CN110642733A - Process for continuously producing aminobenzoate derivative and synthesis system thereof - Google Patents
Process for continuously producing aminobenzoate derivative and synthesis system thereof Download PDFInfo
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- CN110642733A CN110642733A CN201910859404.9A CN201910859404A CN110642733A CN 110642733 A CN110642733 A CN 110642733A CN 201910859404 A CN201910859404 A CN 201910859404A CN 110642733 A CN110642733 A CN 110642733A
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- C07C227/00—Preparation of compounds containing amino and carboxyl groups bound to the same carbon skeleton
- C07C227/04—Formation of amino groups in compounds containing carboxyl groups
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- C07C201/00—Preparation of esters of nitric or nitrous acid or of compounds containing nitro or nitroso groups bound to a carbon skeleton
- C07C201/06—Preparation of nitro compounds
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Abstract
The invention provides a process for continuously producing aminobenzoate derivatives and a synthesis system thereof, and the process for continuously producing aminobenzoate derivatives comprises the steps of putting nitrobenzoic acid derivatives, ethanol and a first catalyst into an esterification reaction device, and reacting for 1-1.5h at the temperature of 70-75 ℃; supplementing nitrobenzoic acid derivatives, ethanol and a first catalyst into the esterification reaction device; the liquid in the esterification reaction device flows into a dehydration esterification kettle; heating to ensure that ethanol-water in the dehydration esterification kettle azeotropes, evaporating the azeotrope out of the dehydration esterification kettle and collecting the azeotrope, and discharging the liquid in the dehydration esterification kettle into an intermediate liquid storage tank; the liquid in the middle liquid storage tank flows into a hydrogenation reaction device, and hydrogenation reaction is carried out under the action of a second catalyst, the reaction temperature is 100 ℃ and 120 ℃, and the pressure is kept at 0.6-1 Mpa; the product is obtained. The invention has the advantages of continuous production and the like.
Description
Technical Field
The invention belongs to the technical field of chemical synthesis, and particularly relates to a process for continuously producing aminobenzoate derivatives and a synthesis system thereof.
Background
Aminobenzoate derivatives are important intermediates for the synthesis of a variety of drugs. The medicine can block the occurrence of sensory nerve impulse in local reversibility at the medicine application part. Typical representatives of drugs are: benzocaine, procaine hydrochloride, tetracaine hydrochloride, procainamide hydrochloride and the like.
The industrial production of aminobenzoate derivatives is basically carried out by esterification of nitrobenzoic acid with alcohol and reduction. The esterification reaction is a reversible reaction, the yield is not very high, the intermittent production has great requirements on the technical operation of workers, the quality is easy to be unstable, the raw material consumption is large and the like. The reduction reaction comprises two processes of iron powder reduction and catalytic hydrogenation. Although the iron powder reduction has low cost, safe reaction and low requirement on the technical operation of workers, the generated iron mud belongs to solid hazardous waste, has the problems of large amount of waste water and the like, is classified as an out-dated elimination process, is forbidden to use in a new project, and is also required to be eliminated in a production process for a limited period.
At present, the catalytic hydrogenation technology in the fine chemical field is basically a batch production technology, and most of hazard sources come from the operation of workers. Meanwhile, intermittent production also brings the defects of unstable product quality, high labor intensity of workers, high labor cost and the like. Nowadays, labor cost is continuously improved, and safety production awareness is increasingly strengthened, a plurality of local governments and chemical industry parks are provided with a regulation of controlling limited number of people in a workshop one after another, so that the development of safe and efficient continuous production process is imperative.
Disclosure of Invention
A first object of the present invention is to solve the above-mentioned problems occurring in the prior art, and to provide a process for continuously producing an aminobenzoate derivative; a second object of the present invention is to provide a synthesis system for realizing the above-mentioned process for continuously producing an aminobenzoate derivative.
The first object of the present invention can be achieved by the following technical solutions: a process for continuously producing aminobenzoate derivatives is characterized by comprising the following steps:
pretreatment: putting nitrobenzoic acid derivative, ethanol and a first catalyst into an esterification reaction device, and reacting for 1-1.5h at the temperature of 70-75 ℃;
continuous production: supplementing nitrobenzoic acid derivatives, ethanol and a first catalyst into the esterification reaction device according to a preset proportion; simultaneously, the liquid in the esterification reaction device flows into a dehydration esterification kettle; simultaneously, heating the liquid in the dehydration esterification kettle to ensure that the ethanol-water in the dehydration esterification kettle is subjected to azeotropic distillation, evaporating the azeotrope out of the dehydration esterification kettle and collecting the azeotrope, and discharging the liquid in the dehydration esterification kettle into an intermediate liquid storage tank; the liquid in the middle liquid storage tank flows into the hydrogenation reaction device, hydrogenation reaction is carried out under the action of a second catalyst, the reaction temperature in the hydrogenation reaction device is kept at 100-120 ℃, and hydrogen is introduced to keep the pressure in the hydrogenation reaction device at 0.6-1 Mpa; and the liquid in the hydrogenation reaction device flows into a product collecting tank to be collected, so as to obtain a product.
Preferably, in the pretreatment, after nitrogen is introduced to remove air in the hydrogenation reaction device, hydrogen is introduced into the hydrogenation reaction device, and a second catalyst is added; in the continuous production, the liquid in the esterification reaction device circulates in the esterification reaction device; the liquid in the hydrogenation reaction device circulates in the hydrogenation reaction device, and the second catalyst circulates in the hydrogenation reaction device.
Preferably, in the pretreatment, the mass ratio of the nitrobenzoic acid derivative, the ethanol and the first catalyst is as follows: 1:10-15: 0.1-0.3; the input amount of the second catalyst is 0.5 to 1 percent of the input amount of the nitrobenzoic acid derivative; during continuous production, the mass ratio of the nitrobenzoic acid derivative, the ethanol and the first catalyst added in each hour is 1:10-15: 0.1-0.3; and supplementing ethanol into the hydrogenation reaction device, wherein the supplementing amount of the ethanol is 5-10 times of that of the nitrobenzoic acid derivative.
Preferably, the first catalyst is one of concentrated sulfuric acid or p-toluenesulfonic acid; the second catalyst is a palladium on carbon catalyst.
Preferably, the material retention time in the esterification reaction device is 1-1.5 hours; the retention time of the materials in the dehydration esterification kettle is 2 to 3 hours; the retention time of the materials in the hydrogenation reaction device is 2-3 hours.
Preferably, the nitrobenzoic acid derivative is one of p-nitrobenzoic acid, 3-nitrobenzoic acid, 2-chloro-4-nitrobenzoic acid, 3-bromo-4-nitrobenzoic acid and 3, 5-dichloro-4-nitrobenzoic acid.
The working principle is as follows: the retention time of the materials in the esterification reaction device is 1 to 1.5 hours, namely the airspeed of the materials in the esterification reaction device is 1 to 1.5 hours-1That is, in normal continuous production, the mass flow rate of all the materials staying in the esterification reaction apparatus divided by all the materials entering the esterification reaction apparatus is 1 to 1.5, similar to the reaction time in a batch reactor.
The retention time of the materials in the dehydration esterification kettle is 2 to 3 hours, namely the airspeed of the materials in the dehydration esterification kettle is 2 to 3 hours-1And during normal continuous production, the mass flow rate of all materials staying in the dehydration esterification kettle divided by the mass flow rate of all materials entering the dehydration esterification kettle is 2-3.
The retention time of the material in the hydrogenation reaction device is 2-3 hours, namely the space velocity of the material in the hydrogenation reaction device is 2-3 hours-1And during normal continuous production, the mass flow rate of all materials staying in the hydrogenation reaction device divided by the mass flow rate of all materials entering the hydrogenation reaction device is 2-3.
The nitrobenzoic acid derivative, the ethanol and the first catalyst are put into an esterification reaction device according to a certain proportion at the early stage, the temperature is raised to 70-75 ℃, the reaction is carried out for 1-1.5 hours in a circulating heat preservation way, after nitrogen is introduced to remove air in the hydrogenation reaction device, hydrogen is introduced into the hydrogenation reaction device, and the second catalyst is added. After the earlier stage work is ready, the continuous production is started.
Supplementing nitrobenzoic acid derivatives, ethanol and a first catalyst into an esterification reaction device according to a certain mass flow rate ratio, simultaneously enabling the esterification reaction device to flow into a dehydration esterification kettle, heating the dehydration esterification kettle to ensure that ethanol-water is azeotropic, thereby taking away water generated by the reaction, enabling liquid in the dehydration esterification kettle to flow into an intermediate liquid storage tank, enabling the liquid in the intermediate liquid storage tank to flow into a hydrogenation reaction device, carrying out hydrogenation reaction under the action of a second catalyst, keeping the reaction temperature in the hydrogenation reaction device at 100-120 ℃, and introducing hydrogen to keep the pressure in the hydrogenation reaction device at 0.6-1 Mpa; and the liquid in the hydrogenation reaction device flows into a product collecting tank to be collected, so as to obtain a product. And (2) continuously adding a nitrobenzoic acid derivative, ethanol and a first catalyst into the esterification reaction device, enabling liquid in the esterification reaction device to flow into a dehydration esterification kettle, enabling the liquid to flow into an intermediate liquid storage tank after azeotropic dehydration, flowing into a hydrogenation reaction device, finally flowing out of a synthesis system, collecting the obtained product, and carrying out continuous production.
The second object of the present invention can be achieved by the following technical solutions: the synthesis system for realizing the process for continuously producing the aminobenzoate derivative is characterized by comprising an esterification reaction device, a dehydration esterification kettle, an intermediate liquid storage tank and a hydrogenation reaction device which are sequentially connected, wherein the esterification reaction device is connected with a continuous solid feeding device, a solvent feeding device and a first catalyst feeding device which are used for feeding the nitrobenzoic acid derivative into the esterification reaction device, the dehydration esterification kettle is connected with an azeotrope collecting tank, and the hydrogenation reaction device is connected with a product collecting tank.
Preferably, the esterification reaction device comprises an esterification reactor and a first circulation pipeline, one end of the first circulation pipeline is connected to the bottom of the esterification reactor, the other end of the first circulation pipeline enters from the top of the esterification reactor and is immersed in the esterification reaction liquid, and the first circulation pipeline is provided with a first nozzle for spraying the liquid in the first circulation pipeline into the esterification reactor.
Preferably, the first circulating pipeline is connected with the dehydration esterification kettle through a dehydration esterification kettle feed valve.
Preferably, the hydrogenation reaction device comprises a hydrogenation reactor and a second circulation pipeline, one end of the second circulation pipeline is connected to the bottom of the hydrogenation reactor, the other end of the second circulation pipeline enters from the top of the hydrogenation reactor and is immersed in the hydrogenation reaction liquid, the second circulation pipeline is provided with a second nozzle for spraying the liquid in the second circulation pipeline into the hydrogenation reactor, and a balance pipe is arranged between the hydrogenation reactor and the second circulation pipeline.
Preferably, the second circulation pipeline is connected with the product collecting tank through a discharge valve of the hydrogenation reactor, and a second catalyst filter is arranged between the second circulation pipeline and the discharge valve of the hydrogenation reactor.
Preferably, the first circulating pipeline and the second circulating pipeline are both provided with a circulating pump and a heat exchanger, steam enters from one end of the heat exchanger, and condensed water flows out from the other end of the heat exchanger.
Preferably, the hydrogenation reactor is connected with an ethanol feeding device, a hydrogen supplementing device and a nitrogen supplementing device, and the ethanol feeding device is used for adding ethanol into the hydrogenation reactor; the hydrogen replenishing device is used for charging hydrogen into the hydrogenation reactor, and the nitrogen replenishing device is used for charging nitrogen into the hydrogenation reactor.
Preferably, a storage tank discharge valve and a hydrogenation feed pump are arranged between the intermediate liquid storage tank and the hydrogenation reactor, and the hydrogenation feed pump is used for pumping the liquid in the intermediate liquid storage tank into the hydrogenation reactor.
Preferably, the bottom of the dehydration esterification kettle is connected with the intermediate liquid storage tank through a discharge valve of the dehydration esterification kettle.
Preferably, a condenser is arranged between the dehydration esterification kettle and the azeotrope collecting tank and is used for condensing the gaseous azeotrope into a liquid state.
Preferably, a jacket is arranged outside the dehydration esterification kettle, and the jacket is used for introducing steam to increase the temperature in the dehydration esterification kettle.
Preferably, the hydrogenation reaction device and the esterification reaction device are also provided with thermometers, and the hydrogenation reaction device is also provided with a pressure sensor.
Preferably, continuous solid charge-in system include the charge-in pipeline and from the top down set gradually screw propeller, feeding runner in the charge-in pipeline, the brush material brush, screw propeller, feeding runner and brush material brush all be provided with driving motor, screw propeller be used for promoting solid material and remove in the charge-in pipeline, the feeding runner be used for controlling the feeding volume, the brush material brush be used for brushing the material of adhesion on the feeding runner into in the esterification reaction device.
Compared with the prior art, the invention has the following advantages:
1. the invention has high production efficiency and stable product quality, the traditional process adopts intermittent reaction at present, the batch production is carried out, the production efficiency is low, and the product quality greatly fluctuates along with different batches. The invention develops a production system capable of continuously producing the aminobenzoate derivative, and has the advantages of high specific production efficiency, stable product quality, low labor intensity, high automation degree and the like.
2. The esterification reaction of the invention has high conversion rate. Because the esterification reaction is a reversible reaction, the conversion rate of the reaction raw material p-nitrobenzoic acid is not high, and the water amount generated in the early stage of the reaction and the later stage of the reaction is different in an intermittent reaction system. In the prior art, a reaction kettle generates little water in the early stage of the reaction, a large amount of solvent ethanol is evaporated, water is not brought in the later stage of the reaction, the reaction time is long, and the conversion rate of the production esterification reaction is low.
According to different characteristics of the early stage and the later stage of the esterification reaction, the esterification reaction is carried out in two devices of an esterification reactor and a dehydration esterification kettle in the early stage and the later stage of the esterification reaction. The concentration of reactants in the early stage of esterification is high, the reaction is violent, the temperature gradient is large, and heat transfer and mass transfer need to be enhanced, so that the esterification reactor adopts an injection type reactor, the mass transfer and heat transfer effects are greatly enhanced, and an external heat exchanger is added for increasing the heat transfer area. The raw material amount of the reaction in the later stage of the esterification reaction is reduced, and the generation amount of product water causes the increase of water amount in the system to seriously affect the reaction speed, so that the water is enhanced to move out of the system in the later stage of the esterification reaction, and the characteristics that ethanol is a solvent and a reactant are utilized, the ethanol in the system is greatly excessive, and the ethanol and water have azeotropic property, a large amount of ethanol-water azeotrope is evaporated out of the system, thereby achieving the purpose that the water is moved out of the system, and the esterification reaction balance moves towards the direction of generating the product.
3. The catalytic hydrogenation system is a three-phase reaction of gas (hydrogen), solid (catalyst palladium carbon) and liquid (nitrobenzoate in solution). The mass transfer rate between the three phases is thus the rate controlling step of the overall reaction. How to strengthen the mass transfer among the three phases is the key of the whole reaction. The three-phase mass transfer requirement of the catalytic hydrogenation reaction cannot be met by the gap reaction of the traditional reaction kettle. Finally resulting in low reaction yield.
The invention adopts the jet reflux type hydrogenation reaction device in the catalytic hydrogenation reaction process, the reaction material is jetted out at high speed through the second nozzle to impact the material below the liquid surface, meanwhile, a certain low-pressure area is formed in the second nozzle, the gas (hydrogen) in the reactor is brought into the second nozzle by the balance pipe arranged in the reactor, and the gas (hydrogen) is jetted to the reaction liquid along with the liquid, thereby achieving the purpose of strengthening mass transfer.
4. The nitrobenzoic acid derivatives are substantially solid. At present, the traditional batch reaction industrial production is manually fed, and the defects of high labor intensity, severe working environment, low feeding quantity precision and the like exist. The invention develops a continuous solid feeding system, and a good linear relation can be formed by the rotating speed of three devices, namely a screw propeller, a feeding rotating wheel and a brush and the feeding quantity of solid materials, so that the aim of accurate and continuous feeding of the solid materials is fulfilled.
Drawings
FIG. 1 is a schematic view of the flow structure of the present invention;
FIG. 2 is a schematic view of the structure of an esterification reaction apparatus according to the present invention;
FIG. 3 is a schematic diagram of the configuration of a dehydration esterification kettle according to the present invention;
FIG. 4 is a schematic view of the structure of a hydrogenation reaction apparatus according to the present invention;
FIG. 5 is a schematic diagram of the continuous solids feeder of the present invention;
fig. 6 is a schematic view of the feed rotor and drive motor of the present invention.
In the figure, 1, an esterification reaction device; 2. a dehydration esterification kettle; 3. a middle liquid storage tank; 4. a hydrogenation reaction device; 5. a continuous solids feed means; 6. a solvent feed means; 7. a first catalyst feed device; 8. an azeotrope collecting tank; 9. a product collection tank; 10. a first circulation pipe; 11. a first nozzle; 12. an esterification reactor; 17. a hydrogenation reactor; 18. a second circulation pipe; 19. a feed valve of the dehydration esterification kettle; 20. a second nozzle; 21. a balance tube; 22. a discharge valve of the hydrogenation reactor; 23. a second catalyst filter; 24. a circulation pump; 25. a heat exchanger; 26. an ethanol feeding device; 27. a hydrogen replenishing device; 28. a nitrogen supplementing device; 29. a storage tank discharge valve; 30. a hydrogenation feed pump; 31. a thermometer; 32. a pressure sensor; 33. a discharge valve of the dehydration esterification kettle; 34. a condenser; 35. a jacket; 36. a feed conduit; 37. a screw propeller; 38. a feeding runner; 39. a material brushing brush; 40. the motor is driven.
Detailed Description
The following are specific embodiments of the present invention and are further described with reference to the drawings, but the present invention is not limited to these embodiments.
Example 1:
reaction raw materials: ethanol (commercial ethanol, content 99%); p-nitrobenzoic acid (commercially available, 98% content); hydrogen (commercially available, 99% content).
Esterification reaction catalyst: industrial concentrated sulfuric acid (commercially available, content 98%) or p-toluenesulfonic acid (commercially available, content 99%);
catalyst for catalytic hydrogenation reaction: 1-5% palladium-containing commercially available palladium on carbon; the dosage of the p-nitrobenzoic acid is 0.5 to 1 percent of that of the p-nitrobenzoic acid.
Solvent: the solvents for the esterification reaction and the catalytic hydrogenation reaction are ethanol (commercial industrial ethanol, the content is 99%);
1380Kg of ethanol, 100Kg of p-nitrobenzoic acid and 20Kg of concentrated sulfuric acid are put into an esterification reactor 12, a circulating pump 24 of the esterification reactor 12 is opened, the temperature is raised to 75 ℃, after the heat preservation circulating residence time is 1 hour, 1380Kg/h of ethanol and 20Kg/h of catalyst concentrated sulfuric acid are introduced into the esterification reactor 12, a continuous solid feeding system is opened to ensure that the feeding amount of the p-nitrobenzoic acid is 100Kg/h, a feeding valve 19 of a dehydration esterification kettle is opened at the same time, the material flow is controlled to be 1500Kg/h, heating steam is opened in a dehydration esterification kettle 2 until the ethanol-water in the kettle reaches azeotropy, the residence time of the dehydration esterification kettle 2 is 3 hours, a discharge valve 33 of the dehydration esterification kettle is opened, and the material flow is controlled to be 1500 Kg/h. And (3) the hydrogenation reactor 17 is charged and discharged with nitrogen for more than 5 times to ensure that the air in the hydrogenation reactor 17 is completely removed, hydrogen is introduced, the pressure in the hydrogenation reactor 17 is kept at 0.6MPa, and 1Kg of 3 percent of commercially available palladium-carbon catalyst is added and introduced. When the filling rate of the materials in the intermediate liquid storage tank 3 reaches about 50%, opening a discharge valve 29 of the storage tank, controlling the flow rate of the materials to be 1500Kg/h, starting a catalytic hydrogenation circulating pump 24, heating by steam, keeping the reaction temperature of the hydrogenation reactor 17 at 100 ℃, and controlling a discharge valve 22 of the hydrogenation reactor to ensure that the materials in the hydrogenation reactor 17 stay for 3 hours. The material from the hydrogenation reactor 17 enters a product collecting tank 9, and then the solvent is further removed and refined to obtain the product ethyl p-nitrobenzoate, wherein the purity is 99.1%, the product yield is 94.1Kg/h, and the molar yield is 96.3%.
Example 2-example 10 the results of contents, molar yields and yields of aminobenzoate derivatives obtained by using the kinds of nitrobenzoic acid derivatives, the amount of ethanol added, the amount of first catalyst added, the esterification reaction temperature, the esterification reaction residence time, the dehydration esterification residence time, the palladium on carbon specification, the amount of second catalyst added, the hydrogenation reaction temperature, the hydrogenation reaction pressure Mpa, the hydrogenation residence time and the like as in example 1 were shown in table 1:
TABLE 1 aminobenzoate derivative content, molar yield and yield
As shown in fig. 1 to 6, a synthesis system for realizing the above process for continuously producing aminobenzoate derivatives comprises an esterification reaction device 1, a dehydration esterification kettle 2, an intermediate reservoir 3, and a hydrogenation reaction device 4, which are connected in sequence, wherein the esterification reaction device 1 is connected with a continuous solid feeding device 5, a solvent feeding device 6, and a first catalyst feeding device 7, which are used for feeding nitrobenzoic acid derivatives into the esterification reaction device 1, the dehydration esterification kettle 2 is connected with an azeotrope collecting tank 8, and the hydrogenation reaction device 4 is connected with a product collecting tank 9.
In further detail, the esterification reaction device 1 comprises an esterification reactor 12 and a first circulation pipeline 10, one end of the first circulation pipeline 10 is connected to the bottom of the esterification reactor 12, the other end of the first circulation pipeline 10 enters from the top of the esterification reactor 12 and is immersed in the esterification reaction liquid, and the first circulation pipeline 10 is provided with a first nozzle 11 for spraying the liquid in the first circulation pipeline 10 into the esterification reactor 12.
The liquid in the esterification reaction device 1 circulates in the esterification reaction device 1 through a first circulating pipeline 10, and the reaction liquid impacts materials below the liquid surface under the high-speed injection of a first nozzle 11.
In further detail, the first circulation pipe 10 is connected to the dehydration esterification reactor 2 through a dehydration esterification reactor feed valve 19.
In further detail, the hydrogenation apparatus 4 includes a hydrogenation reactor 17 and a second circulation pipeline 18, one end of the second circulation pipeline 18 is connected to the bottom of the hydrogenation reactor 17, the other end of the second circulation pipeline 18 enters from the top of the hydrogenation reactor 17 and is immersed in the hydrogenation reaction liquid, the second circulation pipeline 18 is provided with a second nozzle 20 for spraying the liquid in the second circulation pipeline 18 into the hydrogenation reactor 17, and a balance pipe 21 is arranged between the hydrogenation reactor 17 and the second circulation pipeline 18.
The liquid in the hydrogenation reaction device 4 circulates in the hydrogenation reaction device 4 through the second circulation pipeline 18, the reaction liquid impacts the material below the liquid surface under the high-speed injection of the second nozzle 20, meanwhile, a certain low-pressure area is formed in the second nozzle 20, the balance pipe 21 arranged in the hydrogenation reactor 17 brings the gas (hydrogen) in the hydrogenation reactor 17 into the second nozzle 20, the gas is ejected to the reaction liquid along with the liquid, the purpose of mass transfer enhancement is achieved, and the gas-liquid contact is sufficient.
In further detail, the second circulation pipeline 18 is connected with the product collecting tank 9 through a discharge valve 22 of the hydrogenation reactor, and a second catalyst filter 23 is arranged between the second circulation pipeline 18 and the discharge valve of the hydrogenation reactor 17.
In more detail, the first circulation pipeline 10 and the second circulation pipeline 18 are both provided with a circulation pump 24 and a heat exchanger 25, steam enters from one end of the heat exchanger 25, and condensed water flows out from the other end of the heat exchanger 25.
In more detail, the hydrogenation reactor 17 is connected with an ethanol feeding device 26, a hydrogen supplementing device 27 and a nitrogen supplementing device 28, wherein the ethanol feeding device 26 is used for adding ethanol into the hydrogenation reactor 17; the hydrogen replenishing device 27 is used for charging hydrogen into the hydrogenation reactor 17, and the nitrogen replenishing device 28 is used for charging nitrogen into the hydrogenation reactor 17.
In more detail, a storage tank discharge valve 29 and a hydrogenation feed pump 30 are arranged between the intermediate storage tank 3 and the hydrogenation reactor 17, and the hydrogenation feed pump 30 is used for pumping the liquid in the intermediate storage tank 3 into the hydrogenation reactor 17.
In further detail, the bottom of the dehydration esterification kettle 2 is connected with the intermediate liquid storage tank 3 through a discharge valve 33 of the dehydration esterification kettle.
In further detail, a condenser 34 is arranged between the dehydration esterification kettle 2 and the azeotrope collecting tank 8, and the condenser 34 is used for condensing the gaseous azeotrope into a liquid state.
In more detail, a jacket 35 is arranged outside the dehydration esterification kettle 2, and the jacket 35 is used for introducing steam to raise the temperature in the dehydration esterification kettle 2. Hot steam is introduced into the jacket 35, the jacket 35 is sleeved outside the dehydration esterification kettle 2, the steam is fully contacted with the outer wall of the dehydration esterification kettle 2, and the temperature in the dehydration esterification kettle 2 is increased under the action of heat transfer. When the temperature reaches the required temperature, stopping introducing the steam.
In more detail, the hydrogenation apparatus 4 and the esterification apparatus 1 are further provided with thermometers 31, and the hydrogenation apparatus 4 is further provided with pressure sensors 32. The thermometer 31 is used to measure and display the liquid temperatures in the hydrogenation reaction apparatus 4 and the esterification reaction apparatus 1, i.e., the reaction temperature. The pressure sensor 3226 is used for measuring the pressure of the hydrogen gas in the hydrogenation reaction unit 4.
In further detail, the continuous solid feeding system comprises a feeding pipeline 36, a screw propeller 37, a feeding rotating wheel 38 and a brushing brush 39, wherein the screw propeller 37, the feeding rotating wheel 38 and the brushing brush 39 are sequentially arranged in the feeding pipeline 36 from top to bottom, the screw propeller 37, the feeding rotating wheel 38 and the brushing brush 39 are respectively provided with a driving motor 40, the screw propeller 37 is used for pushing solid materials to move in the feeding pipeline 36, the feeding rotating wheel 38 is used for controlling the feeding amount, and the brushing brush 39 is used for brushing materials adhered to the feeding rotating wheel 38 into the esterification reaction device 1.
The continuous solid feeding system feeds nitrobenzoic acid derivatives into the esterification reactor 12 at a set flow rate (Kg/h), it should be understood that the feeding pipe 36 is connected with a storage device for nitrobenzoic acid derivatives, the driving motor 40 drives the screw propeller 37, the screw propeller 37 pushes the nitrobenzoic acid derivatives to move in the feeding pipe 36, the feeding runner 38 rotates under the driving of the driving motor 40, and the amount of the nitrobenzoic acid derivatives entering the system is constant after one circle of the feeding runner 38. The rotational speed of the feed runner 38 and the feed rate are in a linear relationship. However, if material is attached to the feed rotor 38, this relationship is not correct. It is necessary that the brush 39 rotationally brushes off nitrobenzoic acid derivatives adhering to the feed runner 38 under the drive of the drive motor 40. If the brush brushes 39 are not used to remove material adhering to the wheel, feeding inaccuracies can result.
The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.
Although the esterification reaction device 1, the dehydration esterification reactor 2, the intermediate reservoir 3, the hydrogenation reaction device 4, the continuous solid feeding device 5, the solvent feeding device 6, the first catalyst feeding device 7, the azeotrope collecting tank 8, the product collecting tank 9, the first circulation pipeline 10, the first nozzle 11, the esterification reactor 12, the hydrogenation reactor 17, the second circulation pipeline 18, the dehydration esterification reactor feeding valve 19, the second nozzle 20, the balance pipe 21, the hydrogenation reactor discharging valve 22, the second catalyst filter 23, the circulation pump 24, the heat exchanger 25, the ethanol feeding device 26, the hydrogen feeding device 27, the nitrogen feeding device 28, the storage tank discharging valve 29, the hydrogenation feeding pump 30, the thermometer 31, the pressure sensor 32, the dehydration esterification reactor discharging valve 33, the condenser 34, the jacket 35, the feeding pipeline 36, the screw propeller 37, the feeding runner 38, Brush bristles 39, drive motor 40, etc., without excluding the possibility of using other terms. These terms are used merely to more conveniently describe and explain the nature of the present invention; they are to be construed as being without limitation to any additional limitations that may be imposed by the spirit of the present invention.
Claims (10)
1. A process for continuously producing aminobenzoate derivatives is characterized by comprising the following steps:
pretreatment: putting nitrobenzoic acid derivative, ethanol and a first catalyst into an esterification reaction device (1), and reacting for 1-1.5h at the temperature of 70-75 ℃;
continuous production: supplementing nitrobenzoic acid derivatives, ethanol and a first catalyst into the esterification reaction device (1) according to a preset proportion; meanwhile, the liquid in the esterification reaction device (1) flows into a dehydration esterification kettle (2); simultaneously, heating the liquid in the dehydration esterification kettle (2) to ensure that the ethanol-water in the dehydration esterification kettle (2) is subjected to azeotropic distillation, evaporating the azeotrope out of the dehydration esterification kettle (2) and collecting the azeotrope, and discharging the liquid in the dehydration esterification kettle (2) into an intermediate liquid storage tank (3); the liquid in the middle liquid storage tank (3) flows into the hydrogenation reaction device (4), hydrogenation reaction is carried out under the action of a second catalyst, the reaction temperature in the hydrogenation reaction device (4) is kept at 100-120 ℃, and hydrogen is introduced to keep the pressure in the hydrogenation reaction device (4) at 0.6-1 Mpa; the liquid in the hydrogenation reaction device (4) flows into a product collecting tank (9) to be collected, and a product is obtained.
2. The process for continuously producing an aminobenzoate derivative according to claim 1, wherein, in the pretreatment, after introducing nitrogen to remove air in the hydrogenation reaction unit (4), hydrogen is introduced into the hydrogenation reaction unit (4), and a second catalyst is added; in the continuous production, the liquid in the esterification reaction device (1) circulates in the esterification reaction device (1); the liquid in the hydrogenation reaction device (4) circulates in the hydrogenation reaction device (4), and the second catalyst circulates in the hydrogenation reaction device (4).
3. The process for continuously producing an aminobenzoate derivative according to claim 1, wherein the mass ratio of the dosage of the nitrobenzoic acid derivative, the ethanol and the first catalyst in the pretreatment is: 1:10-15: 0.1-0.3; the input amount of the second catalyst is 0.5 to 1 percent of the input amount of the nitrobenzoic acid derivative; during continuous production, the mass ratio of the nitrobenzoic acid derivative, the ethanol and the first catalyst added in each hour is 1:10-15: 0.1-0.3; and supplementing ethanol into the hydrogenation reaction device (4), wherein the supplementing amount of the ethanol is 5-10 times of that of the nitrobenzoic acid derivative.
4. The process for continuously producing an aminobenzoate derivative according to claim 1, wherein the first catalyst is one of concentrated sulfuric acid or p-toluenesulfonic acid; the second catalyst is a palladium on carbon catalyst.
5. The process for continuously producing an aminobenzoate derivative according to claim 1, characterized in that the residence time of the materials in the esterification reaction unit (1) is 1 to 1.5 hours; the retention time of the materials in the dehydration esterification kettle (2) is 2 to 3 hours; the retention time of the materials in the hydrogenation reaction device (4) is 2-3 hours.
6. The process for continuously producing an aminobenzoate derivative according to claim 1, wherein the nitrobenzoic acid derivative is one of p-nitrobenzoic acid, 3-nitrobenzoic acid, 2-chloro-4-nitrobenzoic acid, 3-bromo-4-nitrobenzoic acid, 3, 5-dichloro-4-nitrobenzoic acid.
7. A synthesis system for realizing the process for continuously producing aminobenzoate derivatives according to any one of claims 1 to 6, characterized by comprising an esterification reaction device (1), a dehydration esterification kettle (2), an intermediate liquid storage tank (3) and a hydrogenation reaction device (4) which are connected in sequence, wherein the esterification reaction device (1) is connected with a continuous solid feeding device (5) for feeding nitrobenzoic acid derivatives into the esterification reaction device (1), a solvent feeding device (6) and a first catalyst feeding device (7), the dehydration esterification kettle (2) is connected with an azeotrope collecting tank (8), and the hydrogenation reaction device (4) is connected with a product collecting tank (9).
8. A synthesis system according to claim 7, wherein the esterification reaction device (1) comprises an esterification reactor (12) and a first circulation pipeline (10), one end of the first circulation pipeline (10) is connected to the bottom of the esterification reactor (12), the other end of the first circulation pipeline (10) enters from the top of the esterification reactor (12) and is immersed in the esterification reaction liquid, the first circulation pipeline (10) is provided with a first nozzle (11) for spraying the liquid in the first circulation pipeline (10) into the esterification reactor (12), and the first circulation pipeline (10) is connected with the dehydration esterification kettle (2) through a dehydration esterification kettle feed valve (19); the hydrogenation reaction device (4) comprises a hydrogenation reactor (17) and a second circulating pipeline (18), one end of the second circulating pipeline (18) is connected to the bottom of the hydrogenation reactor (17), the other end of the second circulating pipeline (18) enters from the top of the hydrogenation reactor (17) and is immersed in hydrogenation reaction liquid, the second circulating pipeline (18) is provided with a second nozzle (20) for spraying liquid in the second circulating pipeline (18) into the hydrogenation reactor (17), and a balance pipe (21) is arranged between the hydrogenation reactor (17) and the second circulating pipeline (18); the second circulating pipeline (18) is connected with the product collecting tank (9) through a discharge valve (22) of the hydrogenation reactor, and a second catalyst filter (23) is arranged between the second circulating pipeline (18) and the discharge valve (22) of the hydrogenation reactor; the first circulating pipeline (10) and the second circulating pipeline (18) are both provided with a circulating pump (24) and a heat exchanger (25), steam enters from one end of the heat exchanger (25), and condensed water flows out from the other end of the heat exchanger (25).
9. A synthesis system according to claim 8, characterized in that the hydrogenation reactor (17) is connected with an ethanol feeding device (26), a hydrogen supplementing device (27) and a nitrogen supplementing device (28), the ethanol feeding device (26) is used for adding ethanol into the hydrogenation reactor (17); the hydrogen supplementing device (27) is used for charging hydrogen into the hydrogenation reactor (17), and the nitrogen supplementing device (28) is used for charging nitrogen into the hydrogenation reactor (17); a storage tank discharge valve (29) and a hydrogenation feed pump (30) are arranged between the intermediate liquid storage tank (3) and the hydrogenation reactor (17), the hydrogenation feed pump (30) is used for pumping liquid in the intermediate liquid storage tank (3) into the hydrogenation reactor (17), the hydrogenation reaction device (4) and the esterification reaction device (1) are further provided with thermometers (31), and the hydrogenation reaction device (4) is further provided with a pressure sensor (32).
10. A synthesis system according to claim 7, characterized in that the bottom of the dehydration esterification kettle (2) is connected with the intermediate liquid storage tank (3) through a dehydration esterification kettle discharge valve (33), a condenser (34) is arranged between the dehydration esterification kettle (2) and the azeotrope collecting tank (8), the condenser (34) is used for condensing the gaseous azeotrope into a liquid state, a jacket (35) is arranged outside the dehydration esterification kettle (2), and the jacket (35) is used for introducing steam to raise the temperature in the dehydration esterification kettle (2); continuous solid charge-in system include charge-in pipeline (36) and screw propeller (37), feeding runner (38), brush material brush (39) that set gradually in charge-in pipeline (36) from the top down, screw propeller (37), feeding runner (38) and brush material brush (39) all be provided with driving motor (40), screw propeller (37) be used for promoting solid material and remove in charge-in pipeline (36), feeding runner (38) be used for controlling the feeding volume, brush material brush (39) be arranged in with the material brush income esterification reaction unit (1) of adhesion on feeding runner (38).
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| CN113651713A (en) * | 2021-08-19 | 2021-11-16 | 宁夏中盛新科技有限公司 | Synthesis method of high-purity 2-nitro-4-acetamino anisole |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111732521A (en) * | 2020-06-16 | 2020-10-02 | 浙江优创材料科技股份有限公司 | Preparation method of ethyl p-aminobenzoate |
| CN111732521B (en) * | 2020-06-16 | 2021-04-20 | 浙江优创材料科技股份有限公司 | Preparation method of ethyl p-aminobenzoate |
| CN113651713A (en) * | 2021-08-19 | 2021-11-16 | 宁夏中盛新科技有限公司 | Synthesis method of high-purity 2-nitro-4-acetamino anisole |
| CN113651713B (en) * | 2021-08-19 | 2024-05-14 | 宁夏中盛新科技有限公司 | Synthesis method of high-purity 2-nitro-4-acetamido anisole |
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