Continuous synthesis device

Abstract

The utility model discloses a continuous synthesis device which comprises a feeding device, the feeding device is used for sequentially adding materials into the first bromination kettle and the second bromination kettle; one side of the first bromination kettle and one side of the second bromination kettle are connected with an absorption device; the output end of the second bromination kettle is connected with a washing rectification device, a solvent and a target product are separated, and one side of the washing rectification device is connected with the feeding device; the bromination reaction can be carried out at different temperatures by arranging the two bromination kettles connected in series, the feeding speed is controlled through the feeding device, the continuous reaction can be realized, the byproduct hydrobromic acid is absorbed through the absorption device, and the production cost can be further reduced.

Description

Technical Field

[0001] This utility model relates to the field of chemical equipment, and in particular to a continuous synthesis apparatus. Background Technology

[0002] 3,4-Dichlorobromobenzene is an important fine chemical intermediate with wide applications in the pesticide and pharmaceutical fields. It is a crucial raw material for the synthesis of 3,4-dichlorophenylboronic acid, a key intermediate in the fungicide bifenthrin. The most common industrial process involves the direct bromination of bromine with o-dichlorobenzene. Bromine is added dropwise to o-dichlorobenzene preheated to 45-60°C using iron powder or ferric chloride as a catalyst, or bromine is added dropwise to o-dichlorobenzene at 110°C using iron powder as a catalyst. After the reaction, distillation yields 3,4-dichlorobromobenzene.

[0003] Bromination is an exothermic reaction. Experiments have shown that at higher temperatures, bromine readily reacts with the product to form polybrominated products. Furthermore, as the reaction temperature increases, the selectivity of the bromide ion for the ortho and meta positions of o-dichlorobenzene decreases, leading to the formation of large amounts of 2,3-dichlorobromobenzene. However, at excessively low temperatures, bromine cannot react fully, resulting in a lower yield. Existing production facilities employ batch production, which facilitates temperature control and avoids the effects of excessively high or low temperatures. However, batch production is inefficient, while continuous production, besides being difficult to control in terms of temperature, also suffers from the problem of excessively high bromine concentrations at the dropping point, affecting the reaction of 3,4-dichlorobromobenzene. Utility Model Content

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a continuous synthesis device.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a continuous synthesis apparatus, comprising:

[0006] Feeding device;

[0007] The feeding device sequentially adds materials to the first bromination reactor and the second bromination reactor;

[0008] One side of the first bromination reactor and the second bromination reactor is connected to the absorption device;

[0009] The output end of the second bromination reactor is connected to a water washing distillation device to separate the solvent from the target product. One side of the water washing distillation device is connected to the feeding device.

[0010] As a further description of the above technical solution: the feeding device includes a solvent metering pump and a bromine metering pump, and the output ends of the solvent metering pump and the bromine metering pump are connected to a dilution tank.

[0011] As a further description of the above technical solution: the output end of the dilution tank is connected to a first drip pump.

[0012] As a further description of the above technical solution: the output end of the first drip pump is connected to the first bromination reactor.

[0013] As a further description of the above technical solution: a storage tank is provided on the first bromination reactor, and a second drip pump is provided at the output end of the storage tank, and the output end of the second drip pump is connected to the first bromination reactor.

[0014] As a further description of the above technical solution: a catalyst feeder is also provided on the first bromination reactor.

[0015] As a further description of the above technical solution: the output end of the first bromination reactor is connected to the second bromination reactor, and a stirring rod is provided in both the first bromination reactor and the second bromination reactor.

[0016] As a further description of the above technical solution: a condenser is connected to one side of the first bromination reactor and the second bromination reactor;

[0017] The output end of the condenser is connected to the absorption device.

[0018] As a further description of the above technical solution: the absorption device includes at least one or more water absorption towers and alkali absorption towers connected in sequence.

[0019] As a further description of the above technical solution: the water washing distillation device includes a water washing vessel and a distillation column connected in sequence, one side of the distillation column is connected to the first dropping pump, and the target product is delivered from the output end of the distillation column.

[0020] The above technical solution has the following advantages or beneficial effects:

[0021] This application enables bromination reactions to be carried out at different temperatures by setting up two bromination reactors in series, and the feeding rate can be controlled by a feeding device to achieve continuous reaction. The by-product hydrobromic acid can be absorbed by an absorption device, which can further reduce production costs. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the synthesis device proposed in this utility model.

[0023] Legend:

[0024] 1. Feeding device; 11. Solvent metering pump; 12. Bromine metering pump; 13. Dilution tank; 14. First dropping pump; 2. First bromination reactor; 21. Storage tank; 22. Second dropping pump; 23. Catalyst feeder; 3. Second bromination reactor; 4. Absorption device; 41. Water absorption tower; 42. Alkali absorption tower; 5. Water washing distillation device; 51. Water washing vessel; 52. Distillation column; 6. Condenser. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] Reference Figure 1 The present invention provides an embodiment of a continuous synthesis apparatus, comprising: a feeding device 1; the feeding device 1 sequentially adds materials to a first bromination reactor 2 and a second bromination reactor 3; one side of the first bromination reactor 2 and the second bromination reactor 3 is connected to an absorption device 4; the output end of the second bromination reactor 3 is connected to a water washing distillation device 5 to separate the solvent and the target product, and one side of the water washing distillation device 5 is connected to the feeding device 1.

[0027] In this embodiment, solvent and bromine are continuously added dropwise to the first bromination reactor 2 via the feeding device 1. A bromination reaction takes place in the first bromination reactor 2, where bromine reacts with o-dichlorobenzene and the catalyst. The overflow port of the first bromination reactor 2 is connected to the second bromination reactor 3 via a pipeline, allowing the reaction liquid to continue reacting in the second bromination reactor 3. The first and second bromination reactors 2 and 3 can be set to different heating temperatures according to actual needs to control the internal reaction temperature. The hydrogen bromide gas generated in the second bromination reactor 3 is transported to the absorption device 4 to obtain the byproduct hydrobromic acid. The reaction liquid is transported to the water washing and distillation device 5 for water washing and distillation to separate the solvent and the target product, 3,4-dichlorobromobenzene. The solvent is returned to the feeding device 1 for recycling. By setting up two bromination reactors in series, the bromination reaction can be carried out at different temperatures, and the feeding rate can be controlled by the feeding device, enabling continuous reaction. The absorption of the byproduct hydrobromic acid by the absorption device can further reduce production costs.

[0028] The feeding device 1 includes a solvent metering pump 11 and a bromine metering pump 12, the output ends of which are connected to a dilution tank 13.

[0029] In this embodiment, the feeding rate is controlled by solvent metering pump 11 and bromine metering pump 12. The solvent can be a halogenated hydrocarbon, aromatic hydrocarbon or ether, which can be selected according to actual production needs. The solvent and bromine are added to dilution tank 13 to dilute the bromine. The dilution ratio is controlled by the drip rate of solvent metering pump 11 and bromine metering pump 12.

[0030] The output end of the dilution tank 13 is connected to the first drop pump 14; the output end of the first drop pump 14 is connected to the first bromination reactor 2.

[0031] In this embodiment, the diluted bromine is added dropwise into the first bromination reactor 2 by the first drop pump 14 to carry out the subsequent bromination reaction.

[0032] Specifically, a storage tank 21 is provided on the first bromination reactor 2, and a second drip pump 22 is provided at the output end of the storage tank 21. The output end of the second drip pump 22 is connected to the first bromination reactor 2.

[0033] In this embodiment, o-dichlorobenzene is placed inside the storage tank 21, and the o-dichlorobenzene is added dropwise into the first bromination reactor 2 by the second drip pump 22 to carry out the bromination reaction.

[0034] Specifically, a catalyst feeder 23 is also installed on the first bromination reactor 2.

[0035] In this embodiment, the catalyst is iron powder, and the catalyst feeder 23 can control the addition of the catalyst to the first bromination reactor 2 for catalytic bromination reaction.

[0036] The output end of the first bromination vessel 2 is connected to the second bromination vessel 3, and stirring rods are installed in both the first bromination vessel 2 and the second bromination vessel 3.

[0037] In this embodiment, the output end of the first bromination vessel 2 is an overflow port, allowing the reaction liquid to flow into the second bromination vessel 3 to continue the reaction. The reaction liquid inside the first bromination vessel 2 and the second bromination vessel 3 is stirred by the stirring rods to ensure that the bromination reaction proceeds fully.

[0038] A condenser 6 is connected to one side of the first bromination vessel 2 and the second bromination vessel 3; the output end of the condenser 7 is connected to the absorption device 4.

[0039] In this embodiment, hydrogen bromide gas is generated during the reaction in the first bromination reactor 2 and the second bromination reactor 3. After being condensed by the condenser 7, the gas is transported to the absorption device 4.

[0040] The absorption device 4 includes at least one or more water absorption towers 41 and alkali absorption towers 42 connected in sequence.

[0041] In this embodiment, the water absorption tower 41 includes a primary water absorption tower and a secondary water absorption tower, and is subsequently connected to an alkali absorption tower 42 to prepare hydrobromic acid from the condensed hydrogen bromide.

[0042] The water washing distillation apparatus 5 includes a water washing vessel 51 and a distillation column 52 connected in sequence. One side of the distillation column 52 is connected to the first dropping pump 14, and the target product is delivered from the output end of the distillation column 52.

[0043] In this embodiment, the second bromination reactor 3 transports the reaction solution to the water washing reactor 51 for cleaning, and after cleaning, it is transported to the distillation column 52 to separate the solvent from 3,4-dichlorobromobenzene.

[0044] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A continuous synthesis apparatus, characterized in that, include: Feeding device (1); The feeding device (1) feeds the material sequentially into the first bromination reactor (2) and the second bromination reactor (3); One side of the first bromination vessel (2) and the second bromination vessel (3) is connected to the absorption device (4); The output end of the second bromination vessel (3) is connected to the water washing distillation device (5) to separate the solvent from the target product. One side of the water washing distillation device (5) is connected to the feeding device (1).

2. The synthesis apparatus according to claim 1, characterized in that: The feeding device (1) includes a solvent metering pump (11) and a bromine metering pump (12), the output ends of which are connected to a dilution tank (13).

3. The synthesis apparatus according to claim 2, characterized in that: The output end of the dilution tank (13) is connected to a first drip pump (14).

4. The synthesis apparatus according to claim 3, characterized in that: The output end of the first drip pump (14) is connected to the first bromination vessel (2).

5. The synthesis apparatus according to claim 1, characterized in that: The first bromination reactor (2) is provided with a storage tank (21), and the output end of the storage tank (21) is provided with a second drip pump (22), and the output end of the second drip pump (22) is connected to the first bromination reactor (2).

6. The synthesis apparatus according to claim 1, characterized in that: The first bromination reactor (2) is also equipped with a catalyst feeder (23).

7. The synthesis apparatus according to claim 1, characterized in that: The output end of the first bromination vessel (2) is connected to the second bromination vessel (3), and stirring rods are provided in the first bromination vessel (2) and the second bromination vessel (3).

8. The synthesis apparatus according to claim 1, characterized in that: A condenser (6) is connected to one side of the first bromination vessel (2) and the second bromination vessel (3); The output end of the condenser (6) is connected to the absorption device (4).

9. The synthesis apparatus according to claim 1, characterized in that: The absorption device (4) includes at least one or more water absorption towers (41) and alkali absorption towers (42) connected in sequence.

10. The synthesis apparatus according to claim 3, characterized in that: The water washing distillation apparatus (5) includes a water washing vessel (51) and a distillation column (52) connected in sequence. One side of the distillation column (52) is connected to the first dropping pump (14), and the target product is delivered from the output end of the distillation column (52).

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