Continuous production method and device for preparing cyclic sulfite

Abstract

The invention discloses a continuous production method and device for preparing cyclic sulfite. The continuous production device comprises a raw material alcohol dehydrating tower, a reactive distillation tower, a low-temperature recovery tower, a cyclic sulfite purifying tower, a first heat exchanger and a flash tank, a top outlet of the reactive distillation tower is communicated with an inlet of the low-temperature recovery tower, a side feed port is connected with a thionyl chloride feed pipe, a side outlet is communicated with an inlet of the flash tank, a gas outlet of the flash tank is communicated with an inlet of the low-temperature recovery tower, and a liquid outlet is communicated with an inlet of the cyclic sulfite purification tower; a discharging pipeline is formed at the tower top of the cyclic sulfite purifying tower, and a circulating material at the tower bottom, a material at the tower bottom of the raw material alcohol dehydrating tower and a material at the tower bottom of the low-temperature recovery tower are mixed and conveyed to a tower bottom feeding hole of the reactive distillation tower. According to the continuous production device for preparing the cyclic sulfite, continuous production is achieved through reactive distillation, introduction of other solvents is avoided, and the automation degree is greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical production, and more specifically, relates to a continuous production method and device for preparing cyclic sulfite esters. Background Art

[0002] Cyclic sulfite esters have been widely studied in recent years as additives for lithium-ion battery electrolytes. Due to their relatively high reduction potential, cyclic sulfite esters can preferentially undergo reduction reactions on the surface of graphite anodes over electrolyte solvents such as carbonates, thus effectively preventing further decomposition of the solvents and improving the cycling performance of the batteries. In addition, cyclic sulfite esters are also important raw materials for preparing cyclic sulfate esters (such as DTD, PCS, PEGLST, TS, TDT, etc.) used as electrolyte solvents. With the increasing market demand for lithium-ion batteries in recent years, the corresponding market for electrolyte additives has also been continuously expanding.

[0003] Currently, there are several methods for preparing cyclic sulfite esters: (1) Reacting sulfur dioxide with epoxides to prepare cyclic sulfite esters. For example, CN108658928A reports a method of catalyzing the reaction of sulfur dioxide with ethylene oxide using a composite catalyst (iron(III) chloride, ruthenium(III) chloride, and ruthenium(IV) oxide). This method requires the use of precious metal catalysts, and due to the strong corrosiveness of sulfur dioxide, high requirements are imposed on the equipment, resulting in high preparation costs. (2) Reacting dialkyl sulfites with diol compounds to prepare cyclic sulfite esters. For example, CN101747315A reports this method, but the raw materials used in this method are relatively expensive, and a large amount of by-products such as alkyl alcohols are generated, resulting in low atom economy. (3) Reacting diol compounds with thionyl chloride to prepare cyclic sulfite esters. For example, CN109776486A reports a method of using chloroform as a solvent to react propylene glycol with thionyl chloride to prepare propylene sulfite. This method has great advantages compared to (1) and (2), does not require the use of catalysts, has a high yield, and the raw materials are inexpensive. Therefore, most current industrial devices use this method. However, due to severe exothermic reactions, organic solvents are added to reduce side reactions caused by high temperatures. Recycling and reusing the solvents requires additional equipment such as solvent recovery, so the process flow of this method is relatively complex. In addition, this method mostly uses batch kettle production processes in industrial development and cannot achieve continuous production.

[0004] Regarding the continuous production method of cyclic sulfite esters, certain progress has also been made in recent years. For example, CN114539210A reports a method of preparing cyclic sulfite esters using a microchannel reactor, but this method still requires the addition of organic solvents and additional investment in equipment such as solvent recovery. Summary of the Invention

[0005] To solve the above problems, the present invention provides a continuous production method and device for preparing cyclic sulfite. Through reactive distillation, continuous production is achieved, avoiding the introduction of other solvents and greatly improving the degree of automation.

[0006] Specifically, the present invention provides the following technical solutions:

[0007] A continuous production device for preparing cyclic sulfite, comprising a raw material alcohol dehydration tower T1, a reactive distillation tower T2, a low-temperature recovery tower T3, a cyclic sulfite purification tower T4, a first heat exchanger E1, a flash tank V1, a feed pipeline and a connection pipeline;

[0008] The top outlet of the reactive distillation tower T2 is connected to the inlet of the low-temperature recovery tower T3, the side outlet of the reactive distillation tower T2 is connected to the inlet of the flash tank, the gas outlet of the flash tank is connected to the inlet of the low-temperature recovery tower T3, and the liquid outlet of the flash tank is connected to the inlet of the cyclic sulfite purification tower T4;

[0009] The first heat exchanger E1 is arranged at the bottom discharge port of the raw material alcohol dehydration tower T1, and a discharge pipeline is formed at the top of the cyclic sulfite purification tower T4;

[0010] The circulating material at the bottom of the cyclic sulfite purification tower T4, the material at the bottom discharge port of the raw material alcohol dehydration tower T1, and the circulating material at the bottom of the low-temperature recovery tower T3 are mixed and then transported to the bottom feed port of the reactive distillation tower T2;

[0011] The side feed port of the reactive distillation tower T2 is connected with a thionyl chloride feed pipe, and the top of the low-temperature recovery tower T3 is connected with a material discharge pipeline.

[0012] In an embodiment of the present invention, the continuous production device further comprises a compressor C1. The compressor C1 is arranged at the inlet end of the low-temperature recovery tower T3 and is connected to the inlet of the low-temperature recovery tower T3. The top outlet of the reactive distillation tower T2 and the gas outlet of the flash tank V1 are jointly connected to the compressor C1.

[0013] In an embodiment of the present invention, the raw material alcohol dehydration tower T1, the low-temperature recovery tower T3, and the cyclic sulfite purification tower T4 are all provided with condensers at the top and reboilers at the bottom, and the reactive distillation tower T2 is provided with a condenser at the top.

[0014] In an embodiment of the present invention, the top discharge port of the raw material alcohol dehydration tower T1 is connected with a discharge pipeline for discharging the water-containing raw material alcohol.

[0015] In an embodiment of the present invention, a material discharge pipeline for discharging hydrogen chloride is arranged at the top of the low-temperature recovery tower T3.

[0016] In one embodiment of the present invention, the outlet of the material discharge pipeline of hydrogen chloride is connected to a hydrogen chloride rectification column.

[0017] In one embodiment of the present invention, the outlet of the hydrogen chloride rectification column is connected to an absorption column.

[0018] In one embodiment of the present invention, the thionyl chloride feed pipe is connected to the feed inlet on the 1st to 15th trays from the bottom of the reactive distillation column T2.

[0019] In one embodiment of the present invention, the pressure of the raw material alcohol dehydration column T1 is 0 - 20 kPa, the top operating temperature is 30 - 150 °C, and the reflux ratio is 1 - 50; the pressure of the reactive distillation column T2 is 0 - 100 kPa, the top operating temperature is 30 - 200 °C, and the reflux ratio is 0.01 - 20; the pressure of the low-temperature recovery column T3 is 1 - 5 MPa, the top operating temperature is 5 - 150 °C, and the reflux ratio is 0.1 - 20; the pressure of the cyclic sulfite purification column T4 is 0 - 100 kPa, the top operating temperature is 80 - 200 °C, and the reflux ratio is 0.01 - 50.

[0020] In one embodiment of the present invention, the pressure of the raw material alcohol dehydration column T1 is 1 - 5 kPa, the top operating temperature is 30 - 80 °C, and the reflux ratio is 3 - 25; the pressure of the reactive distillation column T2 is 20 - 50 kPa, the top operating temperature is 30 - 150 °C, and the reflux ratio is 0.01 - 5; the pressure of the low-temperature recovery column T3 is 1 - 5 MPa, the top operating temperature is 5 - 20 °C, and the reflux ratio is 1 - 5; the pressure of the cyclic sulfite purification column T4 is 20 - 60 kPa, the top operating temperature is 100 - 150 °C, and the reflux ratio is 1 - 30.

[0021] According to another aspect of the present invention, there is provided a continuous production method for preparing cyclic sulfite, comprising the following steps:

[0022] S1, introducing raw material alcohol into the feed inlet of the raw material alcohol dehydration column T1, dehydrating the introduced raw material alcohol through the raw material alcohol dehydration column T1, and collecting the water-containing raw material alcohol from the top of the raw material alcohol dehydration column T1;

[0023] S2, subjecting the discharge at the bottom of the raw material alcohol dehydration column T1 to heat exchange through a first heat exchanger and then transporting it from the bottom to the reactive distillation column T2, introducing thionyl chloride into the feed inlet on the side of the reactive distillation column T2, after reacting in the reactive distillation column T2, transporting the discharge at the top of the reactive distillation column T2 to the low-temperature recovery column T3, transporting the discharge on the side of the reactive distillation column T2 to the flash tank V1, performing flash evaporation in the flash tank V1, transporting the liquid material after flash evaporation to the cyclic sulfite purification column T4, and mixing the gas material with the discharge at the top of the reactive distillation column T2 and then transporting them together to the low-temperature recovery column T3;

[0024] S3. Discharge hydrogen chloride from the material discharge pipeline at the top of the low-temperature recovery tower T3.

[0025] S4. Discharge cyclic sulfite from the discharge pipeline at the top of the cyclic sulfite purification tower T4. Mix the circulating material at the bottom of the cyclic sulfite purification tower T4, the circulating material at the bottom of the low-temperature recovery tower T3, and the discharge material at the bottom of the raw material alcohol dehydration tower T1, and then convey them together from the bottom to the reactive distillation tower T2.

[0026] In one embodiment of the present invention, the raw material alcohol includes: ethylene glycol (CAS: 107-21-1), 1,2-propanediol (CAS: 57-55-6), 2,3-butanediol (CAS: 513-85-9), 1,2-pentanediol (CAS: 5343-92-0), 1,3-propanediol (CAS: 504-63-2), 1,3-butanediol (CAS: 107-88-0), pentaerythritol (CAS: 115-77-5).

[0027] The cyclic sulfites prepared by the present invention include ethylene sulfite (CAS: 3741-38-6), 4-methyl ethylene sulfite (CAS: 1469-73-4), 3,4-dimethyl ethylene sulfite (CAS: 4440-90-8), 4-propyl ethylene sulfite, allyl sulfite (CAS: 4176-55-0), butenyl sulfite (CAS: 4426-51-1), pentaerythritol bicyclic sulfite. The corresponding structural formulas are as follows:

[0028]

[0029] Advantages of the present invention:

[0030] 1) Through reactive distillation, the present invention not only realizes continuous production, but also avoids introducing other organic solvents, does not require additional equipment investment such as solvent recovery, greatly improves the degree of automation. Compared with the existing process, the process flow is simple, the yield is high, and the quality is stable.

[0031] 2) The hydrogen chloride in the low-temperature recovery tower can directly enter the distillation tower for refining to obtain industrial-grade and chemical-grade hydrogen chloride, or can be further processed, such as connecting to an absorption tower, etc., to obtain hydrochloric acid products.

[0032] 3) The reactive distillation technology and equipment provided by the present invention can obtain high-purity hydrogen chloride while the raw material alcohol reacts with thionyl chloride in the reactive distillation tower, and the obtained product can be further purified by subsequent distillation. Description of the Drawings

[0033] Figure 1 It is a structural schematic diagram of a device for continuously preparing cyclic sulfite according to an embodiment of the present invention.

[0034] Reference numerals: raw material alcohol dehydration tower T1, reactive distillation column T2, low-temperature recovery tower T3, cyclic sulfite purification tower T4, first heat exchanger E1, second heat exchanger E2, third heat exchanger E3, compressor C1, flash tank V1.

[0035] Materials: raw material alcohol S1, overhead material of raw material alcohol dehydration tower S2, bottom material of raw material alcohol dehydration tower S3, material at the outlet of the first heat exchanger S4, combined material at the bottom inlet of the reactive distillation column S5, raw material thionyl chloride S6, overhead material of the reactive distillation column S8, side stream material of the reactive distillation column S9, gas phase material of the flash tank S10, liquid phase material of the flash tank S11, combined material at the compressor inlet S12, material at the compressor outlet S13, overhead material of the low-temperature recovery tower S14, bottom recycle material of the low-temperature recovery tower S15, overhead material of the cyclic sulfite purification tower S16, bottom recycle material of the cyclic sulfite purification tower S17. Detailed implementation manners

[0036] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be emphasized that the specific embodiments described herein are only used to better illustrate the present invention, and are partial embodiments of the present invention, rather than all embodiments, so they are not used to limit the present invention. In addition, the technical features involved in the embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0037] See Figure 1 As shown, the embodiment of the present invention provides a continuous production device for preparing cyclic sulfite, including a raw material alcohol dehydration tower T1, a reactive distillation column T2, a low-temperature recovery tower T3, a cyclic sulfite purification tower T4, a first heat exchanger E1, a flash tank V1, a feed pipeline and a connecting pipeline;

[0038] The top outlet of the reactive distillation column T2 is connected to the inlet of the low-temperature recovery tower T3, the side outlet of the reactive distillation column T2 is connected to the inlet of the flash tank, the gas outlet of the flash tank is connected to the inlet of the low-temperature recovery tower T3, and the liquid outlet of the flash tank is connected to the inlet of the cyclic sulfite purification tower T4;

[0039] The first heat exchanger E1 is arranged at the bottom discharge port of the raw material alcohol dehydration tower T1, and a discharge pipeline is formed at the top of the cyclic sulfite purification tower T4;

[0040] The recycle material at the bottom of the cyclic sulfite purification tower T4 is mixed with the material at the bottom discharge port of the raw material alcohol dehydration tower T1 and the recycle material at the bottom of the low-temperature recovery tower T3, and then is transported to the bottom feed port of the reactive distillation column T2;

[0041] The feed inlet on the side of the reactive distillation column T2 is connected to a thionyl chloride feed pipe, and the top of the low-temperature recovery column T3 is connected to a material discharge pipeline.

[0042] The continuous production device for producing cyclic sulfite from raw material alcohol and thionyl chloride in the present invention mainly includes a raw material alcohol dehydration column T1, a reactive distillation column T2, a low-temperature recovery column T3, and a cyclic sulfite purification column T4. The main products are cyclic sulfite and hydrogen chloride. The characteristics of the device of the present invention lie in the adoption of reactive distillation technology and equipment, which can obtain high-purity hydrogen chloride while the raw material alcohol reacts with thionyl chloride in the reactive distillation column, and the obtained products can be further purified through subsequent distillation.

[0043] In one embodiment, the continuous production device further includes a compressor C1. The compressor C1 is arranged at the inlet end of the low-temperature recovery column T3 and is communicated with the inlet of the low-temperature recovery column T3. The top outlet of the reactive distillation column T2 and the gas outlet of the flash tank V1 are jointly connected to the compressor C1.

[0044] In this embodiment, by arranging the compressor C1 between the top outlet of the reactive distillation column T2 and the gas outlet of the flash tank V1 and the inlet of the low-temperature recovery column T3, the compressor can be used to compress the overhead product of the reactive distillation column T2 and the top gas of the flash tank V1 after mixing, form a high-pressure gas-liquid mixture, and then enter the low-temperature recovery column T3 for hydrogen chloride purification, improving the working efficiency of the low-temperature recovery column T3 and the hydrogen chloride recovery efficiency and effect.

[0045] In one embodiment, the raw material alcohol dehydration column T1, the low-temperature recovery column T3, and the cyclic sulfite purification column T4 are each provided with a condenser at the top and a reboiler at the bottom, and the reactive distillation column T2 is provided with a condenser at the top.

[0046] In this embodiment, by arranging condensers at the tops of the raw material alcohol dehydration column T1, the reactive distillation column T2, the low-temperature recovery column T3, and the cyclic sulfite purification column T4, the gas materials at the tops of the raw material alcohol dehydration column T1, the low-temperature recovery column T3, and the cyclic sulfite purification column T4 can be condensed. By arranging reboilers at the bottoms of the raw material alcohol dehydration column T1, the low-temperature recovery column T3, and the cyclic sulfite purification column T4, the liquid in the raw material alcohol dehydration column T1, the low-temperature recovery column T3, and the cyclic sulfite purification column T4 can form a gas-phase reflux to ensure the normal operation of the column.

[0047] In one embodiment, the overhead outlet of the raw material alcohol dehydration column T1 is connected to a discharge pipeline for discharging the water-containing raw material alcohol.

[0048] In one embodiment, the raw material alcohol dehydration tower, the low-temperature recovery tower, and the cyclic sulfite purification tower can all reduce the equipment energy consumption through energy-saving distillation methods (including but not limited to heat pump distillation, double-effect distillation, self-heat recovery distillation, and differential pressure thermal coupling distillation).

[0049] In one embodiment, a material discharge pipeline for discharging hydrogen chloride is provided at the top of the low-temperature recovery tower T3. The material discharge pipeline for discharging hydrogen chloride can be connected to a distillation column, and industrial-grade and chemical-grade hydrogen chloride can be obtained through refining in the distillation column. It can also be further processed, such as by connecting to an absorption tower or other means, to obtain hydrochloric acid products.

[0050] In one embodiment of the present invention, the pressure of the raw material alcohol dehydration tower T1 is 0 - 20 kPa, the top operating temperature is 30 - 150 °C, and the reflux ratio is 1 - 50; the pressure of the reactive distillation tower T2 is 0 - 100 kPa, the top operating temperature is 30 - 200 °C, and the reflux ratio is 0.01 - 20; the pressure of the low-temperature recovery tower T3 is 1 - 5 MPa, the top operating temperature is 5 - 150 °C, and the reflux ratio is 0.1 - 20; the pressure of the cyclic sulfite purification tower T4 is 0 - 100 kPa, the top operating temperature is 80 - 200 °C, and the reflux ratio is 0.01 - 50.

[0051] In one embodiment, the pressure of the raw material alcohol dehydration tower T1 is 1 - 5 kPa, the top operating temperature is 30 - 80 °C, and the reflux ratio is 3 - 25; the pressure of the reactive distillation tower T2 is 20 - 50 kPa, the top operating temperature is 30 - 150 °C, and the reflux ratio is 0.01 - 5; the pressure of the low-temperature recovery tower T3 is 1 - 5 MPa, the top operating temperature is 5 - 20 °C, and the reflux ratio is 1 - 5; the pressure of the cyclic sulfite purification tower T4 is 20 - 60 kPa, the top operating temperature is 100 - 150 °C, and the reflux ratio is 1 - 30.

[0052] In one embodiment, the discharge pipeline at the top of the cyclic sulfite purification tower T4 is connected to a distillation and purification column, so as to further purify the discharged cyclic sulfite and obtain a cyclic sulfite with higher purity.

[0053] The continuous production device for producing cyclic sulfite from raw material alcohol and thionyl chloride of the present invention includes a raw material alcohol dehydration tower T1, a reactive distillation tower T2, a low-temperature recovery tower T3, a cyclic sulfite purification tower T4, a first heat exchanger E1, a compressor C1, a flash tank V1, and related feed pipelines and pipelines connecting the above equipment; the raw material alcohol dehydration tower T1, the low-temperature recovery tower T3, and the cyclic sulfite purification tower T4 are all equipped with condensers at the top of the tower and reboilers at the bottom of the tower, and the reactive distillation tower T2 is equipped with a condenser at the top of the tower; the feed of the raw material alcohol dehydration tower T1 is the raw material alcohol S1, the top of the raw material alcohol dehydration tower T1 is the water-containing raw material alcohol S2, and the bottom discharge S3 of the raw material alcohol dehydration tower T1 enters the first heat exchanger E1; the outlet material S4 of the first heat exchanger E1 is combined with the bottom circulating material S17 of the cyclic sulfite purification tower T4 and the bottom circulating material S15 of the low-temperature recovery tower T3 to form the combined feed material S5 at the inlet of the reactive distillation tower, and is connected to the bottom feed port of the reactive distillation tower T2; the raw material thionyl chloride S6 is fed and connected to one or more feed ports of the reactive distillation tower T2, and the side-draw material S9 of the reactive distillation tower is connected to the flash tank V1; the gaseous material S10 of the flash tank is combined with the top discharge S8 of the reactive distillation tower to form the combined feed material S12 at the inlet of the compressor and is connected to the compressor C1, and the liquid material S11 of the flash tank is connected from the liquid outlet of the flash tank V1 to the feed point of the cyclic sulfite purification tower T4; the outlet material S13 of the compressor is connected from the outlet of the compressor C1 to the feed point of the low-temperature recovery tower T3; the top material S14 of the low-temperature recovery tower is hydrogen chloride, and the bottom is the bottom circulating material S15 of the low-temperature recovery tower; the top material S16 of the cyclic sulfite purification tower generates the product of cyclic sulfite, and the bottom of the cyclic sulfite purification tower is the bottom circulating material S17 of the cyclic sulfite purification tower.

[0054] In order to improve the product yield and purity and reduce energy consumption, in the reactive distillation process of producing cyclic sulfite from raw material alcohol and thionyl chloride: the pressure of the raw material alcohol dehydration tower T1 is 1-5 kPa, the top operating temperature is 30-80 °C, and the reflux ratio is 3-25; the pressure of the reactive distillation tower T2 is 20-50 kPa, the top operating temperature is 30-150 °C, and the reflux ratio is 0.01-5; the pressure of the low-temperature recovery tower T3 is 1-5 MPa, the top operating temperature is 5-20 °C, and the reflux ratio is 1-5; the pressure of the cyclic sulfite purification tower T4 is 20-60 kPa, the top operating temperature is 100-150 °C, and the reflux ratio is 1-30.

[0055] There can be one or more thionyl chloride feed ports in the reactive distillation tower. In one embodiment, the thionyl chloride feed pipe is connected to the feed port on the 1st to 15th trays from the bottom of the reactive distillation tower T2.

[0056] The present invention also provides a continuous production method for preparing cyclic sulfite, which includes the following steps:

[0057] S1. Feed the raw material alcohol into the feed port of the raw material alcohol dehydration tower T1. Dehydrate the fed raw material alcohol through the raw material alcohol dehydration tower T1, and collect the water-containing raw material alcohol from the top of the raw material alcohol dehydration tower T1.

[0058] S2. Feed the discharge from the bottom of the raw material alcohol dehydration tower T1 to the reaction distillation tower T2 after heat exchange in the first heat exchanger. Feed thionyl chloride into the side feed port of the reaction distillation tower T2. After the reaction in the reaction distillation tower T2, feed the discharge from the top of the reaction distillation tower T2 to the low-temperature recovery tower T3, feed the discharge from the side of the reaction distillation tower T2 to the flash tank V1, perform flash evaporation in the flash tank V1, and feed the flashed liquid material to the cyclic sulfite purification tower T4. Mix the gas material with the discharge from the top of the reaction distillation tower T2 and then feed them together to the low-temperature recovery tower T3.

[0059] S3. Discharge hydrogen chloride from the discharge pipeline at the top of the low-temperature recovery tower T3.

[0060] S4. Discharge the cyclic sulfite from the discharge pipeline at the top of the cyclic sulfite purification tower T4. Mix the circulating material at the bottom of the cyclic sulfite purification tower T4, the circulating material at the bottom of the low-temperature recovery tower T3, and the discharge from the bottom of the raw material alcohol dehydration tower T1, and then feed them together to the reaction distillation tower T2 from the bottom.

[0061] The raw material alcohol dehydration tower, the low-temperature recovery tower, and the cyclic sulfite purification tower can all reduce the equipment energy consumption through energy-saving distillation methods (including but not limited to heat pump distillation, double-effect distillation, self-heat recovery distillation, and differential pressure heat coupling distillation).

[0062] The product of the cyclic sulfite purification tower can be connected to a distillation purification tower, and through further purification, a higher-purity cyclic sulfite can be obtained.

[0063] The hydrogen chloride from the low-temperature recovery tower can directly enter a distillation tower for refining to obtain industrial-grade and chemical-grade hydrogen chloride, or can be further processed, such as by connecting to an absorption tower or other methods, to obtain hydrochloric acid products.

[0064] Example 1

[0065] The reactive distillation device for producing cyclic sulfite from raw material alcohol and thionyl chloride of the present invention includes a raw material alcohol dehydration tower, a reaction distillation tower, a low-temperature recovery tower, a cyclic sulfite purification tower, a heat exchanger, a compressor, a flash tank, and related feed pipelines and pipelines connecting the above equipment. Condensers are provided at the tops of the raw material alcohol dehydration tower T1, the low-temperature recovery tower T3, and the cyclic sulfite purification tower T4, and reboilers are provided at the bottoms. A condenser is provided at the top of the reaction distillation tower T2.

[0066] The feed to the raw material alcohol dehydration tower T1 is 1,3 - propanediol S1. The operating pressure at the top of the raw material alcohol dehydration tower T1 is 2 kPa, the operating temperature at the top is 68 °C, the reflux ratio is 20. The overhead product is 1,3 - propanediol S2 containing water, and the bottom product S3 is water - free 1,3 - propanediol. The water - free 1,3 - propanediol enters the first heat exchanger E1; the material S4 at the outlet of the first heat exchanger E1, the bottom recycle material S15 of the low - temperature recovery tower, and the bottom recycle material S17 of the cyclic sulfite purification tower are combined to form the combined feed S5 at the inlet of the reactive distillation tower and are connected to the bottom feed port of the reactive distillation tower T2; the feed of the raw material thionyl chloride S6 is connected to the feed ports on the 3rd, 6th, and 9th trays from the bottom of the reactive distillation tower T2. The feed molar ratio of the combined feed S5 at the inlet of the reactive distillation tower to the feed of the raw material thionyl chloride S6 is 1.25:1. The operating pressure at the top of the reactive distillation tower T2 is 40 kPa, the operating temperature at the top is 92 °C, the reflux ratio is 0.4. The overhead product S8 of the reactive distillation tower is a mixture of thionyl chloride and hydrogen chloride. The side - stream product S9 of the reactive distillation tower is a mixture of propylene sulfite, hydrogen chloride, and 1,3 - propanediol, and the side - stream is connected to the flash tank V1; the flash - tank gas - phase material S10 at the gas - phase outlet of the flash tank V1 is hydrogen chloride, which is combined with the overhead product S8 of the reactive distillation tower to form the combined feed S12 at the inlet of the compressor and is connected to the compressor C1. The liquid - phase material S11 of the flash tank is connected to the feed of the cyclic sulfite purification tower T4 from the liquid - phase outlet of the flash tank V1; the material S13 at the outlet of the compressor is connected to the feed of the low - temperature recovery tower T3 from the outlet of the compressor C1; the operating pressure at the top of the low - temperature recovery tower T3 is 3.0 MPa, the top operating temperature is 6 °C, the reflux ratio is 2. The overhead product S14 of the low - temperature recovery tower is hydrogen chloride, and the bottom of the low - temperature recovery tower is the recycle material S15; the pressure of the cyclic sulfite purification tower T4 is 40 kPa, the operating temperature at the top is 135 °C, the reflux ratio is 2. The overhead product S16 of the cyclic sulfite purification tower is propylene sulfite, and the bottom of the cyclic sulfite purification tower is the recycle material S17.

[0067] The materials and their qualities taken from each tower are shown in Table 1. Since the impurity content at the tops of the low - temperature recovery tower and the cyclic sulfite purification tower is extremely low, it shows that the loss of the product propylene sulfite is very low.

[0068] Table 1

[0069]

[0070] Example 2

[0071] The reactive distillation device for producing cyclic sulfite from raw material alcohol and thionyl chloride of the present invention includes a raw material alcohol dehydration tower, a reactive distillation tower, a low-temperature recovery tower, a cyclic sulfite purification tower, a heat exchanger, a compressor, a flash tank, and related feed pipelines and pipelines connecting the above equipment; condensers are provided at the tops of the raw material alcohol dehydration tower T1, the low-temperature recovery tower T3, and the cyclic sulfite purification tower T4, and reboilers are provided at the bottoms of the towers. A condenser is provided at the top of the reactive distillation tower T2.

[0072] The feed of the raw material alcohol dehydration tower T1 is 1,2-propanediol S1. The operating pressure at the top of the raw material alcohol dehydration tower T1 is 1 kPa, the operating temperature at the top is 55 °C, the reflux ratio is 5. The top product is 1,2-propanediol containing water S2, and the bottom product S3 is water-free 1,2-propanediol. The water-free 1,2-propanediol enters the first heat exchanger E1; the material S4 at the outlet of the first heat exchanger E1 is combined with the circulating material S15 at the bottom of the low-temperature recovery tower and the circulating material S17 at the bottom of the cyclic sulfite purification tower to form the combined feed material S5 at the inlet of the reactive distillation tower, and is connected to the bottom feed port of the reactive distillation tower T2; the feed of the raw material thionyl chloride S6 is connected to the feed ports on the 2nd, 5th, and 10th trays from the bottom of the reactive distillation tower T2. The feed molar ratio of the combined feed material S5 at the inlet of the reactive distillation tower to the feed of the raw material thionyl chloride S6 is 1.5:1. The operating pressure at the top of the reactive distillation tower T2 is 40 kPa, the operating temperature at the top is 67 °C, the reflux ratio is 0.1. The top product S8 of the reactive distillation tower is a mixture of thionyl chloride and hydrogen chloride. The side-stream product S9 of the reactive distillation tower is a mixture of 4-ethylsulfite, hydrogen chloride, and 1,2-propanediol, and the side-stream is connected to the flash tank V1; the flash gas material S10 at the gas outlet of the flash tank V1 is hydrogen chloride, which is combined with the top product S8 of the reactive distillation tower to form the combined feed material S12 at the inlet of the compressor, and is connected to the compressor C1. The liquid material S11 of the flash tank is connected to the feed of the cyclic sulfite purification tower T4 from the liquid outlet of the flash tank V1; the material S13 at the outlet of the compressor is connected to the feed of the low-temperature recovery tower T3 from the outlet of the compressor C1; the operating pressure at the top of the low-temperature recovery tower T3 is 3.5 MPa, the top operating temperature is 12 °C, the reflux ratio is 1.5. The top material S14 of the low-temperature recovery tower is hydrogen chloride, and the bottom of the low-temperature recovery tower is the circulating material S15; the pressure of the cyclic sulfite purification tower T4 is 40 kPa, the operating temperature at the top is 131 °C, the reflux ratio is 10. The top material S16 of the cyclic sulfite purification tower is 4-ethylsulfite, and the bottom of the cyclic sulfite purification tower is the circulating material S17.

[0073] The materials and material qualities of each tower are shown in Table 2. Since the impurity content at the tops of the low-temperature recovery tower and the cyclic sulfite purification tower is extremely low, it shows that the loss of the product 4-ethylsulfite is very low.

[0074] Table 2

[0075]

[0076] Example 3

[0077] The reactive distillation device for producing cyclic sulfite from raw material alcohol and thionyl chloride of the present invention includes a raw material alcohol dehydration tower, a reactive distillation tower, a low-temperature recovery tower, a cyclic sulfite purification tower, a heat exchanger, a compressor, a flash tank, and related feed pipelines and pipelines connecting the above equipment; condensers are provided at the tops of the raw material alcohol dehydration tower T1, the low-temperature recovery tower T3, and the cyclic sulfite purification tower T4, and reboilers are provided at the bottoms of the towers, and a condenser is provided at the top of the reactive distillation tower T2.

[0078] The feed of the raw material alcohol dehydration tower T1 is ethylene glycol S1. The operating pressure at the top of the raw material alcohol dehydration tower T1 is 3 kPa, the operating temperature at the top is 71 °C, the reflux ratio is 15, the overhead is ethylene glycol containing water S2, and the bottom discharge S3 is ethylene glycol without water. The ethylene glycol without water enters the first heat exchanger E1; the material S4 at the outlet of the first heat exchanger E1 is combined with the circulating material S15 at the bottom of the low-temperature recovery tower and the circulating material S17 at the bottom of the cyclic sulfite purification tower to form the combined material S5 at the inlet of the reactive distillation tower, and is connected to the bottom feed port of the reactive distillation tower T2; the feed of the raw material thionyl chloride S6 is connected to the feed ports on the 1st, 4th, and 8th trays from the bottom of the reactive distillation tower T2. The feed molar ratio of the combined material S5 at the inlet of the reactive distillation tower to the raw material thionyl chloride S6 is 1.05:1. The operating pressure at the top of the reactive distillation tower T2 is 30 kPa, the operating temperature at the top is 43 °C, the reflux ratio is 0.7, the overhead discharge S8 is a mixture of thionyl chloride and hydrogen chloride, and the side stream withdrawn material S9 from the reactive distillation tower is a mixture of ethylene sulfite, hydrogen chloride, and ethylene glycol, and the side stream is connected to the flash tank V1; the flash gas phase material S10 at the gas phase outlet of the flash tank V1 is hydrogen chloride, which is combined with the overhead discharge S8 of the reactive distillation tower to form the combined material S12 at the inlet of the compressor, and is connected to the compressor C1. The liquid phase material S11 of the flash tank is connected to the feed point of the cyclic sulfite purification tower T4 from the liquid phase outlet of the flash tank V1; the material S13 at the outlet of the compressor is connected to the feed point of the low-temperature recovery tower T3 from the outlet of the compressor C1; the operating pressure at the top of the low-temperature recovery tower T3 is 3.5 MPa, the top operating temperature is 12 °C, the reflux ratio is 3, the overhead material S14 of the low-temperature recovery tower is hydrogen chloride, and the bottom of the low-temperature recovery tower is the circulating material S15; the pressure of the cyclic sulfite purification tower T4 is 30 kPa, the operating temperature at the top is 118 °C, the reflux ratio is 3, the overhead material S16 of the cyclic sulfite purification tower is ethylene sulfite, and the bottom of the cyclic sulfite purification tower is the circulating material.

[0079] The materials and material qualities withdrawn from each tower are shown in Table 3. Since the impurity content at the tops of the low-temperature recovery tower and the cyclic sulfite purification tower is extremely low, it shows that the loss of the product ethylene sulfite is very low.

[0080] Table 3

[0081]

[0082] The above are only the preferred application embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principles of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A continuous production device for preparing cyclic sulfite, characterized in that, It includes a raw material alcohol dehydration tower T1, a reactive distillation tower T2, a low-temperature recovery tower T3, a cyclic sulfite purification tower T4, a first heat exchanger E1, a flash tank V1, a feed pipeline and a connecting pipeline; The top outlet of the reactive distillation tower T2 is communicated with the inlet of the low-temperature recovery tower T3, the side outlet of the reactive distillation tower T2 is communicated with the inlet of the flash tank, the gas outlet of the flash tank is communicated with the inlet of the low-temperature recovery tower T3, and the liquid outlet of the flash tank is communicated with the inlet of the cyclic sulfite purification tower T4; The first heat exchanger E1 is arranged at the bottom discharge port of the raw material alcohol dehydration tower T1, and a discharge pipeline is formed at the top of the cyclic sulfite purification tower T4; The circulating material at the bottom of the cyclic sulfite purification tower T4 is mixed with the material at the bottom discharge port of the raw material alcohol dehydration tower T1 and the circulating material at the bottom of the low-temperature recovery tower T3, and then is transported to the bottom feed port of the reactive distillation tower T2; The side feed port of the reactive distillation tower T2 is connected with a thionyl chloride feed pipe, and the top of the low-temperature recovery tower T3 is connected with a hydrogen chloride discharge pipeline.

2. The continuous production device according to claim 1, characterized in that The continuous production device further includes a compressor C1. The compressor C1 is arranged at the inlet end of the low-temperature recovery tower T3 and is communicated with the inlet of the low-temperature recovery tower T3. The top outlet of the reactive distillation tower T2 and the gas outlet of the flash tank V1 are jointly connected to the compressor C1.

3. The continuous production device according to claim 1, wherein, The raw material alcohol dehydration tower T1, the low-temperature recovery tower T3, and the cyclic sulfite purification tower T4 are each provided with a condenser at the top and a reboiler at the bottom, and the reactive distillation tower T2 is provided with a condenser at the top.

4. The continuous production device according to claim 1, characterized in that, The top discharge port of the raw material alcohol dehydration tower T1 is connected with a discharge pipeline for discharging the water-containing raw material alcohol.

5. The continuous production device according to claim 1, characterized in that, A material discharge pipeline for discharging hydrogen chloride is arranged at the top of the low-temperature recovery tower T3.

6. The continuous production device according to claim 5, characterized in that, The outlet of the hydrogen chloride material discharge pipeline is connected with a hydrogen chloride distillation tower.

7. The continuous production device according to claim 6, characterized in that The outlet of the hydrogen chloride distillation tower is connected with an absorption tower.

8. The continuous production device according to claim 1, characterized in that, The thionyl chloride feed pipe is connected to the feed port on the 1st to 15th trays from the bottom of the reactive distillation tower T2.

9. The continuous production device according to claim 1, characterized in that, The pressure of the raw material alcohol dehydration tower T1 is 0 - 20 kPa, the top operating temperature is 30 - 150 °C, and the reflux ratio is 1 - 50; the pressure of the reactive distillation tower T2 is 0 - 100 kPa, the top operating temperature is 30 - 200 °C, and the reflux ratio is 0.01 - 20; the pressure of the low-temperature recovery tower T3 is 1 - 5 MPa, the top operating temperature is 5 - 150 °C, and the reflux ratio is 0.1 - 20; the pressure of the cyclic sulfite purification tower T4 is 0 - 100 kPa, the top operating temperature is 80 - 200 °C, and the reflux ratio is 0.01 - 50.

10. A continuous production method for preparing cyclic sulfite, characterized in that, It includes the following steps: S1, Feed the raw material alcohol into the feed port of the raw material alcohol dehydration tower T1, dehydrate the fed raw material alcohol through the raw material alcohol dehydration tower T1, and collect the water-containing raw material alcohol from the top of the raw material alcohol dehydration tower T1; S2. The discharge at the bottom of the raw material alcohol dehydration tower T1 is heat-exchanged by the first heat exchanger and then conveyed from the bottom to the reactive distillation column T2. Thionyl chloride is introduced through the side feed port of the reactive distillation column T2. After the reaction in the reactive distillation column T2, the discharge at the top of the reactive distillation column T2 is conveyed to the low-temperature recovery tower T3, and the side discharge of the reactive distillation column T2 is conveyed to the flash tank V1. Flash evaporation is carried out in the flash tank V1, and the liquid material after flash evaporation is conveyed to the cyclic sulfite purification tower T4. The gas material is mixed with the discharge at the top of the reactive distillation column T2 and then conveyed to the low-temperature recovery tower T3 together; S3. Hydrogen chloride is discharged from the discharge pipeline at the top of the low-temperature recovery tower T3; S4. The cyclic sulfite is discharged from the discharge pipeline at the top of the cyclic sulfite purification tower T4. The circulating material at the bottom of the cyclic sulfite purification tower T4, the circulating material at the bottom of the low-temperature recovery tower T3, and the discharge at the bottom of the raw material alcohol dehydration tower T1 are mixed and then conveyed from the bottom to the reactive distillation column T2 together.

Images