阅读说明：本技术 一种连续生产靛红酸酐的工艺及装置 (Process and device for continuously producing isatoic anhydride ) 是由 岳涛 郭鹏 张智慧 唐晓婵 杨松 于 2020-07-17 设计创作，主要内容包括：本发明公开了一种以苯酐为原料连续化生产靛红酸酐的工艺及装置。一种以苯酐为原料连续化生产靛红酸酐的工艺,包括以下步骤：(1)苯酐水溶液、氨水溶液各自按照一定流量进入管道反应器、消气过滤器中,之后与氢氧化钠溶液进入二级管道反应器混合反应后进入暂存罐；(2)暂存罐的溶液通过聚丙烯中空纤维膜装置分离出过量的氨气和溶液,氨气通过水环真空泵、膜压机、干燥吸收塔进入氨气储罐,溶液进入暂存罐；(3)暂存罐溶液、次氯酸钠溶液各自按照一定流量进入反应釜发生霍夫曼重排反应,再缓慢加入盐酸溶液发生关环反应,得到靛红酸酐溶液；(4)溶液经过板框压滤机,滤液返回第一步重复套用,滤饼干燥得到靛红酸酐,纯度高达99％以上。本发明解决了目前苯酐生成靛红酸酐耗能高、有机溶剂难以处理的问题,具有耗能减少90％、生产设备操作简单、运行稳定、生产效率高、产品纯度低、废水量减少60％的特点。(The invention discloses a process and a device for continuously producing isatoic anhydride by taking phthalic anhydride as a raw material. A process for continuously producing isatoic anhydride by taking phthalic anhydride as a raw material comprises the following steps: (1) the phthalic anhydride aqueous solution and the ammonia aqueous solution respectively enter a pipeline reactor and a degassing filter according to certain flow, then enter a secondary pipeline reactor with a sodium hydroxide solution for mixing reaction, and then enter a temporary storage tank; (2) the solution in the temporary storage tank is separated into excessive ammonia gas and solution through a polypropylene hollow fiber membrane device, the ammonia gas enters an ammonia gas storage tank through a water ring vacuum pump, a membrane press and a drying absorption tower, and the solution enters the temporary storage tank; (3) respectively feeding the temporary storage tank solution and the sodium hypochlorite solution into a reaction kettle according to a certain flow rate to perform Hofmann rearrangement reaction, and slowly adding a hydrochloric acid solution to perform ring closing reaction to obtain an isatoic anhydride solution; (4) the solution passes through a plate-and-frame filter press, the filtrate returns to the first step for repeated use, and the filter cake is dried to obtain the isatoic anhydride with the purity of more than 99 percent. The method solves the problems of high energy consumption and difficult treatment of organic solvent in the prior method for generating the isatoic anhydride from the phthalic anhydride, and has the characteristics of energy consumption reduction of 90 percent, simple operation of production equipment, stable operation, high production efficiency, low product purity and waste water amount reduction of 60 percent.)

1. The utility model provides a device for continuous production isatoic anhydride, its characterized in that, aqueous ammonia storage tank (1) bottom pass through pipeline a and be connected with the upper portion of one-level pipeline reactor (3), the bottom of phthalic anhydride stirred tank (2) passes through pipeline b and is connected with the upper portion of one-level pipeline reactor (3), the bottom of one-level pipeline reactor (3) pass through pipeline c and be connected with the upper portion of second grade pipeline reactor (6), the upper portion of second grade pipeline reactor (6) pass through pipeline d and be connected with the bottom of sodium hydroxide storage tank (5), second grade pipeline reactor (6) bottom pass through pipeline e and be connected with temporary storage tank (7) top, the bottom of temporary storage tank a (7) passes through pipeline f and links to each other with polypropylene hollow fiber membrane separator (8) upper portion, the top of polypropylene hollow fiber membrane separator (8) pass through the top of pipeline g temporary storage tank b (13) and link to each other, the bottom of the temporary storage tank b (13) is connected with the top of the reaction kettle (16) through a pipeline k, the bottom n of the reaction kettle (16) is connected with the top of the filtrate storage tank (19), and the bottom of the filtrate storage tank (19) is connected with the top of the ammonia water storage tank (1) through a pipeline o; the lower part of the polypropylene hollow fiber membrane separation device (8) is connected with the top of an ammonia buffer tank (10) through a pipeline h, the upper part of the ammonia buffer tank (10) is connected with the upper part of a membrane press (11) through a pipeline i, the upper part of the membrane press (11) is connected with an ammonia storage tank (12) through a pipeline j, and the ammonia storage tank (12) is connected with an ammonia storage tank (1) through a pipeline p; the bottoms of the sodium hypochlorite storage tank (14) and the dilute hydrochloric acid storage tank (15) are respectively connected with the top of the reaction tank (16) through a pipeline (l) and a pipeline (m).

2. The process for continuous production of isatoic anhydride according to claim 1 wherein the conduit c is provided with a degassing filter (4);

a water ring vacuum pump (9) is arranged on the pipeline h; a plate and frame filter (17) is arranged on the pipeline n;

a drying tower is arranged on the pipeline j; and valves and pumps are arranged on the pipelines.

3. The process for continuously producing the isatoic anhydride by adopting the device for continuously producing the isatoic anhydride in the claim 1 is characterized by comprising the following specific steps of:

(1) adding phthalic anhydride and pure water into a phthalic anhydride stirring tank (2), starting stirring, adjusting the rotating speed of a motor to enable the material to reach a turbulent flow state, and uniformly mixing solid and liquid;

(2) the ammonia water storage tank (1) and the phthalic anhydride stirring tank (2) are opened with corresponding pumps, and respectively enter a primary pipeline reactor (3) according to a certain flow rate through the interlocking control of a flowmeter and a valve, and then enter a secondary pipeline reactor (6) from the primary pipeline reactor (3), and a gas elimination filter (4) is connected between pipeline reactions to eliminate generated gas and prevent the phenomena of pipeline water hammer and gas resistance caused by the formation of air bags;

(3) opening a corresponding pump of a sodium hydroxide storage tank (5), entering a secondary pipeline reactor (6) through the interlocking control of a pH meter and a valve, maintaining the pH value of the solution in the secondary pipeline reactor to be 10.0-10.5, and entering the generated solution into a temporary storage tank a (7) for later use;

(4) After being pressurized, the solution in the temporary storage tank a (7) enters a polypropylene hollow fiber membrane device (8), ammonia water and absorption liquid are separated at two sides by using a hydrophobic microporous membrane as an isolation layer, excessive ammonia escaping from water can easily pass through the membrane, water and other ionic substances cannot pass through, ammonia gas passes through a water ring vacuum pump (9), a membrane press (11) and a drying tower and then enters an ammonia gas storage tank (12) for standby, and the solution enters a temporary storage tank b (13) for standby;

(5) opening a valve of the temporary storage tank b (13), enabling the solution to enter a reaction kettle (16), starting stirring, opening a refrigerant inlet and outlet valve of the reaction kettle (16), and controlling the temperature of the solution to be-20 to-5 ℃;

(7) opening a valve of sodium hypochlorite (14), controlling the dropping speed by utilizing the interlocking of a flowmeter and the valve, keeping the dropping time of the sodium hypochlorite to be 20-20min, continuing to react for 5-10min after the dropping is finished, opening a valve of a dilute hydrochloric acid storage tank (15), slowly dropping a 32% hydrochloric acid solution, titrating until the pH value is 1-5, and continuing to react for 10-20min after the dropping is finished;

the low temperature is carried out to prevent the generated product from being hydrolyzed under the environment with high temperature, so the low temperature adjusts the pH to be neutral.

(8) Closing a refrigerant valve, heating to 20-50 ℃, and stirring for 2-3 h;

(9) And opening a valve at the bottom of the reaction kettle (16), filtering by a plate and frame filter (17) and drying by a rake dryer (18), wherein the solid is isatoic anhydride, and the liquid solution is returned for reuse.

4. The process for continuously producing isatoic anhydride according to claim 3, wherein the ratio of step (1) phthalic anhydride: the pure water mass ratio is 1: 4-1: 6, and the stirring grade is 6-8.

5. The process for continuously producing isatoic anhydride according to claim 3, wherein the feeding pipes of the ammonia water and the aqueous solution of phthalic anhydride in the step (2) are correspondingly arranged, so that the feeding direction of the ammonia water and the feeding direction of the aqueous solution of phthalic anhydride form an included angle of 90-180 ℃, and the ammonia water and the aqueous solution of phthalic anhydride are mixed by ammonia: the molar ratio of phthalic anhydride is 2.2-2.5: 1.

6. The process for continuously producing isatoic anhydride according to claim 3, wherein the concentration of the aqueous ammonia in the step (2) is 20 to 30%.

7. The process for continuously producing isatoic anhydride according to claim 3, wherein the concentration of the sodium hydroxide solution in the step (3) is 15 to 30%.

8. The process for continuously producing isatoic anhydride according to claim 3, wherein the step (4) uses a polypropylene hollow fiber membrane device, and the ammonia gas chamber is slightly negative pressure, -0.01 to-0.03 pa.

9. The process for continuously producing isatoic anhydride according to claim 3, wherein the molar ratio of sodium hypochlorite to phthalic anhydride in step (7) is 1-1.2: 1.

10. The process for continuously producing isatoic anhydride according to claim 3, wherein the dropping rate of sodium hypochlorite in the step (7) is 2 to 4.5 kg/min.

Technical Field

The invention belongs to the technical field of chemical equipment, and particularly relates to a process and a device for continuously producing isatoic anhydride.

Technical Field

Isatoic anhydride or etodolac anhydride, chemical name: 2H-3, 1-benzoxazine-2, 4(1H) -dione. Isatoic anhydride and homologues and derivatives thereof are widely used for synthesizing fine chemical products such as agricultural chemicals, dyes, pigments, perfumes, essences, medicines, ultraviolet absorbers, foaming agents, flame retardants, preservatives, bleaches, bactericides, sanitizers and the like, and are chemical intermediates with wide application.

One method adopted by the existing method for synthesizing isatoic anhydride from phthalic anhydride is to dehydrate phthalic anhydride and ammonia water at high temperature after reaction, continuously add sodium hypochlorite for reaction to obtain isatoic anhydride, and the other method is to melt phthalic anhydride and urea in an organic solvent or at high temperature for reaction, and continuously add sodium hypochlorite for reaction to obtain isatoic anhydride. Both methods have a large amount of waste liquid, and high-temperature dehydration and melting reaction consume a large amount of energy.

CN104402840A discloses a synthesis process of isatoic anhydride, wherein the first step is a melting reaction of phthalic anhydride and urea (melting point of phthalimide: 238 ℃), and then the temperature is reduced to 10-20 ℃, so that a large amount of energy is consumed in the reaction process, and the production cost is greatly increased.

Disclosure of Invention

The invention mainly aims at the problems of high energy consumption and more waste liquid in the existing production, and provides a process and a device for continuously producing isatoic anhydride, which can realize continuous production, stable product quality and performance, low energy consumption and less waste liquid.

In order to achieve the purpose, the technical scheme adopted by the application is as follows:

the utility model provides a device for continuous production isatoic anhydride, aqueous ammonia storage tank bottom pass through pipeline a and be connected with the upper portion of one-level pipeline reactor, the bottom of phthalic anhydride agitator tank passes through pipeline b and is connected with the upper portion of one-level pipeline reactor, the bottom of one-level pipeline reactor pass through pipeline c and be connected with the upper portion of second grade pipeline reactor, the upper portion of second grade pipeline reactor pass through pipeline d and be connected with the bottom of sodium hydroxide storage tank, second grade pipeline reactor bottom pass through pipeline e and be connected with the groove top of keeping in, the bottom of keeping in groove a passes through pipeline f and links to each other with polypropylene hollow fiber membrane separator upper portion, polypropylene hollow fiber membrane separator's top pass through the top of pipeline g groove b of keeping in and link to each other, keeping in groove b bottom pass through pipeline k and link to each other with the reation kettle top, reation kettle bottom n links to each other with filtrating storage tank top, the bottom of the filtrate storage tank is connected with the top of the ammonia water storage tank through a pipeline o; the lower part of the polypropylene hollow fiber membrane separation device is connected with the top of an ammonia buffer tank through a pipeline h, the upper part of the ammonia buffer tank is connected with the upper part of a membrane press through a pipeline i, the upper part of the membrane press is connected with an ammonia storage tank through a pipeline j, and the ammonia storage tank is connected with an ammonia storage tank through a pipeline p; the bottom parts of the sodium hypochlorite storage tank and the dilute hydrochloric acid storage tank are respectively connected with the top part of the reaction tank through a pipeline and a pipe m. The pipeline c is provided with an air elimination filter; a water ring vacuum pump is arranged on the pipeline h; the pipeline n is provided with a plate-and-frame filter; a drying tower is arranged on the pipeline j; and valves and pumps are arranged on the pipelines.

The device for continuously producing the isatoic anhydride is adopted to carry out the process for continuously producing the isatoic anhydride, and the specific steps are as follows:

(1) adding phthalic anhydride and pure water into a phthalic anhydride stirring tank, starting stirring, adjusting the rotating speed of a motor to enable the material to reach a turbulent flow state, and uniformly mixing solid and liquid;

(2) corresponding pumps are started in the ammonia water storage tank and the phthalic anhydride stirring tank, the ammonia water storage tank and the phthalic anhydride stirring tank respectively enter a primary pipeline reactor according to a certain flow rate through the interlocking control of a flowmeter and a valve, the ammonia water storage tank and the phthalic anhydride stirring tank then enter a secondary pipeline reactor from the primary pipeline reactor, and a degassing filter is connected between pipeline reactions to eliminate generated gas and prevent the phenomena of pipeline water hammer and gas resistance caused by the formation of an air bag;

(3) opening a corresponding pump of the sodium hydroxide storage tank, entering a secondary pipeline reactor through the interlocking control of a pH meter and a valve, maintaining the pH value of the solution in the secondary pipeline reactor to be 10.0-10.5, and entering the generated solution into a temporary storage tank a for later use;

(4) after being pressurized, the solution in the temporary storage tank a enters a polypropylene hollow fiber membrane device, ammonia water and absorption liquid are separated on two sides by using a hydrophobic microporous membrane as an isolation layer, excessive ammonia escaping from water can easily pass through the membrane, water and other ionic substances cannot pass through, the ammonia gas enters an ammonia gas storage tank for standby after passing through a water ring vacuum pump, a membrane press and a drying tower, and the solution enters a temporary storage tank b for standby;

(5) Opening a valve of the temporary storage tank b, enabling the solution to enter the reaction kettle, starting stirring, opening a refrigerant inlet and outlet valve of the reaction kettle, and controlling the temperature of the solution to be-20 to-5 ℃;

(7) opening a valve of sodium hypochlorite, controlling the dropping speed by utilizing the interlocking of a flowmeter and the valve, continuing to react for 5-10min after the dropping is finished, opening a valve of a dilute hydrochloric acid storage tank, slowly dropping a 32% hydrochloric acid solution, titrating to a pH value between 1 and 5, and continuing to react for 10-20min after the dropping is finished;

(8) closing a refrigerant valve, heating to 20-50 ℃, and stirring for 2-3 h;

(9) and opening a valve at the bottom of the reaction kettle, filtering by using a plate and frame filter and drying by using a rake dryer 18 to obtain solid isatoic anhydride, and returning the liquid solution for reuse.

The molar ratio of the sodium hypochlorite to the phthalic anhydride in the step (7) is 1-1.2: 1;

the dropping speed of the sodium hypochlorite in the step (7) is 2-4.5 kg/min;

the phthalic anhydride in the step (1): the pure water mass ratio is 1: 4-1: 6, and the stirring grade is 6-8.

The step (2) aqueous ammonia, phthalic anhydride aqueous solution inlet pipe correspond the setting, make aqueous ammonia feed direction and the feed direction of phthalic anhydride aqueous solution form 90 ~ 180 ℃ contained angle, and aqueous ammonia and phthalic anhydride water are with ammonia: the molar ratio of phthalic anhydride is 2.2-2.5: 1. Ensuring the phthalic anhydride to fully react.

The concentration of the ammonia water in the step (2) is 20-30%.

The concentration of the sodium hydroxide solution in the step (3) is 15-30%.

The step (4) uses a polypropylene hollow fiber membrane device, and the ammonia gas cavity is under micro negative pressure of-0.01 to-0.03 pa.

The invention relates to a device for continuously producing isatoic anhydride, which comprises a phthalic anhydride stirring tank and an ammonia water storage tank, wherein solution flows into a pipeline reactor according to a certain proportion of flow, then enters a temporary storage tank, escapes ammonia gas through a polypropylene hollow fiber membrane device, passes through a water ring pump, is pressed into a dryer through a membrane press, and enters the ammonia water storage tank; and (3) filtering the ammonia gas, allowing the filtrate to flow into a temporary storage tank, allowing the filtrate to enter a reaction kettle, allowing the filtrate to enter a plate-and-frame filter press, and allowing the filtrate to be pressed into an ammonia water storage tank or a phthalic anhydride stirring tank by a pump for reuse.

The invention has the beneficial effects that:

(1) the continuous reaction from the phthalic anhydride to the isatoic anhydride avoids the technical problems of separation and drying of intermediate products for producing the isatoic anhydride, and reduces the industrial operation amount, thereby avoiding the consumption in the separation and drying processes and saving the cost by 10 to 15 percent for each ton of products;

(2) the phthalic anhydride aqueous solution and ammonia water reactor adopts a pipeline reactor, so that firstly, the material inlet pressure is high, the flow speed is high, the reaction mixing effect is good, and the conversion rate of the reaction is improved; secondly, the concentration of ammonia water is ensured to be 20-30% all the time, the conversion rate of the reaction is improved, and the side reaction of the phthalic anhydride hydrolysis is reduced; thirdly, the residence time distribution density function E (t) of the materials in the pipeline reactor is small enough, and the residence time distribution function F (t) is large enough, so that the generated heat can meet the design requirement by utilizing air cooling, the overall reaction conversion rate is improved from 75% to 96%, and the energy consumption for producing one ton is reduced by 3-5%.

(3) Adopt the separation of polypropylene hollow fiber membrane device to retrieve the ammonia, reduced the consumption of sodium hypochlorite on the one hand, on the other hand has reduced the emission of waste liquid, waste gas, saves 60% waste liquid consumption about per ton isatoic anhydride.

(4) The degree of automation is higher, has reduced personnel's operation, has reduced the contact frequency of personnel with the material, has both reduced the cost of labor, has improved factor of safety again.

Drawings

FIG. 1 is a schematic diagram of a plant for the continuous production of isatoic anhydride;

Detailed Description

In order to better understand the technical scheme of the present invention, the following detailed description of the present invention is provided by way of examples, but the present invention should not be construed as limited to the above description.