Method for preparing 2, 5-dihydroxy-1, 4-dithiane by using continuous turbulent tubular reactor

Abstract

The invention provides a method for preparing 2, 5-dihydroxy-1, 4-dithiane by using a continuous turbulent tubular reactor, and belongs to the technical field of organic synthesis application. In a continuous turbulent tubular reactor, a sodium hydrosulfide aqueous solution and a chloroacetaldehyde aqueous solution are used as raw materials, and 2, 5-dihydroxy-1, 4-dithiane is generated within a short reaction time of dozens of seconds to several minutes. The method has the characteristics of simplicity, convenience and safety in operation and high-yield continuous production of the 2, 5-dihydroxy-1, 4-dithiane product. In addition, the environmental pollution of the process is greatly reduced. And the safety performance is greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis application technology, specifically relating to a method for preparing 2,5-dihydroxy-1,4-dithiaane using sodium hydrosulfide aqueous solution and chloroacetaldehyde aqueous solution as raw materials. Background Technology

[0002] 2,5-Dihydroxy-1,4-dithiane is a key intermediate in the active pharmaceutical ingredients lametafenidine and emtricitabine, and is also used in the synthesis of antibiotics, antitumor drugs, and cardiovascular drugs. Due to its strong biological activity and biocompatibility, this compound is widely used in various pharmaceutical and pesticide fields, resulting in a huge market demand.

[0003] Currently, the mainstream production process of 2,5-dihydroxy-1,4-dithiane is to obtain it by condensation of chloroacetaldehyde and sodium hydrosulfide, as shown in the following formula. For example, patents such as CN 109608433 and WO 2010049466 have reported the synthesis process of dithiane. These reports all use the method of mixing haloaldehyde solution and sodium hydrosulfide solution and carrying out the reaction in a traditional batch reactor.

[0004]

[0005] However, due to the specific nature of the reaction, the traditional batch reactor process has the following drawbacks: The inner wall of the reactor easily agglomerates, making discharge impossible, resulting in yield loss and reduced heat exchange efficiency, thus increasing energy costs. Furthermore, the limited mixing effect of traditional batch reactors leads to impurities in the product, including black particulate matter. Compared to continuous reactions, batch reactor production cannot achieve continuous feeding and discharging; the long processing times for feeding and unloading significantly reduce production efficiency. Additionally, the large feed volume and intense exothermic reaction in the reactor pose certain safety hazards. Finally, each operation of a traditional reactor requires multiple personnel, resulting in high labor and management costs.

[0006] Chinese Patent 202311346618.9 describes a method for the continuous production of 2,5-dihydroxy-1,4-dithiane, involving the continuous reaction of an aqueous solution of dichloroacetaldehyde and a sodium hydrosulfide solution. This method requires pre-cooling of the raw materials, and the dichloroacetaldehyde aqueous solution needs to be prepared by further processing the first chloroacetaldehyde raw material. The raw material processing is relatively complex, and the pH needs to be adjusted in the reaction vessel by using an in-vessel pH meter and a second alkali reagent in a chain. The material stays in the reaction vessel for 2-4 hours. Therefore, this method is complex, has a high operational risk factor, and is time-consuming.

[0007] In conclusion, there is an urgent need for equipment capable of large-scale industrial production of dithiane to solve the various problems associated with traditional batch reactors. Summary of the Invention

[0008] The present invention provides an apparatus and method for preparing 2,5-dihydroxy-1,4-dithiane in a continuous flow manner within a continuous turbulent tubular reactor.

[0009] The continuous high-efficiency turbulent flow reactor, also known as the dynamic tubular reactor, is a revolutionary design that surpasses traditional tubular reactors. It is more flexible and versatile than static reactors, and is not limited by residence time, reaction temperature, or other conditions. When the tube length is much greater than the tube diameter and the material is in a turbulent state, the equipment approximates an ideal plug flow.

[0010] The reaction principle of this invention is as follows: Sodium hydrosulfide solution and chloroacetaldehyde solution are precisely and continuously injected into a continuous-flow dynamic tubular reactor. The unique design of the tubular reactor causes the materials to flow forward in a piston-like manner. Combined with different impeller configurations, the high turbulence overcomes interfacial tension, thereby achieving thorough mixing at the microscale. At this point, the kinetically superior product preferentially precipitates and rapidly separates from the system, while impurities dissolve into the mother liquor. This inhibits the precipitation of impurities from the system, achieving purification within the reactor to obtain a high-melting-point, high-purity dithiane product.

[0011] In a first aspect, the present invention provides a method for preparing 2,5-dihydroxy-1,4-dithiane using a continuous turbulent tubular reactor, comprising the following steps:

[0012] S1. Sodium hydrosulfide aqueous solution and chloroacetaldehyde aqueous solution are respectively introduced into a continuous turbulent tubular reactor, with the flow rate controlled by their respective metering pumps, and they are introduced into the continuous turbulent tubular reactor simultaneously for mixing, and the reaction is completed within 2-10 minutes.

[0013] S2. The product obtained in step S1 is further subjected to a series of stirring crystallization processes. After the reaction process is completed, the product flows out from the outlet of the reactor.

[0014] S3. The product obtained in step S2 is filtered, washed with water, and then dried to obtain the final product.

[0015] In another preferred embodiment, in step S1, the sodium hydrosulfide aqueous solution has a mass concentration of 10% to 35%, preferably 30%; and the chloroacetaldehyde aqueous solution has a mass concentration of 5% to 20%, preferably 10%.

[0016] In another preferred embodiment, in step S1, the molar ratio of sodium hydrosulfide aqueous solution to chloroacetaldehyde aqueous solution is 1.1:1 to 2.2:1, preferably 1.4:1.

[0017] In another preferred embodiment, in step S2, the flow rate of the sodium hydrosulfide solution is 300 ml / min to 500 ml / min, preferably 400 ml / min; the flow rate of the chloroacetaldehyde solution is 1000 ml / min to 1500 ml / min, preferably 1260 ml / min.

[0018] In another preferred embodiment, in step S2, the reaction residence time in the continuous turbulent tubular reactor is 2 to 10 minutes, preferably 180 seconds.

[0019] In another preferred embodiment, in step S2, the reaction temperature of the continuous turbulent tubular reactor is 0°C to 40°C, preferably 25°C to 30°C.

[0020] In another preferred embodiment, in step S2, the reaction mixture enters a series crystallizer, and the product crystallizes out by gradient cooling.

[0021] In a second aspect of the invention, a continuous high-efficiency turbulent reactor is used in the preparation of 2,5-dihydroxy-1,4-dithiane, the continuous high-efficiency turbulent reactor comprising: a first inlet, a second inlet, a first metering pump, a second metering pump, a reaction chamber, an outlet, and an emergency discharge port;

[0022] The reactor has two feed ports: a first feed port and a second feed port. A first metering pump pumps material from the first feed port into the reaction chamber, and a second metering pump pumps material from the second feed port into the reaction chamber. Reaction products are discharged from the discharge port, and waste liquid is discharged from the emergency discharge port.

[0023] In another preferred embodiment, the safe operating temperature range of the device is -25℃ to 200℃, the safe operating pressure range is 0 to 2MPa, and the material for the material pipeline connection is HC-276.

[0024] In another preferred embodiment, the continuous turbulent tubular reactor of the device is made of HC-276, and the metering pump is made of polytetrafluoroethylene.

[0025] It should be understood that, within the scope of this invention, the above-described technical features of this invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here.

[0026] The beneficial effects of this invention are:

[0027] 1. One of the advantages of using the dynamic tubular reactor in this invention to prepare dithiane is that it can produce dithiane products with high yield and high purity. Since the raw materials can be mixed at the microscale in the continuous turbulent tubular reactor, it is easy to control the temperature precisely, so the selectivity of the product is significantly improved, specifically manifested in a significant reduction of black impurities, thus the purity of the product increases significantly.

[0028] 2. The second advantage of using the dynamic tubular reactor in this invention to prepare dithiane is that, due to the continuous operation, the relative amount of material remaining in the reactor is small, which reduces the safety risks caused by exothermic reactions, and at the same time greatly improves the production capacity and efficiency.

[0029] 3. The third advantage of using the dynamic tubular reactor in this invention to prepare dithiane is that, due to the better mixing effect, the amount of water used for subsequent washing can be greatly reduced, which is more environmentally friendly.

[0030] The fourth advantage of using the dynamic tubular reactor in this invention to prepare dithiane is that, compared with the traditional batch reactor, it occupies a smaller area and requires less investment in plant and equipment.

[0031] 4. The fourth advantage of using the dynamic tubular reactor in this invention to prepare dithiane is that rapid mixing and mass transfer are achieved through the turbulent tubular reactor, the reaction time is shortened to tens of seconds to a few minutes, the production efficiency is greatly improved, and continuous production is possible, avoiding the batch instability problem of traditional batch processes.

[0032] 5. The fourth advantage of using the dynamic tubular reactor in this invention to prepare dithiane is that it directly uses sodium hydrosulfide and chloroacetaldehyde aqueous solution as raw materials, eliminating intermediate steps (such as the need to synthesize dithioethylene glycol first in traditional processes), making the operation simpler, the raw material utilization rate higher, and the product yield improved. Attached Figure Description

[0033] Figure 1 The process flow diagram for preparing 2,5-dihydroxy-1,4-dithiane according to the present invention is shown below.

[0034] Figure 2 This is a schematic diagram of the process flow of the Onco Micro continuous turbulent tubular reactor used in this invention.

[0035] 1-Reaction chamber, 2-Sodium hydrosulfide inlet, 3-Chloroacetaldehyde inlet, 4-Outlet, 5-Emergency discharge outlet. Detailed Implementation

[0036] The purpose of this invention is to provide a method for the continuous production of 2,5-dihydroxy-1,4-dithiane with high yield, short reaction time, simple operation, and industrial-scale production capability.

[0037] Reference Figure 1The process flow of this invention utilizes Figure 2 The apparatus diagram is as follows: (1) First, the raw material 1 sodium hydrosulfide aqueous solution and the raw material 2 chloroacetaldehyde aqueous solution in the storage tank are respectively pumped into the reaction chamber 1 through their respective metering pumps in a certain ratio. (2) At the same time as the materials are fed, the continuous turbulent tubular reactor is started. (3) The product obtained by the continuous turbulent tubular reactor is collected through the discharge port 4, filtered, washed with water, acid washed and pulped, washed with water again, and finally alcohol washed and pulped, and dried to obtain the final product 2,5-dihydroxy-1,4-dithiaane. (4) After the experiment, the reaction liquid in the chamber is drained through the emergency discharge port 5.

[0038] In a first aspect, the present invention provides a method for preparing 2,5-dihydroxy-1,4-dithiane using a continuous turbulent tubular reactor, comprising the following steps:

[0039] S1. Sodium hydrosulfide aqueous solution and chloroacetaldehyde aqueous solution are respectively introduced into a continuous turbulent tubular reactor, with the flow rate controlled by their respective metering pumps, and they are introduced into the continuous turbulent tubular reactor simultaneously for mixing, and the reaction is completed within 2-10 minutes.

[0040] S2. The product obtained in step S1 is further subjected to a series of stirring crystallization processes. After the reaction process is completed, the product flows out from the outlet of the reactor.

[0041] S3. The product obtained in step S2 is filtered, washed with water, and then dried to obtain the final product.

[0042] In step S1, the sodium hydrosulfide aqueous solution has a mass concentration of 10% to 35%, preferably 30%; the chloroacetaldehyde aqueous solution has a mass concentration of 5% to 20%, preferably 10%.

[0043] In step S1, the molar ratio of sodium hydrosulfide aqueous solution to chloroacetaldehyde aqueous solution is 1.1:1 to 2.2:1, preferably 1.4:1.

[0044] In step S2, the flow rate of the sodium hydrosulfide solution is 300 ml / min to 500 ml / min, preferably 400 ml / min; the flow rate of the chloroacetaldehyde solution is 1000 ml / min to 1500 ml / min, preferably 1260 ml / min.

[0045] In step S2, the reaction residence time in the continuous turbulent tubular reactor is 2 to 10 minutes, preferably 180 seconds.

[0046] In step S2, the reaction temperature of the continuous turbulent tubular reactor is 0℃~40℃, preferably 25~30℃.

[0047] In step S2, the reaction is completed in 2-10 minutes using a continuous turbulent tubular reactor.

[0048] In step S2, the reaction mixture enters a series crystallizer, and the product crystallizes out by gradient cooling.

[0049] In a second aspect of the invention, a continuous high-efficiency turbulent reactor is used in the preparation of 2,5-dihydroxy-1,4-dithiane, the continuous high-efficiency turbulent reactor comprising: a first inlet, a second inlet, a first metering pump, a second metering pump, a reaction chamber, an outlet, and an emergency discharge port;

[0050] The reactor has two feed ports: a first feed port and a second feed port. A first metering pump pumps material from the first feed port into the reaction chamber, and a second metering pump pumps material from the second feed port into the reaction chamber. Reaction products are discharged from the discharge port, and waste liquid is discharged from the emergency discharge port.

[0051] The safe operating temperature range of the device is -25℃ to 200℃, the safe operating pressure range is 0 to 2MPa, and the material for material pipeline connection is HC-276.

[0052] The continuous turbulent tubular reactor of the device is made of HC-276, and the metering pump is made of polytetrafluoroethylene.

[0053] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below. However, it should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention. All raw materials used in the embodiments of this invention are commercially available.

[0054] Example 1

[0055] The present invention will be further described below through examples, but these examples do not limit the scope of the invention.

[0056] Prepare a 10% chloroacetaldehyde solution in storage tank 1, stir well, and adjust the metering pump flow rate to stabilize the flow rate at 120 ml / min. Prepare a 30% sodium hydrosulfide solution in storage tank 2, stir well, and set aside. Adjust the metering pump flow rate to stabilize the flow rate at 40 ml / min. Start the tubular reactor, adjust the main shaft speed to 300 rpm, and feed both materials simultaneously. Control the pressure and temperature of the reaction chamber according to the flow rate, ensuring the chamber temperature is 0–10℃. After a residence time of 5 minutes in the reactor, begin continuous discharge. Collect the product, filter, wash with water, and dry to obtain a white to light yellow crystalline powder with a yield of 85% and a melting point of 137–140℃.

[0057] Example 2:

[0058] Prepare a 10% chloroacetaldehyde solution in storage tank 1, stir well, and adjust the metering pump flow rate to stabilize the flow rate at 120 ml / min. Prepare a 30% sodium hydrosulfide solution in storage tank 2, stir well, and set aside. Adjust the metering pump flow rate to stabilize the flow rate at 40 ml / min. Start the tubular reactor, adjust the main shaft speed to 300 rpm, and feed both materials simultaneously. Control the pressure and temperature of the reaction chamber according to the flow rate, ensuring the chamber temperature is 10–25°C. After a residence time of 5 minutes in the reactor, begin continuous discharge. Collect the product, filter, wash with water, and dry to obtain a white to light yellow crystalline powder with a yield of 90% and a melting point of 139–140°C.

[0059] Example 3:

[0060] Prepare a 10% chloroacetaldehyde solution in storage tank 1, stir well, and adjust the metering pump flow rate to stabilize the flow rate at 120 ml / min. Prepare a 30% sodium hydrosulfide solution in storage tank 2, stir well, and adjust the metering pump flow rate to stabilize the flow rate at 40 ml / min. Start the tubular reactor, adjust the main shaft speed to 300 rpm, and feed both materials simultaneously. Control the pressure and temperature of the reaction chamber according to the flow rate, and ensure and control the chamber temperature at 25-30℃. After a residence time of 5 minutes in the reactor, start continuous discharge. Collect the product, filter, wash with water, and dry to obtain a white to light yellow crystalline powder with a yield of 94% and a melting point of 141-143℃.

[0061] Example 4:

[0062] Prepare a 10% chloroacetaldehyde solution in storage tank 1 and stir until homogeneous. Adjust the metering pump flow rate to stabilize the flow rate at 120 ml / min. Prepare a 30% sodium hydrosulfide solution in storage tank 2 and stir until homogeneous. Adjust the metering pump flow rate to stabilize the flow rate at 40 ml / min. Start the tubular reactor and adjust the spindle speed to 400 rpm. Feed both materials simultaneously, controlling the pressure and temperature of the reaction chamber according to the flow rate, ensuring the chamber temperature is 25–30°C. After a residence time of 5 minutes in the reactor, begin continuous discharge. Collect the product, filter, wash with water, and dry to obtain a white to light yellow crystalline powder with a yield of 96% and a melting point of 142–143°C.

[0063] Example 5:

[0064] Prepare a 10% chloroacetaldehyde solution in storage tank 1 and stir until homogeneous. Adjust the metering pump flow rate to stabilize the flow rate at 120 ml / min. Prepare a 30% sodium hydrosulfide solution in storage tank 2 and stir until homogeneous. Adjust the metering pump flow rate to stabilize the flow rate at 40 ml / min. Start the tubular reactor and adjust the spindle speed to 300 rpm. Feed both materials simultaneously, controlling the pressure and temperature of the reaction chamber according to the flow rate, ensuring the chamber temperature is 30–35°C. After a residence time of 5 minutes in the reactor, begin continuous discharge. Collect the product, filter, wash with water, and dry to obtain a white to light yellow crystalline powder with a yield of 90% and a melting point of 141–142°C.

[0065] Example 6:

[0066] Prepare a 10% chloroacetaldehyde solution in storage tank 1 and stir until homogeneous. Adjust the metering pump flow rate to stabilize the flow rate at 100 ml / min. Prepare a 30% sodium hydrosulfide solution in storage tank 2 and stir until homogeneous. Adjust the metering pump flow rate to stabilize the flow rate at 33 ml / min. Start the tubular reactor and adjust the spindle speed to 400 rpm. Feed both materials simultaneously, controlling the pressure and temperature of the reaction chamber according to the flow rate, ensuring the chamber temperature is 30–35°C. After a residence time of 7 minutes in the reactor, begin continuous discharge. Collect the product, filter, wash with water, acid wash and pulp, wash again with water, and finally alcohol wash and pulp. Dry to obtain a white to light yellow crystalline powder with a yield of 91% and a melting point of 142–143°C.

[0067] Example 7:

[0068] Prepare a 10% chloroacetaldehyde solution in storage tank 1 and stir until homogeneous. Adjust the metering pump flow rate to stabilize the flow rate at 150 ml / min. Prepare a 30% sodium hydrosulfide solution in storage tank 2 and stir until homogeneous. Adjust the metering pump flow rate to stabilize the flow rate at 50 ml / min. Start the tubular reactor and adjust the spindle speed to 400 rpm. Feed both materials simultaneously, controlling the pressure and temperature of the reaction chamber according to the flow rate, ensuring the chamber temperature is 25–30°C. After a residence time of 4 minutes in the reactor, begin continuous discharge. Collect the product, filter, wash with water, acid wash and pulp, wash again with water, and finally alcohol wash and pulp. Dry to obtain a white to light yellow crystalline powder with a yield of 92% and a melting point of 140–141°C.

[0069] Example 8:

[0070] Prepare a 10% chloroacetaldehyde solution in storage tank 1 and stir until homogeneous. Adjust the metering pump flow rate to stabilize the flow rate at 180 ml / min. Prepare a 30% sodium hydrosulfide solution in storage tank 2 and stir until homogeneous. Adjust the metering pump flow rate to stabilize the flow rate at 60 ml / min. Start the tubular reactor and adjust the spindle speed to 400 rpm. Feed both materials simultaneously, controlling the pressure and temperature of the reaction chamber according to the flow rate, ensuring the chamber temperature is 25–30°C. After a residence time of 3 minutes in the reactor, begin continuous discharge. Collect the product, filter, wash with water, acid wash and pulp, wash again with water, and finally alcohol wash and pulp. Dry to obtain a white to light yellow crystalline powder with a yield of 88% and a melting point of 140–142°C.

[0071] Example 9:

[0072] Prepare a 10% chloroacetaldehyde solution in storage tank 1 and stir until homogeneous. Adjust the metering pump flow rate to stabilize the flow rate at 120 ml / min. Prepare a 30% sodium hydrosulfide solution in storage tank 2 and stir until homogeneous. Adjust the metering pump flow rate to stabilize the flow rate at 40 ml / min. Start the tubular reactor and adjust the spindle speed to 200 rpm. Feed both materials simultaneously, controlling the pressure and temperature of the reaction chamber according to the flow rate, ensuring the chamber temperature is 25–30°C. After a residence time of 5 minutes in the reactor, begin continuous discharge. Collect the product, filter, wash with water, acid wash and pulp, wash again with water, and finally alcohol wash and pulp. Dry to obtain a white to light yellow crystalline powder with a yield of 88% and a melting point of 142–143°C.

[0073] Summary of experimental conclusions

[0074] 1. Relationship between reaction conditions and yield

[0075] Temperature effect:

[0076] The yield was low (85%) at low temperature (10°C) (Example 1), possibly due to limited reaction kinetics; the yield stabilized at 90%-96% at 10-35°C (Examples 2-9), indicating that this temperature range is the optimal reaction window. Spindle speed:

[0077] 300-400 rpm is a better condition, with 400 rpm being the optimal condition (Examples 2-8). In Example 4, the yield was significantly increased to 96%, indicating that increasing the spindle speed can improve the conversion rate. However, the yield decreased at 200 rpm (Example 9). Therefore, considering the production spindle speed, 400 rpm is the best reaction condition.

[0078] 2. Material proportioning and flow rate optimization

[0079] Molar ratio (sodium hydrosulfide: chloroacetaldehyde = 1.4:1): This ratio was used in all examples with stable yields, demonstrating that excess sodium hydrosulfide (NaHS) can drive the reaction forward and reduce byproducts.

[0080] Flow rate and scale-up production: The same yield was maintained in both small-scale and large-scale production (Examples 2-3, Examples 7-8), indicating that the turbulent tubular reactor has good scale-up properties and that changes in flow rate have little impact on reaction efficiency.

[0081] 3. Process stability and product quality

[0082] Yield consistency: Under conditions of 25-35℃, the yield fluctuation of different scale experiments was only ±6% (90%-96%), indicating that the process is highly controllable.

[0083] Melting point: The product has a melting point of 139-143℃, which meets the literature standard. The purity is stable (white solid, no complex purification required).

[0084] 4. Optimal reaction conditions and performance indicators

[0085] Maximum yield: 96% (Examples 7-9)

[0086] Key parameters: Temperature: 25-30℃ (yield decreases slightly when temperature is >30℃, such as 91% in Example 6); Molar ratio: NaHS:chloroacetaldehyde = 1.4:1 (constant); Rotation speed: 400 rpm (Examples 6-8 show that high rotation speed is beneficial to mixing efficiency).

[0087] In summary, this invention addresses the shortcomings of existing 2,5-dihydroxy-1,4-dithiane technologies, such as low yield, long reaction time, and low production capacity. Compared with existing technologies, this invention can increase the product yield from 90% to 96%, reduce the continuous processing time from 3 hours to 10 minutes, and shorten the product melting range from 135–150°C to 142–143°C. The shortened melting range results in higher product content and better product quality. Furthermore, it significantly increases the rate at which the equipment produces materials, which is beneficial for reducing product costs and enhancing product competitiveness.

[0088] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A method for preparing 2,5-dihydroxy-1,4-dithiane using a continuous turbulent tubular reactor, comprising the following steps: S1. Sodium hydrosulfide aqueous solution and chloroacetaldehyde aqueous solution are respectively introduced into a continuous turbulent tubular reactor, with the flow rate controlled by their respective metering pumps, and they are introduced into the continuous turbulent tubular reactor simultaneously for mixing, and the reaction is completed within 2-10 minutes. S2. The product obtained in step S1 is further crystallized by stirring. After the reaction process is completed, the product flows out from the outlet of the reactor. S3. The product obtained in step S2 is filtered, washed with water, and then dried to obtain the final product.

2. The method as described in claim 1, characterized in that, In step S1, the sodium hydrosulfide aqueous solution has a mass concentration of 10% to 40%; the chloroacetaldehyde aqueous solution has a mass concentration of 5% to 20%.

3. The method as described in claim 1, characterized in that, In step S1, the molar ratio of sodium hydrosulfide aqueous solution to chloroacetaldehyde aqueous solution is 1.1:1 to 2.2:

1.

4. The method as described in claim 1, characterized in that, In step S2, the flow rate of the sodium hydrosulfide solution is 300 ml / min to 500 ml / min; the flow rate of the chloroacetaldehyde solution is 1000 ml / min to 1500 ml / min.

5. The method as described in claim 1, characterized in that, In step S2, the reaction residence time in the continuous turbulent tubular reactor is 2 to 10 minutes.

6. The method as described in claim 1, characterized in that, In step S2, the reaction temperature of the continuous turbulent tubular reactor is 0℃~40℃.

7. Application of continuous high-efficiency turbulent reactor in the preparation of 2,5-dihydroxy-1,4-dithiane.

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