Method for synthesizing 1, 3-propane sultone through initiation of visible light catalysis free radicals

Abstract

The invention provides a method for synthesizing 1, 3-propane sultone through initiation of visible light catalysis free radicals, and belongs to the technical field of organic synthesis. The method comprises the following steps: firstly, uniformly mixing an allyl alcohol solution, a compound A, a photocatalyst and water, and irradiating with visible light to initiate a reaction to generate 3-hydroxyl propane sodium sulfonate; then, concentrating sodium 3-hydroxypropane sulfonate, and then acidizing to obtain HPS (Hydroxypropyl Sulfonate); carrying out post-treatment on the HPS, and then concentrating to obtain an HPS concentrated solution; and finally, carrying out reduced pressure distillation on the HPS concentrated solution to obtain the 1, 3-PS. The cobalt phthalocyanine compound, the zinc phthalocyanine compound and the pyranium tetrafluoroborate compound are used as photocatalysts, a single electron transfer mechanism initiated by visible light catalysis is used for accurately controlling reaction sites, a traditional thermal decomposition path of peroxide is replaced by a photocatalytic path, the hidden danger of explosion in the production process is thoroughly eliminated, and the production efficiency is improved. The reaction efficiency is high, side reactions are few, and the yield can reach 85% or above.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, and specifically to a method for synthesizing 1,3-propanesulfonate lactone by visible light photocatalysis and free radical initiation. Background Technology

[0002] 1,3-Propanesultone (1,3-PS) is a colorless liquid or white crystal with a wide range of applications in industries such as pharmaceuticals, chemicals, photosensitive materials, lithium batteries, biochemistry, textiles, lubrication, wastewater treatment, and surface treatment.

[0003] Currently, the industrial synthesis of 1,3-propanesulfonate lactone mainly utilizes free radical addition reactions initiated by peroxides (such as hydrogen peroxide, benzoyl peroxide, and di-tert-butyl peroxide). However, this process has the following problems: ① Peroxides (such as di-tert-butyl peroxide) have poor thermal stability and pose a potential explosion risk, which threatens the safety of production equipment and operators; ② The free radical chain reaction initiated by peroxides is difficult to control precisely, resulting in poor reaction selectivity and numerous side reactions (such as allyl alcohol polymerization), leading to low product purity and high residue (the residue ratio can reach 15%-20%); ③ An excessively high residue ratio or too many acidic byproducts requires additional neutralization treatment, increasing the environmental burden and waste disposal costs.

[0004] In existing technologies, researchers have attempted to improve reaction selectivity and production safety by optimizing reaction conditions (such as low-temperature initiation and gradient temperature increase) or by using slow-release peroxides or peroxide substitutes (such as azo initiators). For example, Chinese patent CN119285602A discloses a method for preparing 1,3-propanesulfonate lactone. First, calcium peroxide is embedded in stearic acid, followed by secondary embedding with polydopamine to obtain a slow-release peroxide with a special structure. Using this slow-release peroxide to replace conventional hydrogen peroxide or benzoyl peroxide as an initiator significantly improves the selectivity of sodium 3-hydroxypropanesulfonate. While the aforementioned methods improve the selectivity of sodium 3-hydroxypropanesulfonate, further research is needed to address technical issues such as improving reaction efficiency and reducing production costs.

[0005] In view of this, it is necessary to design a method for the synthesis of 1,3-propanesulfonate lactone by visible light photocatalysis and free radical initiation to solve the above-mentioned technical problems. Summary of the Invention

[0006] In view of the technical problems existing in the background art, this application provides a method for the synthesis of 1,3-propanesulfonate lactone by visible light photocatalysis and free radical initiation. Cobalt phthalocyanine compounds, zinc phthalocyanine compounds, and pyranonium tetrafluoroborate compounds are selected as photocatalysts. Allyl alcohol aqueous solution, sodium bisulfite, and the photocatalytic initiator are mixed uniformly, and reacted under visible light irradiation to generate sodium 3-hydroxypropanesulfonate. The sodium 3-hydroxypropanesulfonate is then acidified to obtain 3-hydroxypropanesulfonic acid (HPS). Finally, the HPS is distilled under reduced pressure to obtain 1,3-PS. The photocatalytic synthesis method provided by this application is not only fast, safe, and has few side reactions, but also uses an aqueous solvent system throughout the process. The prepared product can be efficiently separated without complex post-treatment, making it green, environmentally friendly, and energy-efficient, with good application prospects.

[0007] This application provides a method for synthesizing 1,3-propanesulfonate lactone via visible light photocatalysis and free radical initiation, comprising the following steps:

[0008] S1, Allyl alcohol solution, compound A, photocatalyst and water are mixed evenly to obtain a mixed solution, and the mixed solution is irradiated with visible light to initiate the reaction to generate sodium 3-hydroxypropanesulfonate;

[0009] S2, the sodium 3-hydroxypropanesulfonate obtained in step S1 is concentrated and then acidified to obtain 3-hydroxypropanesulfonic acid.

[0010] S3. The HPS obtained in step S2 is post-processed and then concentrated to obtain HPS concentrate.

[0011] S4. The HPS concentrate obtained in step S3 is subjected to vacuum distillation to obtain 1,3-propanesulfonate lactone.

[0012] Wherein, compound A is sodium bisulfite, or a mixture of sodium metabisulfite and sodium sulfite, or a mixture of sodium bisulfite and sodium sulfite; the photocatalyst is one of cobalt phthalocyanine compounds, zinc phthalocyanine compounds, or pyranium tetrafluoroborate compounds.

[0013] Furthermore, the photocatalyst is at least one selected from CoPSNa, ZnPBSK, and TMP; the structural formula of CoPSNa is as follows: The structural formula of ZnPBSK is as follows: The structural formula of the TMP is as follows:

[0014] Furthermore, in step S1, the mass concentration of the allyl alcohol solution is 50-70%.

[0015] Furthermore, in step S1, the equivalence ratio of the allyl alcohol, the compound A, and the photocatalyst is 1:(1.01-1.2):(0.0001-0.001).

[0016] Furthermore, in step S1, the visible light wavelength is 400-700 nm, and the visible light irradiation power is 5-50 mW·cm⁻¹. -2 The irradiation time is 3-4 hours, and the reaction temperature under visible light irradiation is 20-50℃.

[0017] Furthermore, in step S2, acidification is performed using hydrochloric acid solution or sulfuric acid solution, with the mass concentration of acid in the solution being 20-30% and the amount of acid used being 1.5-3 eq.

[0018] Furthermore, in step S2, the acidification treatment temperature is 60-80℃, and the acidification treatment time is 1-2 hours.

[0019] Furthermore, in step S3, the post-processing specifically refers to first concentrating the HPS, then adding an alcohol reagent for salting out, filtering, and retaining the filtrate; the alcohol reagent is methanol or ethanol, and the amount of the alcohol reagent used is 3-6 times the volume of the allyl alcohol solution added in step S1.

[0020] Furthermore, in step S3, the salting-out treatment temperature is 10-30℃; the water content of the HPS concentrate is 15-25%.

[0021] Furthermore, in step S4, the temperature of the vacuum distillation is 130-150℃, and the vacuum degree is less than or equal to 600Pa.

[0022] The beneficial effects of this application are as follows:

[0023] This application provides a method for the visible light-catalyzed free radical-initiated synthesis of 1,3-propanesulfonate lactone. Cobalt phthalocyanine (CoPSNa), zinc phthalocyanine (ZnPBSK), and pyranium tetrafluoroborate (TMP) are selected as photocatalysts. Allyl alcohol aqueous solution, sodium bisulfite, and the photocatalytic initiator are mixed uniformly and reacted under visible light irradiation to generate sodium 3-hydroxypropanesulfonate. The sodium 3-hydroxypropanesulfonate is then acidified to obtain HPS. Finally, the HPS is distilled under reduced pressure to obtain 1,3-PS.

[0024] The mechanism by which CoPSNa, ZnPBSK, and TMP photocatalyze the formation of sodium 3-hydroxypropanesulfonate is as follows: Under visible light irradiation, the photocatalyst absorbs photons and transitions to a singlet excited state (S1), which then undergoes intersystem crossing (ISC) to generate a long-lived triplet excited state (T1) photocatalyst. Subsequently, the T1 photocatalyst transfers electrons to sodium bisulfite to generate sulfite radicals (·SO3).- ), (·SO3 - The radical then attacks the β-carbon of allyl alcohol (CH2=CH-CH2OH) (following the anti-Markovnikov rule, radical nucleophilic addition) to generate a more stable secondary carbon radical intermediate; then, the secondary carbon radical intermediate loses a single electron to form a sulfonic acid allyl cation, which is then reacted with HSO3 in the system. - SO3 2- Nucleophilic attack generates sodium β-sulfonate intermediate, which is further hydrolyzed to generate sodium 3-hydroxypropanesulfonate.

[0025] Among them, phthalocyanine catalysts pass through a metal center (Co) 2+ / Zn 2+ ) and sulfite (SO3) - The coordination of sulfite radicals (·SO3) directs their movement. - ) undergoes selective addition with allyl alcohol to generate a secondary carbon radical intermediate; while pyranium tetrafluoroborate catalysts induce HO bond cleavage by guiding hydrogen atom transfer to generate hydroxyl radicals, which are then used to directionally guide sulfite radicals (·SO3) - The photocatalyst undergoes selective addition with allyl alcohol (CH2=CH-CH2OH) to generate a secondary carbon radical intermediate. This application utilizes a visible light band of 400-700 nm (red light band) to better match the maximum absorption peak of the photocatalyst, improve light energy utilization, and suppress side reactions.

[0026] The preparation method provided in this application precisely controls the reaction site through a single-electron transfer mechanism initiated by visible light photocatalysis. It replaces the traditional thermal decomposition pathway of peroxides with a photocatalytic pathway, completely eliminating the risk of explosion during production. This method not only boasts rapid reaction efficiency but also high safety, few side reactions, and a yield exceeding 85%. The entire process utilizes an aqueous solvent system, resulting in mild reaction conditions. The prepared product can be efficiently separated without complex post-processing, making it environmentally friendly, energy-efficient, and promising for future applications.

[0027] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0029] Figure 1 The 1H NMR spectrum of the HPS concentrate prepared in Example 1 of this application;

[0030] Figure 2 The gas phase (GC) spectrum of 1,3-PS prepared in Example 1 of this application. Detailed Implementation

[0031] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0033] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0034] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0035] In the description of the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0036] Traditional industrial synthesis of 1,3-propanesulfonate lactone primarily utilizes free radical addition reactions initiated by peroxides (such as hydrogen peroxide, benzoyl peroxide, and di-tert-butyl peroxide). However, this process suffers from the following problems: ① Peroxides (such as di-tert-butyl peroxide) have poor thermal stability and pose a potential explosion risk, threatening the safety of production equipment and operators; ② The free radical chain reaction initiated by peroxides is difficult to control precisely, resulting in poor reaction selectivity and numerous side reactions (such as allyl alcohol polymerization), leading to low product purity and high residue levels (residue ratio can reach 15%-20%); ③ Excessive residue or acidic byproducts necessitates additional neutralization treatment, increasing environmental burden and waste disposal costs.

[0037] To address the aforementioned technical problems, this application provides a method for the visible-light photocatalytic radical-initiated synthesis of 1,3-propanesulfonate lactone. Cobalt phthalocyanine compounds, zinc phthalocyanine compounds, and pyranium tetrafluoroborate compounds are selected as photocatalysts. The reaction site is precisely controlled through a single-electron transfer mechanism initiated by visible-light photocatalysis. This photocatalytic pathway replaces the traditional thermal decomposition pathway of peroxides, completely eliminating the explosion hazard in the production process. The method not only boasts rapid reaction efficiency but also high safety, few side reactions, and a yield exceeding 85%. The entire process utilizes an aqueous solvent system, resulting in mild reaction conditions. The prepared product can be efficiently separated without complex post-treatment, making it environmentally friendly, energy-efficient, and promising for future applications.

[0038] This application provides a method for synthesizing 1,3-propanesulfonate lactone via visible light photocatalysis and free radical initiation, comprising the following steps:

[0039] S1, allyl alcohol solution, compound A, photocatalyst and water are mixed evenly to obtain a mixed solution, and the mixed solution is irradiated with visible light to initiate the reaction to generate sodium 3-hydroxypropanesulfonate.

[0040] In the embodiments of this application, compound A is sodium bisulfite, or a mixture of sodium metabisulfite and sodium sulfite, or a mixture of sodium bisulfite and sodium sulfite.

[0041] In the embodiments of this application, the photocatalyst is one of cobalt phthalocyanine compounds, zinc phthalocyanine compounds, and pyranonium tetrafluoroborate compounds. More specifically, the photocatalyst is at least one of CoPSNa, ZnPBSK, and TMP, wherein the structural formula of CoPSNa is [insert structural formula here]. The structural formula of ZnPBSK is: The structural formula of TMP is:

[0042] When photocatalysts CoPSNa, ZnPBSK, and TMP are dissolved in water, the solutions appear blue-green or yellow, and the solutions become colorless after catalysis. The mechanism by which CoPSNa, ZnPBSK, and TMP photocatalyze the formation of sodium 3-hydroxypropanesulfonate is as follows: Under visible light irradiation, the photocatalyst absorbs photons and transitions to a singlet excited state (S1), which then undergoes intersystem crossing (ISC) to generate a long-lived triplet excited state (T1) photocatalyst; subsequently, the T1 photocatalyst transfers electrons to sodium bisulfite to generate sulfite radicals (·SO3). - ), (·SO3 - The radical then attacks the β-carbon of allyl alcohol (CH2=CH-CH2OH) (undergoing anti-Markovnikov nucleophilic addition) to generate a more stable secondary carbon radical intermediate; subsequently, the secondary carbon radical intermediate loses a single electron to form a sulfonic acid allyl cation, which is then reacted with HSO3 in the system. - SO3 2- Nucleophilic attack generates sodium β-sulfonate intermediate, which is further hydrolyzed to generate sodium 3-hydroxypropanesulfonate.

[0043] Among them, phthalocyanine catalysts pass through a metal center (Co) 2+ / Zn 2+ ) and sulfite (SO3) - The coordination of sulfite radicals (·SO3) directs their movement. - ) undergoes selective addition with allyl alcohol to generate a secondary carbon radical intermediate; while pyranium tetrafluoroborate catalysts induce HO bond cleavage by guiding hydrogen atom transfer to generate hydroxyl radicals, which are then used to directionally guide sulfite radicals (·SO3) - It undergoes selective addition with allyl alcohol (CH2=CH-CH2OH) to generate a secondary carbon radical intermediate.

[0044] In the embodiments of this application, in step S1, the mass concentration of the allyl alcohol solution is 50-70%, preferably 50%, 60% or 70%.

[0045] In the embodiments of this application, in step S1, the equivalence ratio of allyl alcohol, compound A and photocatalyst is 1:(1.01-1.2):(0.0001-0.001).

[0046] In this embodiment, in step S1, the visible light wavelength is preferably 400-700 nm, i.e., the red light band. This is beneficial for matching the maximum absorption peak of the photocatalyst and improving light energy utilization. The power of visible light irradiation is 5-50 mW·cm⁻¹. -2 The irradiation time (i.e., reaction time) is 3-4 hours, and the reaction temperature under visible light irradiation is 20-50℃.

[0047] S2, the sodium 3-hydroxypropanesulfonate obtained in step S1 is concentrated and then acidified to obtain 3-hydroxypropanesulfonic acid (HPS).

[0048] In the embodiments of this application, in step S2, hydrochloric acid solution or sulfuric acid solution is used for acidification treatment, the mass concentration of acid in the solution is 20-30%, and the amount of acid used is 1.5-3 eq.

[0049] In this embodiment of the application, in step S2, the acidification temperature is 60-80℃ and the acidification time is 1-2h.

[0050] S3. The HPS obtained in step S2 is post-processed and then concentrated to obtain HPS concentrate.

[0051] In this embodiment, step S3 specifically refers to concentrating the HPS, then adding an alcohol reagent for salting out, filtering, and retaining the filtrate. The alcohol reagent is methanol or ethanol, and the amount of alcohol reagent used is 3-6 times the volume of the allyl alcohol solution added in step S1.

[0052] In this embodiment of the application, in step S3, the salting-out treatment temperature is 10-30°C, and the water content of the HPS concentrate is 15-25%.

[0053] S4. The HPS concentrate obtained in step S3 is subjected to vacuum distillation to obtain 1,3-propanesulfonate lactone (1,3-PS).

[0054] In this embodiment of the application, in step S4, the temperature of vacuum distillation is 130-150°C, and the vacuum degree is less than or equal to 600Pa.

[0055] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0056] Example 1

[0057] Example 1 provides a method for the visible light-catalyzed radical-initiated synthesis of 1,3-propanesulfonate lactone, comprising the following steps:

[0058] S1, accurately weigh 142.9 g of allyl alcohol solution (70% mass concentration), 217.2 g of sodium bisulfite (99% purity), and 300 g of deionized water, mix thoroughly, heat to 45°C, and after the solution becomes clear, add 418.6 mg of TMP under light-protected conditions, stir well, and a blue mixed solution is obtained. Then, use a spectrophotometer with a wavelength of 420 nm and a power of 40 mW·cm⁻¹. -2 The aforementioned mixed solution was irradiated with visible light and reacted for 3.5 h. After catalysis, the solution became colorless, thus yielding sodium 3-hydroxypropanesulfonate.

[0059] S2, concentrate the sodium 3-hydroxypropanesulfonate obtained in step S1 to remove 280g of water, wait for the temperature of the liquid to drop to room temperature, add 390g of hydrochloric acid (mass concentration 30%) and stir at 50℃ for 1h to obtain HPS.

[0060] S3. Concentrate the HPS obtained in step S2 to remove 280g of water, then add 400mL of anhydrous ethanol, stir at 20℃ for 1h, filter, and concentrate the filtrate again to obtain HPS concentrate with a water content between 10-20%.

[0061] S4. The HPS concentrate obtained in step S3 was distilled under reduced pressure at a temperature of 135℃ and a vacuum degree of 300Pa to obtain 191.5g of 1,3-PS, with a yield of 91.1% and a purity greater than 99.0%.

[0062] In Example 1, the 1H NMR spectrum of the HPS concentrate prepared in step S3 is shown below. Figure 1 As shown, the gas phase (GC) spectrum of 1,3-PS prepared in step S4 is shown in [reference]. Figure 2 As shown.

[0063] Example 2

[0064] Example 2 provides a method for the visible light-catalyzed radical-initiated synthesis of 1,3-propanesulfonate lactone, comprising the following steps:

[0065] S1, accurately weigh 260.0 g of allyl alcohol solution (50% mass concentration), 260.5 g of sodium bisulfite (99% purity), and 420 g of deionized water, mix thoroughly, heat to 45°C, and after the solution becomes clear, add 732.1 mg of CoPSNa under light-protected conditions, stir well, and a blue mixed solution is obtained. Then, use a spectrophotometer with a wavelength of 533 nm and a power of 30 mW·cm⁻¹. -2 The aforementioned mixed solution was irradiated with visible light and reacted for 3.5 h. After catalysis, the solution became colorless, thus yielding sodium 3-hydroxypropanesulfonate.

[0066] S2, concentrate the sodium 3-hydroxypropanesulfonate obtained in step S1 to remove 380g of water, wait for the temperature of the liquid to drop to room temperature, add 420g of hydrochloric acid (mass concentration 30%) and stir at 50℃ for 1h to obtain HPS.

[0067] S3. Concentrate the HPS obtained in step S2 to remove 310g of water, then add 500mL of anhydrous ethanol, stir at 20℃ for 1h, filter, and concentrate the filtrate again to obtain HPS concentrate with a water content between 10-20%.

[0068] S4. The HPS concentrate obtained in step S3 was distilled under reduced pressure at a temperature of 144℃ and a vacuum degree of 400Pa to obtain 244g of 1,3-PS, with a yield of 89.2% and a purity greater than 99.0%.

[0069] Example 3

[0070] Example 3 provides a method for the visible light-catalyzed free radical-initiated synthesis of 1,3-propanesulfonate lactone, comprising the following steps:

[0071] S1, accurately weigh 142.9 g of allyl alcohol solution (70% mass concentration), 199.1 g of sodium bisulfite (99% purity), and 450 g of deionized water, mix thoroughly, heat to 45°C, and after the solution becomes clear, add 123.3 mg of CoPSNa under light-protected conditions, stir well, and a blue mixed solution is obtained. Then, use a spectrophotometer with a wavelength of 533 nm and a power of 20 mW·cm⁻¹. -2 The aforementioned mixed solution was irradiated with visible light and reacted for 3 hours. After catalysis, the solution became colorless, thus yielding sodium 3-hydroxypropanesulfonate.

[0072] S2, concentrate the sodium 3-hydroxypropanesulfonate obtained in step S1 to remove 370g of water, wait for the temperature of the liquid to drop to room temperature, add 313.5g of hydrochloric acid (mass concentration 30%) and stir at 50℃ for 1h to obtain HPS.

[0073] S3. Concentrate the HPS obtained in step S2 to remove 180g of water, then add 400mL of anhydrous ethanol, stir at 20℃ for 1h, filter, and concentrate the filtrate again to obtain HPS concentrate with a water content between 10-20%.

[0074] S4. The HPS concentrate obtained in step S3 was distilled under reduced pressure at a temperature of 140℃ and a vacuum degree of 400Pa to obtain 183.1g of 1,3-PS, with a yield of 87.1% and a purity greater than 99.0%.

[0075] Example 4

[0076] Example 4 provides a method for the visible light-catalyzed free radical-initiated synthesis of 1,3-propanesulfonate lactone, comprising the following steps:

[0077] S1, accurately weigh 214.3 g of allyl alcohol solution (70% mass concentration), 271.5 g of sodium bisulfite (99% purity), and 550 g of deionized water, mix thoroughly, heat to 45°C, and after the solution becomes clear, add 1.83 g of ZnPBSK under light-protected conditions, stir well, and a blue mixed solution is obtained. Then, use a spectrophotometer with a wavelength of 533 nm and a power of 20 mW·cm⁻¹. -2 The aforementioned mixed solution was irradiated with visible light and reacted for 3 hours. After catalysis, the solution became colorless, thus yielding sodium 3-hydroxypropanesulfonate.

[0078] S2, concentrate the sodium 3-hydroxypropanesulfonate obtained in step S1 to remove 470g of water, wait for the temperature of the liquid to drop to room temperature, add 470.1g of hydrochloric acid (mass concentration 30%) and stir at 50℃ for 1h to obtain HPS.

[0079] S3. Concentrate the HPS obtained in step S2 to remove 270g of water, then add 500mL of anhydrous ethanol, stir at 20℃ for 1h, filter, and concentrate the filtrate again to obtain HPS concentrate with a water content between 10-20%.

[0080] S4. The HPS concentrate obtained in step S3 was distilled under reduced pressure at a temperature of 140℃ and a vacuum degree of 400Pa to obtain 280.3g of 1,3-PS, with a yield of 88.9% and a purity greater than 99.0%.

[0081] Example 5

[0082] Example 5 provides a method for the visible light-catalyzed radical-initiated synthesis of 1,3-propanesulfonate lactone, comprising the following steps:

[0083] S1, accurately weigh 142.9 g of allyl alcohol solution (70% mass concentration), 122.2 g of sodium bisulfite (99% purity), and 96.7 g of sodium sulfite (98% purity) and mix them thoroughly with 500 g of deionized water (mix the sodium sulfite and water first, then add the sodium bisulfite to prevent clumping). Heat to 45°C, and after the solution becomes clear, add 343.1 mg of CoPSNa under light-protected conditions and stir until homogeneous to obtain a blue mixed solution. Then, use a spectrophotometer with a wavelength of 533 nm and a power of 20 mW·cm⁻¹. -2 The aforementioned mixed solution was irradiated with visible light and reacted for 4 hours. After catalysis, the solution became colorless, thus yielding sodium 3-hydroxypropanesulfonate.

[0084] S2, concentrate the sodium 3-hydroxypropanesulfonate obtained in step S1 to remove 420g of water, wait for the temperature of the liquid to drop to room temperature, add 363.5g of hydrochloric acid (mass concentration 30%) and stir at 50℃ for 1h to obtain HPS.

[0085] S3. Concentrate the HPS obtained in step S2 to remove 230g of water, then add 400mL of anhydrous ethanol, stir at 20℃ for 1h, filter, and concentrate the filtrate again to obtain HPS concentrate with a water content between 10-20%.

[0086] S4. The HPS concentrate obtained in step S3 was distilled under reduced pressure at a temperature of 140℃ and a vacuum degree of 400Pa to obtain 184.7g of 1,3-PS, with a yield of 88.9% and a purity greater than 99.0%.

[0087] In summary, this application provides a method for the visible light-catalyzed radical-initiated synthesis of 1,3-propanesulfonate lactone. Cobalt phthalocyanine, zinc phthalocyanine, and pyranium tetrafluoroborate compounds are selected as photocatalysts. The photocatalytic pathway replaces the traditional thermal decomposition pathway of peroxides to prepare sodium 3-hydroxypropanesulfonate. Sodium 3-hydroxypropanesulfonate is then acidified to obtain HPS, and finally, the HPS is distilled under reduced pressure to obtain 1,3-PS, with a yield exceeding 85%. This preparation method is not only fast, safe, and has few side reactions, but it is also environmentally friendly and energy-efficient, showing promising application prospects.

[0088] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for synthesizing 1,3-propanesulfonate lactone by visible light photocatalysis and free radical initiation, characterized in that, Includes the following steps: S1, Allyl alcohol solution, compound A, photocatalyst and water are mixed evenly to obtain a mixed solution, and the mixed solution is irradiated with visible light to initiate the reaction to generate sodium 3-hydroxypropanesulfonate; S2, the sodium 3-hydroxypropanesulfonate obtained in step S1 is concentrated and then acidified to obtain 3-hydroxypropanesulfonic acid. S3. The HPS obtained in step S2 is post-processed and then concentrated to obtain HPS concentrate. S4. The HPS concentrate obtained in step S3 is subjected to vacuum distillation to obtain 1,3-propanesulfonate lactone. Wherein, compound A is sodium bisulfite, or a mixture of sodium metabisulfite and sodium sulfite, or a mixture of sodium bisulfite and sodium sulfite; the photocatalyst is one of cobalt phthalocyanine compounds, zinc phthalocyanine compounds, or pyranium tetrafluoroborate compounds.

2. The method for synthesizing 1,3-propanesulfonate lactone by visible light photocatalysis and free radical initiation according to claim 1, characterized in that, The photocatalyst is at least one of CoPSNa, ZnPBSK, and TMP; the structural formula of CoPSNa is […]. The structural formula of ZnPBSK is as follows: The structural formula of the TMP is as follows:

3. The method for synthesizing 1,3-propanesulfonate lactone by visible light photocatalysis and free radical initiation according to claim 1, characterized in that, In step S1, the mass concentration of the allyl alcohol solution is 50-70%.

4. The method for synthesizing 1,3-propanesulfonate lactone by visible light photocatalysis and free radical initiation according to claim 1, characterized in that, In step S1, the equivalence ratio of the allyl alcohol, compound A and the photocatalyst is 1:(1.01-1.2):(0.0001-0.001).

5. The method for synthesizing 1,3-propanesulfonate lactone by visible light photocatalysis and free radical initiation according to claim 1, characterized in that, In step S1, the visible light wavelength is 400-700 nm, and the visible light irradiation power is 5-50 mW·cm⁻¹. -2 The irradiation time is 3-4 hours, and the reaction temperature under visible light irradiation is 20-50℃.

6. The method for synthesizing 1,3-propanesulfonate lactone by visible light photocatalysis and free radical initiation according to claim 1, characterized in that, In step S2, acidification is performed using hydrochloric acid solution or sulfuric acid solution, with the mass concentration of acid in the solution being 20-30% and the amount of acid used being 1.5-3 eq.

7. The method for synthesizing 1,3-propanesulfonate lactone by visible light photocatalysis and free radical initiation according to claim 6, characterized in that, In step S2, the acidification treatment temperature is 60-80℃, and the acidification treatment time is 1-2 hours.

8. The method for synthesizing 1,3-propanesulfonate lactone by visible light photocatalysis and free radical initiation according to claim 1, characterized in that, In step S3, the post-processing specifically refers to first concentrating the HPS, then adding an alcohol reagent for salting out, filtering, and retaining the filtrate; the alcohol reagent is methanol or ethanol, and the amount of the alcohol reagent is 3-6 times the volume of the allyl alcohol solution added in step S1.

9. The method for synthesizing 1,3-propanesulfonate lactone by visible light photocatalysis and free radical initiation according to claim 8, characterized in that, In step S3, the salting-out treatment temperature is 10-30℃; the water content of the HPS concentrate is 15-25%.

10. The method for synthesizing 1,3-propanesulfonate lactone by visible light photocatalysis and free radical initiation according to claim 1, characterized in that, In step S4, the temperature of the vacuum distillation is 130-150℃, and the vacuum degree is less than or equal to 600Pa.

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