Continuous synthesis and rectification production system for benzoyl chloride

Abstract

The utility model relates to a benzoyl chloride continuous synthesis rectification production system which comprises a reaction kettle, the upper part of an outlet of the reaction kettle is connected with a distillation tower, the upper part of the distillation tower is provided with a condenser, and the middle part of the distillation tower and the top of the condenser are respectively communicated with a benzoyl chloride product collecting tank through pipelines; a gas-phase outlet of the condenser and a gas-phase outlet of the benzoyl chloride product collecting tank are respectively and sequentially communicated with the falling film absorption tower and the vacuum pump through pipelines; and the hydrochloric acid absorption tank circularly absorbs hydrogen chloride gas through a hydrochloric acid circulating pump to prepare hydrochloric acid. According to the method, trichlorotoluene and benzoic acid are used as raw materials, continuous heating, continuous feeding and continuous rectification are carried out in a vacuum state to obtain a finished product, a condensation reaction is carried out to generate a benzoyl chloride finished product, and hydrogen chloride gas generated by the reaction is continuously absorbed by water to prepare hydrochloric acid. The device disclosed by the utility model has the advantages of simple process route, high reaction speed, continuous production, one-step completion of synthesis and rectification, energy conservation, few preparation facilities and low emission of three wastes.

Description

Technical Field

[0001] The utility model belongs to the field of organic compound preparation and purification methods, in particular to a benzoyl chloride continuous synthesis and rectification production system. Background Art

[0002] Benzoyl chloride is widely used as a monomer in the production of pesticides, pharmaceuticals, and dyes. It is also used to manufacture the initiator dibenzoyl peroxide, and is also used as an important chemical raw material for the production of benzophenone, benzyl benzoate, benzyl cellulose, benzamide, and tert-butyl peroxybenzoate. In pesticides and herbicides, benzoyl chloride is a new induction-type insecticide and an intermediate for isoxathion (Karphos). Benzoic acid and benzoyl chloride can also react to produce benzoic anhydride. Due to fierce market competition, there is a need to reduce production costs and improve market competitiveness. Currently, there are multiple main production processes for benzoyl chloride, most of which use a batch reaction between trichlorotoluene and benzoic acid, which results in slow production, high equipment investment, and high energy consumption. Utility Model Content

[0003] In view of the above problems, the utility model provides a continuous synthesis and distillation production system for benzoyl chloride.

[0004] Technical solution of this utility model:

[0005] A continuous synthesis and distillation production system for benzoyl chloride comprises a reactor, wherein the upper portion of the reactor outlet is connected to a distillation tower, a condenser is provided on the upper portion of the distillation tower, the middle portion of the distillation tower and the top of the condenser are respectively connected to a benzoyl chloride product collecting tank via pipelines, the gas phase outlet of the condenser and the gas phase outlet of the benzoyl chloride product collecting tank are respectively connected to a falling film absorption tower and a vacuum pump in sequence via pipelines, and a hydrochloric acid absorption tank circulates and absorbs hydrogen chloride gas via a hydrochloric acid circulation pump to prepare hydrochloric acid.

[0006] Preferably, the benzoic acid melt tank and the trichlorotoluene preparation tank are connected to the reactor through pipelines respectively.

[0007] Preferably, a material collecting tray is provided between the condenser and the distillation tower, and the material collecting tray is connected to the distillation tower through a pipeline to form a reflux pipeline; the material reflux port of the reflux pipeline is connected to the lower part of the weir of the material collecting tray, the material reflux port is connected to the distributor in the tower, and the material is evenly distributed back into the distillation tower through the distributor, and the material collecting port is connected to the upper part of the weir of the material collecting tray, so that the material can preferentially meet the reflux requirements.

[0008] Further preferably, the material collection plate includes a collection trough arranged along the inner wall of the distillation tower, and a collection plate is arranged on the upper part of the collection trough. The collection plate includes a plurality of collection plates arranged in an upper and lower layers. The collection plate is a groove structure, the concave surface of the upper collection plate is downward, and the concave surface of the lower collection plate is upward. After condensation, the liquid flows from the upper collection plate into the lower collection plate and then into the collection trough to collect the material. A spacing is provided between the upper and lower collection plates to ensure the gas phase channel. A material collection port is provided on the upper side of the collection trough, and a material reflux port is provided on the lower side of the collection trough; further preferably, the collection trough is 4-6 cm wide and 6-8 cm high; and a spacing of 9-12 cm is provided between the upper and lower collection plates.

[0009] Preferably, a hydrochloric acid absorption tank is provided below the falling film absorption tower; preferably, the height difference between the falling film absorption tower and the hydrochloric acid absorption tank is greater than 10 meters, so as to prevent liquid hydrochloric acid in the hydrochloric acid storage tank from entering the falling film absorption tower under high vacuum conditions.

[0010] Preferably, the bottom of the benzoyl chloride product collecting tank is connected to the product external transfer pump through a pipeline, and the benzoyl chloride product collecting tank is more than 6 meters higher than the product external transfer pump.

[0011] The production system performs a continuous synthesis and rectification preparation method for benzoyl chloride, and the method comprises the following steps:

[0012] 1) Adding benzotrichloride and a catalyst (the catalyst is added for the first time and not added for continuous production) into a benzotrichloride preparation tank and mixing them to obtain a benzotrichloride mixed solution; adding benzoic acid into a benzoic acid melting tank and heating and melting it into a benzoic acid liquid; and heating the reactor;

[0013] 2) The trichlorotoluene mixed solution and benzoic acid liquid are continuously introduced into the reactor, and the temperature is increased to vaporize the reaction products into the distillation tower. The materials are condensed and recovered through the condenser, and gradually distilled and refluxed to make the product qualified, and then collected into the benzoyl chloride product collection tank. The benzoyl chloride product collection tank is more than 6 meters higher than the product external transfer pump. When the product in the benzoyl chloride product collection tank reaches a certain amount, the product external transfer pump is used to transfer it to the storage tank for packaging.

[0014] Preferably, the temperature in steps 1) and 2) is raised to 135-155° C., and the pressure inside the reactor is less than 1 KPa, to ensure that the generated benzoyl chloride can be continuously distilled into the collection tank.

[0015] Preferably, the reflux ratio of the distillation reflux in step 2) is full reflux during the initial production. After the product sampling and testing meets the quality standard, the reflux rate is gradually reduced and the benzoyl chloride product is collected. After the reaction is normal, the reflux ratio is controlled between 8-12%. The high-boiling-point trichlorotoluene is cooled and returned to the reactor with the product benzoyl chloride to ensure that the trichlorotoluene content in the benzoyl chloride product is below 0.3%.

[0016] Preferably, in step 1), the temperature at which benzoic acid is put into the benzoic acid melt tank and heated to melt is 130±5°C.

[0017] Preferably, in step 1), the molar ratio of benzotrichloride to benzoic acid is (1.03-1.5):1, and the catalyst is a Lewis acid (the catalyst is a Lewis acid including AlCl3, BF3, SbCl5, FeBr3, FeCl3, SnCl4, TiCl4, ZnCl2).

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. This utility model combines the reaction and distillation of trichlorotoluene with a catalyst and benzoic acid, with continuous feed, reaction, and discharge for synthetic distillation. The generated hydrogen chloride gas is continuously absorbed to produce hydrochloric acid. The condensation reaction and distillation temperatures are controlled between 135°C and 155°C. Conventionally, the reaction temperature is raised from room temperature to 130°C, followed by distillation at 135-155°C before entering the distillation tower. This method now directly reacts the liquid and distills at 135-155°C, saving energy (previously, it was added dropwise). Furthermore, the catalyst is not discharged and remains in use, saving catalyst usage. Previously, the catalyst entered the distillation kettle, becoming residue and hazardous waste.

[0020] 2. The gas phase outlet on the upper part of the condenser is connected to the gas phase outlet of the collection tank, and then connected to the hydrochloric acid absorption device. The hydrogen chloride gas is absorbed by the falling film absorption tower to prepare hydrochloric acid. The gas phase outlet of the falling film absorption tower is connected to the vacuum system. The synthesis distillation system is brought to high vacuum, and the material is distilled during the synthesis process to collect the finished product.

[0021] 3. Benzoic acid is liquefied by heating to make solid benzoic acid into liquid state, which is convenient for continuous addition.

[0022] 4. The material is collected in a collection tray, and reflux is used to increase the product content. The reflux pipe outlet is connected to the lower part of the collection tank weir, and the discharge port is connected to the upper part of the collection tray weir. This ensures the reflux volume and prioritizes the material to meet reflux requirements. A double sampling valve is added to the lower part of the reflux pipe. Based on the sampling test results, if the product meets the requirements, the reflux is reduced and product collection begins. The falling film absorption tower is installed at a high position, with the lower pipe inserted below the liquid level to prevent hydrochloric acid from being drawn into the vacuum system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The process flow chart of this utility model;

[0024] Figure 2 Schematic diagram of the material collection tray structure;

[0025] Figure 3 Top view of the material collection tray;

[0026] Wherein: trichlorotoluene flowmeter 1, trichlorotoluene regulating valve 2, benzoic acid flowmeter 3, benzoic acid regulating valve 4, reactor 5, condenser 6, material collecting tray 7, collecting tank 7-1, collecting tray 7-2, material collecting port 7-3, material reflux port 7-4, reflux regulating valve 8, reflux distributor 9, benzoyl chloride product collecting tank 10, falling film absorption tower 11, hydrochloric acid absorption tank 12, hydrochloric acid transfer pump 13, hydrochloric acid circulation pump 14, trichlorotoluene preparation tank 15, benzoic acid melt tank 16, distillation tower 17, first sampling switch valve 18, second sampling switch valve 19, product external transfer pump 20. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the technical solution of the present invention, the applicant will further explain the present invention in detail with reference to the embodiments and drawings.

[0028] Example 1

[0029] A continuous synthesis and distillation production system for benzoyl chloride comprises a reactor 5, wherein the upper portion of the reactor 5 outlet is connected to a distillation tower 17, a condenser 6 is provided on the upper portion of the distillation tower 17, the middle portion of the distillation tower 17 and the top of the condenser 6 are respectively connected to a benzoyl chloride product collecting tank 10 via pipelines, and the gas phase outlet of the condenser 6 and the gas phase outlet of the benzoyl chloride product collecting tank 10 are respectively connected to a falling film absorption tower 11 and a vacuum pump via pipelines in sequence.

[0030] Preferably, the benzoic acid melt tank 16 and the trichlorotoluene preparation tank 15 are connected to the reactor 5 through pipelines respectively.

[0031] Preferably, a material collecting tray 7 is provided between the condenser 6 and the distillation tower 17, and the material collecting tray 7 is connected to the distillation tower 17 through a pipeline to form a reflux pipeline; the material reflux port 7-4 of the reflux pipeline is connected to the lower part of the weir of the material collecting tray 7, and the material reflux port 7-4 is connected to the distributor 9 in the tower 17, and is evenly distributed back into the distillation tower 17 through the distributor 9, and the material collecting port 7-3 is connected to the upper part of the weir of the material collecting tray 7, so that the material meets the reflux requirements first.

[0032] Preferably, the material collecting tray 7 includes a collecting tank 7-1 arranged along the inner wall of the distillation tower 17, and a collecting tray 7-2 is arranged on the upper part of the collecting tank 7-1. The collecting tray 7-2 includes a plurality of collecting plates arranged in an upper and lower layers. The collecting plates are groove structures, the concave surface of the upper collecting plate is downward, and the concave surface of the lower collecting plate is upward. After condensation, the liquid flows from the upper collecting plate into the lower collecting plate, and then flows into the collecting tank 7-1 to collect the material. A spacing is provided between the upper and lower collecting plates to ensure a gas phase channel. A material collecting port 7-3 is provided on the upper side of the collecting tank 7-1, and a material reflux port 7-4 is provided on the lower side of the collecting tank 7-1; more preferably, the collecting tank 7-1 is 5 cm wide and 7 cm high; and a spacing of 10 cm is provided between the upper and lower collecting plates.

[0033] Preferably, a hydrochloric acid absorber 12 is provided below the falling film absorber 11 ; further preferably, the height difference between the falling film absorber 11 and the hydrochloric acid absorber 12 is greater than 10 meters to prevent liquid hydrochloric acid from entering the falling film absorber 11 .

[0034] Preferably, the bottom of the benzoyl chloride product collecting tank 10 is connected to the product external transfer pump 20 through a pipeline, and the benzoyl chloride product collecting tank 10 is more than 206 meters higher than the product external transfer pump.

[0035] A method for preparing benzoyl chloride by continuous synthesis and rectification using any one of the production systems described herein comprises the following steps:

[0036] 1) adding benzotrichloride and a catalyst into a benzotrichloride preparation tank 15 and mixing them to obtain a benzotrichloride mixed solution; adding benzoic acid into a benzoic acid melting tank 16 and heating and melting it to obtain a benzoic acid liquid; and heating the reactor 5;

[0037] 2) The trichlorotoluene mixed solution and benzoic acid liquid are continuously introduced into the reactor 5, and the temperature is increased to vaporize the reaction products into the distillation tower 17. The products are condensed and recovered by the condenser 6, and gradually distilled and refluxed to meet the requirements, and then collected into the finished product collection tank.

[0038] Preferably, the temperature in steps 1) and 2) is raised to 140°C.

[0039] Preferably, the reflux ratio of the distillation reflux in step 2) is full reflux during initial production. After the product sampling and testing meets the quality standard, the reflux rate is gradually reduced and the benzoyl chloride product is collected. After the reaction is normal, the reflux ratio is controlled between 8-12%. The high-boiling-point trichlorotoluene is cooled and returned to the reactor 5 with the product benzoyl chloride to ensure that the trichlorotoluene content in the benzoyl chloride product is below 0.3%.

[0040] Preferably, in step 1), the temperature at which benzoic acid is put into the benzoic acid melt tank 16 and heated to melt is 130°C.

[0041] Preferably, in step 1), the molar ratio of trichlorotoluene to benzoic acid is 1.03:1, and the catalyst is FeCl3.

[0042] Example 2

[0043] Based on Example 1, the reflux ratio in step 2) is full reflux during initial production. After product sampling and testing meet quality standards, the reflux rate is gradually reduced and the benzoyl chloride product is collected. After the reaction is normal, the reflux ratio is controlled between 8-12%. The high-boiling benzoyl chloride is cooled and returned to the reactor 5 with the benzoyl chloride product to ensure that the benzoyl chloride content in the benzoyl chloride product is below 0.3%. The results of different reflux ratios are shown in Table 1 below.

[0044] Table 1

[0045]

[0046] As can be seen from Table 1, it is more appropriate to control the reflux ratio at 8-12%, the product content can meet market requirements, and the product collection volume is large.

[0047] Example 3

[0048] Based on Example 1, the temperature of heating in step 2) was changed.

[0049] Table 2

[0050]

[0051] As can be seen from Table 2, the reaction temperature of reactor 5 is 140-150°C, which is a suitable reaction temperature.

[0052] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field within the technical scope disclosed by the present invention can make equivalent replacements or changes based on the technical solution and utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A continuous synthesis and distillation production system for benzoyl chloride, comprising a reactor (5), characterized in that: The upper portion of the outlet of the reactor (5) is connected to a distillation tower (17), a condenser (6) is provided on the upper portion of the distillation tower (17), the middle portion of the distillation tower (17) and the top portion of the condenser (6) are respectively connected to a benzoyl chloride product collecting tank (10) through pipelines, the gas phase outlet of the condenser (6) and the gas phase outlet of the benzoyl chloride product collecting tank (10) are respectively connected to a falling film absorption tower (11) and a vacuum pump in sequence through pipelines, and the hydrochloric acid absorption tank (12) is circulated by a hydrochloric acid circulation pump (14) to absorb hydrogen chloride gas to prepare hydrochloric acid.

2. The benzoyl chloride continuous synthesis and distillation production system according to claim 1, wherein: The benzoic acid melt tank (16) and the trichlorotoluene preparation tank (15) are connected to the reactor (5) through pipelines.

3. The benzoyl chloride continuous synthesis and distillation production system according to claim 1, characterized in that: A material collecting tray (7) is provided between the condenser (6) and the distillation tower (17). The material collecting tray (7) is connected to the distillation tower (17) through a pipeline to form a reflux pipeline. The material reflux port (7-4) of the reflux pipeline is connected to the lower part of the weir groove of the material collecting tray (7). The material reflux port (7-4) is connected to the distributor (9) in the distillation tower (17). The material is evenly distributed and returned to the distillation tower (17) through the distributor (9). The material collecting port (7-3) is connected to the upper part of the weir groove of the material collecting tray (7).

4. The benzoyl chloride continuous synthesis and distillation production system according to claim 1, characterized in that: The material collecting tray (7) includes a collecting trough (7-1) arranged along the inner wall of the distillation tower (17), a collecting tray (7-2) is arranged on the upper part of the collecting trough (7-1), and the collecting tray (7-2) includes a plurality of collecting plates arranged in a staggered manner in two layers. The collecting plates are groove structures, the concave surface of the upper collecting plate is downward, and the concave surface of the lower collecting plate is upward. A material collecting port (7-3) is provided on the upper side of the collecting trough (7-1), and a material reflux port (7-4) is provided on the lower side of the collecting trough (7-1).

5. The benzoyl chloride continuous synthesis and distillation production system according to claim 4, characterized in that: The collecting trough (7-1) has a width of 4-6 cm and a height of 6-8 cm; a spacing of 9-12 cm is provided between the upper and lower collecting plates.

6. The continuous synthesis and distillation production system of benzoyl chloride according to claim 1, characterized in that: A hydrochloric acid absorption tank (12) is provided below the falling film absorption tower (11).

7. The continuous synthesis and distillation production system of benzoyl chloride according to claim 6, characterized in that: The height difference between the falling film absorption tower (11) and the hydrochloric acid absorption tank (12) is greater than 10 meters.

8. The continuous synthesis and distillation production system of benzoyl chloride according to claim 1, characterized in that: The bottom of the benzoyl chloride product collecting tank (10) is connected to the product external transfer pump (20) through a pipeline, and the benzoyl chloride product collecting tank (10) is more than 6 meters higher than the product external transfer pump (20).

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