阅读说明：本技术 一种对硝基苯胺管道反应合成方法 (Pipeline reaction synthesis method of p-nitroaniline ) 是由 徐德伟 于 2018-09-10 设计创作，主要内容包括：本发明涉及化工技术领域,尤其为一种对硝基苯胺管道反应合成方法,包括首先将氯化苯与混酸进行硝化反应,得到含有：对硝基氯化苯63%、邻硝基氣化苯35%、问硝基氯化苯1%、二硝基氯化苯1%的混合物；将上述混合物放入磨粉机中,磨成粒径为1000目的粉末状对硝基氯化苯,放入反应釜中,在反应釜底部安装振动电机,对反应釜进行振动,同时通过压缩机外接管道向反应釜中不断加入冷气,本发明对传统的釜式反应进行改进,采用管式反应连续用料,出料,压力可以稳定,易控制,没有爆炸风险,压力稳定,产量大,管式反应成本低,产品质量稳定,安全,并且在后续增加氨水回收工艺,能够有效的将过量氨水进行回收再利用,大大增加了成本。(The invention relates to the technical field of chemical industry, in particular to a method for synthesizing p-nitroaniline by pipeline reaction, which comprises the following steps of firstly carrying out nitration reaction on chlorobenzene and mixed acid to obtain a product containing: a mixture of 63% of p-nitrochlorobenzene, 35% of o-nitrobenzoquinone, 1% of m-nitrochlorobenzene and 1% of dinitrochlorobenzene; the method comprises the steps of putting the mixture into a pulverizer, grinding the mixture into powdery p-nitrochlorobenzene with the particle size of 1000 meshes, putting the powdery p-nitrochlorobenzene into a reaction kettle, installing a vibrating motor at the bottom of the reaction kettle, vibrating the reaction kettle, and continuously adding cold air into the reaction kettle through an external pipeline of a compressor.)

1. A method for synthesizing p-nitroaniline by pipeline reaction is characterized by comprising the following steps: the method comprises the following steps:

step 1: firstly, benzene chloride and mixed acid are subjected to nitration reaction to obtain a product containing: a mixture of 63% of p-nitrochlorobenzene, 35% of o-nitrobenzoquinone, 1% of m-nitrochlorobenzene and 1% of dinitrochlorobenzene;

step 2: putting the mixture into a pulverizer, grinding the mixture into powdery p-nitrochlorobenzene with the particle size of 1000 meshes, putting the powdery p-nitrochlorobenzene into a reaction kettle, installing a vibration motor at the bottom of the reaction kettle, vibrating the reaction kettle, continuously adding cold air into the reaction kettle through an external pipeline of a compressor, controlling the temperature in the reaction kettle to be 5-10 ℃, controlling the pressure to be 1MPa, and keeping the temperature for 5-10 min;

and step 3: adding ammonia water with the concentration of 39-41% into the powder subjected to full temperature reduction in the step 2, quickly adding the ammonia water into a pipeline type reactor by using a feeding pump, and keeping the pressure of 6-6.9 MPa and the temperature of 180-190 ℃;

and 4, step 4: continuously repeating the steps 1-3 to continuously feed the pipeline reactor, continuously discharging the material by using a constant pressure valve, putting the discharged material into a cooling kettle to be cooled to below 20 ℃, and releasing pressure to recover the gaseous ammonia for recycling;

and 5: 1.2-1.5 wt% of melt-index modifier, 1.5-1.8 wt% of flow modifier, 0.4-0.8 wt% of stabilizer, 0.5-0.8 wt% of curing agent, 0.2-0.3 wt% of pH regulator, 0.1-0.2 wt% of smoke inhibitor, 0.5-1.2 wt% of antioxidant, 0.2-0.8 wt% of nucleating agent, 0.6-1.2 wt% of processing aid, 2-3 wt% of mineral filler, 0.5-1.2 wt% of lubricant, 0.6-0.8 wt% of antistatic agent and 0.8-0.9 wt% of odor remover are added into the recovered ammonia water, and the mixture is introduced into the pipeline reactor again for cyclic reaction.

2. The method for synthesizing p-nitroaniline by pipeline reaction according to claim 1, which is characterized in that: the melt index modifier is phenetole peroxide; the flow modifier is a PP cooling master batch; the stabilizer is octadecyl thiodipropionate or titanium dioxide; the curing agent is ammonium polyacrylate or melamine ether resin; the pH regulator is ammonia water; the smoke suppressant is molybdenum oxide or zinc oxide; the antioxidant is an alcohol ester or acid ester antioxidant; the nucleating agent is a gamma-nucleating agent; the processing aid is stearic acid or stearate; the mineral filling agent is a mixture of bentonite and calcium carbonate, and the mass ratio of the bentonite to the calcium carbonate is 2-3: 1; the lubricant is polyethylene wax; the antistatic agent takes polypropylene fiber as a carrier, and metal salt is arranged on the carrier; the smell removing agent is rosin.

3. The method for synthesizing p-nitroaniline by pipeline reaction according to claim 1, which is characterized in that: the pulverizer in the step 2 is a high-pressure micro-powder pulverizer, the diameter of a grinding roller is 260mm, the inner diameter of a grinding ring is 780mm, and the rotating speed of a main engine is 160 r/min.

4. The method for synthesizing p-nitroaniline by pipeline reaction according to claim 1, which is characterized in that: the weight ratio of the chlorobenzene to the ammonia water in the step 3 is 1: 4.0-1: 4.5.

5. The method for synthesizing p-nitroaniline by pipeline reaction according to claim 1, which is characterized in that: the temperature of the nitration reaction in step 1 is kept below 5 ℃.

6. The method for synthesizing p-nitroaniline by pipeline reaction according to claim 1, which is characterized in that: and (3) separating by distillation, column chromatography or steam distillation between the step 1 and the step 2 to obtain the p-nitroaniline.

Technical Field

The invention relates to the technical field of chemical industry, in particular to a method for synthesizing p-nitroaniline by pipeline reaction.

Background

The p-nitroaniline is an important intermediate of pesticide and dye, the dosage of the p-nitroaniline is about 4 ten thousand tons in China, the reaction synthesis method of the p-nitroaniline in the prior art adopts a kettle type reaction mode, the pressure of the p-nitroaniline is high, the content of the p-nitroaniline is low, the equipment investment is large, the risk of melt-frying is easy to occur, the produced p-nitroaniline has pungent taste, the raw materials are wasted, and meanwhile, the high-quality p-nitroaniline cannot be obtained. In view of the above, we propose a method for synthesizing p-nitroaniline by pipeline reaction.

Disclosure of Invention

The invention aims to provide a method for synthesizing p-nitroaniline by pipeline reaction, which aims to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme:

a method for synthesizing p-nitroaniline by pipeline reaction comprises the following steps:

step 1: firstly, benzene chloride and mixed acid are subjected to nitration reaction to obtain a product containing: a mixture of 63% of p-nitrochlorobenzene, 35% of o-nitrobenzoquinone, 1% of m-nitrochlorobenzene and 1% of dinitrochlorobenzene;

step 2: putting the mixture into a pulverizer, grinding the mixture into powdery p-nitrochlorobenzene with the particle size of 1000 meshes, putting the powdery p-nitrochlorobenzene into a reaction kettle, installing a vibration motor at the bottom of the reaction kettle, vibrating the reaction kettle, continuously adding cold air into the reaction kettle through an external pipeline of a compressor, controlling the temperature in the reaction kettle to be 5-10 ℃, controlling the pressure to be 1MPa, and keeping the temperature for 5-10 min;

and step 3: adding ammonia water with the concentration of 39-41% into the powder subjected to full temperature reduction in the step 2, quickly adding the ammonia water into a pipeline type reactor by using a feeding pump, and keeping the pressure of 6-6.9 MPa and the temperature of 180-190 ℃;

and 4, step 4: continuously repeating the steps 1-3 to continuously feed the pipeline reactor, continuously discharging the material by using a constant pressure valve, putting the discharged material into a cooling kettle to be cooled to below 20 ℃, and releasing pressure to recover the gaseous ammonia for recycling;

and 5: adding 0.8-0.9 wt% of the recovered ammonia water, and introducing the ammonia water into the pipeline type reactor again for circular reaction.

As a preferred choice of the invention, the melt-index modifier is phenetole peroxide; the flow modifier is a PP cooling master batch; the stabilizer is octadecyl thiodipropionate or titanium dioxide; the curing agent is ammonium polyacrylate or melamine ether resin; the pH regulator is ammonia water; the smoke suppressant is molybdenum oxide or zinc oxide; the antioxidant is an alcohol ester or acid ester antioxidant; the nucleating agent is a gamma-nucleating agent; the processing aid is stearic acid or stearate; the mineral filling agent is a mixture of bentonite and calcium carbonate, and the mass ratio of the bentonite to the calcium carbonate is 2-3: 1; the lubricant is polyethylene wax; the antistatic agent takes polypropylene fiber as a carrier, and metal salt is arranged on the carrier; the smell removing agent is rosin.

Preferably, the mill in the step 2 is a high-pressure micro-powder mill, the diameter of a grinding roller is 260mm, the inner diameter of a grinding ring is 780mm, and the rotating speed of a main machine is 160 r/min.

Preferably, the weight ratio of the chlorobenzene to the ammonia water in the step 3 is 1: 4.0-1: 4.5.

Preferably, the temperature of the nitration reaction in step 1 is kept at 5 ℃ or lower.

Preferably, the p-nitroaniline is obtained by separating between the step 1 and the step 2 through distillation, column chromatography or steam distillation.

Compared with the prior art, the invention has the beneficial effects that:

1. the invention improves the traditional kettle type reaction, adopts the tubular reaction continuous material, discharges materials, has stable pressure, easy control, no explosion risk, stable pressure, large yield, low tubular reaction cost, stable and safe product quality, and can effectively recycle the excessive ammonia water by subsequently adding the ammonia water recycling process, thereby greatly increasing the cost.

2. The invention adds various blending agents into the recovered ammonia water for continuous reaction, realizes that the produced paranitroaniline has no peculiar smell, strong antistatic performance and better adhesiveness through various modified blending agents, and is more convenient for blending pesticides.

3. The method comprises the steps of placing the paranitrochlorobenzene powder into a reaction kettle, vibrating the reaction kettle, and continuously adding cold air into the reaction kettle through an external pipeline of a compressor, so that the paranitrochlorobenzene powder is fully cooled before reaction, the reaction is more fully ensured, the cost is saved, the utilization rate of raw materials is increased, and the waste is avoided.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the following 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 of the 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 technical scheme provided by the invention is as follows: