Method for producing 4, 4 '-dichlorodiphenyl sulfone through continuous reaction of microchannel reactor

Abstract

The invention provides a method for producing 4, 4 '-dichlorodiphenyl sulfone by continuous reaction of a microchannel reactor, which comprises the following steps: uniformly mixing thionyl chloride and aluminum chloride to obtain a solution A; uniformly mixing hydrogen peroxide and glacial acetic acid to obtain a solution B; a first feeding pump and a second feeding pump are adopted for conveying chlorobenzene and a solution A into a first silicon carbide micro-channel reactor for reaction, an outlet of the reactor is connected with a gas-liquid separator, through separation, a gas phase is used for preparing a byproduct hydrochloric acid, and a liquid phase is a chlorobenzene solution of 4, 4 '-dichlorodiphenyl sulfoxide; and continuously conveying the chlorobenzene solution of 4, 4 '-dichlorodiphenyl sulfoxide to the second silicon carbide microchannel reactor by adopting a third feeding pump, and meanwhile, conveying the solution B to the second silicon carbide microchannel reactor by adopting a fourth feeding pump for reaction to prepare 4, 4'-dichlorodiphenyl sulfone. Compared with the prior art, the micro-channel reactor is used for continuous production, the mass and heat transfer effect is good, impurity generation is effectively inhibited, and the reaction time is shortened.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, and specifically to a method for the continuous production of 4,4'-dichlorodiphenyl sulfone using a microchannel reactor. Background Technology

[0002] 4,4'-Dichlorodiphenyl sulfone (DDS) is an important organic synthetic product and a major raw material for manufacturing engineering plastics such as polysulfone and polyethersulfone (e.g., bisphenol A type polysulfone, polyphenylene ethersulfone, and polyamide sulfone resins). It is also an intermediate in pharmaceuticals, dyes, and pesticides, and has wide applications in engineering plastics and fine chemicals.

[0003] Currently, the main methods for synthesizing 4,4'-dichlorodiphenyl sulfone are: (1) Chlorosulfonic acid method: Chlorobenzene, sulfuric acid and chlorosulfonic acid are used as the main raw materials. First, chlorobenzene and sulfuric acid react at high temperature to generate p-chlorobenzenesulfonic acid, which then reacts with chlorosulfonic acid under the action of a catalyst to generate p-chlorobenzenesulfonyl chloride, which then reacts with chlorobenzene to generate the product 4,4'-dichlorodiphenyl sulfone. This method has a complicated synthesis route, complex process, many equipment, and high cost.

[0004] The reaction equation is:

[0005] (2) Diethyl sulfate method: US3415887 describes a method for synthesizing 4,4'-dichlorodiphenyl sulfone using sulfur trioxide, diethyl sulfate and chlorobenzene as raw materials. This method is prone to producing the isomer 2,4-dichlorodiphenyl sulfone, has poor selectivity, low product content and is difficult to purify.

[0006] The reaction equation is:

[0007] (3) Sulfuric acid method: p-chlorobenzenesulfonic acid is synthesized by sulfonation of chlorobenzene and sulfuric acid, and then condensed with excess chlorobenzene to obtain the product 4,4'-dichlorodiphenyl sulfone. The yield of this method is 46-47%, which is relatively low. The reaction temperature is >200℃, the equipment is severely corroded, the crude product has poor purity and dark color, and it needs to be refined and decolorized to obtain a qualified product.

[0008] The reaction equation is:

[0009] (4) Thionyl chloride method: Chlorobenzene and thionyl chloride undergo a Friedel-Crafts reaction under the action of a catalyst to purify 4,4'-dichlorodiphenyl sulfoxide, which is then dissolved in glacial acetic acid and oxidized with hydrogen peroxide to obtain the product 4,4'-dichlorodiphenyl sulfoxide. In this method, 4,4'-dichlorodiphenyl sulfoxide is precipitated as an encapsulation of 4,4'-dichlorodiphenyl sulfoxide during the oxidation process, resulting in incomplete reaction and ultimately limiting the improvement in the purity and yield of 4,4'-dichlorodiphenyl sulfoxide. At the same time, existing technologies often use excessive amounts of hydrogen peroxide, leading to difficult post-processing, high costs, and unfavorable industrial scale-up.

[0010] The reaction equation is: Summary of the Invention

[0011] In order to overcome the shortcomings of the existing technology, the present invention aims to provide a method for producing 4,4'-dichlorodiphenyl sulfone by continuous reaction using a microchannel reactor, which has good mass and heat transfer effect, effectively suppresses the generation of impurities, shortens the reaction time, saves the amount of catalyst and hydrogen peroxide, and produces products with high purity and high yield.

[0012] This invention is achieved through the following technical solution: A method for the continuous production of 4,4'-dichlorodiphenyl sulfone using a microchannel reactor includes the following steps: (1) Thionyl chloride and aluminum chloride are reacted at a temperature of 40°C. Stir at 50℃ for 1 minute After 2 hours of mixing, solution A is obtained. (2) React hydrogen peroxide and glacial acetic acid at a temperature of 20°C. Mix thoroughly at 25℃ to obtain solution B; (3) Chlorobenzene is fed to the first silicon carbide microchannel reactor using a first feed pump, while solution A is fed to the same reactor using a second feed pump. The temperature of the first silicon carbide microchannel reactor is controlled at 65°C. The reaction is carried out at 85℃. The reactor outlet is connected to a gas-liquid separator. After separation, the gas phase is used to prepare hydrochloric acid as a by-product, and the liquid phase is a chlorobenzene solution of 4,4'-dichlorodiphenyl sulfoxide. (4) The chlorobenzene solution of 4,4'-dichlorodiphenyl sulfoxide is continuously fed to the second silicon carbide microchannel reactor using a third feed pump, while solution B is fed to the second silicon carbide microchannel reactor using a fourth feed pump. The temperature of the second silicon carbide microchannel reactor is controlled at 60°C. The material from the reactor outlet at 80℃ is received into the reaction vessel and cooled to 0℃. Crystallization was performed at 10℃, followed by filtration, washing with water, and drying to obtain the product 4,4'-dichlorodiphenyl sulfone.

[0013] Preferably, in step (1), the mass ratio of thionyl chloride to aluminum chloride is 0.45. 1.12.

[0014] Preferably, in step (2), the hydrogen peroxide used is a commercially available 30% concentration, and the mass ratio of hydrogen peroxide to glacial acetic acid is 0.37. 0.80.

[0015] Preferably, in step (3), the volumetric flow rate ratio of the first feed pump and the second feed pump is controlled at (4.33). 5.37):1.

[0016] Preferably, in step (3), the volumetric flow rate of the first feed pump is controlled at 1200. 2000 mL / min, the volumetric flow rate of the second feed pump is controlled at 240. 500 mL / min.

[0017] Preferably, in step (3), the residence time of the reactants in the first silicon carbide microchannel reactor is 4 hours. 8 minutes.

[0018] Preferably, in step (3), the pressure of the first silicon carbide microchannel reactor is controlled to be 0.01. 0.4MPa.

[0019] Preferably, in step (4), the volumetric flow rate ratio of the third feed pump and the fourth feed pump is controlled at (2.57). 2.85):1.

[0020] Preferably, in step (4), the volumetric flow rate of the third feed pump is controlled at 1000. 1800 mL / min, the volumetric flow rate of the fourth feed pump is controlled at 380. 650ml / min.

[0021] Preferably, in step (4), the residence time of the reactants in the second silicon carbide microchannel reactor is 2 hours. 8 minutes.

[0022] Preferably, in step (4), the pressure of the first silicon carbide microchannel reactor is controlled to be 0.01. 0.2MPa.

[0023] Compared with the prior art, the present invention has the following advantages: 1. This invention uses a microchannel reactor instead of a traditional batch reactor, which has better mass and heat transfer effects, effectively inhibits the formation of the impurity dichlorodiphenyl sulfone isomer, improves product purity, and shortens reaction time; 2. This invention uses a microchannel reactor to carry out the oxidation reaction, which improves the conversion rate of 4,4'-dichlorodiphenyl sulfoxide, while reducing the amount of hydrogen peroxide used, thereby increasing the product yield and reducing the unit consumption of raw materials. 3. Compared with other thionyl chloride methods, this invention reduces the high-temperature hydrolysis step, simplifies the process flow, and reduces energy consumption and equipment costs, thereby reducing production costs.

[0024] The 4,4'-dichlorodiphenyl sulfone obtained by this invention has a purity greater than 99.8%, an isomer content of less than 0.1%, and a 4,4'-dichlorodiphenyl sulfoxide content of less than 0.05%. Therefore, the preparation method of this invention has advantages over existing methods for preparing 4,4'-dichlorodiphenyl sulfone, such as improved purity, simplified process, and reduced cost. These advantages help improve product quality and competitiveness, thereby meeting the growing demand in related fields. Attached Figure Description

[0025] Figure 1 The liquid chromatogram of 4,4'-dichlorodiphenyl sulfone prepared in Example 1 of this invention. Detailed Implementation

[0026] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0027] It should be noted that, unless otherwise specified, the experimental instruments and reagents described in the following examples are all commercially available.

[0028] In this invention, the method employs a first silicon carbide microchannel reactor, a gas-liquid separator, and a second silicon carbide microchannel reactor connected in series. There are no special limitations on the silicon carbide microchannel reactor; any silicon carbide microchannel reactor well-known to those skilled in the art can be used. The designations "first" and "second" are merely distinguishing numbers and have no other meaning. The gas-liquid separator has no special requirements; it only needs to release the gas from the outlet pipe of the first silicon carbide microchannel reactor.

[0029] Example 1 (1) Add 11 kg of thionyl chloride and 10 kg of aluminum chloride to a 50 L glass reactor A, stir at 45 °C for 1 h to dissolve and clarify the solution, mix evenly to obtain solution A; (2) Add 40 kg of glacial acetic acid to a 100 L glass reactor B, add 28 kg of 30% hydrogen peroxide dropwise, stir at 20 °C for 1 hour to obtain solution B; (3) A silicon carbide microchannel reactor with a pipeline volume of 12L is used. The first feed pump delivers chlorobenzene from the chlorobenzene raw material storage tank to the first silicon carbide microchannel reactor at a volume flow rate of 1200mL / min. At the same time, the second feed pump delivers solution A to the first silicon carbide microchannel reactor at a volume flow rate of 240mL / min. The reaction temperature of the material in the first silicon carbide microchannel reactor is controlled at 70℃. The residence time of the reactants in the first silicon carbide microchannel is 8min. The material at the reactor outlet is received to a 50L gas-liquid separator. The gas phase is absorbed through the tail gas pipeline to prepare by-product hydrochloric acid, and the liquid phase is stored in the tank of the gas-liquid separator. Continuing with the 12L silicon carbide microchannel reactor, the third feed pump delivers liquid from the gas-liquid separator tank to the second silicon carbide microchannel reactor at a volumetric flow rate of 1200 mL / min. Simultaneously, the fourth feed pump delivers solution B to the second silicon carbide microchannel reactor at a volumetric flow rate of 450 mL / min. The reaction temperature within the second silicon carbide microchannel reactor is controlled at 70℃, and the residence time of the reactants within the second silicon carbide microchannel is 7 minutes. The reactor outlet... The material was received into a 50L glass reactor C, and crystallization was carried out while stirring and cooling. The crystals were filtered at 5℃ to obtain a white solid. The white solid was transferred to a 50L glass reactor D, 10Kg of water was added, the temperature was raised to 40℃ and stirred for 30min, the temperature was lowered to 5℃ and filtered, and the solid was dried at 80℃ to obtain 3.81Kg of white solid. Liquid chromatography analysis showed that the content of 4,4'-dichlorodiphenyl sulfone was 99.92%, the content of the isomer 2,4-dichlorodiphenyl sulfone was 0.03%, and the content of 4,4'-dichlorodiphenyl sulfoxide was 0.02%.

[0030] Example 2 The difference from Example 1 is that the reaction temperature of the material in the first silicon carbide microchannel reactor was controlled at 85°C, while other conditions were the same. 3.66 kg of the target product 4,4'-dichlorodiphenyl sulfone was obtained, with a liquid phase detection content of 99.86%, a 2,4'-dichlorodiphenyl sulfone isomer content of 0.07%, and a 4,4'-dichlorodiphenyl sulfoxide content of 0.01%.

[0031] Example 3 The difference from Example 1 is that the reaction temperature of the material in the second silicon carbide microchannel reactor was controlled at 80°C, while other conditions were the same. 3.72 kg of the target product 4,4'-dichlorodiphenyl sulfone was obtained, with a liquid phase detection content of 99.59%, a 2,4'-dichlorodiphenyl sulfone isomer content of 0.08%, and a 4,4'-dichlorodiphenyl sulfoxide content of 0.01%.

[0032] Example 4 (1) Add 10 kg of thionyl chloride and 9.5 kg of aluminum chloride to a 50 L glass reactor A, stir at 45 °C for 1 h to dissolve and make clear, mix evenly to obtain solution A; (2) Add 40 kg of glacial acetic acid to a 100 L glass reactor B, add 32 kg of 30% hydrogen peroxide dropwise, stir at 20 °C for 1 hour to obtain solution B; (3) A silicon carbide microchannel reactor with a pipeline volume of 12L is used. The first feed pump delivers chlorobenzene from the chlorobenzene raw material storage tank to the first silicon carbide microchannel reactor at a volume flow rate of 1500mL / min. At the same time, the second feed pump delivers solution A to the first silicon carbide microchannel reactor at a volume flow rate of 300mL / min. The reaction temperature of the material in the first silicon carbide microchannel reactor is controlled at 65℃. The residence time of the reactant in the first silicon carbide microchannel is 7min. The material at the reactor outlet is received to a 50L gas-liquid separator. The gas phase is absorbed through the tail gas pipeline to prepare by-product hydrochloric acid, and the liquid phase is stored in the tank of the gas-liquid separator. Continuing with the 12L silicon carbide microchannel reactor, the third feed pump delivers liquid from the gas-liquid separator tank to the second silicon carbide microchannel reactor at a volumetric flow rate of 1180 mL / min. Simultaneously, the fourth feed pump delivers solution B to the second silicon carbide microchannel reactor at a volumetric flow rate of 420 mL / min. The reaction temperature within the second silicon carbide microchannel reactor is controlled at 75℃, and the residence time of the reactants within the second silicon carbide microchannel is 7 minutes. The reactor outlet... The material was received into a 50L glass reactor C, and crystallization was carried out while stirring and cooling. The crystals were filtered at 5℃ to obtain a white solid. The white solid was transferred to a 50L glass reactor D, 10Kg of water was added, the temperature was raised to 40℃ and stirred for 30min, the temperature was lowered to 5℃ and filtered, and the solid was dried at 80℃ to obtain 3.49Kg of white solid. Liquid chromatography analysis showed that the content of 4,4'-dichlorodiphenyl sulfone was 99.74%, the content of the isomer 2,4-dichlorodiphenyl sulfone was 0.08%, and the content of 4,4'-dichlorodiphenyl sulfoxide was 0.02%.

[0033] Example 5 (1) Add 10 kg of thionyl chloride and 20 kg of aluminum chloride to a 50 L glass reactor A, stir at 45 °C for 1 h to dissolve and clarify the solution, mix evenly to obtain solution A; (2) Add 40 kg of glacial acetic acid to a 100 L glass reactor B, add 16 kg of 30% hydrogen peroxide dropwise, stir at 20 °C for 1 hour to obtain solution B; (3) A silicon carbide microchannel reactor with a pipeline volume of 12L is used. The first feed pump delivers chlorobenzene from the chlorobenzene raw material storage tank to the first silicon carbide microchannel reactor at a volume flow rate of 1800mL / min. At the same time, the second feed pump delivers solution A to the first silicon carbide microchannel reactor at a volume flow rate of 340mL / min. The reaction temperature of the material in the first silicon carbide microchannel reactor is controlled at 75℃. The residence time of the reactants in the first silicon carbide microchannel is 6min. The material at the reactor outlet is received to a 50L gas-liquid separator. The gas phase is absorbed through the tail gas pipeline to prepare by-product hydrochloric acid, and the liquid phase is stored in the tank of the gas-liquid separator. Continuing with the 12L silicon carbide microchannel reactor, the third feed pump delivers liquid from the gas-liquid separator tank to the second silicon carbide microchannel reactor at a volumetric flow rate of 1650 mL / min. Simultaneously, the fourth feed pump delivers solution B to the second silicon carbide microchannel reactor at a volumetric flow rate of 610 mL / min. The reaction temperature within the second silicon carbide microchannel reactor is controlled at 80℃, and the residence time of the reactants within the second silicon carbide microchannel is 5 min. The reactor outlet... The material was received into a 50L glass reactor C, and crystallization was carried out while stirring and cooling. The crystals were filtered at 5℃ to obtain a white solid. The white solid was transferred to a 50L glass reactor D, 10Kg of water was added, the temperature was raised to 40℃ and stirred for 30min, the temperature was lowered to 5℃ and filtered, and the solid was dried at 80℃ to obtain 2.16Kg of white solid. Liquid chromatography analysis showed that the content of 4,4'-dichlorodiphenyl sulfone was 99.61%, the content of the isomer 2,4-dichlorodiphenyl sulfone was 0.10%, and the content of 4,4'-dichlorodiphenyl sulfoxide was 0.03%.

[0034] Comparative Example 1 The difference from Example 1 is that the reaction temperature of the material in the first silicon carbide microchannel reactor was controlled at 30°C, while other conditions were the same. 1.24 kg of the target product 4,4'-dichlorodiphenyl sulfone was obtained, with a liquid phase detection content of 98.70%, a 2,4-dichlorodiphenyl sulfone isomer content of 0.01%, and a 4,4'-dichlorodiphenyl sulfoxide content of 0.02%.

[0035] Comparative Example 2 The difference from Example 1 is that the reaction temperature of the material in the second silicon carbide microchannel reactor was controlled at 50°C, while other conditions were the same. 2.07 kg of the target product 4,4'-dichlorodiphenyl sulfone was obtained, with a liquid phase detection content of 97.92%, a 2,4'-dichlorodiphenyl sulfone isomer content of 0.01%, and 4,4'-dichlorodiphenyl sulfoxide content of 2.01%.

[0036] Comparative Example 3 The difference from Example 1 is that the reaction temperature of the material in the second silicon carbide microchannel reactor was controlled at 85°C, while other conditions were the same. 2.69 kg of the target product 4,4'-dichlorodiphenyl sulfone was obtained, with a liquid phase detection content of 99.12%, a 2,4'-dichlorodiphenyl sulfone isomer content of 0.25%, and a 4,4'-dichlorodiphenyl sulfoxide content of 0.03%.

[0037] Comparative Example 4 The difference from Example 1 is that the mass ratio of thionyl chloride to aluminum chloride in solution A is 1.3, and other conditions are the same. The target product 4,4'-dichlorodiphenyl sulfone was obtained in 0.83 kg, with a liquid phase detection content of 99.89%, the content of the isomer 2,4-dichlorodiphenyl sulfone was 0.12%, and the content of 4,4'-dichlorodiphenyl sulfone was 0.04%.

[0038] Comparative Example 5 The difference from Example 1 is that the volumetric flow rate of chlorobenzene feed is 1200 mL / min, the volumetric flow rate of solution A feed is 300 mL / min, and other conditions are the same. 3.31 kg of the target product 4,4'-dichlorodiphenyl sulfone was obtained, with a liquid phase detection content of 99.69%, a 2,4-dichlorodiphenyl sulfone isomer content of 0.25%, and a 4,4'-dichlorodiphenyl sulfoxide content of 0.03%.

[0039] Comparative Example 6 The difference from Example 1 is that the mass ratio of hydrogen peroxide to acetic acid in solution B is 0.2, and other conditions are the same. 3.12 kg of the target product 4,4'-dichlorodiphenyl sulfone was obtained, with a liquid phase detection content of 98.15%, a 2,4-dichlorodiphenyl sulfone isomer content of 0.08%, and a 4,4'-dichlorodiphenyl sulfoxide content of 1.37%.

[0040] Comparative Example 7 The difference from Example 1 is that the volumetric flow rate of the third feed pump is 1200 mL / min, the volumetric flow rate of solution B is 400 mL / min, and other conditions are the same. 2.97 kg of the target product 4,4'-dichlorodiphenyl sulfone was obtained, with a liquid phase detection content of 97.69%, a 2,4'-dichlorodiphenyl sulfone isomer content of 0.02%, and a 4,4'-dichlorodiphenyl sulfoxide content of 1.96%.

[0041] Comparative Example 8 1.4 kg of aluminum chloride and 7.74 kg of chlorobenzene were added to a 50 L glass reactor. The mixture was heated to 40 °C and stirred until homogeneous. 1.25 kg of thionyl chloride was slowly added dropwise over approximately 4 hours, during which time the temperature was raised from 40 °C to 60 °C and maintained at 60 °C with stirring for 1 hour to obtain a chlorobenzene solution of 4,4'-dichlorodiphenyl sulfoxide. 1.75 kg of acetic acid was added to the glass reactor. The mixture was heated to 75 °C and stirred until homogeneous. 1.2 kg of 30% hydrogen peroxide was slowly added dropwise over approximately 3 hours, during which time the temperature was maintained at 75 °C with stirring for 2 hours. The mixture was then cooled to 0-10 °C to crystallize. After filtration, the solid was washed with 20 kg of water, filtered, and dried to obtain 2.25 kg of a white solid. Liquid chromatography analysis showed a purity of 98.12%, with 1.32% of the isomer 2,4'-dichlorodiphenyl sulfoxide and 0.27% of 4,4'-dichlorodiphenyl sulfoxide.

Claims

1. A method for the continuous production of 4,4'-dichlorodiphenyl sulfone using a microchannel reactor, characterized in that, Includes the following steps: (1) Mix thionyl chloride and aluminum chloride evenly to obtain solution A; (2) Mix hydrogen peroxide and glacial acetic acid evenly to obtain solution B; (3) Chlorobenzene is fed to the first silicon carbide microchannel reactor using the first feed pump, and solution A is fed to the same reactor using the second feed pump. The reaction is controlled in the first silicon carbide microchannel reactor. The reactor outlet is connected to a gas-liquid separator. After separation, the gas phase is used to prepare by-product hydrochloric acid, and the liquid phase is a chlorobenzene solution of 4,4'-dichlorodiphenyl sulfoxide. (4) The chlorobenzene solution of 4,4'-dichlorodiphenyl sulfoxide is continuously fed to the second silicon carbide microchannel reactor using a third feed pump, while solution B is fed to the second silicon carbide microchannel reactor using a fourth feed pump for reaction. The material from the reactor outlet is received into the reaction vessel and cooled to 0°C. Crystallization was performed at 10℃, followed by filtration, washing with water, and drying to obtain the product 4,4'-dichlorodiphenyl sulfone.

2. The method according to claim 1, characterized in that, In step (1), thionyl chloride and aluminum chloride react at a temperature of 40°C. Stir at 50℃ for 1 minute 2h; the mass ratio of thionyl chloride to aluminum chloride is 0.

45. 1.

12.

3. The method according to claim 1, characterized in that, In step (2), commercially available 30% hydrogen peroxide is used, and the mass ratio of hydrogen peroxide to glacial acetic acid is 0.

37. 0.

80.

4. The method according to claim 1, characterized in that, In step (3), the volumetric flow rate ratio of the first feed pump and the second feed pump is controlled at (4.33). 5.37):1, reaction temperature is 65 85℃.

5. The method according to claim 1, characterized in that, In step (3), the volumetric flow rate of the first feed pump is controlled at 1200. 2000 mL / min, the volumetric flow rate of the second feed pump is controlled at 240. 500 mL / min.

6. The method according to claim 1, characterized in that, In step (3), the residence time of the reactants in the first silicon carbide microchannel reactor is 4 hours. 8 minutes.

7. The method according to claim 1, characterized in that, In step (3), the pressure inside the first silicon carbide microchannel reactor is 0.

01. 0.4MPa.

8. The method according to claim 1, characterized in that, In step (4), the volumetric flow rate ratio of the third and fourth feed pumps is controlled at (2.57). 2.85):1, controlling the temperature of the second silicon carbide microchannel reactor at 60°C. 80℃.

9. The method according to claim 1, characterized in that, In step (4), the volumetric flow rate of the third feed pump is controlled at 1000-1800 mL / min, and the volumetric flow rate of the fourth feed pump is controlled at 380-650 mL / min; the residence time of the reactants in the second silicon carbide microchannel reactor is 2-8 min.

10. The method according to claim 1, characterized in that, In step (4), the pressure inside the second silicon carbide microchannel reactor is 0.

01. 0.2MPa.

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