A method for producing benzyl alcohol and benzyltoluene by hydrolysis of benzyl chloride.

Abstract

This invention relates to a method for producing benzyl alcohol and co-producing benzyltoluene by hydrolysis of benzyl chloride, belonging to the field of chemical raw material preparation technology. It includes a micro-interface circulating reactor and a multi-stage extraction centrifuge. The bottom of the micro-interface circulating reactor is connected to the reaction liquid inlet of the multi-stage extraction centrifuge via a reaction liquid metering pump. The top of the micro-interface circulating reactor has a gas phase inlet and a condensate reflux inlet connected to the condenser body. The aqueous phase outlet of the multi-stage extraction centrifuge is connected to the buffer tank body. The bottom of the buffer tank is connected to the top inlet of the micro-interface circulating reactor via a mixing pump and a mixer. The organic phase outlet of the multi-stage extraction centrifuge is connected to the light phase removal tower body. The top of the light phase removal tower is connected to the micro-interface circulating reactor via a Venturi mixer. This process has low reaction temperature and pressure, significantly reduces by-product generation, and significantly lowers energy consumption and production costs. Simultaneously, the process produces hydrochloric acid as a by-product, making it a preferred green upgrade solution for traditional alkaline hydrolysis processes.

Description

Technical Field

[0001] This invention relates to a method for producing benzyl alcohol and benzyltoluene by hydrolysis of benzyl chloride, belonging to the field of chemical raw material preparation technology. Background Technology

[0002] Benzyl alcohol is an important product and organic synthesis intermediate in the fine chemical industry, widely used in photosensitive materials, papermaking, pharmaceuticals, dyes, fragrances, and many other industries. Benzyl chloride, as a typical chlorine-consuming product, is a crucial carrier for chlor-alkali enterprises to achieve a balance between chlorine production and sales. Furthermore, the preparation of benzyl alcohol through the hydrolysis of benzyl chloride and its reaction with toluene to synthesize benzyltoluene is an effective way to increase the added value of benzyl chloride products. The core applications of benzyltoluene are concentrated in two major areas: impregnating agents for power capacitors and high-temperature synthetic heat transfer oils, possessing excellent dielectric properties, thermal stability, and a wide temperature range.

[0003] Currently, the main methods for preparing benzyl alcohol include benzyl chloride (phenyl chloride) hydrolysis, benzoic acid (ester) reduction, direct toluene oxidation, benzaldehyde catalytic reduction, and benzene-formaldehyde synthesis. Among these, benzyl chloride alkaline hydrolysis is the mainstream process for industrial production both domestically and internationally. However, theoretically, producing 1 ton of benzyl alcohol requires 1 ton of soda ash and 0.34 tons of hydrogen chloride (1 ton of hydrochloric acid), generating 1.1 tons of 100% salt waste (8-10 tons of saline wastewater). This process involves high reaction temperatures (180-275℃) and high pressures (1-6.8 MPa), resulting in large investment in equipment. The benzyl chloride conversion rate is only 75-80%. Furthermore, in an alkaline environment, benzyl alcohol easily dehydrates, producing dibenzyl ether as a byproduct, with byproducts reaching 8-12%. The process suffers from significant problems such as harsh reaction conditions, high dibenzyl ether byproduct production, low benzyl alcohol selectivity, large volume of high-salt, chlorine-containing wastewater discharged after alkaline hydrolysis, and high environmental costs. The benzyl ester hydrolysis process developed by Nanjing University of Technology uses benzyl chloride as a raw material and directly esterifies it with sodium acetate to produce benzyl acetate, generating sodium chloride waste salt. This waste salt is then hydrolyzed under acidic catalyst conditions to produce benzyl alcohol, with the acetic acid recycled or hydrogenated to produce benzyl alcohol and co-produce ethanol. Compared to the alkaline hydrolysis process, this process produces half the waste salt and yields 0.55 tons of sodium chloride, but it is a longer process and has a pungent acetic acid odor.

[0004] In view of the above-mentioned shortcomings, the present invention aims to create a method for producing benzyl alcohol and benzyltoluene by hydrolysis of benzyl chloride, so as to make it more industrially valuable. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a method for producing benzyl alcohol and co-producing benzyltoluene by hydrolysis of benzyl chloride.

[0006] The present invention discloses an apparatus for the production of benzyl alcohol and co-production of benzyltoluene by hydrolysis of benzyl chloride, comprising a micro-interface circulating reactor and a multi-stage extraction centrifuge. The bottom of the micro-interface circulating reactor is connected to the reaction liquid inlet of the multi-stage extraction centrifuge via a reaction liquid metering pump. The top gas phase inlet and condensate reflux inlet of the micro-interface circulating reactor are connected to the condenser body. The aqueous phase outlet of the multi-stage extraction centrifuge is connected to the buffer tank body. The bottom of the buffer tank is connected to the top feed inlet of the micro-interface circulating reactor via a mixing pump and a Venturi mixer. The organic phase outlet of the multi-stage extraction centrifuge is connected to the light phase removal tower body. The top of the light phase removal tower is connected to the micro-interface circulating reactor via a Venturi mixer.

[0007] Furthermore, the micro-interface circulating reactor has a built-in micron-sized microporous titanium alloy titanium powder sintered plate or ceramic membrane tube with a pore size of 20-100μm at the top, and is externally equipped with a circulation pump. Under a pressure difference of 0.5-1.2MPa, it forms emulsified microdroplets with a median diameter of 50-200μm, with a material circulation ratio of 20-50 times, maintaining a high shear, high dispersion, and fully mixed flow state. The micro-interface circulating reactor drives the material to circulate in the external circulation pipeline at a flow rate of 5m / s through the circulation pump, and the diameter of the microdroplets is controlled by adjusting the speed of the circulation pump.

[0008] The micro-interface circulating reactor 1 of this invention has a micron-sized microporous titanium alloy titanium powder sintered plate or ceramic membrane tube built into the top. The micron-sized micropores have a pore size of 20-100 μm. An aqueous phase, a mixture of water, catalyst, and part of toluene, is forced into a continuous organic phase of benzyl chloride and toluene, forming emulsion microdroplets with a diameter of 50-200 μm, thus constructing an ultra-micro interface. By controlling the reaction droplets through the micro-interface circulating reactor, when the median droplet diameter is controlled at 50-200 μm, the selectivity of benzyl alcohol is improved by 15% compared with traditional stirred tank reactors, effectively suppressing intermolecular dehydration. In addition, the micro-interface circulating reactor 1 is equipped with an external circulation pump. Under a pressure difference of 0.5-1.2 MPa, the aqueous phase passes through the micropores into the organic phase fluid composed of toluene and benzyl chloride, forming a highly dispersed emulsion system. At the same time, the circulation pump drives the material at a flow rate of 5 m / s, continuously circulating it through the micropore region through the external circulation pipeline. By adjusting the speed of the circulation pump, the shear stress at the micropore outlet can be changed, thereby changing the diameter of the microdroplets. It enables high-speed circulation of materials in the micro-interface region and reaction zone, with a circulation ratio of 20 to 50 times, maintaining a high-shear, high-dispersion, and fully mixed state, thereby improving reaction efficiency and increasing product yield.

[0009] Furthermore, the multi-stage extraction centrifuge device consists of multiple centrifugal extractors connected in series, with a total of five centrifugal extractors. The first-stage centrifugal extractor has a first-stage aqueous phase outlet at the top connected to a buffer tank, and a first-stage reaction liquid inlet at the bottom connected to a micro-interface circulating reactor 1 via a reaction liquid metering pump. The first-stage aqueous phase inlet at the bottom of the first-stage centrifugal extractor is connected to the aqueous phase outlet of the next-stage centrifugal extractor, and the first-stage organic phase outlet at the top of the first-stage centrifugal extractor is connected to the organic phase inlet of the next-stage centrifugal extractor. The fifth-stage centrifugal extractor has a fifth-stage organic phase inlet at the bottom connected to the organic phase outlet of the previous-stage centrifugal extractor, a fifth-stage aqueous phase outlet at the top of the fifth-stage centrifugal extractor connected to the aqueous phase inlet of the previous-stage centrifugal extractor, and a fifth-stage organic phase outlet at the top of the fifth-stage centrifugal extractor connected to a light-weight removal tower. The fifth-stage centrifugal extractor has a pure water inlet at its bottom.

[0010] This invention uses a series of multi-stage centrifugal extractors to extract and recover catalyst and water from the reaction solution, and recycles the catalyst-containing aqueous phase, effectively reducing the amount of catalyst used and wastewater discharged. In addition, the high-temperature reaction solution produced by the hydrolysis vessel and the added room-temperature pure water can be directly mixed in the multi-stage centrifugal extractor to achieve efficient recovery and utilization of the waste heat of the reaction solution.

[0011] Furthermore, an online detector is installed at the top of the micro-interface circulating reactor to monitor the benzyl chloride conversion rate in real time.

[0012] The specific preparation steps for the hydrolysis of benzyl chloride to produce benzyl alcohol and benzyltoluene are as follows: (1) Benzyl chloride, water, toluene and catalyst are introduced into a micro-interface circulating reactor and heated to 100-115°C under circulating mixing to produce benzyl alcohol, benzyl toluene and hydrogen chloride as a byproduct. The hydrogen chloride is condensed and refluxed back to the reactor and collected and treated in the gas phase. (2) When the online detection of benzyl chloride conversion rate reaches 95-100%, the reaction liquid is continuously discharged to the multi-stage centrifugal extraction device, and benzyl chloride, water and toluene mixture is continuously added. The average residence time of the material in the micro-interface circulating reactor (1) is 3-5 hours. (3) The reaction solution is subjected to multi-stage centrifugal extraction and washing. The aqueous phase containing the catalyst is recovered and recycled. The organic phase metal ion content is less than 0.2 ppm before being sent to the light phase removal tower. (4) The light components at the top of the light removal tower are refluxed to the micro-interface circulating reactor, and the bottom material is separated by distillation to obtain benzyl alcohol and benzyl toluene; Furthermore, the catalyst is composed of a metal salt and polyethylene glycol, and the amount used is 0.1% to 5% of the mass of benzyl chloride; the molar ratio of benzyl chloride, water and toluene is 50:50:(10 to 50).

[0013] Furthermore, the metal salt mentioned in step (1) is at least one of ferric sulfate, zinc chloride, and tin chloride.

[0014] Furthermore, in step (1), the mass ratio of metal salt to polyethylene glycol in the catalyst is 1:2.

[0015] Furthermore, the reaction temperature in step (1) is 100–110 °C.

[0016] Furthermore, the fresh material added in step (4) is a mixture of toluene and benzyl chloride, wherein the molar amount of toluene is equal to the molar amount of benzyltoluene produced by the reaction, and the molar amount of benzyl chloride is equal to the sum of the molar amounts of benzyl alcohol and benzyltoluene produced by the reaction.

[0017] In this invention, toluene not only serves as a raw material but also acts as an in-situ extractant, rapidly removing the generated benzyl alcohol from the aqueous phase interface to prevent over-reaction and improve product yield. This invention employs a benzyl chloride-free hydrolysis process to synthesize benzyl alcohol. Compared to traditional alkaline hydrolysis processes, this process involves lower reaction temperatures and pressures, significantly reduces the generation of high-salt, chlorine-containing wastewater and byproducts such as dibenzyl ether, and substantially lowers energy consumption and production costs. Simultaneously, the process produces hydrochloric acid as a byproduct, making it a preferred green upgrade solution for traditional alkaline hydrolysis processes. This invention can also simultaneously produce high-value-added benzyltoluene insulating oil during benzyl alcohol production, enriching the process product system and improving overall production efficiency.

[0018] By means of the above-described solution, the present invention has at least the following advantages: (1) The micro-interface circulating reactor 1 of this invention has a built-in micron-sized microporous titanium alloy titanium powder sintered plate or ceramic membrane tube at the top. The micron-sized micropores have a diameter of 20-100 μm. The aqueous phase, which is a mixture of water, catalyst and part of toluene, is pressed into the continuous organic phase of benzyl chloride and toluene to form emulsion microdroplets with a diameter of 50-200 μm, thus constructing an ultra-micro interface. By controlling the reaction droplets through the micro-interface circulating reactor, when the median diameter of the droplets is controlled at 50-200 μm, the selectivity of benzyl alcohol is increased by 15% compared with the traditional stirred tank, effectively inhibiting intermolecular dehydration. In addition, the micro-interface circulating reactor 1 is equipped with a circulation pump. Under the action of a pressure difference of 0.5-1.2 MPa, the aqueous phase passes through the micropores into the organic phase fluid composed of toluene and benzyl chloride, forming a highly dispersed emulsion system. At the same time, the circulation pump drives the material at a flow rate of 5 m / s, continuously circulating it through the micropore region through the external circulation pipeline. By adjusting the speed of the circulation pump, the shear stress at the micropore outlet can be changed, thereby changing the diameter of the microdroplets. It enables high-speed circulation of materials in the micro-interface region and reaction zone, with a circulation ratio of 20 to 50 times, maintaining a high-shear, high-dispersion, and fully mixed state, thereby improving reaction efficiency and increasing product yield.

[0019] (2) In this invention, toluene is not only a raw material for the product, but also acts as an in-situ extractant, rapidly carrying the generated benzyl alcohol away from the aqueous phase interface, preventing over-reaction and improving product yield. This invention uses a benzyl chloride-free hydrolysis process to synthesize benzyl alcohol. Compared with the traditional alkaline hydrolysis process, this process has lower reaction temperature and pressure, significantly reduces the amount of high-salt chlorine-containing wastewater and byproducts such as dibenzyl ether, and significantly reduces energy consumption and production costs; at the same time, the process produces hydrochloric acid as a byproduct, which is a preferred green upgrade solution for the traditional alkaline hydrolysis process.

[0020] (3) The present invention uses a series of multi-stage centrifugal extractors to extract and recover the catalyst and water in the reaction solution, and recycles the aqueous phase containing the catalyst, which effectively reduces the amount of catalyst used and the amount of wastewater discharged. In addition, the high-temperature reaction solution produced by the hydrolysis kettle and the added room-temperature pure water can be directly mixed in the multi-stage centrifugal extractor to achieve efficient recovery and utilization of the waste heat of the reaction solution.

[0021] (4) The present invention can simultaneously produce high-value-added benzyl toluene insulating oil during the production of benzyl alcohol, which enriches the process product system and can improve the overall production efficiency.

[0022] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show a certain embodiment of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the apparatus for producing benzyl alcohol and co-producing benzyltoluene by hydrolysis of benzyl chloride according to the present invention; In the figure; 1. Micro-interface circulating reactor; 2. Condenser; 3. Online detector; 4. Reaction liquid metering pump; 5. Multistage extraction centrifuge; 6. Buffer tank; 7. Mixing pump; 8. Venturi mixer; 9. Light weight removal tower; 10. Circulation pump; 11. Vapor inlet; 12. Condensate reflux inlet; 13. Feed inlet; 51. Single-stage centrifugal extractor; 52. Five-stage centrifugal extractor; 511. Primary reaction liquid inlet; 512. Primary aqueous phase inlet; 513. Primary aqueous phase outlet; 514. Primary organic phase outlet; 521. Pure water inlet; 522. Grade 5 organic phase inlet; 523. Grade 5 aqueous phase outlet; 524. Grade 5 organic phase outlet. Detailed Implementation

[0025] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0026] See Figure 1 The apparatus for producing benzyl alcohol and benzyltoluene by hydrolysis of benzyl chloride according to a preferred embodiment of the present invention includes a micro-interface circulating reactor 1 and a multi-stage extraction centrifuge device 5. The bottom of the micro-interface circulating reactor 1 is connected to the reaction liquid inlet (511) of the multi-stage extraction centrifuge device 5 via a reaction liquid metering pump 4. The top of the micro-interface circulating reactor 1 has a gas phase port 11 and a condensate reflux port 12 connected to the body of a condenser 2. The aqueous phase outlet 513 of the multi-stage extraction centrifuge device 5 is connected to the body of a buffer tank 6. The bottom of the buffer tank 6 is connected to the top feed port 13 of the micro-interface circulating reactor 1 via a mixing pump 7 and a Venturi mixer 8. The organic phase outlet 524 of the multi-stage extraction centrifuge device 5 is connected to the body of a light-light removal tower 9. The top of the light-light removal tower 9 is connected to the micro-interface circulating reactor 1 via the Venturi mixer 8.

[0027] The micro-interface circulating reactor 1 has a built-in micron-sized microporous titanium alloy titanium powder sintered plate or ceramic membrane tube at the top. The micron-sized micropores have a diameter of 20-100 μm. An aqueous phase, a mixture of water, catalyst, and a portion of toluene, is forced into a continuous organic phase of benzyl chloride and toluene, forming emulsion microdroplets with a diameter of 50-200 μm, thus constructing an ultra-micro interface. An external circulation pump 10 is installed on the micro-interface circulating reactor 1. Under a pressure difference of 0.5-1.2 MPa, the aqueous phase passes through the micropores into the organic phase fluid composed of toluene and benzyl chloride, forming a highly dispersed emulsion system. Simultaneously, the circulation pump 10 drives the material at a flow rate of 5 m / s, continuously circulating it through the micropore region via the external circulation pipeline. By adjusting the rotational speed of the circulation pump 10, the shear stress at the micropore outlet can be changed, thereby altering the diameter of the microdroplets. This achieves high-speed circulation of the material in the micro-interface region and reaction zone, with a circulation multiple of 20-50 times, maintaining a high-shear, highly dispersed, and fully mixed state.

[0028] The multi-stage extraction centrifugal device 5 consists of multiple centrifugal extractors connected in series, totaling five centrifugal extractors. The first-stage centrifugal extractor 51 has a first-stage aqueous phase outlet 513 at its top connected to a buffer tank 6. The first-stage centrifugal extractor 51 has a first-stage reaction liquid inlet 511 at its bottom, connected to a micro-interface circulating reactor 1 via a reaction liquid metering pump 4. The first-stage aqueous phase inlet 512 at its bottom is connected to the aqueous phase outlet of the next-stage centrifugal extractor. The first-stage organic phase outlet 514 at its top is connected to the organic phase inlet of the next-stage centrifugal extractor. The fifth-stage centrifugal extractor 52 has a fifth-stage organic phase inlet 522 at its bottom connected to the organic phase outlet of the previous-stage centrifugal extractor. The fifth-stage aqueous phase outlet 523 at its top is connected to the aqueous phase inlet of the previous-stage centrifugal extractor. The fifth-stage organic phase outlet 524 at its top is connected to a light-weight removal tower 9. The fifth-stage centrifugal extractor 52 has a pure water inlet 521 at its bottom.

[0029] An online detector 3 is installed at the top of the micro-interface circulating reactor 1.

[0030] The steps for producing benzyl alcohol using the apparatus for the hydrolysis of benzyl chloride to produce benzyl alcohol and co-produce benzyltoluene are as follows: (1) Benzyl chloride, water, toluene and catalyst are mixed in proportion and introduced from the top of the micro-interface circulating reactor 1. The molar ratio of benzyl chloride, water and toluene is 50:50:(10~50). The catalyst is composed of metal salt and polyethylene glycol and the amount used is 0.1%~5% of the mass of benzyl chloride. The material in the micro-interface circulating reactor 1 is slowly heated to 100~115°C under the circulation mixing of the external circulation pump 10. Under the action of the catalyst, benzyl chloride reacts with water and toluene to generate benzyl alcohol and benzyl toluene. The generated hydrogen chloride is cooled by the condenser 2 and returned to the micro-interface circulating reactor 1 in liquid phase and in gas phase to hydrogen chloride absorption. (2) When the online detector 3 detects that the conversion rate of benzyl chloride reaches 95-100%, the reaction liquid metering pump 4 is used to continuously and slowly discharge the material to the multi-stage extraction centrifuge device 5, and toluene, benzyl chloride and water mixture are continuously added. The average residence time of the material in the micro-interface circulation reactor is 3-5 hours. (3) The reaction solution is continuously added from the bottom of the first-stage centrifugal extractor 51 via the reaction solution metering pump 4, and mixed with the aqueous phase from the next-stage centrifugal extractor. The aqueous phase continuously separated from the top of the first-stage centrifugal extractor 51 enters the buffer tank 6, and the organic phase enters the next-stage centrifugal extractor for further washing. Pure water is continuously introduced into the bottom of the fifth-stage centrifugal extractor 52, and the molar amount of fresh pure water introduced is equal to the molar amount of benzyl alcohol produced in the reaction. After the organic phase is washed by the fifth-stage centrifugal extractor and the metal ion content is less than 0.2 ppm, it enters the light-weight removal tower 9. (4) The bottom of the light component removal tower 9 is distilled and separated. The material containing water, toluene, benzyl chloride and other light components obtained from the top of the light component removal tower 9 is mixed with the fresh material from the buffer tank 6 and the replenished fresh material in the Venturi mixer 8 and then enters the micro-interface circulating reactor 1. The replenished fresh material is a mixture of toluene and benzyl chloride, wherein the molar amount of toluene is equal to the molar amount of benzyltoluene produced in the reaction, and the molar amount of benzyl chloride is equal to the sum of the molar amounts of benzyl alcohol and benzyltoluene produced in the reaction. Example

[0031] (1) 6.33 kg benzyl chloride, 900.8 g water, and 4.61 kg toluene (molar ratio 50:50:50) were added from the top into a 15 L micro-interface circulation reactor 1. The top of the micro-interface circulation reactor 1 is equipped with a micron-sized microporous titanium alloy titanium powder sintered plate with a micron-sized micropore diameter of 50 μm. 2.5% by mass of benzyl chloride catalyst (composed of 52.7 g ferric sulfate and 105.5 g polyethylene glycol) was added. The external circulation pump was turned on at a circulation ratio of 35 times. Under the circulation mixing of the external circulation pump 10, the material in the micro-interface circulation reactor 1 was slowly heated to 100 °C. Under the action of the catalyst, benzyl chloride reacted with water and toluene. The generated hydrogen chloride was cooled by condenser 2 and returned to the micro-interface circulation reactor 1 in liquid phase, while the gas phase was absorbed by hydrogen chloride. (2) When the online detector 3 detects that the conversion rate of benzyl chloride reaches 98.1%, the reaction liquid metering pump 4 continuously and slowly discharges the material to the five-stage centrifugal extractor 5 at a flow rate of about 3.44 L / h, and continuously replenishes the mixture of benzyl chloride, water and toluene (molar ratio of 50:50:50) at a flow rate of about 3.99 L / h. The average residence time of the material in the micro-interface circulating reactor is 3 h. (3) The reaction solution is continuously added from the bottom of the first-stage centrifugal extractor via the reaction solution metering pump 4, and mixed with the aqueous phase from the next-stage centrifugal extractor. The aqueous phase continuously separated from the top of the first-stage centrifugal extractor 51 enters the buffer tank 6, and the organic phase enters the next-stage centrifugal extractor for further washing. Pure water is continuously introduced into the bottom of the fifth-stage centrifugal extractor 52 at a flow rate of 0.118 L / h, and the molar amount of fresh pure water introduced is equal to the molar amount of benzyl alcohol produced in the reaction. The metal ion content of the organic phase after washing by the fifth-stage centrifugal extractor is 0.12 ppm, and the organic phase is sent to the light-weight removal tower 9. (4) A mixture of light components such as toluene and benzyl chloride containing a small amount of water is obtained from the top of the light component removal tower 9. After being mixed with fresh material from the buffer tank 6 and replenished at 2.92 L / h in the Venturi mixer 8, it enters the micro-interface circulating reactor 1. The molar ratio of toluene to benzyl chloride in the replenished fresh material is approximately 29.4:49. The molar amount of toluene is approximately equal to the molar amount of benzyltoluene produced in the reaction, and the molar amount of benzyl chloride is approximately equal to the sum of the molar amounts of benzyl alcohol and benzyltoluene produced in the reaction. The bottom material of the light component removal tower 9 is subjected to distillation separation to obtain approximately 2.07 kg of benzyl alcohol (purity 99.95%, yield 97.7%) and approximately 5.25 kg of benzyltoluene (purity 98.2%, yield 98%). Example

[0032] (1) 6.33 kg benzyl chloride, 900.8 g water, and 2.77 kg toluene (molar ratio of 50:50:30) were added from the top into a 15 L micro-interface circulation reactor 1. The top of the micro-interface circulation reactor 1 is equipped with a micron-sized microporous titanium alloy titanium powder sintered plate with a micron-sized micropore diameter of 20 μm. 1.5% of the mass of benzyl chloride catalyst (the catalyst is composed of zinc chloride and polyethylene glycol in a mass ratio of 1:2) was added. The external circulation pump was turned on with a circulation ratio of 20 times. Under the circulation mixing of the external circulation pump 10, the material in the micro-interface circulation reactor 1 was slowly heated to 105 °C. Under the action of the catalyst, benzyl chloride reacted with water and toluene. The generated hydrogen chloride was cooled by condenser 2 and returned to the micro-interface circulation reactor 1 in liquid phase, while the gas phase was absorbed by hydrogen chloride. (2) When the online detector 3 detects that the conversion rate of benzyl chloride reaches 98.2%, the reaction liquid metering pump 4 continuously and slowly discharges the material to the five-stage centrifugal extractor 5 at a flow rate of about 1.83 L / h, and continuously replenishes the mixture of benzyl chloride, water and toluene (molar ratio of 50:50:30) at a flow rate of about 2.19 L / h. The average residence time of the material in the micro-interface circulating reactor is 4.5 h. (3) The reaction solution is continuously added from the bottom of the first-stage centrifugal extractor via the reaction solution metering pump 4, and mixed with the aqueous phase from the next-stage centrifugal extractor. The aqueous phase continuously separated from the top of the first-stage centrifugal extractor 51 enters the buffer tank 6, and the organic phase enters the next-stage centrifugal extractor for further washing. Pure water is continuously introduced into the bottom of the fifth-stage centrifugal extractor 52 at a flow rate of 0.132 L / h, and the molar amount of fresh pure water introduced is equal to the molar amount of benzyl alcohol produced in the reaction. The metal ion content of the organic phase after the fifth-stage centrifugal extraction and washing is 0.13 ppm, and the organic phase is sent to the light-weight removal tower 9. (4) A mixture of light components such as toluene and benzyl chloride containing a small amount of water is obtained from the top of the light component removal tower 9. This mixture is then mixed with fresh material from the buffer tank 6 and replenished at a rate of 1.64 L / h in the Venturi mixer 8 before entering the micro-interface circulating reactor 1. The molar ratio of toluene to benzyl chloride in the replenished fresh material is approximately 16.2:49.1. The molar amount of toluene is approximately equal to the molar amount of benzyltoluene produced in the reaction, and the molar amount of benzyl chloride is approximately equal to the sum of the molar amounts of benzyl alcohol and benzyltoluene produced in the reaction. The bottom material of the light component removal tower 9 is then subjected to distillation separation to obtain approximately 3.5 kg of benzyl alcohol (purity 99.97%, yield 98.4%) and approximately 2.87 kg of benzyltoluene (purity 97.9%, yield 97.2%). Example

[0033] (1) 6.33 kg benzyl chloride, 900.8 g water, and 3.69 kg toluene (molar ratio of 50:50:40) were added from the top into a 15 L micro-interface circulation reactor 1. The top of the micro-interface circulation reactor 1 is equipped with a micron-sized microporous titanium alloy titanium powder sintered plate with a micron-sized micropore diameter of 100 μm. 0.8% by mass of benzyl chloride catalyst (the catalyst is composed of tin chloride and polyethylene glycol in a mass ratio of 1:2) was added. The external circulation pump was turned on with a circulation ratio of 50 times. Under the circulation mixing of the external circulation pump 10, the material in the micro-interface circulation reactor 1 was slowly heated to 110 °C. Under the action of the catalyst, benzyl chloride reacted with water and toluene. The generated hydrogen chloride was cooled by condenser 2 and returned to the micro-interface circulation reactor 1 in liquid phase, while the gas phase was absorbed by hydrogen chloride. (2) When the online detector 3 detects that the conversion rate of benzyl chloride reaches 98.5%, the reaction liquid metering pump 4 continuously and slowly discharges the material to the five-stage centrifugal extractor 5 at a flow rate of about 2.65 L / h, and continuously replenishes the mixture of benzyl chloride, water and toluene (molar ratio of 50:50:40) at a flow rate of about 3.12 L / h. The average residence time of the material in the micro-interface circulating reactor is 3.5 h. (3) The reaction solution is continuously added from the bottom of the first-stage centrifugal extractor via the reaction solution metering pump 4, and mixed with the aqueous phase from the next-stage centrifugal extractor. The aqueous phase continuously separated from the top of the first-stage centrifugal extractor 51 enters the buffer tank 6, and the organic phase enters the next-stage centrifugal extractor for further washing. Pure water is continuously introduced into the bottom of the fifth-stage centrifugal extractor 52 at a flow rate of 0.122 L / h, and the molar amount of fresh pure water introduced is equal to the molar amount of benzyl alcohol produced in the reaction. The metal ion content of the organic phase after washing by the fifth-stage centrifugal extractor is 0.12 ppm, and the organic phase is sent to the light-weight removal tower 9. (4) A mixture of light components such as toluene and benzyl chloride containing a small amount of water is obtained from the top of the light component removal tower 9. This mixture is then mixed with fresh material from the buffer tank 6 and replenished at a rate of 2.4 L / h in the Venturi mixer 8 before entering the micro-interface circulating reactor 1. The molar ratio of toluene to benzyl chloride in the replenished fresh material is 25.61:49.25. The molar amount of toluene is equal to the molar amount of benzyltoluene produced in the reaction, and the molar amount of benzyl chloride is approximately equal to the sum of the molar amounts of benzyl alcohol and benzyltoluene produced in the reaction. The bottom material of the light component removal tower 9 is then subjected to distillation separation to obtain 2.5 kg of benzyl alcohol (purity 99.96%, yield 97.9%) and approximately 4.56 kg of benzyltoluene (purity 98.1%, yield 97.2%).

[0034] Compare with Example 1 (1) 6.33 kg of benzyl chloride and soda ash were added to the micro-interface circulation reactor at a mass ratio of 1:1. The micro-interface circulation reactor 1 was equipped with a micron-sized microporous titanium alloy titanium powder sintered plate at the top. The micron-sized micropores had a pore size of 50 μm. The system was heated to 220 °C and the pressure was controlled at 3 MPa for alkaline hydrolysis reaction. (2) No online monitoring or continuous discharge was set up during the reaction process; an intermittent reaction was adopted, and the reaction time was 6 hours. (3) After the reaction was completed, centrifugal extraction was not performed. Instead, the mixture was allowed to stand and separate into layers. The aqueous phase was high-salt chlorine-containing wastewater, and the organic phase was directly distilled. (4) Post-distillation testing: benzyl chloride conversion rate was 78%, dibenzyl ether by-product rate was 10%, 9 tons of high-salt wastewater were generated per ton of benzyl alcohol product, and the process produced no benzyl toluene product.

[0035] Compare with Example 2 (1) 6.33 kg benzyl chloride, 900.8 g water, and 4.61 kg toluene (molar ratio 50:50:50) were added to a 15 L micro-interface circulating reactor 1. The micro-interface circulating reactor 1 was equipped with a micron-sized microporous titanium alloy titanium powder sintered plate at the top. The micron-sized micropores had a pore size of 50 μm. 2.5% by mass of benzyl chloride catalyst (the catalyst was composed of ferric sulfate and polyethylene glycol in a mass ratio of 1:2) was added. The materials in the micro-interface circulating reactor 1 were slowly heated to 100 °C under stirring to react. Hydrogen chloride was condensed and refluxed, and the gas phase was absorbed. (2) When the online detector detects a conversion rate of 98.1%, the material is continuously discharged without undergoing five-stage centrifugal extraction and washing, and the reaction solution is directly sent to the light-weight removal tower 9; (3) The light components at the top of the light removal tower 9 are directly refluxed to the micro-interface circulating reactor, and the bottom material is separated by distillation. (4) Product testing: The organic phase metal ion content is 109 ppm, the catalyst loss rate is 20%, the purity of benzyl alcohol is 99.8%, the purity of benzyl toluene is 95%, the chlorine content of benzyl toluene is 0.032% wt, and the acid value is 0.049 (mg KOH / g). Benzyl toluene cannot meet the requirements for use as an impregnating agent for power capacitors.

[0036] Compare with Example 3 This Comparative Example 1 is basically the same as Example 1 of the present invention, except that a conventional hydrolysis vessel is used instead of the micro-interface circulating reactor 1 of the present invention. Other steps remain unchanged. The material in the bottom of the light removal tower 9 is separated by distillation to obtain about 1.45 kg of benzyl alcohol (purity 99.5%, yield 88.6%) and about 4.05 kg of benzyl toluene (purity 95%, yield 87.3%).

[0037] Traditional hydrolysis reactors rely on conventional stirring, resulting in droplet sizes typically in the millimeter range and small specific surface areas. The hydrolysis and alkylation reactions compete within the same system, and the hydrolysis reaction is more dependent on catalyst concentration. Local material concentration inconsistencies exist within the reactor, reducing benzyl alcohol selectivity. Furthermore, the long residence time (3-5 hours) easily leads to further dehydration of benzyl alcohol to form dibenzyl ether, resulting in reduced product yield and purity.

[0038] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A device for the hydrolysis of chlorobenzyl to produce benzyl alcohol co-product benzyl toluene, characterized by: The device includes a micro-interface circulating reactor and a multi-stage extraction centrifuge. The bottom of the micro-interface circulating reactor is connected to the reaction liquid inlet of the multi-stage extraction centrifuge via a reaction liquid metering pump. The top of the micro-interface circulating reactor has a gas phase inlet and a condensate reflux inlet connected to the condenser body. The aqueous phase outlet of the multi-stage extraction centrifuge is connected to the buffer tank body. The bottom of the buffer tank is connected to the top feed inlet of the micro-interface circulating reactor via a mixing pump and a Venturi mixer. The organic phase outlet of the multi-stage extraction centrifuge is connected to the light-weight removal tower body. The top of the light-weight removal tower is connected to the micro-interface circulating reactor via a Venturi mixer.

2. The apparatus for producing benzyl alcohol and co-producing benzyltoluene by hydrolysis of benzyl chloride according to claim 1, characterized in that: The micro-interface circulating reactor has a built-in microporous titanium alloy titanium powder sintered plate or ceramic membrane tube with a pore size of 20-100 μm at the top, and is externally equipped with a circulation pump at 0.5 A median diameter of 50 mm is formed under a pressure difference of 1.2 MPa. 200μm emulsified microdroplets, material circulation ratio of 20 to 50 times, maintaining a high shear, high dispersion, and fully mixed state; the micro-interface circulation reactor drives the material to circulate in the outer circulation pipeline at a flow rate of 5m / s through a circulation pump, and the diameter of the microdroplets is controlled by adjusting the speed of the circulation pump.

3. The apparatus for producing benzyl alcohol and co-producing benzyltoluene by hydrolysis of benzyl chloride according to claim 1, characterized in that: The multi-stage extraction centrifuge device consists of multiple centrifugal extractors connected in series, totaling five centrifugal extractors. The first-stage centrifugal extractor has its top aqueous phase outlet connected to a buffer tank, and its bottom reaction liquid inlet connected to a micro-interface circulating reactor 1 via a reaction liquid metering pump. The bottom aqueous phase inlet of the first-stage centrifugal extractor is connected to the aqueous phase outlet of the next-stage centrifugal extractor, and its top organic phase outlet is connected to the organic phase inlet of the next-stage centrifugal extractor. The fifth-stage centrifugal extractor has its bottom organic phase inlet connected to the organic phase outlet of the previous-stage centrifugal extractor, its top aqueous phase outlet connected to the aqueous phase inlet of the previous-stage centrifugal extractor, and its top organic phase outlet connected to a light-weight removal tower. The fifth-stage centrifugal extractor has a pure water inlet at its bottom.

4. The apparatus for producing benzyl alcohol and co-producing benzyltoluene by hydrolysis of benzyl chloride according to claim 1, characterized in that: An online detector is installed at the top of the micro-interface circulating reactor to monitor the conversion rate of benzyl chloride in real time.

5. A method for producing benzyl alcohol and co-producing benzyltoluene by hydrolysis of benzyl chloride using the apparatus of any one of claims 1-4, characterized in that: The specific preparation steps are as follows: (1) Benzyl chloride, water, toluene and catalyst are introduced into a micro-interface circulating reactor and heated to 100-115°C under circulating mixing to produce benzyl alcohol, benzyl toluene and hydrogen chloride as a byproduct. The hydrogen chloride is condensed and refluxed back to the reactor and collected and treated in the gas phase. (2) When the online detection of benzyl chloride conversion rate reaches 95-100%, the reaction liquid is continuously discharged to the multi-stage centrifugal extraction device, and benzyl chloride, water and toluene mixture is continuously added. The average residence time of the material in the micro-interface circulating reactor (1) is 3-5 hours. (3) The reaction solution is subjected to multi-stage centrifugal extraction and washing. The aqueous phase containing the catalyst is recovered and recycled. The organic phase metal ion content is less than 0.2 ppm before being sent to the light phase removal tower. (4) The light components at the top of the light removal tower are refluxed to the micro-interface circulating reactor, and the bottom material is separated by distillation to obtain benzyl alcohol and benzyl toluene.

6. The method for producing benzyl alcohol and co-producing benzyltoluene by hydrolysis of benzyl chloride according to claim 5, characterized in that: The catalyst is composed of a metal salt and polyethylene glycol, and the amount used is 0.1% to 5% of the mass of benzyl chloride; the molar ratio of benzyl chloride, water and toluene is 50:50:(10 to 50).

7. The method for producing benzyl alcohol and co-producing benzyltoluene by hydrolysis of benzyl chloride according to claim 6, characterized in that: The metal salt mentioned in step (1) is at least one of ferric sulfate, zinc chloride, and tin chloride.

8. The method for producing benzyl alcohol and co-producing benzyltoluene by hydrolysis of benzyl chloride according to claim 6, characterized in that: The mass ratio of metal salt to polyethylene glycol in the catalyst described in step (1) is 1:

2.

9. The method for producing benzyl alcohol and co-producing benzyltoluene by hydrolysis of benzyl chloride according to claim 6, characterized in that: The reaction temperature in step (1) is 100-110℃.

10. The method for producing benzyl alcohol and co-producing benzyltoluene by hydrolysis of benzyl chloride according to claim 6, characterized in that: The fresh material added in step (4) is a mixture of toluene and benzyl chloride, wherein the molar amount of toluene is equal to the molar amount of benzyltoluene produced by the reaction, and the molar amount of benzyl chloride is equal to the sum of the molar amounts of benzyl alcohol and benzyltoluene produced by the reaction.

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