Device and method for producing 2, 4-dichlorobenzyl alcohol

Abstract

The invention is applicable to the technical field of fine chemical engineering, and provides a device and method for producing 2, 4-dichlorobenzyl alcohol, and the device comprises a reaction kettle, a sodium hydroxide dripping tank, a condenser, a phase splitting tank, an ester phase tank, a water phase tank, a three-in-one reaction kettle and a solvent flash tank. The method comprises an esterification reaction, a hydrolysis reaction and a purification process. Through the continuous reaction split-phase integrated system, the three-in-one purification system and the closed-loop solvent recovery technology, high-efficiency, high-purity, economical and environment-friendly production of the 2, 4-dichlorobenzyl alcohol is realized, the yield and the product quality are remarkably improved, and meanwhile, the cost and the environmental burden are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of fine chemicals, and in particular relates to a device and a method for producing 2,4-dichlorobenzyl alcohol. Background Art

[0002] As a key organic compound, 2,4-dichlorobenzyl alcohol has a unique molecular structure - chlorine atoms are introduced at the 2nd and 4th positions of the benzene ring, and equipped with a hydroxymethyl functional group - which gives it both the stability of chlorinated aromatic hydrocarbons and the reactivity of alcohols. This makes it have a wide range of application potentials in many fields such as medicine, pesticides and fine chemicals, such as being an important intermediate for the preparation of antibacterial and antifungal drugs, or being used in the development of high-efficiency functional chemicals such as herbicides and plant growth regulators.

[0003] At present, the industrial synthesis of 2,4-dichlorobenzyl alcohol mainly adopts the traditional chlorination or reduction reaction pathway, such as the catalytic hydrogenation of 2,4-dichlorobenzaldehyde. However, these existing technologies face a series of challenges:

[0004] 1) Low reaction efficiency: Some processes rely on expensive and difficult-to-recycle precious metal catalysts (such as palladium and platinum), which increases production costs.

[0005] 2) Poor selectivity: Dechlorination side reactions are prone to occur during the reduction of chlorinated aromatics, affecting the purity of the product.

[0006] 3) Heavy environmental burden: Some methods use highly toxic reagents (such as thionyl chloride) or produce chlorine-containing wastewater, which violates the principles of green chemistry.

[0007] 4) Complex process: The multi-step reaction requires strict control of temperature and pressure, which will significantly increase energy consumption and operational risks in large-scale production.

[0008] With the growing demand for high-purity chlorinated aromatic alcohols in the pharmaceutical and agricultural industries, traditional production processes are unable to reduce costs, increase yields, and be environmentally friendly. Therefore, developing a new technology for the synthesis of 2,4-dichlorobenzyl alcohol that is both efficient, economical, and sustainable has become an important issue that needs to be addressed. Summary of the invention

[0009] The object of the present invention is to provide a device and method for producing 2,4-dichlorobenzyl alcohol, aiming to solve the problems mentioned in the above background technology.

[0010] The present invention is implemented as follows. A device for producing 2,4-dichlorobenzyl alcohol includes a reaction kettle, a sodium hydroxide dropping tank, a condenser, a phase separation tank, an ester phase tank, an aqueous phase tank, a three-in-one reaction kettle, and a solvent flash evaporation tank. The discharge port of the reaction kettle is connected to the feed port of the phase separation tank. The top of the reaction kettle is equipped with a sodium hydroxide dropping tank and a condenser. The discharge port of the phase separation tank is respectively connected to the feed ports of the ester phase tank and the aqueous phase tank through pipelines. The discharge port of the ester phase tank is respectively connected to the feed ports of the reaction kettle and the three-in-one reaction kettle through pipelines. The discharge port of the three-in-one reaction kettle is connected to the feed port of the solvent flash evaporation tank. The vapor discharge port of the solvent flash evaporation tank is connected to the feed port of the three-in-one reaction kettle.

[0011] In a further technical solution, the materials added to the reaction kettle include 2,4-dichlorobenzyl chloride, sodium acetate, pure water, and a phase transfer catalyst. The phase transfer catalyst is tetrabutylammonium bromide, tetraphenylphosphonium bromide, or 18-crown-6. The reaction kettle is an enamel reaction kettle with a volume of 2m 3 , equipped with a double spiral ribbon stirrer and a steam jacket, and an in-line pH probe is installed inside, which is linked and controlled with a NaOH dropping pump. Among them, the rotation speed of the double spiral ribbon stirrer is 60 - 300 rpm; the temperature control accuracy of the steam jacket is ±1°C; the in-line pH probe uses Mettler-Toledo InPro3250.

[0012] In a further technical solution, the condenser adopts a vapor phase condensation and reflux system.

[0013] In a further technical solution, the diameter of the phase separation tank is 2m, and it is internally provided with a 45° inclined corrugated plate group for sedimentation, with a residence time ≥ 15 min and a phase separation efficiency > 99.0%.

[0014] In a further technical solution, the three-in-one reaction kettle is equipped with a 2,4-dichlorobenzyl alcohol product discharge pipeline and a vacuum pumping system. The volume of the three-in-one reaction kettle is 3m 3 , equipped with a PTFE filter plate and a double-cone vacuum drying bin. Among them, the pore diameter of the PTFE filter plate is 1.0 μm; the ultimate vacuum degree of the double-cone vacuum drying bin is 10 Pa.

[0015] In a further technical solution, a condensation device is also provided on the pipeline between the vapor discharge port of the solvent flash evaporation tank and the feed port of the three-in-one reaction kettle. The solvent flash evaporation tank adopts a multi-stage decompression design from 0.00 MPa to -0.08 MPa, and is internally provided with a scraper evaporator, and the heat transfer coefficient of the scraper evaporator > 500 W / m 2 ·K.

[0016] Another object of the present invention is a method for producing 2,4-dichlorobenzyl alcohol by using the above-mentioned device, including the following steps:

[0017] Step 1: Esterification reaction

[0018] 2,4-Dichlorobenzyl chloride and aqueous sodium acetate solution are continuously added to the reactor in a molar ratio of 1:1 - 1:5, and an esterification reaction is carried out under the action of a phase transfer catalyst. The reaction conditions are a temperature of 80 - 150 °C and a reaction time of 3 - 12 hours; after the reaction is completed, the mixture is subjected to liquid-liquid separation through a phase separation tank, and the separated organic phase is sent to the ester phase tank;

[0019] Step 2. Hydrolysis reaction

[0020] From the ester phase tank, the organic phase is pumped back into the reactor, and 5% - 20% aqueous sodium hydroxide solution is added here, and a hydrolysis reaction is carried out in a molar ratio of 1:1 - 1:0.96. The hydrolysis conditions are a temperature of 80 - 100 °C and a reaction time of 4 - 8 hours; after the reaction is completed, liquid separation is carried out again through the phase separation tank, and the obtained 2,4-dichlorobenzyl alcohol enters the three-in-one reactor for treatment;

[0021] Step 3. Purification process

[0022] In the three-in-one reactor, recrystallization of 2,4-dichlorobenzyl alcohol is carried out using dichloromethane, petroleum ether or cyclohexane solvent to remove impurities; then, drying treatment is carried out in the same reactor to remove the solvent and moisture. The specific operation is to add 2.5 - 3.5 times the volume of the above solvent for extraction and recrystallization, and the solvent is recovered and reused after filtration; after this step, the obtained 2,4-dichlorobenzyl alcohol is dried and then enters the packaging machine for packaging.

[0023] In a further technical solution, the yield of the obtained 2,4-dichlorobenzyl alcohol is more than 94%, and the purity is more than 99.7%.

[0024] An apparatus and method for producing 2,4-dichlorobenzyl alcohol provided by the present invention have the following beneficial effects:

[0025] The present invention realizes seamless continuous operation of the esterification and hydrolysis steps through the design of a series of reactors and phase separation tanks, which not only avoids the loss of intermediate transfer, but also increases the yield to not less than 94%, significantly higher than the yield of not more than 80% of the traditional process; a lamella settler is configured in the phase separation tank to make the separation efficiency of the organic phase and the aqueous phase exceed 99%, effectively reducing the impurity content. The three-in-one purification system integrating crystallization, filtration and drying functions reduces the risk of material exposure, ensures that the product purity reaches or exceeds 99.7%, and controls the solvent residue below 50 ppm through the vacuum drying module, greatly reducing the risk of cross-contamination, and increasing the first-pass yield of the product from 92% to 98%. In addition, the solvent flash tank with a gradient decompression design realizes a solvent recovery rate of at least 90%, reduces the unit consumption cost by about 40%, and the recovered solvent purity exceeds 99.5% and can be directly recycled, further enhancing the economy and environmental protection of production. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 FIG. is a schematic structural diagram of an apparatus for producing 2,4 - dichlorobenzyl alcohol provided by an embodiment of the present invention.

[0027] In the figure: 1 - reaction kettle, 2 - sodium hydroxide dropping tank, 3 - condenser, 4 - phase separation tank, 5 - ester phase tank, 6 - aqueous phase tank, 7 - three - in - one reaction kettle, 8 - solvent flash evaporation tank. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] The following describes the specific implementation of the present invention in detail with reference to specific embodiments.

[0030] As Figure 1 shown, an apparatus for producing 2,4 - dichlorobenzyl alcohol provided by an embodiment of the present invention uses 2,4 - dichlorobenzyl chloride as a raw material, and prepares high - purity 2,4 - dichlorobenzyl alcohol through a continuous esterification, hydrolysis, crystallization and solvent recovery process. It is suitable for industrial production of pharmaceutical and pesticide intermediates, and has the characteristics of high yield, excellent purity and high solvent recycling rate, and is especially suitable for large - scale continuous production.

[0031] The apparatus includes a reaction kettle 1, a sodium hydroxide dropping tank 2, a condenser 3, a phase separation tank 4, an ester phase tank 5, an aqueous phase tank 6, a three - in - one reaction kettle 7 and a solvent flash evaporation tank 8. The discharge port of the reaction kettle 1 is connected to the feed port of the phase separation tank 4. The top of the reaction kettle 1 is equipped with a sodium hydroxide dropping tank 2 and a condenser 3. The discharge port of the phase separation tank 4 is respectively connected to the feed ports of the ester phase tank 5 and the aqueous phase tank 6 through pipelines. The discharge port of the ester phase tank 5 is respectively connected to the feed ports of the reaction kettle 1 and the three - in - one reaction kettle 7 through pipelines. The discharge port of the three - in - one reaction kettle 7 is connected to the feed port of the solvent flash evaporation tank 8. The vapor discharge port of the solvent flash evaporation tank 8 is connected to the feed port of the three - in - one reaction kettle 7.

[0032] Among them, the materials added to the reaction kettle 1 include 2,4 - dichlorobenzyl chloride, sodium acetate, pure water and a phase transfer catalyst. The phase transfer catalyst is tetrabutylammonium bromide, tetraphenylphosphonium bromide or 18 - crown - 6. The reaction kettle 1 is an enamel reaction kettle with a volume of 2m 3 , equipped with a double - spiral ribbon stirrer and a steam jacket, and an on - line pH probe is installed inside, which is linked with a NaOH dropping pump for control. Among them, the rotation speed of the double - spiral ribbon stirrer is 60 - 300 rpm; the temperature control accuracy of the steam jacket is ±1°C; the on - line pH probe uses Mettler - Toledo InPro3250.

[0033] The condenser 3 adopts a vapor-phase condensation reflux system.

[0034] The diameter of the phase separation tank 4 is 2 m, and it is internally provided with a 45° inclined corrugated plate group for sedimentation. The residence time is ≥15 min, and the phase separation efficiency is >99.0%. Among them, the 45° inclined corrugated plate group in the phase separation tank 4 promotes the coalescence of liquid droplets and shortens the phase separation time by increasing the sedimentation area and extending the flow path. The corrugated plate material can be polytetrafluoroethylene (PTFE), which is corrosion-resistant and has a low surface energy, and can reduce the adhesion loss of the organic phase.

[0035] The three-in-one reactor 7 is equipped with a product discharge pipeline for 2,4-dichlorobenzyl alcohol and a vacuum pumping system. The volume of the three-in-one reactor 7 is 3 m 3 , and it is equipped with a PTFE filter plate and a double-cone vacuum drying chamber; among them, the pore diameter of the PTFE filter plate is 1.0 μm; the ultimate vacuum degree of the double-cone vacuum drying chamber is 10 Pa.

[0036] A condensation device is also provided on the pipeline between the vapor-phase discharge port of the solvent flash tank 8 and the feed port of the three-in-one reactor 7. The solvent flash tank 8 adopts a multi-stage decompression design of 0.00 MPa → -0.08 MPa, and is internally provided with a scraper evaporator, and the heat transfer coefficient of the scraper evaporator is >500 W / m 2 ·K.

[0037] In addition, the device design includes a rupture disk and an emergency pressure relief valve for handling possible abnormal pressures during the reaction process. Both the reactor 1 and the solvent flash tank 8 are equipped with a nitrogen protection system to avoid the risk of combustion caused by the contact of organic solvents with oxygen. Operators need to wear acid and alkali-resistant protective clothing and gas masks to ensure production safety.

[0038] Example 1

[0039] As Figure 1 shown, an embodiment of the present invention provides a method for producing 2,4-dichlorobenzyl alcohol, which is carried out using the above device for producing 2,4-dichlorobenzyl alcohol, and includes the following steps:

[0040] Step 1. Esterification reaction

[0041] 2,4-dichlorobenzyl chloride and an aqueous solution of sodium acetate are continuously added to the reactor 1 in a molar ratio of 1:1, and an esterification reaction is carried out under the action of a phase transfer catalyst tetrabutylammonium bromide. The reaction conditions are a temperature of 80 °C and a reaction time of 12 hours; after the reaction is completed, the mixture is subjected to liquid-liquid separation through the phase separation tank 4, and the separated organic phase is sent to the ester phase tank 5;

[0042] Step 2. Hydrolysis reaction

[0043] From the ester phase tank 5, the organic phase is pumped back into the reactor 1, and an aqueous solution of 5% sodium hydroxide is added here. The hydrolysis reaction is carried out at a molar ratio of 1:1. The hydrolysis conditions are a temperature of 80 °C and a reaction time of 8 hours. After the reaction, liquid-liquid separation is carried out again through the phase separation tank 4, and the separated 2,4-dichlorobenzyl alcohol enters the three-in-one reactor 7 for treatment;

[0044] Step 3. Purification process

[0045] In the three-in-one reactor 7, recrystallization of 2,4-dichlorobenzyl alcohol is carried out using dichloromethane solvent to remove impurities. Then, drying treatment is carried out in the same reactor to remove the solvent and moisture. The specific operation is to add 2.5 times the volume of the above solvent for extraction and recrystallization, and the solvent is recovered and reused after filtration. After this step, the obtained 2,4-dichlorobenzyl alcohol is dried and then enters the packaging machine for packaging.

[0046] Among them, the yield of the obtained 2,4-dichlorobenzyl alcohol is 96%, and the purity reaches 99.8%.

[0047] Example 2

[0048] As Figure 1 shown, an embodiment of the present invention provides a method for producing 2,4-dichlorobenzyl alcohol, which is carried out using the above device for producing 2,4-dichlorobenzyl alcohol, and includes the following steps:

[0049] Step 1. Esterification reaction

[0050] 2,4-dichlorobenzyl chloride and an aqueous solution of sodium acetate are continuously added to the reactor 1 at a molar ratio of 1:3. Under the action of the phase transfer catalyst tetraphenylphosphonium bromide, the esterification reaction is carried out. The reaction conditions are a temperature of 110 °C and a reaction time of 8 hours. After the reaction is completed, the mixture is subjected to liquid-liquid separation through the phase separation tank 4, and the separated organic phase is sent to the ester phase tank 5;

[0051] Step 2. Hydrolysis reaction

[0052] From the ester phase tank 5, the organic phase is pumped back into the reactor 1, and an aqueous solution of 10% sodium hydroxide is added here. The hydrolysis reaction is carried out at a molar ratio of 1:0.99. The hydrolysis conditions are a temperature of 90 °C and a reaction time of 6 hours. After the reaction, liquid-liquid separation is carried out again through the phase separation tank 4, and the separated 2,4-dichlorobenzyl alcohol enters the three-in-one reactor 7 for treatment;

[0053] Step 3. Purification process

[0054] In the three-in-one reactor 7, petroleum ether solvent is used to recrystallize 2,4-dichlorobenzyl alcohol to remove impurities; then, drying treatment is carried out in the same reactor to remove the solvent and moisture. The specific operation is to add 3 times the volume of the above solvent for extraction and recrystallization, and the solvent is recovered and reused after filtration; after this step, the obtained 2,4-dichlorobenzyl alcohol is dried and then enters the packaging machine for packaging.

[0055] Among them, the yield of the obtained 2,4-dichlorobenzyl alcohol is 94%, and the purity reaches 99.9%.

[0056] Example 3

[0057] As Figure 1 shown, an embodiment of the present invention provides a method for producing 2,4-dichlorobenzyl alcohol, which is carried out by using the above device for producing 2,4-dichlorobenzyl alcohol, and includes the following steps:

[0058] Step 1. Esterification reaction

[0059] 2,4-Dichlorobenzyl chloride and aqueous sodium acetate solution are continuously added to the reactor 1 in a molar ratio of 1:5, and an esterification reaction is carried out under the action of the phase transfer catalyst 18-crown-6. The reaction conditions are a temperature of 150 °C and a reaction time of 3 hours; after the reaction is completed, the mixture is subjected to liquid-liquid separation through the phase separation tank 4, and the separated organic phase is sent to the ester phase tank 5;

[0060] Step 2. Hydrolysis reaction

[0061] From the ester phase tank 5, the organic phase is pumped back into the reactor 1, and 20% aqueous sodium hydroxide solution is added here, and a hydrolysis reaction is carried out according to a molar ratio of 1:0.96. The hydrolysis conditions are a temperature of 100 °C and a reaction time of 4 hours; after the reaction is completed, liquid separation is carried out again through the phase separation tank 4, and the obtained 2,4-dichlorobenzyl alcohol enters the three-in-one reactor 7 for treatment;

[0062] Step 3. Purification process

[0063] In the three-in-one reactor 7, cyclohexane solvent is used to recrystallize 2,4-dichlorobenzyl alcohol to remove impurities; then, drying treatment is carried out in the same reactor to remove the solvent and moisture. The specific operation is to add 3.5 times the volume of the above solvent for extraction and recrystallization, and the solvent is recovered and reused after filtration; after this step, the obtained 2,4-dichlorobenzyl alcohol is dried and then enters the packaging machine for packaging.

[0064] Among them, the yield of the obtained 2,4-dichlorobenzyl alcohol is 97.5%, and the purity reaches 99.7%.

[0065] In the process of the present invention, the selection of the phase transfer catalyst (such as tetrabutylammonium bromide, tetraphenylphosphonium bromide, 18-crown-6) is based on its partition coefficient and catalytic efficiency in different solvent systems. Tetrabutylammonium bromide is suitable for organic phase systems with relatively low polarity, while crown ether catalysts (such as 18-crown-6) have strong complexing ability with alkali metal ions, which can significantly improve the reaction rate.

[0066] Reaction mechanism description:

[0067] 1) Esterification reaction: As a nucleophile, the acetate group can attack the benzyl carbon atom of 2,4-dichlorobenzyl chloride, replacing one chlorine atom to form 2,4-dichlorobenzyl acetate and sodium chloride. The excess of sodium acetate raw material helps to accelerate the reaction rate. Since sodium acetate has high solubility in water, the addition of the phase transfer catalyst tetrabutylammonium bromide promotes the transfer of acetate ions from the aqueous phase to the organic phase, and at the same time, it can bring the organic phase into the aqueous phase to increase the nucleophilicity.

[0068] 2) Hydrolysis reaction: The ester group (-OOCCH3) of 2,4-dichlorobenzyl acetate is hydrolyzed by sodium hydroxide to form 2,4-dichlorobenzyl alcohol and sodium acetate. As a strong base, sodium hydroxide provides OH- ions, causing the ester bond to break, forming an alcohol and a carboxylate salt. Due to the strong nucleophilicity of sodium hydroxide, in the final step, sodium hydroxide participates in the decisive substitution reaction. When hydrolyzing, if the amount of water added during esterification is too small, salt will precipitate during the reaction process, which will hinder the mass transfer between the oil and water phases, thereby affecting the conversion rate of benzyl ester and the yield of benzyl alcohol. When the amount of water is too much, it will reduce the concentration of alkali and substrate in the reaction system, resulting in a decrease in the hydrolysis rate.

[0069] In the above embodiments of the present invention, a device and method for producing 2,4-dichlorobenzyl alcohol are provided, and the main advantages are as follows:

[0070] 1) Continuous reaction and phase separation integrated system

[0071] By adopting the design of the series reaction kettle 1 and the phase separation tank 4, seamless continuous operation of the esterification and hydrolysis steps is realized. This not only avoids the loss of intermediates during the transfer process, but also significantly improves the yield to no less than 94%. In contrast, the yield of the traditional process usually does not exceed 80%. In addition, an inclined plate settler is configured in the phase separation tank 4, so that the separation efficiency of the organic phase and the aqueous phase exceeds 99%, effectively reducing the impurity content.

[0072] 2) Three-in-one purification system

[0073] Integrating the three functions of crystallization, filtration and drying into one, it reduces the risk of material exposure and ensures that the product purity reaches or exceeds 99.7%. By adopting a vacuum drying module in the temperature range of 50 - 80°C, the solvent residue is controlled to be less than 50 ppm. Compared with the traditional drying method that requires transferring the material to an independent device for processing, the present invention greatly reduces the possibility of cross - contamination and increases the first - pass yield of the product from 92% to 98%.

[0074] 3) Closed - loop solvent recovery technology

[0075] By using a solvent flash tank 8 with a gradient pressure reduction design (pressure range from - 0.08 to - 0.05 MPa), a solvent recovery rate of at least 90% is achieved, thus reducing the unit consumption cost by about 40%. The recovered solvent purity exceeds 99.5% and can be directly recycled, further enhancing the economy and environmental protection of production.

[0076] The technical features of the above - described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above - described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as within the scope described in this specification.

[0077] The above - described embodiments only represent several implementation manners of the present invention. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. An apparatus for producing 2,4-dichlorobenzyl alcohol, characterized in that, It includes a reaction kettle, a sodium hydroxide dropping tank, a condenser, a phase separation tank, an ester phase tank, an aqueous phase tank, a three-in-one reaction kettle and a solvent flash evaporation tank; The discharge port of the reaction kettle is connected to the feed port of the phase separation tank. The top of the reaction kettle is equipped with a sodium hydroxide dropping tank and a condenser. The discharge port of the phase separation tank is respectively connected to the feed ports of the ester phase tank and the aqueous phase tank through pipelines. The discharge port of the ester phase tank is respectively connected to the feed ports of the reaction kettle and the three-in-one reaction kettle through pipelines. The discharge port of the three-in-one reaction kettle is connected to the feed port of the solvent flash evaporation tank. The vapor discharge port of the solvent flash evaporation tank is connected to the feed port of the three-in-one reaction kettle.

2. The device for producing 2,4-dichlorobenzyl alcohol according to claim 1, characterized in that, The materials added to the reaction kettle include 2,4-dichlorobenzyl chloride, sodium acetate, pure water and a phase transfer catalyst. The phase transfer catalyst is tetrabutylammonium bromide, tetraphenylphosphonium bromide or 18-crown-6; The reactor used is an enamel reactor with a volume of 2 m 3 , equipped with a double screw ribbon agitator and a steam jacket, and an on-line pH probe is installed inside, which is linked and controlled with a NaOH dropping pump; among them, the rotation speed of the double screw ribbon agitator is 60 - 300 rpm; the temperature control accuracy of the steam jacket is ±1 °C; the on-line pH probe uses Mettler-Toledo InPro3250.

3. The device for producing 2,4-dichlorobenzyl alcohol according to claim 1, characterized in that, The condenser adopts a vapor phase condensation reflux system.

4. The device for producing 2,4-dichlorobenzyl alcohol according to claim 1, characterized in that, The diameter of the phase separation tank is 2 m, and it is internally provided with a 45° inclined corrugated plate group for sedimentation. The residence time is ≥15 min, and the phase separation efficiency is >99.0%.

5. The device for producing 2,4-dichlorobenzyl alcohol according to any one of claims 1-4, characterized in that, The three-in-one reaction kettle is equipped with a 2,4-dichlorobenzyl alcohol product discharge pipeline and a vacuum pumping system; The volume of the said three-in-one reactor is 3 m 3 , equipped with a PTFE filter plate and a double-cone vacuum drying bin; among them, the pore size of the PTFE filter plate is 1.0 μm; the ultimate vacuum degree of the double-cone vacuum drying bin is 10 Pa.

6. The device for producing 2,4-dichlorobenzyl alcohol according to claim 5, characterized in that, A condensation device is also provided on the pipeline between the vapor discharge port of the solvent flash evaporation tank and the feed port of the three-in-one reaction kettle; The solvent flash tank adopts a multi-stage pressure reduction design from 0.00 MPa to -0.08 MPa, and is equipped with a scraper evaporator inside, and the heat transfer coefficient of the scraper evaporator > 500 W / m 2 ·K.

7. A method for producing 2,4-dichlorobenzyl alcohol using the apparatus according to any one of claims 1-6, characterized in that, It includes the following steps: Step 1. Esterification reaction 2,4-Dichlorobenzyl chloride and an aqueous solution of sodium acetate are continuously added to the reaction kettle at a molar ratio of 1:1 - 1:5, and an esterification reaction is carried out under the action of a phase transfer catalyst. The reaction conditions are a temperature of 80 - 150 °C and a reaction time of 3 - 12 hours; after the reaction is completed, the mixture is subjected to liquid-liquid separation through the phase separation tank, and the separated organic phase is sent to the ester phase tank; Step 2. Hydrolysis reaction From the ester phase tank, the organic phase is pumped back into the reaction kettle, and a 5% - 20% aqueous sodium hydroxide solution is added here, and a hydrolysis reaction is carried out at a molar ratio of 1:1 - 1:0.

96. The hydrolysis conditions are a temperature of 80 - 100 °C and a reaction time of 4 - 8 hours; after the reaction ends, liquid separation is carried out again through the phase separation tank, and the obtained 2,4-dichlorobenzyl alcohol enters the three-in-one reaction kettle for treatment; Step 3. Purification process In the three-in-one reaction kettle, 2,4-dichlorobenzyl alcohol is recrystallized using solvents such as dichloromethane, petroleum ether or cyclohexane to remove impurities; then, a drying treatment is carried out in the same reaction kettle to remove the solvent and moisture. The specific operation is to add 2.5 - 3.5 times the volume of the above solvents for extraction and recrystallization, and the solvent is recovered and reused after filtration; after this step, the obtained 2,4-dichlorobenzyl alcohol is dried and then enters the packaging machine for packaging.

8. The method for producing 2,4-dichlorobenzyl alcohol according to claim 7, characterized in that, The yield of the obtained 2,4-dichlorobenzyl alcohol is above 94%, and the purity is above 99.7%.

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