Continuous synthesis and rectification production system and method for benzoyl chloride
By adopting the method of combining continuous reaction and distillation in the benzoyl chloride production system, the problems of slow production speed and high energy consumption in the prior art are solved, and efficient benzoyl chloride synthesis and distillation are achieved, and production efficiency is improved. Product quality.
Patent Information
- Application Number
- CN202411470277.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-21
- Publication Date
- 2025-02-18
AI Technical Summary
In the prior art, the production process routes of benzoyl chloride are numerous and complex, resulting in slow production speed, large equipment investment and high energy consumption, making it difficult to meet the fierce market competition needs.
A benzoyl chloride continuous synthesis and distillation production system is adopted, the system includes a reactor, a distillation tower, a condenser and a hydrochloric acid absorption tower. Through continuous reaction and distillation merging, the condensation reaction temperature and distillation temperature are controlled to achieve continuous absorption of hydrogen chloride gas and Preparation of hydrochloric acid.
It realizes efficient continuous synthesis and distillation of benzoyl chloride, reduces energy consumption, saves the amount of catalyst, and improves production efficiency and product quality.
Smart Images
Figure CN119455820A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of organic compound preparation and purification methods, in particular to a benzoyl chloride continuous synthesis and distillation production system and method. Background Art
[0002] Benzoyl chloride is widely used in the production of pesticides, medicines and dyes, and is used to manufacture initiator dibenzoyl peroxide, and is secondly used in the production of benzophenone, benzyl benzoate, benzyl cellulose and benzamide, etc. Important chemical raw materials, tert-butyl peroxybenzoate, in terms of pesticides, pesticide herbicides, benzoyl chloride is a new type of induction insecticide and is an intermediate of isoxathion (Karphos). In addition, benzoic acid and benzoyl chloride can also produce benzoic anhydride. Due to the fierce market competition now, it is necessary to reduce the production cost of products to improve market competitiveness. At present, there are many main production process routes for preparing benzoyl chloride, and most of them adopt intermittent reaction of trichlorotoluene and benzoic acid, which has slow production speed, large equipment investment and high energy consumption. Summary of the invention
[0003] In view of the above problems, the present invention provides a continuous synthesis and distillation production system and method for benzoyl chloride.
[0004] Technical solution of the present invention: A benzoyl chloride continuous synthesis and distillation production system comprises a reactor, wherein the upper part of the reactor outlet is connected to a distillation tower, a condenser is arranged on the upper part of the distillation tower, the middle part of the distillation tower and the top of the condenser are respectively connected to a benzoyl chloride product collecting tank through 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 through pipelines, and a hydrochloric acid absorption tank is circulated and absorbed by a hydrochloric acid circulating pump to prepare hydrochloric acid through hydrogen chloride gas.
[0005] Preferably, the benzoic acid melt tank and the trichlorotoluene preparation tank are connected to the reactor through pipelines respectively.
[0006] 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. Further preferably, the material collecting plate comprises a collecting trough arranged along the inner wall of the distillation tower, a collecting plate is arranged on the upper part of the collecting trough, the collecting plate comprises a plurality of collecting plates arranged in a staggered manner in the upper and lower layers, the collecting plates are of a groove structure, the concave surface of the upper collecting plate faces downward, and the concave surface of the lower collecting plate faces upward, and the condensed liquid flows from the upper collecting plate into the lower collecting plate, and then flows into the collecting trough to collect the material, a spacing is provided between the upper and lower collecting plates to ensure the gas phase channel, a material collecting port is provided on the upper side of the collecting trough, and a material reflux port is provided on the lower side of the collecting trough; further preferably, the collecting trough is 4-6 cm wide and 6-8 cm high; a spacing of 9-12 cm is provided between the upper and lower collecting plates.
[0007] 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 a high vacuum state.
[0008] The production system performs a continuous synthesis and rectification preparation method for benzoyl chloride, and the method comprises the following steps: 1) Adding benzotrichloride and a catalyst (the catalyst is added for the first time and will not be added for continuous production) into a benzotrichloride preparation tank to mix to obtain a benzotrichloride mixed solution, adding benzoic acid into a benzoic acid melting tank to heat and melt into benzoic acid liquid, and heating the reactor; 2) Add the trichlorotoluene mixed solution and benzoic acid liquid into the reactor continuously, heat it up, vaporize the reaction products into the distillation tower, condense and recover the materials through the condenser, gradually distill and reflux to make the products qualified, and then collect them 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.
[0009] Preferably, the temperature in steps 1) and 2) is raised to 135-155° C., and the pressure inside the reactor (5) is less than 1 KPa, so as to ensure that the generated benzoyl chloride can be continuously distilled into the collection tank.
[0010] Preferably, the reflux ratio of the distillation reflux in step 2) is full reflux during the initial production. After the product sampling and testing reaches the quality standard, the reflux amount 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 reaction kettle (5) with the product benzoyl chloride to ensure that the benzoyl chloride content in the benzoyl chloride product is below 0.3%.
[0011] 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±5°C.
[0012] Preferably, in step 1), the molar ratio of trichlorotoluene 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).
[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention combines trichlorotoluene with catalyst and benzoic acid, and performs reaction and distillation together. The synthetic distillation is continuously fed, reacted and discharged. The hydrogen chloride gas produced by the reaction is continuously absorbed to prepare hydrochloric acid. The condensation reaction temperature and the distillation temperature are controlled between 135°C and 155°C. Conventionally, the temperature is raised to 130°C for reaction at room temperature, and then distilled at 135-155°C in the distillation tower. Now, the temperature is directly 135-155°C after the reaction liquid is directly reacted, which achieves energy saving (previously, it was added dropwise). In addition, the catalyst is not discharged and has been in use, which saves the amount of catalyst. Previously, the catalyst entered the distillation kettle and became residue and was discharged as hazardous waste.
[0014] 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 falling film absorption tower absorbs the hydrogen chloride gas 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 and the finished product is collected during the synthesis process.
[0015] 3. Benzoic acid is liquefied by heating to make solid benzoic acid into liquid state, which is convenient for continuous addition.
[0016] 4. The materials are collected in the collection tray, and the product content is increased by reflux. The outlet of the reflux pipe is connected to the lower part of the weir of the collection tank, and the outlet is connected to the upper part of the weir of the collection tray to ensure the amount of reflux materials so that the materials can meet the reflux requirements first. A sampling double valve is added to the lower part of the reflux pipeline. According to the sampling test results, after the product is qualified, the reflux is reduced and the product is collected. The falling film absorption tower is installed at a high position, and the lower pipeline is inserted into the bottom of the liquid surface to prevent hydrochloric acid from being drawn into the vacuum system. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 Process flow chart of the present invention Figure 2 Schematic diagram of the material collection tray structure; Figure 3 Top view of the material collection tray; 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 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 below with reference to the embodiments and drawings.
[0018] Example 1 A benzoyl chloride continuous synthesis and distillation production system, the system comprises a reactor 5, the upper part of the reactor 5 outlet is connected to a distillation tower 17, the upper part of the distillation tower 17 is provided with a condenser 6, the middle part of the distillation tower 17 and the top of the condenser 6 are respectively connected to a benzoyl chloride product collecting tank 10 through 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 in sequence through pipelines.
[0019] Preferably, the benzoic acid melt tank 16 and the trichlorotoluene preparation tank 15 are connected to the reaction kettle 5 through pipelines, respectively.
[0020] 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, the material reflux port 7-4 is connected to the distributor 9 in the tower 17, and the material 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 can preferentially meet the reflux requirements.
[0021] Preferably, the material collecting plate 7 includes a collecting groove 7-1 arranged along the inner wall of the distillation tower 17, and a collecting plate 7-2 is arranged on the upper part of the collecting groove 7-1. The collecting plate 7-2 includes a plurality of collecting plates arranged in an upper and lower layers. The collecting plate is a groove structure, and 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 groove 7-1 to collect the material. A spacing is provided between the upper and lower collecting plates to ensure the gas phase channel. A material collecting port 7-3 is provided on the upper side of the collecting groove 7-1, and a material reflux port 7-4 is provided on the lower side of the collecting groove 7-1; more preferably, the collecting groove 7-1 has a width of 5 cm and a height of 7 cm; and a spacing of 10 cm is provided between the upper and lower collecting plates.
[0022] 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 .
[0023] A method for preparing benzoyl chloride by continuous synthesis and rectification using any one of the production systems described above comprises the following steps: 1) putting benzotrichloride and a catalyst into a benzotrichloride preparation tank 15 to mix to obtain a benzotrichloride mixed solution, putting benzoic acid into a benzoic acid melting tank 16 to heat and melt into benzoic acid liquid, and heating the reactor 5; 2) The trichlorotoluene mixed solution and benzoic acid liquid are continuously introduced into the reactor 5, and the temperature is raised to vaporize the reaction products into the distillation tower 17, and the materials are condensed and recovered through the condenser 6. After the products are gradually distilled and refluxed to meet the standards, they are collected into the finished product collection tank.
[0024] Preferably, the temperature in steps 1) and 2) is raised to 140°C.
[0025] Preferably, the reflux ratio of the distillation reflux in step 2) is full reflux during the initial production. After the product sampling and testing reaches the quality standard, the reflux amount is gradually reduced, and the benzoyl chloride product is collected. After the reaction is normal, the reflux ratio is controlled between 8-12%, and the high-boiling-point trichlorotoluene is cooled with the product benzoyl chloride and returned to the reactor 5 to ensure that the trichlorotoluene content in the benzoyl chloride product is below 0.3%.
[0026] 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.
[0027] Preferably, in step 1), the molar ratio of trichlorotoluene to benzoic acid is 1.03:1, and the catalyst is FeCl3.
[0028] Example 2 Based on Example 1, the reflux ratio in step 2) is full reflux during the initial production. After the product sampling and testing reaches the quality standard, the reflux amount 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 reaction kettle (5) with the product benzoyl chloride to ensure that the benzoyl chloride content in the benzoyl chloride product is below 0.3%. The situation of different reflux ratios is shown in Table 1 below.
[0029] Table 1
[0030] 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.
[0031] Example 3 Based on Example 1, the temperature of heating in step 2) was changed.
[0032] Table 2
[0033] As can be seen from Table 2, the reaction temperature of the reactor is suitable at 140-150°C.
[0034] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by 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, the system comprising a reaction kettle (5), characterized in that: The upper part of the outlet of the reactor (5) is connected to a distillation tower (17), and a condenser (6) is provided at the upper part of the distillation tower (17). The middle part of the distillation tower (17) and the top 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 through pipelines. The hydrochloric acid absorption tank (12) absorbs hydrogen chloride gas through a hydrochloric acid circulation pump (14) to prepare hydrochloric acid. The benzoic acid melting tank (16) and the trichlorotoluene preparation tank (15) are respectively connected to the reactor (5) through pipelines.
2. 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 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).
3. The benzoyl chloride continuous synthesis and distillation production system according to claim 1, characterized in that: The material collecting tray (7) comprises a collecting trough (7-1) arranged along the inner wall of a distillation tower (17), the collecting tray (7-1) being arranged on the upper part of the collecting trough (7-1), the collecting tray (7-1) comprising a plurality of collecting plates (7-2) arranged in a staggered manner in two layers, the collecting plates being of a groove structure, the concave surface of the upper collecting plate facing downward, and the concave surface of the lower collecting plate facing upward, the upper side of the collecting trough (7-1) being provided with a material collecting port (7-3), and the lower side of the collecting trough (7-1) being provided with a material reflux port (7-4); preferably, the collecting trough (7-1) has a width of 4-6 cm and a height of 6-8 cm; and a spacing of 9-12 cm is provided between the upper and lower collecting plates.
4. The benzoyl chloride continuous synthesis and distillation production system according to claim 1, characterized in that: A hydrochloric acid absorption tank (12) is provided below the falling film absorption tower (11); preferably, the height difference between the falling film absorption tower (11) and the hydrochloric acid absorption tank (12) is greater than 10 meters.
5. A method for preparing benzoyl chloride by continuous synthesis and rectification using the production system according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: 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 into benzoic acid liquid; and heating the reactor (5); 2) The trichlorotoluene mixed solution and benzoic acid liquid are continuously introduced into a reaction kettle (5), the temperature is raised, and the reaction product is vaporized into a distillation tower (17), the material is condensed and recovered through a condenser (6), and after the product is gradually distilled and refluxed to meet the standards, it is collected in a benzoyl chloride product collection tank (10), and transferred to a storage tank by a product external transfer pump (20) for packaging.
6. The method for preparing benzoyl chloride by continuous synthesis and rectification according to claim 5, characterized in that: In the steps 1) and 2), the temperature is raised to 135-155° C., and the pressure inside the reactor (5) is less than 1 KPa, so as to ensure that the generated benzoyl chloride can be continuously distilled into the collection tank.
7. The method for preparing benzoyl chloride by continuous synthesis and rectification according to claim 5, characterized in that: 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 ratio is controlled at 8-12%. The high-boiling-point trichlorotoluene is cooled with the product benzoyl chloride and returned to the reaction kettle (5) to ensure that the trichlorotoluene content in the benzoyl chloride product is below 0.3%.
8. The method for preparing benzoyl chloride by continuous synthesis and rectification according to claim 5, characterized in that: In the step 1), benzoic acid is put into a benzoic acid melting tank (16) and heated to melt at a temperature of 120-140°C.
9. The method for preparing benzoyl chloride by continuous synthesis and rectification according to claim 5, characterized in that: In the step 1), the molar ratio of trichlorotoluene to benzoic acid is (1.03-1.5):1, and the catalyst is a Lewis acid.