the present invention by the following technical solutions.

[1] The synthesis method of the 2-cyano-4-nitro-6-bromoaniline diazonium salt is characterized by comprising the following steps:

(1) mixing 2-cyano-4-nitroaniline, sulfuric acid and a surfactant to obtain a mixed solution;

(2) adding a brominating reagent and an oxidant into the mixed solution obtained in the step (1) to carry out bromination reaction to obtain a brominated mixture;

(3) and (3) reacting the bromo mixture obtained in the step (2) with a diazotization reagent to obtain the 2-cyano-4-nitro-6-bromoaniline diazonium salt.

[2] The synthesis method according to [1], characterized in that the surfactant is a nonionic surfactant, preferably fatty alcohol-polyoxyethylene ether or alkylphenol ethoxylates.

[3] The synthesis method according to [1] or [2], wherein the amount of the surfactant is 0.1 to 1.0 wt% of the 2-cyano-4-nitroaniline.

[4] The method according to item [1] or [2], wherein the content of 2-cyano-4-nitroaniline in the mixed solution is 20 to 40 wt% based on the total weight of the mixed solution.

[5] The method according to [1] or [2], wherein the concentration of the sulfuric acid is 50 to 80%.

[6] The synthesis method according to [1] or [2], characterized in that the brominating reagent is one or more selected from liquid bromine, hydrobromic acid, bromides of alkali metals, bromides of alkaline earth metals and ammonium bromide, preferably liquid bromine; the molar ratio of bromine element to 2-cyano-4-nitroaniline in the brominating reagent is (2.00-2.20): 1; the temperature of the bromination reaction is 20-40 ℃.

[7] The synthesis method according to [1] or [2], wherein the oxidant is one or more selected from hypochlorous acid, chloric acid, hypochlorite, chlorate, sulfur trioxide, chlorine dioxide or hydrogen peroxide, preferably hydrogen peroxide; the molar ratio of the oxidant to the brominating agent is (0.95-2.10): 1.

[8] The synthetic method according to [1] or [2], characterized in that the diazotizing agent is selected from one or more of nitrosylsulfuric acid and nitrite, preferably nitrosylsulfuric acid; the temperature of the diazotization reaction is 0-10 ℃; the molar ratio of the diazotization reagent to the 2-cyano-4-nitroaniline is (1.00-1.06): 1.

[9] An apparatus for carrying out the synthesis method according to any one of [1] to [8], which comprises a mixing unit, a bromination unit and a diazotization unit in this order; wherein

The mixing unit is configured to mix 2-cyano-4-nitroaniline, sulfuric acid and a surfactant to obtain a mixed solution;

the bromination unit is configured to perform bromination reaction on the mixed solution, a bromination reagent and an oxidant to obtain a bromination mixture;

the diazotization unit is configured for subjecting the brominated mixture to a diazotization reaction with a diazotization reagent.

[10] The apparatus according to [9], wherein the mixing unit and the bromination unit are equipped with spoilers inside the pipes.

ADVANTAGEOUS EFFECTS OF INVENTION

The invention provides a method for synthesizing 2-cyano-4-nitro-6-bromoaniline overlapped salt, which has the advantages of less solvent consumption, low energy consumption, less wastewater and high production efficiency.

The invention also provides a simple, low-cost apparatus for carrying out the synthesis method of the invention.

Drawings

FIG. 1 is a schematic flow diagram of the synthetic method of the present invention.

Detailed Description

< terms and definitions >

In the present specification, the numerical range represented by "numerical value a to numerical value B" means a range including the end point numerical value A, B.

In the present specification, the numerical ranges indicated by "above" or "below" mean the numerical ranges including the numbers.

In the present specification, the meaning of "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

As used herein, the use of "optionally" or "optional" means that certain materials, components, performance steps, application conditions, and the like are used or not used.

In the present specification, the unit names used are all international standard unit names, and the "%" used means weight or mass% content, if not specifically stated.

Reference throughout this specification to "a preferred embodiment," "an embodiment," and so forth, means that a particular element (e.g., feature, structure, property, and/or characteristic) described in connection with the embodiment is included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various embodiments.

< method >

One purpose of the invention is to provide a synthetic method of 2-cyano-4-nitro-6-bromoaniline diazonium salt, which is characterized by comprising the following steps:

(1) mixing 2-cyano-4-nitroaniline, sulfuric acid and a surfactant to obtain a mixed solution;

(2) adding a brominating reagent and an oxidant into the mixed solution obtained in the step (1) to carry out bromination reaction to obtain a brominated mixture;

(3) and (3) reacting the bromo mixture obtained in the step (2) with a diazotization reagent to obtain the 2-cyano-4-nitro-6-bromoaniline diazonium salt.

The respective steps of the synthesis method of the present invention will be described in detail below.

Step (1)

The mixing in step (1) can be carried out with stirring and optionally circulation, for example by means of beating, as is customary in industry. The mixing temperature is 20-40 ℃, too high temperature can cause the hydrolysis of cyano, and too low temperature is not beneficial to the dissolution and dispersion of the 2-cyano-4-nitroaniline. Circulation can help better dispersion of suspended materials, prevent the materials from settling, increase material uniformity and reduce blocking risk

The surfactant used in step (1) may be one or any combination of cationic, anionic and nonionic surfactants. Examples of cationic surfactants include, but are not limited to, N-dimethyloctadecyl amine hydrochloride, octadecyl amine hydrochloride, dioctadecyl amine hydrochloride, dodecyltrimethyl ammonium bromide, octadecyltrimethyl ammonium chloride, hexadecyltrimethyl ammonium chloride, and like amine salts. Examples of anionic surfactants include, but are not limited to, sodium lauryl sulfate, sodium lauryl alcohol polyoxyethylene ether sulfate, sodium lauryl sulfate, secondary alkyl sodium sulfonate, ammonium lauryl sulfate, sodium fatty alcohol isethionate, dodecylbenzene sulfonic acid, sodium dodecylbenzene sulfonate and like sulfonates, phosphate ester salts such as lauryl phosphate triethanolamine, lauryl phosphate, potassium lauryl phosphate and like phosphate ester salts. The nonionic surfactant may be fatty alcohol polyoxyethylene ether or alkylphenol polyoxyethylene ether, and examples thereof include, but are not limited to, octylphenol polyoxyethylene ether, nonylphenol polyoxyethylene ether, dodecylphenol polyoxyethylene ether, hydroxy-synthetic alcohol polyoxyethylene ether, and the like.

Among the surfactants enumerated above, nonionic surfactants are preferred, and AEO-3, AEO-9, TX-10 and peregal are more preferred, and AEO-3 is most preferred.

The dosage of the surfactant in the step (1) is 0.1-1.0 wt% of the 2-cyano-4-nitroaniline, and preferably 0.3-0.6 wt%.

The method of the invention utilizes the surface modification effect of the surfactant, greatly improves the dispersibility of the 2-cyano-4-nitroaniline in the sulfuric acid, reduces the settling velocity of the solid 2-cyano-4-nitroaniline in the sulfuric acid phase, and enables the 2-cyano-4-nitroaniline to exist in the sulfuric acid in a suspension state, thereby realizing the metering continuous conveying. In addition, the surfactant can reduce the surface repulsion of the brominated product molecules and slow down the increase of the viscosity of the system in the later reaction period, thereby reducing the required amount of sulfuric acid. Finally, the introduction of the surfactant improves the solubility of the 2-cyano-4-nitroaniline, so that the bromination reaction rate is improved.

The surfactant can reduce the dosage of the sulfuric acid, so that the content of the 2-cyano-4-nitroaniline in the mixed solution in the step (1) can be 20-40 wt%, preferably 27.5-32.5 wt%, based on the weight of the mixed solution. The lower content of 2-cyano-4-nitroaniline leads to the increase of the consumption of brominating agent and oxidizing agent, and the increase of the consumption of sulfuric acid, while the higher content thereof leads to the decrease of the dispersibility of raw materials, the increase of the viscosity of the system, the influence on the reaction speed and the disadvantage of continuous metering.

The concentration of the sulfuric acid used in the step (1) is 50-80%, and preferably 55-65%. The acid value of the sulfuric acid is too low, nitrosyl sulfuric acid can be decomposed in the diazotization process, and the bromination reaction rate is influenced when the acid value of the sulfuric acid is too high.

Step (2)

And (3) carrying out bromination reaction on the 2-cyano-4-nitroaniline in the step (2) to generate 2-cyano-4-nitro-6-bromoaniline, wherein the reaction temperature is 20-40 ℃, and the bromination retention time is 2-8 hours.

The brominating reagent used in the step (2) is one or more selected from the group consisting of liquid bromine, hydrobromic acid, alkali metal bromides, alkaline earth metal bromides and ammonium bromide. Wherein the bromide of alkali metal can be sodium bromide and potassium bromide, and the bromide of alkaline earth metal can be calcium bromide and magnesium bromide. Among the above-listed brominating reagents, liquid bromine is preferred. Liquid bromine is used as a brominating reagent, so that the introduction of metal ions into a reaction system can be avoided, and the difficulty of wastewater treatment is reduced.

In the step (2), the molar ratio of the bromine element serving as a brominating reagent to the 2-cyano-4-nitroaniline is (2.00-2.20): 1, preferably (2.06-2.14): 1. Too little use of the brominating agent may result in insufficient reaction conversion rate, and too much use of the brominating agent may result in too high hydrogen bromide content in the brominating mixture, thereby increasing the cost of wastewater treatment.

The oxidant used in step (2) is one or more selected from hypochlorous acid, chloric acid, hypochlorite, chlorate, sulfur trioxide, chlorine dioxide or hydrogen peroxide, and hydrogen peroxide is preferred. The molar ratio of the oxidant to the brominating agent is (0.95-1.05): 1, and preferably (0.98-1.02): 1.

In one embodiment, the bromination reaction of step (2) is carried out in a plurality of stages, and the oxidizing agent is added to the reaction system in respective stages in corresponding portions. For example, the bromination reaction may be carried out in 1 to 4 stages, preferably in 2 to 3 stages. The proportion of the oxidant added in each stage is 0.6-0.8: 0.3-0.15: 0.05-0.1. The time of each reaction stage is 1 to 4 hours, preferably 2 to 3 hours, too short a time results in a lower conversion of the reaction and too long a time increases the risk of hydrolysis of the cyano group. As a way of implementing this embodiment, the bromination reaction may be carried out, for example, in a multistage reactor.

Step (3)

The step (3) is a step of carrying out diazotization reaction of 2-cyano-4-nitro-6-bromoaniline. And (3) directly taking the bromo mixture obtained in the step (2) as a reaction starting material, and carrying out diazotization reaction on the 2-cyano-4-nitro-6-bromoaniline and a diazotization reagent to generate the 2-cyano-4-nitro-6-bromoaniline diazonium salt. By the method, the steps of filtering, washing and drying after bromination are reduced, so that the energy consumption is reduced, the waste water is reduced, and the production efficiency is improved.

The temperature of the diazotization reaction in the step (3) is 0-10 ℃, and the reaction time is 2-6 hours.

The diazotising agent may be one or more selected from nitrosylsulfuric acid and nitrite salts, preferably nitrosylsulfuric acid, more preferably in a concentration of greater than 28 wt%. Nitrosyl sulfuric acid is used as a diazotization reagent, so that metal ions can be prevented from being introduced into a reaction system, and the difficulty of post-treatment is reduced.

The molar ratio of the diazotizing agent to the 2-cyano-4-nitroaniline is (1.00-1.06): 1, preferably (1.02-1.04): 1.

The 2-cyano-4-nitro-6-bromoaniline diazonium salt obtained by the synthesis method can be used for synthesizing various dyes through subsequent coupling reaction. The synthetic method of the invention has less surfactant consumption, and can be used as a dispersing reagent in the subsequent coupling reaction process, so that the surfactant is not required to be removed by an additional purification step, and the process flow is simple.

In a preferred embodiment, the synthesis method of the invention is a continuous synthesis method of 2-cyano-4-nitro-6-bromoaniline diazonium salt. Specifically, in the step (1), 2-cyano-4-nitroaniline, sulfuric acid and a surfactant are continuously added into a mixing container, and the obtained mixed solution is continuously transferred into a bromination reactor; in the step (2), continuously adding a bromination reagent and an oxidant into the mixed solution obtained in the step (1) to perform bromination reaction, and continuously transferring the obtained bromo mixture into a diazotization reactor; in step (3), the bromo mixture obtained in step (2) is continuously reacted with a diazotizing agent to obtain 2-cyano-4-nitro-6-bromoaniline diazonium salt which is continuously withdrawn from the diazotization reactor. Wherein the bromination reaction of step (2) may be carried out in a plurality of stages in series as described above.

< apparatus >

It is another object of the present invention to provide an apparatus for carrying out the synthetic method of the present invention, comprising, in order, a mixing unit, a bromination unit and a diazotization unit; wherein

The mixing unit is configured to mix 2-cyano-4-nitroaniline, sulfuric acid and a surfactant to obtain a mixed solution;

the bromination unit is configured to perform bromination reaction on the mixed solution, a bromination reagent and an oxidant to obtain a bromination mixture;

the diazotization unit is configured for subjecting the brominated mixture to a diazotization reaction with a diazotization reagent.

The mixing unit comprises a mixing vessel, such as a beater, equipped with stirring means, a material inlet and a material outlet.

The bromination unit comprises a bromination reactor, and the bromination reactor can be a kettle reactor, a tubular reactor or a tower reactor. The bromination reactor is preferably a multistage reactor or a plurality of reactors in series, wherein each reactor is optionally equipped with a recycling device for recycling the contents of the reactor to a location upstream of the reactor. The individual reactors are also preferably equipped with stirring devices.

In the device, spoilers are arranged inside the pipelines of the mixing unit and the bromination unit and are used for enhancing the mixing of materials and keeping the system in a suspension state. The baffles are arranged in the container with the solid-liquid state material and the pipeline, so that the material moves in a turbulent manner in the pipeline, the solid material in the material is prevented from settling, and the material is dispersed more uniformly.

The diazotization unit comprises a diazotization reactor, and the diazotization reactor is not particularly limited in the present invention, and may be any reactor known in the art suitable for diazotization.

Examples

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The following examples are conducted under conditions not specified, usually according to conventional conditions, or according to conditions recommended by the manufacturer.

It should be noted that: since the diazonium salt after diazotization cannot be subjected to direct purity analysis, the coupling reaction proceeds to produce disperse blue 183 in the following example: 1 filter cake, by dispersing blue 183: 1 mass of filter cake to illustrate the process feasibility of the synthesis method of the present invention.

Example 1

Adding 2-cyano-4-nitroaniline, 55% sulfuric acid and AEO-3 into a pulping kettle, wherein the 2-cyano-4-nitroaniline is fed by using a packing auger feeder at a feeding speed of 35kg/h, the feeding mass of the 55% sulfuric acid is 72.7kg/h, the dropping speed of the AEO-3 is 105g/h, and the retention time of the pulping kettle is 0.5 hour. Feeding the obtained pulping material and bromine into a circulating pipeline of a 1-stage reaction kettle together, wherein the feeding speed of the bromine is 35.4kg/h, the 1-stage circulating pipeline is provided with a bypass to allow part of the material to enter a 2-stage reactor, the 2-stage reactor performs circulating discharging in the same way, hydrogen peroxide (the content is 27.5 wt%) is added into the circulating pipeline of the 1-3-stage reaction kettle, the feeding speeds of the 1-3-stage reactor are 18.5kg/h, 6.5kg/h and 2.9kg/h, the temperature of each stage of reactor is controlled to be 30-35 ℃, and the retention time of each stage of reactor is 1.5 hours. The material discharged from the 3-stage reactor is fed into a diazotization reaction kettle, nitrosyl sulfuric acid (with the content of 28.0 wt%) is added into the diazotization reaction kettle, the feeding speed of the nitrosyl sulfuric acid is 99.35kg/h, the temperature in the diazotization process is controlled to be 2-6 ℃, and the retention time of the diazotization reaction kettle is 8 hours. The obtained 2-cyano-4-nitro-6-bromaniline diazonium salt. The sampling detection result of the 3-grade bromination reactor is that the purity of the 2-cyano-4-nitro-6-bromoaniline medium control sample is 97.82 percent.

And (2) the obtained 2-cyano-4-nitro-6-bromoaniline diazonium salt and an intermediate pulping liquid (the content of sulfuric acid is 5%, the content of N, N-diethyl-m-acetamino aniline is 10%, the content of sulfamic acid is 0.2%, and the content of peregal is 0.02%) are fed into a coupling reaction kettle at a feeding speed of 453kg/h, the temperature of the coupling reaction kettle is controlled to be 0-5 ℃, the retention time is 3 hours, the mixture overflows to a subsequent 2-stage crystal conversion kettle, the gradient temperature rise is carried out at 60 ℃, the temperature reduction is not needed, and a product is filtered, washed and dried to obtain disperse blue 183: 1 filter cake, disperse blue 183: the purity of 1 is 93.4 percent, and the product yield is 93.22 percent.

Example 2

Adding 2-cyano-4-nitroaniline, 55% sulfuric acid and AEO-3 into a pulping kettle, wherein the 2-cyano-4-nitroaniline is fed by using an auger feeder at a feeding speed of 35kg/h and a 65% sulfuric acid feeding speed of 92.3kg/h, the AEO-3 dropping speed of 110g/h, and the retention time of the pulping kettle is 0.5 hour. Feeding the obtained pulping material and bromine into a circulating pipeline of a 1-stage reaction kettle together, wherein the feeding speed of the bromine is 36.8kg/h, the 1-stage circulating pipeline is provided with a bypass to allow part of the material to enter a 2-stage reactor, the 2-stage reactor performs circulating discharging in the same way, hydrogen peroxide (the content is 27.5 wt%) is added into the circulating pipeline of the 1-3-stage reaction kettle, the feeding speeds of the 1-3-stage reactor are 18.5kg/h, 6.0kg/h and 3.3kg/h, the temperature of each stage of reactor is controlled to be 30-35 ℃, and the retention time of each stage of reactor is 2.5 hours. The material discharged from the 3-stage reactor is fed into a diazotization reaction kettle, nitrosyl sulfuric acid (with the content of 28.0 wt%) is added into the diazotization reaction kettle, the feeding speed of the nitrosyl sulfuric acid is 99.35kg/h, the temperature in the diazotization process is controlled to be 2-6 ℃, and the retention time of the diazotization reaction kettle is 4 hours. The obtained 2-cyano-4-nitro-6-bromaniline diazonium salt. Wherein the sampling detection result of the 3-grade bromination reactor is that the purity of the 2-cyano-4-nitro-6-bromoaniline medium control sample is 97.83 percent,

and (2) allowing the obtained 2-cyano-4-nitro-6-bromoaniline diazonium salt and an intermediate slurrying liquid (the sulfuric acid content is 5%, the N, N-diethyl-m-acetamino aniline content is 10%, the sulfamic acid content is 0.2%, and the peregal content is 0.02%) to enter a coupling reaction kettle at a feeding speed of 453kg/h, controlling the temperature of the coupling reaction kettle at 0-5 ℃, allowing the temperature to stay for 3 hours, overflowing to a subsequent 2-stage crystal conversion kettle, performing gradient temperature rise at 60 ℃, and not cooling, and filtering, washing and drying a product to obtain disperse blue 183: 1 filter cake. Disperse blue 183: the purity of 1 is 93.6 percent, and the product yield is 93.34 percent.

Example 3

Adding 2-cyano-4-nitroaniline, 55% sulfuric acid and AEO-3 into a pulping kettle, wherein the 2-cyano-4-nitroaniline is fed by using a packing auger feeder at a feeding speed of 35kg/h, a 65% sulfuric acid feeding speed of 81.7kg/h and an AEO-3 dropping speed of 105g/h, and the retention time of the pulping kettle is 0.5 hour. Feeding the obtained pulping material and bromine into a circulating pipeline of a 1-stage reaction kettle together, wherein the feeding speed of the bromine is 36.1kg/h, the 1-stage circulating pipeline is provided with a bypass to allow part of the material to enter a 2-stage reactor, the 2-stage reaction adopts the same way to circularly discharge, hydrogen peroxide (the content is 27.5 wt%) is added into the circulating pipeline of the 1-3-stage reaction kettle, the feeding speeds of the 1-3-stage reactor are 18.5kg/h, 6.2kg/h and 3.0kg/h, the temperature of each stage of reactor is controlled to be 30-35 ℃, and the retention time of each stage of reactor is 2.5 hours. The material discharged from the 3-stage reactor is fed into a diazotization reaction kettle, nitrosyl sulfuric acid (with the content of 28.0 wt%) is added into the diazotization reaction kettle, the feeding speed of the nitrosyl sulfuric acid is 99.35kg/h, the temperature in the diazotization process is controlled to be 2-6 ℃, and the retention time of the diazotization reaction kettle is 4 hours. The obtained 2-cyano-4-nitro-6-bromaniline diazonium salt. Wherein the sampling detection result of the 3-grade bromination reactor is that the purity of the 2-cyano-4-nitro-6-bromoaniline medium control sample is 97.87 percent,

the obtained 2-cyano-4-nitro-6-bromoaniline diazonium salt and an intermediate pulping liquid (the content of sulfuric acid is 5%, the content of N, N-diethyl-m-acetamino aniline is 10%, the content of sulfamic acid is 0.2%, and the content of peregal is 0.02%) enter a coupling reaction kettle at a feeding speed of 453kg/h, the temperature of the coupling reaction kettle is controlled to be 0-5 ℃, the retention time is 3 hours, the product overflows to a subsequent 2-stage crystal conversion kettle, the gradient temperature rise is carried out at 60 ℃, the temperature reduction is not needed, and the product is filtered, washed and dried to obtain disperse blue 183: 1 filter cake. Disperse blue 183: the purity of 1 is 93.9 percent, and the product yield is 93.51 percent.

Comparative example 1

8t of 60% sulfuric acid is added into an enamel reaction kettle of 10000L, 500kg of 2-cyano-4-nitroaniline is added, the temperature is controlled to be 35-40 ℃, 525kg of bromine is slowly added after 4 hours, the temperature is kept for 2 hours, 405kg of hydrogen peroxide (27.5 wt%) is dropwise added, and the dropwise addition is finished after 6 hours. The temperature was maintained for 4 hours. Cooling to below 3 ℃, dripping 1420kg of nitrosyl sulfuric acid, keeping the temperature for 4 hours after dripping is finished, and preparing the diazo liquid for subsequent coupling. 6500kg of 5% sulfuric acid, 50kg of sulfamic acid and 5kg of peregal are put into a coupling kettle, 650kg of N, N-diethyl-m-acetaminophenylamine is then put into the coupling kettle for pulping for 2 hours, the temperature is reduced to 0 ℃, prepared diazo liquid is dripped in the coupling kettle, after 1 hour dripping is finished, the temperature is increased to 60 ℃ for crystal transformation after 3 hours of heat preservation, and then the coupling kettle is filtered, washed and dried to obtain disperse blue 183: 1 filter cake. Disperse blue 183: the purity of 1 is 90.8%, and the yield is 91.2%.

Comparative example 2

6.5t of 60% sulfuric acid is added into an enamel reaction kettle of 10000L, 500kg of 2-cyano-4-nitroaniline is added, the temperature is controlled to be 35-40 ℃, 525kg of bromine is slowly added, the addition is finished within 4 hours, the temperature is kept for 2 hours, 405kg of hydrogen peroxide (27.5 wt%) is dropwise added, after the dropwise addition is finished within 6 hours, the material is viscous when the temperature is kept for 2 hours, and the stirring current is over-large, and the motor is automatically stopped and protected. 3t of 60% sulfuric acid is added, nitrogen pipelines are used for bottom insertion mixing, and stirring is started again. Cooling to below 3 ℃, dripping 1420kg of nitrosyl sulfuric acid, keeping the temperature for 4 hours after dripping is finished, and preparing the diazo liquid for subsequent coupling. 6500kg of 5% sulfuric acid, 50kg of sulfamic acid and 5kg of peregal are put into a coupling kettle, 650kg of N, N-diethyl-m-acetaminophenylamine is then put into the coupling kettle for pulping for 2 hours, the temperature is reduced to 0 ℃, prepared diazo liquid is dripped in the coupling kettle, after 1 hour dripping is finished, the temperature is increased to 60 ℃ for crystal transformation after 3 hours of heat preservation, and then the coupling kettle is filtered, washed and dried to obtain disperse blue 183: 1 filter cake. Disperse blue 183: the purity of 1 is 89.8 percent, and the yield is 90.1 percent.

Comparative example 3

The preparation method comprises the steps of adding 5.5t of 60% sulfuric acid into a 10000L enamel reaction kettle, adding 8kg of AEO-3 and 500kg of 2-cyano-4-nitroaniline, controlling the temperature to be 35-40 ℃, slowly adding 525kg of bromine for 4 hours, preserving the temperature for 2 hours, dropwise adding 405kg of hydrogen peroxide (27.5 wt%), and completing dropwise adding for 6 hours. The temperature was maintained for 4 hours. Cooling to below 3 ℃, dripping 1420kg of nitrosyl sulfuric acid, keeping the temperature for 4 hours after dripping is finished, and preparing the diazo liquid for subsequent coupling. 6500kg of 5% sulfuric acid, 50kg of sulfamic acid and 5kg of peregal are put into a coupling kettle, 650kg of N, N-diethyl-m-acetaminophenylamine is then put into the coupling kettle for pulping for 2 hours, the temperature is reduced to 0 ℃, prepared diazo liquid is dripped in the coupling kettle, after 1 hour dripping is finished, the temperature is increased to 60 ℃ for crystal transformation after 3 hours of heat preservation, and then the coupling kettle is filtered, washed and dried to obtain disperse blue 183: 1 filter cake. Disperse blue 183: the purity of 1 was 91.2%, and the yield was 91.6%.

As can be seen from the comparison between examples 1-3 and comparative examples 1-3, the method of the present invention can reduce the amount of sulfuric acid used and significantly improve the purity and yield of the product.

Industrial applicability

The synthesis method and the device can be widely used for industrially synthesizing 2-cyano-4-nitro-6-bromoaniline diazonium salt and further used for dispersing blue 183: 1, and the like.