Continuous preparation method of pentaerythritol bisulfite

Abstract

The invention relates to a continuous preparation method of pentaerythritol bisulfite, which comprises the following steps: respectively and continuously introducing pentaerythritol emulsion and thionyl chloride into a continuous flow oscillation stirring reactor for continuous flow reaction, controlling the reaction temperature to be 40-90 DEG C, controlling the temperature to be 40-90 DEG C, and controlling the reaction time to be 1-3 hours; the stirring rotating speed is 200 to 800 r / min, the reaction pressure is 0.3 to 0.8 MPa, and the reaction time is 30 to 120 minutes. By using the continuous flow oscillation stirring reactor and specific reaction conditions, the continuous preparation is realized, and the pentaerythritol conversion rate, the product yield and purity, the reaction efficiency and the post-treatment simplicity are considered at the same time. The method has the remarkable advantages of simple process, low reaction operation difficulty, high reaction efficiency and the like, and can meet the comprehensive requirements of large-scale continuous industrial production on efficiency, cost and product quality.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis technology, and specifically relates to a continuous preparation method of pentaerythritol disulfite. Background Technology

[0002] Lithium-ion batteries have become the preferred technology for current electronics, electric vehicles, and energy storage systems due to their high energy density, long cycle life, and environmental friendliness. However, they also have drawbacks such as sensitivity to overcharge and over-discharge and high-temperature thermal runaway. Electrolyte additives significantly improve battery performance through mechanisms such as preferential film formation, metal ion complexation, suppression of side reactions, or enhancement of ion migration, resulting in improved high-temperature cycling, low-temperature discharge, rate performance, overcharge safety, and interface stability. Electrolyte additives play a crucial role in lithium-ion batteries, effectively enhancing battery performance and safety, and represent one of the important directions for battery technology development.

[0003] Pentaerythritol dicyclic sulfate, as a novel battery electrolyte additive, can form a high-quality SEI protective layer on the surfaces of the positive and negative electrodes, effectively suppressing the decline in initial battery capacity, increasing initial discharge capacity, reducing battery swelling after high-temperature storage, and improving battery charge-discharge performance and cycle life. It also effectively inhibits the oxidative decomposition of the electrolyte under high pressure, thus enhancing battery cycle life. Therefore, the efficient and large-scale synthesis of pentaerythritol dicyclic sulfate is attracting increasing attention.

[0004] Pentaerythritol disulfite is a key intermediate in the synthesis of pentaerythritol dicyclic sulfate. Its preparation efficiency and quality directly affect the purity, yield, and production cost of the final product; therefore, optimizing its synthesis process is crucial. Patent CN 112694484 A reports a batch reactor method for preparing dicyclic sulfites and dicyclic sulfates. This method involves heating and stirring pentaerythritol and thionyl chloride for 6 hours, cooling to room temperature, and then separating the solid and liquid phases to obtain the dicyclic sulfite, with a yield of 86%–92%. Patent CN 112592353 A reports a similar batch reactor method based on pentaerythritol and thionyl chloride as raw materials, with a reaction time of 24 hours and a yield of 94%–95%. Patent CN 11285884 A reports a batch reactor method for preparing pentaerythritol sulfite. Pentaerythritol and thionyl chloride are reacted at 60~90℃ for 12~16h. After the reaction is completed, the reaction solution is filtered, washed with water to obtain a solution, and then crystallized by vacuum distillation to obtain the finished pentaerythritol disulfite with a purity of 99%.

[0005] Although the methods described above can all achieve the preparation of the target intermediate, they generally employ batch reactor processes and share some common problems, such as relatively long reaction times, cumbersome operating procedures, or room for improvement in the final yield. These factors, to some extent, limit further improvements in production efficiency and cost optimization. Summary of the Invention

[0006] The purpose of this invention is to provide a continuous preparation method for pentaerythritol disulfite, which is simple to operate, has a high product yield and high purity, and is suitable for large-scale industrial production.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A continuous preparation method for pentaerythritol disulfite involves continuously feeding pentaerythritol emulsion and thionyl chloride into a continuous flow stirred reactor to carry out a continuous flow reaction, thereby obtaining a reaction solution containing the pentaerythritol disulfite.

[0008] This invention uses a continuous flow oscillating stirred reactor for the continuous preparation of pentaerythritol disulfite, and balances product quality and production cost by optimizing the reaction system and reaction conditions.

[0009] Specifically, in some embodiments, the pentaerythritol emulsion is composed of pentaerythritol powder with a particle size of 10-60 µm and a first organic solvent.

[0010] In some embodiments, the reaction temperature is controlled at 40~90℃, for example 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃ or 90℃; the stirring speed is controlled at 200~800 r / min, for example 200 r / min, 300 r / min, 400 r / min, 500 r / min, 600 r / min, 700 r / min or 800 r / min; and the reaction pressure is controlled at 0.3~0.8 M. Pa, for example 0.3MPa, 0.35MPa, 0.4MPa, 0.45MPa, 0.5MPa, 0.55MPa, 0.6MPa, 0.65MPa, 0.7MPa, 0.75MPa or 0.8MPa, with the reaction time controlled at 30~120min, for example 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min, 120min.

[0011] In some preferred embodiments, the reaction temperature is controlled at 60~80°C.

[0012] In some preferred embodiments, the stirring speed is controlled to be 300~600 r / min.

[0013] In some preferred embodiments, the reaction pressure is controlled at 0.3~0.6 MPa.

[0014] In some preferred embodiments, the reaction time is 30 to 60 minutes.

[0015] In some embodiments, the molar ratio of pentaerythritol to thionyl chloride in the pentaerythritol emulsion is 1:(2~3), for example 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9 or 1:3.

[0016] In some embodiments, the mass ratio of the pentaerythritol powder to the first organic solvent is 1:(2.5~5.5), for example 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5 or 1:5.5, and the feed rate of the pentaerythritol emulsion is controlled to be 2 to 3 times the feed rate of the thionyl chloride, for example 2 times, 2.1 times, 2.2 times, 2.3 times, 2.4 times, 2.5 times, 2.6 times, 2.7 times, 2.8 times, 2.9 times or 3 times.

[0017] In some specific embodiments, the feed rate of the pentaerythritol emulsion is controlled at 5~15 g / min, and the feed rate of the thionyl chloride is controlled at 1.5~8 g / min.

[0018] Furthermore, the feed rate of the pentaerythritol emulsion is controlled at 10-15 g / min, and the feed rate of the thionyl chloride is controlled at 5-8 g / min.

[0019] In some embodiments, the first organic solvent is an organic solvent with a boiling point of not less than 70°C.

[0020] In some embodiments, the pentaerythritol powder has a particle size of 30-50 µm, for example 30 µm, 35 µm, 40 µm, 45 µm or 50 µm.

[0021] In some preferred embodiments, the first organic solvent is one or more of dichloroethane, toluene, and cyclohexane.

[0022] In some embodiments, the preparation method further includes post-treatment of the reaction solution, which includes filtering the reaction solution, washing the resulting solid with a mixture of water and a second organic solvent, and then drying it to obtain purified pentaerythritol disulfite.

[0023] Furthermore, the second organic solvent is a polar solvent miscible with water.

[0024] Furthermore, the volume ratio of water to the second organic solvent is 1:(0.8~1.2), for example 1:0.8, 1:0.9, 1:1, 1:1.1 or 1:1.2.

[0025] Furthermore, the second organic solvent is one or more of ethanol, methanol, acetonitrile, and N,N-dimethylformamide.

[0026] Further, the mass ratio of the solid to the mixed solvent is 1:(0.5~1), for example 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9 or 1:1.

[0027] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: This invention utilizes a continuous-flow oscillating stirred reactor for the continuous preparation of pentaerythritol disulfite. By selecting specific reaction conditions, it achieves continuous preparation while simultaneously considering pentaerythritol conversion, pentaerythritol disulfite yield and purity, reaction efficiency, and ease of post-processing. Compared to traditional batch reactor methods, this invention offers significant advantages such as simple process, low operational difficulty, and high efficiency, meeting the comprehensive requirements of efficiency, cost, and product quality for large-scale continuous industrial production. Attached Figure Description

[0028] Figure 1 The gas chromatogram of pentaerythritol disulfite in Example 1 is shown. Figure 2 The pentaerythritol disulfite of Example 1 1 H NMR spectrum; Figure 3 The pentaerythritol disulfite of Example 1 13 C10 NMR spectrum. Detailed Implementation

[0029] To address the challenges of balancing product quality, production efficiency, and production cost in existing batch reactor methods for preparing pentaerythritol disulfite, the inventors of this application have attempted to use a continuous flow oscillating stirred reactor for the continuous preparation of pentaerythritol disulfite. Through systematic optimization of the reaction system and reaction conditions, and after extensive experimental verification, a preparation scheme was finally obtained that can achieve continuous preparation while simultaneously ensuring pentaerythritol conversion, yield and purity of pentaerythritol disulfite, reaction efficiency, and ease of post-processing.

[0030] Specifically, the technical solution of this invention is as follows: pentaerythritol emulsion and thionyl chloride are continuously fed into a continuous flow stirred reactor for continuous flow reaction. The pentaerythritol emulsion consists of pentaerythritol powder with a particle size of 10-60 µm and a first organic solvent. The reaction temperature is controlled at 40-90 °C, the stirring speed at 200-800 r / min, the reaction pressure at 0.3-0.8 MPa, and the reaction time at 30-120 min. Through synergistic optimization of the above reaction system and reaction conditions, the conversion rate of raw materials and product quality are improved while the difficulty of post-processing is effectively reduced. Because this continuous reaction can obtain a better quality product in a shorter reaction time, it also reduces the burden of subsequent purification processes, thereby achieving overall improvement in production efficiency and control of production costs.

[0031] The present invention will be further described below with reference to embodiments, but the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific applications, and the implementation conditions not specified are conventional conditions in this industry.

[0032] Unless otherwise specified, the instruments and materials used in the following examples and comparative examples are all commercially available products.

[0033] Unless otherwise specified, all operations in the following examples and comparative examples were conducted at room temperature, which is 20±5℃.

[0034] Example 1: This example provides a continuous preparation method for pentaerythritol disulfite, as detailed below: Pentaerythritol (particle size 50 µm) and dichloroethane were mixed and homogenized at a mass ratio of 1:3 to obtain a pentaerythritol emulsion. The pentaerythritol emulsion and thionyl chloride were continuously fed into a continuous-flow stirred reactor via a pump for continuous-flow reaction. The feed rate of the pentaerythritol emulsion was set at 13.33 g / min, the feed rate of thionyl chloride at 6.41 g / min, the stirring speed at 500 rpm, the reaction temperature at 60 °C, the reaction pressure at 0.35 MPa (controlled by a back pressure valve), and the residence time at 30 min. The effluent (reaction liquid) was collected and filtered. The resulting solid was washed with 0.5 times its weight of solid in 50% (v / v) ethanol solution and dried to obtain a white solid product, which was pentaerythritol disulfite. The conversion rate of the raw material pentaerythritol was 99.5%, the product yield was 99.1%, and the purity was 99.8% as determined by gas chromatography (see [link to relevant documentation]). Figure 1 The chloride ion content was determined to be 5 ppm by potentiometric titration, and the acid value (calculated as HF) was 50 ppm. The product structure identification results are as follows: 1 H NMR (400 MHz, DMSO- d6 ) δ 4.86 (d, J = 12.1 Hz, 2H), 4.48 (d, J =11.9 Hz, 2H), 4.33 (dd, J = 12.0, 2.2 Hz, 2H), 3.96 (dd, J = 11.9, 2.4 Hz, 2H). (See Figure 2 ).

[0035] 13 C NMR (101 MHz, DMSO- d 6 ) δ 59.73, 34.82. (See) Figure 3 ).

[0036] Example 2: This example provides a continuous preparation method for pentaerythritol disulfite, as detailed below: Pentaerythritol (particle size 40µm) and dichloroethane were mixed and homogenized at a mass ratio of 1:4 to obtain a pentaerythritol emulsion. The pentaerythritol emulsion and thionyl chloride were continuously fed into a continuous flow stirred reactor by a pump for continuous flow reaction. The feed rate of pentaerythritol emulsion was set to 8.33 g / min, the feed rate of thionyl chloride was set to 3.64 g / min, the stirring speed was set to 300 r / min, the reaction temperature was set to 80℃, the reaction pressure was set to 0.5 MPa (controlled by a back pressure valve), and the residence time was set to 60 min. The reaction solution was collected and filtered. The resulting solid was washed with 0.5 times its weight of solid in 50% (v / v) ethanol solution and dried to obtain a white solid product, namely pentaerythritol disulfite. The conversion rate of the raw material pentaerythritol was 99.4%, the product yield was 98.8%, the purity was 99.6% as determined by gas chromatography, the chloride ion content was 5 ppm as determined by potentiometric titration, and the acid value (calculated as HF) was 80 ppm.

[0037] Example 3: This example provides a continuous preparation method for pentaerythritol disulfite, as detailed below: Pentaerythritol (particle size 30µm) and dichloroethane were mixed and homogenized at a mass ratio of 1:5 to obtain a pentaerythritol emulsion. The pentaerythritol emulsion and thionyl chloride were continuously fed into a continuous flow stirred reactor by a pump for continuous flow reaction. The feed rate of pentaerythritol emulsion was set to 5.0 g / min, the feed rate of thionyl chloride was set to 1.82 g / min, the stirring speed was set to 800 r / min, the reaction temperature was set to 50℃, the reaction pressure was set to 0.8 MPa (controlled by a back pressure valve), and the residence time was set to 120 min. The reaction solution was collected and filtered. The resulting solid was washed with 0.5 times its weight of solid in 50% (v / v) ethanol solution and dried to obtain a white solid product, namely pentaerythritol disulfite. The conversion rate of the raw material pentaerythritol was 99.8%, the yield of the product pentaerythritol disulfite was 99.3%, the purity was 99.7% as determined by gas chromatography, the chloride ion content was 4 ppm as determined by potentiometric titration, and the acid value (calculated as HF) was 45 ppm.

[0038] Comparative Example 1: This comparative example provides a method for preparing pentaerythritol disulfite, as detailed below: 1000g of pentaerythritol (particle size 50µm) was mixed and homogenized with 3000g of dichloroethane to obtain a pentaerythritol emulsion. This emulsion was transferred to a batch reactor, and thionyl chloride was added dropwise at 60℃. The molar ratio of thionyl chloride to pentaerythritol was controlled at 2:1, and the addition time of thionyl chloride was controlled at 1h. After the addition was complete, the reaction was continued at 60℃ for 2h with a stirring speed of 200r / min. After the reaction was completed, the reaction solution was filtered. The obtained solid was washed with 0.5 times its weight of solid in 50% (v / v) ethanol solution and dried to obtain a white solid product, which was pentaerythritol disulfite. The conversion rate of the raw material pentaerythritol was 90.0%, and the yield of the product pentaerythritol disulfite was 82.5%. The purity was 99.0% as determined by gas chromatography, and the chloride ion content was 10ppm as determined by potentiometric titration. The acid value (calculated as HF) was 200ppm.

[0039] Comparative Example 2: This comparative example provides a method for preparing pentaerythritol disulfite, as detailed below: 1000g of pentaerythritol (particle size 50µm) was mixed and homogenized with 3000g of dichloroethane to obtain a pentaerythritol emulsion. This emulsion was transferred to a batch reactor, and thionyl chloride was added dropwise at 80℃. The molar ratio of thionyl chloride to pentaerythritol was controlled at 2.5:1, and the addition time of thionyl chloride was controlled at 2 hours. After the addition was complete, the reaction was continued at 80℃ for 3 hours with a stirring speed of 300 r / min. After the reaction was completed, the reaction solution was filtered. The obtained solid was washed with 0.5 times its weight of solid in 50% (v / v) ethanol solution and dried to obtain a white solid product, which was pentaerythritol disulfite. The conversion rate of the raw material pentaerythritol was 91.0%, and the yield of the product pentaerythritol disulfite was 86.5%. The purity was 98.9% as determined by gas chromatography, and the chloride ion content was 160 ppm as determined by potentiometric titration. The acid value (calculated as HF) was 850 ppm.

[0040] Comparative Example 3: This comparative example provides a method for preparing pentaerythritol disulfite, as detailed below: 1000g of pentaerythritol (particle size 40µm) was mixed and homogenized with 4000g of dichloroethane to obtain a pentaerythritol emulsion. This emulsion was transferred to a batch reactor, and thionyl chloride was added dropwise at 50°C. The molar ratio of thionyl chloride to pentaerythritol was controlled at 2.05:1, and the addition time was controlled at 2 hours. After the addition was complete, the reaction was continued at 50°C for 5 hours with a stirring speed of 300 rpm. After the reaction was complete, the reaction solution was filtered. The resulting solid was washed with 0.5 times its weight of solid in 50% (v / v) ethanol solution and dried to obtain a white solid product, which was pentaerythritol disulfite. The conversion rate of the raw material pentaerythritol was 88.9%, and the yield of the product pentaerythritol disulfite was 84.5%. The purity was 98.9% as determined by gas chromatography, and the chloride ion content was 150 ppm as determined by potentiometric titration. The acid value (calculated as HF) was 450 ppm.

[0041] Comparative Example 4: This comparative example provides a continuous preparation method for pentaerythritol disulfite, as detailed below: Pentaerythritol (particle size 50µm) and dichloroethane were mixed and homogenized at a mass ratio of 1:3 to obtain a pentaerythritol emulsion. The pentaerythritol emulsion and thionyl chloride were continuously fed into a continuous flow stirred reactor by a pump for continuous flow reaction. The feed rate of pentaerythritol emulsion was set to 13.33 g / min, the feed rate of thionyl chloride was set to 6.41 g / min, the stirring speed was set to 500 r / min, the reaction temperature was set to 60℃, the reaction pressure was set to 1 MPa (controlled by a back pressure valve), and the residence time was set to 30 min. The reaction solution was collected and filtered. The resulting solid was washed with 0.5 times its weight of solid in 50% (v / v) ethanol solution and dried to obtain a white solid product, namely pentaerythritol disulfite. The conversion rate of the raw material pentaerythritol was 89.0%, and the yield of the product pentaerythritol disulfite was 90.5%. The purity was 99.1% as determined by gas chromatography, and the chloride ion content was 50 ppm as determined by potentiometric titration. The acid value (calculated as HF) was 200 ppm.

[0042] Comparative Example 5: This comparative example provides a continuous preparation method for pentaerythritol disulfite, as detailed below: Pentaerythritol (particle size 50µm) and dichloroethane were mixed and homogenized at a mass ratio of 1:3 to obtain a pentaerythritol emulsion. The pentaerythritol emulsion and thionyl chloride were continuously fed into a continuous flow stirred reactor by a pump for continuous flow reaction. The feed rate of pentaerythritol emulsion was set to 13.33 g / min, the feed rate of thionyl chloride was set to 6.41 g / min, the stirring speed was set to 500 r / min, the reaction temperature was set to 60℃, the reaction pressure was set to 0.2 MPa (controlled by a back pressure valve), and the residence time was set to 30 min. The reaction solution was collected and filtered. The resulting solid was washed with 0.5 times its weight of solid in 50% (v / v) ethanol solution and dried to obtain a white solid product, namely pentaerythritol disulfite. The conversion rate of the raw material pentaerythritol was 85.9%, the yield of the product pentaerythritol disulfite was 89.7%, the purity was 89.6% as determined by gas chromatography, the chloride ion content was 50 ppm as determined by potentiometric titration, and the acid value (calculated as HF) was 380 ppm.

[0043] Comparative Example 6: This comparative example provides a continuous preparation method for pentaerythritol disulfite, as detailed below: Pentaerythritol (particle size 50µm) and dichloroethane were mixed and homogenized at a mass ratio of 1:3 to obtain a pentaerythritol emulsion. The pentaerythritol emulsion and thionyl chloride were continuously fed into a continuous flow stirred reactor by a pump for continuous flow reaction. The feed rate of pentaerythritol emulsion was set to 13.33 g / min, the feed rate of thionyl chloride was set to 6.41 g / min, the stirring speed was set to 100 r / min, the reaction temperature was set to 60℃, the reaction pressure was set to 0.2 MPa (controlled by a back pressure valve), and the residence time was set to 150 min. The reaction solution was collected and filtered. The resulting solid was washed with 0.5 times its weight of solid in 50% (v / v) ethanol solution and dried to obtain a white solid product, namely pentaerythritol disulfite. The conversion rate of the raw material pentaerythritol was 85.5%, the yield of the product pentaerythritol disulfite was 88.2%, the purity was 99.3% as determined by gas chromatography, the chloride ion content was 70 ppm as determined by potentiometric titration, and the acid value (calculated as HF) was 400 ppm.

[0044] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A continuous preparation method for pentaerythritol disulfite, characterized in that: Pentaerythritol emulsion and thionyl chloride were continuously fed into a continuous-flow stirred reactor for continuous-flow reaction to obtain a reaction solution containing the pentaerythritol disulfite. The pentaerythritol emulsion is composed of pentaerythritol powder with a particle size of 10~60µm and a first organic solvent. The reaction temperature is controlled at 40~90℃, the stirring speed is 200~800r / min, the reaction pressure is 0.3~0.8MPa, and the reaction time is 30~120min.

2. The continuous preparation method of pentaerythritol disulfite according to claim 1, characterized in that: The reaction temperature should be controlled at 60~80℃; And / or, control the stirring speed to 300~600 r / min; And / or, control the reaction pressure to 0.3~0.6MPa; And / or, the reaction time is 30~60 min.

3. The continuous preparation method of pentaerythritol disulfite according to claim 1, characterized in that: The molar ratio of pentaerythritol to thionyl chloride in the pentaerythritol emulsion is 1:(2~3).

4. The continuous preparation method of pentaerythritol disulfite according to claim 3, characterized in that: The mass ratio of the pentaerythritol powder to the first organic solvent is 1:(2.5~5.5), and the feed rate of the pentaerythritol emulsion is controlled to be 2 to 3 times the feed rate of the thionyl chloride.

5. The continuous preparation method of pentaerythritol disulfite according to claim 4, characterized in that: The feed rate of the pentaerythritol emulsion is controlled at 5~15 g / min, and the feed rate of the thionyl chloride is controlled at 1.5~8 g / min.

6. The continuous preparation method of pentaerythritol disulfite according to claim 1, characterized in that: The first organic solvent is an organic solvent with a boiling point of not less than 70°C; And / or, the pentaerythritol powder has a particle size of 30~50µm.

7. The continuous preparation method of pentaerythritol disulfite according to claim 6, characterized in that: The first organic solvent is one or more of dichloroethane, toluene, and cyclohexane.

8. The continuous preparation method of pentaerythritol disulfite according to claim 1, characterized in that: The preparation method further includes post-treatment of the reaction solution, which includes filtering the reaction solution, washing the obtained solid with a mixed solvent of water and a second organic solvent, and then drying it to obtain purified pentaerythritol disulfite.

9. The continuous preparation method of pentaerythritol disulfite according to claim 8, characterized in that: The second organic solvent is a polar solvent miscible with water; And / or, the volume ratio of the water to the second organic solvent is 1:(0.8~1.2).

10. The continuous preparation method of pentaerythritol disulfite according to claim 8, characterized in that: The second organic solvent is one or more of ethanol, methanol, acetonitrile, and N,N-dimethylformamide; And / or, the mass ratio of the solid to the mixed solvent is 1:(0.5~1).

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