Continuous reactor for preparing 1-(4-chlorphenyl)-3-pyrazole alcohol through oxidation

Abstract

The invention relates to a continuous reactor for preparing 1-(4-chlorphenyl)-3-pyrazole alcohol through oxidation. The reactor is internally provided with a push-down stirring region, a heat exchange region, a reaction region and a push-up stirring region, the push-down type stirring area is provided with a push-down type paddle stirrer used for mixing original materials, the heat exchange area is provided with a tubular heat exchanger used for controlling the temperature of the original materials, the original materials are dissolving liquid of 1-(4-chlorphenyl) pyrazolidine-3-ketone, and a certain amount of filler is added into the reaction area, so that efficient oxidation reaction is facilitated; a gas distributor is arranged below the reaction zone and used for uniformly dispersing air or oxygen, a push-up type three-blade stirring paddle is arranged in the push-up type stirring zone and used for lifting a product to a discharge port, and the product is 1-(4-chlorphenyl)-3-pyrazol alcohol. The continuous reactor provided by the invention can be used for quickly and uniformly mixing materials and improving the reaction efficiency of preparing 1-(4-chlorphenyl)-3-pyrazole alcohol through oxidation.

Description

Technical Field

[0001] The invention relates to the technical field of fine organic synthesis equipment, and in particular to a continuous reactor for oxidative preparation of 1-(4-chlorophenyl)-3-pyrazolol. Background Art

[0002] Pyraclostrobin is a new type of methoxyacrylate fungicide with low toxicity, low residue, safety to non-target organisms, small dosage and environmental friendliness. 1-(4-chlorophenyl)-3-pyrazolol is a key intermediate in the preparation of pyraclostrobin. It is currently prepared by hydrogen peroxide oxidation, which has the disadvantages of large amount of hydrogen peroxide, high hazard, large amount of wastewater, and inorganic ions in the wastewater are mixed salts, which makes it impossible to prepare high-content by-product salts and difficult to recycle, becoming a bottleneck restricting the production of pyraclostrobin. It can be seen that the optimization of its preparation method is crucial to improving the efficiency of the entire production process and product quality.

[0003] Air or oxygen is a clean and cheap oxidant. Using air or oxygen to catalytically oxidize 1-(4-chlorophenyl)pyrazolidine-3-one to prepare 1-(4-chlorophenyl)-3-pyrazolol can avoid the safety hazards caused by hydrogen peroxide as an oxidant, increase the yield of 1-(4-chlorophenyl)-3-pyrazolol, reduce the cost of raw materials, improve economic benefits, reduce the amount of wastewater generated, and achieve clean production. At present, in industry, microchannel reactors, plug flow tubular reactors and kettle reactors are mostly used to oxidize 1-(4-chlorophenyl)pyrazolidine-3-one with air or oxygen to prepare 1-(4-chlorophenyl)-3-pyrazolol. However, microchannel reactors have the problem that the reactor is easy to clog and difficult to clean; in the plug flow tubular reactor, the gas phase material of air or oxygen and the material of the reactant are very easy to separate into layers, making it difficult to fully mix and react, and the yield is low; in the kettle reactor, the air or oxygen oxidation reaction is easy to cause material backmixing, and the product yield is low and the quality is poor.

[0004] Therefore, it is necessary to provide a continuous reactor for preparing 1-(4-chlorophenyl)-3-pyrazolol by oxidation with air or oxygen to solve the above problems. Summary of the invention

[0005] The invention aims to provide a continuous reactor for preparing 1-(4-chlorophenyl)-3-pyrazolol with high efficiency by oxidation with air or oxygen.

[0006] The present invention provides a continuous reactor for preparing 1-(4-chlorophenyl)-3-pyrazolol by oxidation, which adopts the following technical scheme:

[0007] In the first aspect, the present invention provides a continuous reactor for preparing 1-(4-chlorophenyl)-3-pyrazolol by oxidation, wherein a push-down stirring zone, a heat exchange zone, a reaction zone and an upward pushing stirring zone are arranged in the reactor; the push-down stirring zone is provided with a push-down paddle stirrer for mixing, the heat exchange zone is provided with a shell-and-tube heat exchanger for controlling the temperature of the original material, the original material is a solution of 1-(4-chlorophenyl)pyrazolidine-3-one, a certain amount of filler is added to the reaction zone to help the oxidation reaction to proceed efficiently, a gas distributor is provided below the reaction zone for uniformly dispersing air or oxygen, the upward pushing stirring zone is provided with an upward pushing three-blade stirring paddle for lifting the product to the discharge port, and the product is 1-(4-chlorophenyl)-3-pyrazolol; a mist collector is provided above the reactor, the exhaust port of the reaction equipment is above the mist collector, and an air inlet and a sewage outlet are provided at the bottom of the reactor.

[0008] By adopting the above technical scheme, the air oxidation reaction is continuously carried out in the same reactor by setting up partitions, thereby improving the reaction efficiency and system stability; the original material is fed into the push-down stirring zone from the top feed port of the reaction equipment; the push-down paddle stirrer pushes the original material down to the gas distributor, and the first oxidation reaction is carried out in the pre-reaction zone with the air or oxygen entering the reactor through the air inlet and heat is released; the shell-and-tube heat exchanger in the heat exchange zone cools the first mixed liquid after the first oxidation reaction; the first mixed liquid enters the first reaction zone, and the rising airflow of the air or oxygen entering the reactor through the air inlet and the first mixed liquid flowing downward undergo a second oxidation reaction The second mixed liquid is formed; the second mixed liquid enters the second reaction zone under the action of power and gravity, and the rising airflow of air or oxygen entering the reactor through the air inlet and the second mixed liquid flowing upward undergo a third oxidation reaction in the second reaction zone to form a product; the shell and tube heat exchanger in the heat exchange zone is used to control the temperature of the product, and the upward push three-blade stirrer pushes the product upward to the discharge port or performs a continuous reaction again; in the reaction equipment, the material passes through the feed port to the discharge port and then to the feed port to form a closed loop and realize continuous circulation, thereby realizing the continuous reaction of preparing 1-(4-chlorophenyl)-3-pyrazole alcohol by oxidation with air or oxygen, and improving the reaction efficiency and system stability.

[0009] Preferably, the raw material feed port is a 45° bevel port, which is used to stabilize the feed flow rate of the raw material and prevent continuous material and airflow from hindering the feed.

[0010] Preferably, the push-down paddle agitator is a three-blade paddle with a stable rotation speed of 1500-2000 r / min.

[0011] Preferably, the total outlet area of ​​the gas distributor should be controlled to be 1.5 times the inlet area to ensure uniform and effective distribution of the gas.

[0012] Preferably, the upward push paddle agitator is a three-blade paddle with a stable rotation speed of 1500-2000 r / min.

[0013] Preferably, the discharge port is an inverted arc-shaped 45° angled port, which is used to stabilize the discharge flow rate of the product and prevent continuous materials and airflow from hindering the discharge.

[0014] Preferably, the outlet between the top of the reaction equipment and the mist collector is a clockwise arc angle outlet, which is used to stabilize the flow rate of the outlet gas flow and prevent continuous material flow from flowing out of the exhaust port.

[0015] By adopting the above technical scheme, during implementation, the continuous reaction process of preparing 1-(4-chlorophenyl)-3-pyrazolol by oxidation with air or oxygen can be completed by following the above steps in sequence; the method has the advantages of mild reaction conditions, low cost, high product yield and purity, and can continuously produce 1-(4-chlorophenyl)-3-pyrazolol.

[0016] Compared with traditional equipment, the present invention has the following characteristics:

[0017] 1. By setting up partitions, continuous air or oxygen oxidation reaction is achieved in the same reactor, thereby improving reaction efficiency and system stability; by setting up a push-down paddle stirrer, it is convenient to evenly mix the raw materials and push the raw materials down to the reaction zone, thereby providing power for continuous reaction; by setting up a gas distributor, the airflow is evenly dispersed, and the original materials and the airflow are evenly mixed and contacted in the reaction zone; by setting up a gas distributor on the other side, the bottom rising airflow is evenly dispersed, and the materials after two reactions reach the second reaction zone through the thrust of the bottom rising airflow, and the unreacted 1-(4-chlorophenyl)pyrazolidine-3-one is reacted to completion; the product 1-(4-chlorophenyl)-3-pyrazolol continues to rise under the thrust of the airflow, enters the shell-and-tube heat exchanger for cooling and enters the push-up stirring zone; the push-up three-blade stirrer is provided with an upward thrust by an electric motor to deliver the product to the discharge port.

[0018] 2. By setting up a gas separation device, the stable operation of the system can be further guaranteed; during implementation, the mist generated by the air or oxygen oxidation reaction is collected by the mist collector and discharged to the outside of the reactor through the exhaust pipe, which can prevent the mist or airflow from accumulating inside the reactor and having an adverse effect on the system. At the same time, the setting of the gas separation device also helps to maintain the gas concentration and distribution uniformity inside the reactor, thereby improving the treatment effect and service life of the reactor.

[0019] 3. It avoids the problems existing in the commonly used microchannel reactors, plug flow tubular reactors and kettle reactors in industry. The reaction conditions are mild, the cost is low, the product yield and purity are high, and it has good social and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention provides a cross-sectional view of the front side of a continuous reactor for preparing 1-(4-chlorophenyl)-3-pyrazolol by oxidation.

[0021] In the figure: 1-feed port; 2-motor; 3-push-down agitator; 4-gas distributor; 5-pre-reaction zone; 6-first air inlet; 7-first heat exchange zone; 8-first reaction zone; 9-gas distributor; 10-second air inlet; 11-drain port; 12-third air inlet; 13-gas distributor; 14-second reaction zone; 15-second heat exchange zone; 16-push-up agitator; 17-discharge port; 18-mist collector; 19-exhaust port. DETAILED DESCRIPTION

[0022] The following is combined with Figure 1 The present invention is described in further detail.

[0023] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. Unless otherwise defined, the technical terms or scientific terms used in the present invention should be the common meanings understood by technicians in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components.

[0024] Embodiment 1:

[0025] This embodiment discloses a continuous reactor for the oxidation preparation of 1-(4-chlorophenyl)-3-pyrazolol. Figure 1The reactor is provided with a push-down stirring zone, a heat exchange zone, a reaction zone and an upward stirring zone; the raw material is fed into the push-down stirring zone from the top feed port (1) of the reaction device; the push-down paddle stirrer (3) pushes the dissolved solution of 1-(4-chlorophenyl)pyrazolidine-3-one down to the gas distributor (4) to carry out a first oxidation reaction with the air or oxygen entering the reactor through the first air inlet (6) in the pre-reaction zone (5) and release heat; the heat exchanger of the first heat exchange zone (7) is a shell-and-tube heat exchanger, which is used to cool the first mixed solution after the first oxidation reaction, wherein the first mixed solution contains a large amount of raw material and a small amount of product; the first mixed solution enters the first reaction zone (8) to which filler has been added, and the air or oxygen entering the reactor through the second air inlet (10) is passed through the gas distributor (4). The air or oxygen enters the first reaction zone (8) after passing through the reactor (9), and the rising airflow of air or oxygen undergoes a second oxidation reaction with the first mixed liquid flowing downward to form a second mixed liquid, wherein the second mixed liquid contains a small amount of original material and a large amount of product; the second mixed liquid enters the second reaction zone (14) to which filler has been added under the action of power and gravity, and the air or oxygen entering the reactor through the third air inlet (12) passes through the gas distributor (13) and enters the second reaction zone (14), and the rising airflow of air or oxygen undergoes a third oxidation reaction with the second mixed liquid flowing upward to form a product; the heat exchanger in the second heat exchange zone (15) is a shell-and-tube heat exchanger for controlling the temperature of the product, and the upward-pushing three-blade agitator (16) is used to push the product upward to the discharge port (17) or to perform a continuous reaction again.

[0026] Continue to refer to Figure 1 The push-down stirring zone is composed of a motor (2) and a push-down paddle stirrer (3). The raw materials enter from the feed port (1). The push-down paddle stirrer (3) mixes the raw materials evenly and provides power for conveying the raw materials downward. At the same time, it overcomes the upward thrust of the rising airflow at the bottom, ensuring that the raw materials are conveyed downward and smoothly enter the pre-reaction zone for the first oxidation reaction.

[0027] Continue to refer to Figure 1 The first heating zone (7) inside the reaction device is provided with a shell-and-tube heat exchanger, the upper part of the shell-and-tube heat exchanger is connected to the push-down stirring zone, and the lower part is connected to the first reaction zone, and its function is to cool the first mixed liquid and provide a suitable reaction temperature for the air or oxygen oxidation reaction; in the shell-and-tube heat exchanger used for heating, the first mixed liquid enters the tube side of the shell-and-tube heat exchanger from top to bottom, and the heat exchange medium such as high-temperature steam enters the shell side from the lower inlet of the shell-and-tube heat exchanger to control the temperature of the first mixed liquid. The medium after heat exchange by the first mixed liquid leaves the shell side from the upper outlet of the shell-and-tube heat exchanger, ensuring that the first mixed liquid reaches a suitable reaction temperature.

[0028] Continue to refer to Figure 1During implementation, the first mixed liquid is sent into the first reaction zone for air or oxygen oxidation reaction; a gas distributor (9) is also provided inside the reaction device for uniformly dispersing the air or oxygen entering the reaction device from the air inlet (10) at the bottom of the reaction device, ensuring that the gas is uniformly dispersed and smoothly enters the first reaction zone above the gas distributor, so that the first mixed liquid is fully in contact with the air or oxygen, increasing the reaction contact area and promoting efficient reaction.

[0029] Continue to refer to Figure 1 During the implementation, the second mixed liquid after the first reaction on the right side flows to the left side of the reaction device, and air or oxygen enters from the second air inlet (12) at the bottom. The rising airflow passing through the gas distributor is evenly dispersed and provides rising power for the second mixed liquid. The second mixed liquid smoothly enters the second reaction zone and reacts 1-(4-chlorophenyl)pyrazolidine-3-one to completion, and the product is sent to the shell-and-tube heat exchanger in the second heat exchange zone (15) for cooling; in the shell-and-tube heat exchanger used for cooling, the product enters the tube side of the shell-and-tube heat exchanger from bottom to top, and the cooling medium such as cooling water enters the shell side from the lower inlet of the shell-and-tube heat exchanger to cool the high-temperature product. The cooling medium heated by the high-temperature product leaves the shell side from the upper outlet of the shell-and-tube heat exchanger, ensuring that the product is smoothly cooled to a suitable outlet temperature.

[0030] Continue to refer to Figure 1 The upward push stirring zone is composed of an upward push three-blade stirrer (16) and a motor. The product enters the upward push stirring zone from the cooling zone, and the upward push three-blade stirrer (16) mixes the product evenly and provides power for the product to be transported upward, thereby ensuring that the material is transported upward and smoothly taken out at the discharge port (17) at the top of the reaction equipment, or ensuring that the material enters the right side of the equipment for the next cycle, thereby realizing the continuous reaction of preparing 1-(4-chlorophenyl)-3-pyrazolol by air oxidation, and ensuring the efficiency of equipment operation and the stability of the system.

[0031] Embodiment 2:

[0032] The difference between Example 2 and Example 1 is that a gas separation device is also provided at the top of the reactor. The gas separation device comprises a mist trap (18) located at the top of the reactor and a gas outlet (19) connected to the mist trap (18); the mist trap (18) can capture the mist generated during the reaction to achieve gas separation, and discharge it to the outside of the reactor through the gas outlet (19); by providing the gas separation device, the stable operation of the system can be further guaranteed; during implementation, the mist generated by the air or oxygen oxidation reaction is collected by the mist trap (18) and then discharged to the outside of the reactor through the gas outlet (19), thereby preventing the mist or air from accumulating inside the reactor and causing adverse effects on the system. At the same time, the provision of the gas separation device also helps to maintain the gas concentration and distribution uniformity inside the reactor, thereby improving the treatment effect and service life of the reactor.

[0033] The implementation principle of the above embodiment is: by setting up partitions, continuous air or oxygen oxidation reaction is achieved in the same reactor, thereby improving the reaction efficiency and system stability. By setting up a push-down paddle agitator, it is convenient to evenly mix the raw materials and push the raw materials down to the heat exchange zone and the reaction zone, providing power for continuous reaction; by setting up a gas distributor, the air of the bottom rising airflow is evenly dispersed, and the raw materials and oxygen are evenly mixed and contacted in the reaction zone; by setting up a gas distributor on the other side, the air of the bottom rising airflow is evenly dispersed, and the material after a reaction reaches the second reaction zone through the thrust of the bottom rising airflow, and the unreacted 1-(4-chlorophenyl)pyrazolidine-3-one is reacted to completion; the product 1-(4-chlorophenyl)-3-pyrazolol continues to rise under the thrust of the airflow, enters the shell-and-tube heat exchanger for cooling and enters the push-up agitation zone; the push-up three-blade agitator is provided with an upward thrust by an electric motor to deliver the product to the discharge port. In the reaction equipment, the material flows from the feed port to the discharge port and then to the feed port to form a closed loop and realize continuous circulation, thereby realizing the continuous production of 1-(4-chlorophenyl)-3-pyrazolol by air oxidation.

[0034] During implementation, the above steps are sequentially followed to complete the reaction process of preparing 1-(4-chlorophenyl)-3-pyrazolol by oxidation with air or oxygen; the method has the advantages of mild reaction conditions, low cost, high product yield and purity, and can realize the continuous production of preparing 1-(4-chlorophenyl)-3-pyrazolol by oxidation with air or oxygen.

[0035] The above are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A continuous reactor for preparing 1-(4-chlorophenyl)-3-pyrazolol by oxidation, It is characterized in that The reactor is provided with a push-down stirring zone, a heat exchange zone, a reaction zone and an upward pushing stirring zone; the push-down stirring zone is provided with a push-down paddle stirrer for mixing the original material, the original material is a solution of 1-(4-chlorophenyl)pyrazolidine-3-one (containing a solvent and a catalyst); the heat exchange zone is provided with a heat exchanger for controlling the temperature of the mixed liquid, the mixed liquid is a mixed solution of the original material and the product, the product is 1-(4-chlorophenyl)-3-pyrazolol; the reaction zone is provided with a filler for oxidation reaction, a gas distributor is provided below the reaction zone for uniformly dispersing air or oxygen, the heat exchange zone is provided with a shell-and-tube heat exchanger for controlling the temperature of the mixed liquid, and the upward pushing stirring zone is provided with an upward pushing three-blade stirrer for lifting the product to the discharge port.

2. A continuous reactor for preparing 1-(4-chlorophenyl)-3-pyrazolol by oxidation as claimed in claim 1, It is characterized in that The raw material is fed into the push-down stirring zone through the top feed port (1) of the reaction device; the push-down paddle stirrer (3) pushes the dissolved liquid of 1-(4-chlorophenyl)pyrazolidine-3-one down to the gas distributor (4) to undergo a first oxidation reaction with the air or oxygen entering the reactor through the first air inlet (6) in the pre-reaction zone (5) and release heat; the heat exchanger of the first heat exchange zone (7) is a shell-and-tube heat exchanger, which is used to cool the first mixed liquid after the first oxidation reaction, wherein the first mixed liquid contains more raw material and a small amount of product; the first mixed liquid enters the first reaction zone (8) to which filler has been added, and the air or oxygen entering the reactor through the second air inlet (10) passes through the gas distributor (9) and enters the first reaction zone (8), and the rising airflow of air or oxygen undergoes a second oxidation reaction with the downwardly flowing first mixed liquid to form a second mixed liquid, wherein the second mixed liquid contains a small amount of raw material and a large amount of product; The second mixed liquid enters the second reaction zone (14) to which filler has been added under the action of power and gravity, and the air or oxygen entering the reactor through the third air inlet (12) enters the second reaction zone (14) after passing through the gas distributor (13). The rising airflow of air or oxygen reacts with the upwardly flowing second mixed liquid to undergo a third oxidation reaction to form a product. The heat exchanger in the second heat exchange zone (15) is a shell-and-tube heat exchanger for controlling the temperature of the third mixed liquid, and the upward push three-blade stirrer (16) is used to push the product upward to the discharge port (17) or to perform a continuous reaction again. The downward push three-blade stirrer (3) and the upward push three-blade stirrer (16) are connected to a power device, which is an electric motor (2).

3. A continuous reactor for preparing 1-(4-chlorophenyl)-3-pyrazolol by oxidation as claimed in claim 1, It is characterized in that A sewage outlet (11) is arranged at the bottom of the reaction device, and the sewage outlet is used to clean the dirt inside the reaction device when the device stops running; a mist collector (18) is arranged at the top of the reaction device to separate the mist from the air or oxygen, and the air or oxygen is discharged from the exhaust port (19) at the top of the reaction device.

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