Polydithiodipropane sulfonate and preparation method thereof

Abstract

The invention relates to the technical field of organic matter synthesis, in particular to polydithiodipropane sulfonate and a preparation method thereof. The preparation method comprises the following steps: mixing a thiourea source, propane sultone and a solvent at the temperature of 35-65 DEG C, and carrying out ring-opening reaction to prepare isothiourea propane sulfonic acid inner salt; the method comprises the following steps: mixing isothiourea propane sulfonic acid inner salt and an alkali metal hydroxide solution, and carrying out alkaline hydrolysis reaction at 40-100 DEG C to prepare alkali metal salt of 3-mercaptopropane sulfonic acid; the ratio of the mole number of alkali metal hydroxide contained in the alkali metal hydroxide solution to the mole number of the isothiourea propane sulfonic acid inner salt is (2.1-2.5): 1; the method comprises the following steps: adding an oxidizing agent into alkali metal salt of 3-mercaptopropane sulfonic acid, and carrying out oxidation reaction at 15-35 DEG C to prepare the polydithiodipropane sulfonate. The preparation method provided by the invention has the advantages of low preparation temperature, effective reduction of side reactions, safety, and high yield and purity.

Description

Technical Field

[0001] The present application relates to the technical field of organic synthesis, and in particular to a polydipropane disulfide sulfonate and a preparation method thereof. Background Art

[0002] In acid copper electroplating, brighteners are substances that can reduce cathode polarization and accelerate the reduction deposition rate of copper ions. Among them, polydipropylene disulfide sulfonate, especially sodium polydipropylene disulfide sulfonate (SPS), is a copper plating brightener widely used in copper plating of printed circuit boards and acid copper plating.

[0003] At present, the main synthesis methods of poly (sodium disulfide propane sulfonate) are as follows: (1) Using hydrogen sulfide or sodium hydrosulfide and propane sultone as raw materials, the reaction generates sodium 3-mercaptopropane sulfonate (MPS), and then converting MPS into SPS by adding oxidants such as bromine water, iodine, and peroxide. The raw materials used in this synthesis involve highly toxic hydrogen sulfide gas during the preparation process, which poses a high safety hazard. (2) Sodium thiosulfate and propane sultone generate the corresponding pentasulfate, which is then hydrolyzed under acidic or alkaline conditions, and finally an oxidant is added to react to generate SPS. The oxidation reaction temperature used in this method is relatively high (≥55°C), and the hydrolysis process is accompanied by the production of an equimolar ratio of sodium sulfate, resulting in a low yield and purity of SPS. (3) Sodium sulfide and sulfur powder generate sodium persulfide, which is then added to propane sultone to react to obtain SPS. This method produces polysulfide side reaction products, which affect product performance. Summary of the invention

[0004] Based on this, the present application provides a polydipropane disulfide sulfonate and a preparation method thereof. The preparation method of the polydipropane disulfide sulfonate provided in the present application has a lower preparation temperature, can effectively reduce the occurrence of side reactions, and has the advantages of safety, high yield and purity.

[0005] In a first aspect of the present application, a method for preparing polydipropane disulfide sulfonate is provided, comprising the following steps:

[0006] The thiourea source, propane sultone and a solvent are mixed at a temperature of 35°C to 65°C to carry out a ring-opening reaction to prepare isothiourea propane sultone;

[0007] The isothiourea propane sulfonic acid inner salt and an alkali metal hydroxide solution are mixed, and an alkaline hydrolysis reaction is carried out at a temperature of 40° C. to 100° C. to prepare an alkali metal salt of 3-mercaptopropane sulfonic acid; the molar ratio of the alkali metal hydroxide in the alkali metal hydroxide solution to the molar ratio of the isothiourea propane sulfonic acid inner salt is (2.1 to 2.5): 1;

[0008] An oxidant is added to the alkali metal salt of 3-mercaptopropane sulfonic acid, and an oxidation reaction is carried out at a temperature of 15° C. to 35° C. to prepare the polydisulfide dipropane sulfonate. In one embodiment, after the oxidation reaction is completed, the preparation method further includes:

[0009] The crude product obtained by the oxidation reaction is mixed with a recrystallization solvent at a temperature of 50° C. to 70° C., cooled to room temperature, and the precipitated solid is collected to prepare the polydisulfide dipropane sulfonate.

[0010] In one embodiment, the step of preparing isothiourea propane sulfonic acid inner salt has one or more of the following characteristics:

[0011] (1) The molar ratio of the thiourea source to the propane sultone is 1:(1-1.15);

[0012] (2) The solvent includes one or more of methanol, ethanol, isopropanol and tert-butanol.

[0013] In one embodiment, the step of mixing a thiourea source, propane sultone and a solvent at a temperature of 35° C. to 65° C. and performing a ring-opening reaction comprises:

[0014] Dissolving the thiourea source in the solvent at a temperature of 35° C. to 65° C. to prepare an intermediate solution;

[0015] Adding the propane sultone into the intermediate solution in batches, and performing a ring-opening reaction at a temperature of 35° C. to 65° C. to prepare the isothiourea propane sulfonic acid inner salt;

[0016] The batch addition time of the propane sultone is 1.5 h to 2.5 h, and the ring-opening reaction time is 4 h to 6 h.

[0017] In one embodiment, the step of preparing the alkali metal salt of 3-mercaptopropane sulfonic acid has one or more of the following characteristics:

[0018] (1) The alkali metal hydroxide solution includes one or more of a sodium hydroxide solution and a potassium hydroxide solution;

[0019] (2) The alkaline hydrolysis reaction time is 1h~4h.

[0020] In one embodiment, an oxidant is added to the alkali metal salt of 3-mercaptopropane sulfonic acid, and an oxidation reaction is carried out at a temperature of 15° C. to 35° C. The step of preparing the polydisulfide dipropane sulfonate has one or more of the following characteristics:

[0021] (1) The oxidant includes one or more of air, oxygen and hydrogen peroxide;

[0022] (2) The oxidation reaction time is 2h~4h;

[0023] (3) The poly(dipropane disulfide sulfonate) comprises one or more of sodium poly(dipropane disulfide sulfonate) and potassium poly(dipropane disulfide sulfonate).

[0024] In one embodiment, the preparation method has one or more of the following characteristics:

[0025] (1) The recrystallization reagent includes one or more of methanol, ethanol, isopropanol, acetonitrile, N,N-dimethylformamide and dimethyl sulfoxide;

[0026] (2) The step of mixing the crude product obtained from the oxidation reaction with a recrystallization solvent at a temperature of 50° C. to 70° C. comprises: adding the recrystallization reagent to the crude product obtained from the oxidation reaction in batches at a temperature of 50° C. to 70° C., mixing, and stirring for 1.5 h to 2.5 h.

[0027] In one embodiment, the thiourea source includes one or more of thiourea, tetramethylthiourea, 1,3-diethylthiourea and guanylthiourea.

[0028] In one embodiment, the preparation method has one or more of the following characteristics:

[0029] (1) The isothiourea propane sulfonic acid inner salt comprises , , and One or more of;

[0030] (2) The anion of the alkali metal salt of 3-mercaptopropane sulfonic acid is .

[0031] In a second aspect of the present application, there is provided a poly(dipropane disulfide sulfonate) prepared by the preparation method described in any one of the embodiments of the first aspect of the present application, wherein the purity of the poly(dipropane disulfide sulfonate) is ≥98.5%.

[0032] The beneficial effects of the preparation method of polydisulfide dipropane sulfonate provided in the present application include at least:

[0033] In the preparation method of polydisulfide propane sulfonate provided in the present application, thiourea source and propane sultone are first selected as reaction raw materials, and inorganic substances such as hydrogen sulfide are not selected, so the preparation method has the advantage of relative safety. Further, the thiourea source, propane sultone and solvent are mixed at a temperature of 35°C to 65°C and a ring-opening reaction is carried out, which is conducive to controlling the reaction rate and avoiding the generation of by-products. Alkali metal hydroxide is selected, and it is directed to generate an alkali metal salt of 3-mercaptopropane sulfonic acid with isothiourea propane sulfonic acid inner salt. In this step, the molar number of alkali metal hydroxide and isothiourea propane sulfonic acid inner salt is limited, so that one molecule of isothiourea propane sulfonic acid inner salt can first undergo a neutralization reaction with one molecule of sodium hydroxide to become an alkali metal salt of isothiourea propane sulfonic acid, and then react with another molecule of sodium hydroxide to form 3-mercaptopropane sulfonate, ensuring that the reaction is fully carried out. Further carrying out the oxidation reaction at a low temperature of 15°C to 35°C can improve the selectivity of the oxidation reaction and reduce the generation of other by-products caused by excessive oxidation due to excessive temperature.

[0034] In summary, the preparation method of polydipropane disulfide sulfonate provided in the present application has a lower preparation temperature, can effectively reduce the occurrence of side reactions, and has the advantages of safety, high yield and purity. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The present invention provides a flow chart of the method for preparing polydipropane disulfide sulfonate. DETAILED DESCRIPTION

[0036] The following is a further complete and clear description of the polydipropane disulfide sulfonate and the preparation method thereof of the present application in conjunction with specific examples. The present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0037] Polydipropane disulfide sulfonate mainly includes potassium polydipropane disulfide sulfonate and sodium polydipropane disulfide sulfonate. The molecular formula of potassium polydipropane disulfide sulfonate is C6H 12 K2O6S4, the structural formula is .

[0038] Poly(disulfide dipropane sulfonate) Sodium 12 Na2O6S4, the structural formula is , is a white to light yellow solid powder, mainly used as a brightener in copper plating solutions.

[0039] The main synthesis methods of poly(sodium disulfide propane sulfonate) are as follows: (1) Inorganic substances such as hydrogen sulfide or sodium hydrosulfide are used as raw materials to react with propane sultone to generate sodium 3-mercaptopropane sulfonate (MPS), and then MPS is converted into SPS by adding oxidants such as bromine water, iodine, and peroxide. The raw materials used in this synthesis involve highly toxic hydrogen sulfide gas during the preparation process, which poses a high safety hazard. (2) Sodium thiosulfate and propane sultone generate the corresponding pentasulfate, which is then hydrolyzed under acidic or alkaline conditions, and finally an oxidant is added to react to generate SPS. The oxidation reaction temperature used in this method is relatively high (≥55°C), and the hydrolysis process is accompanied by the production of an equimolar ratio of sodium sulfate, resulting in a low yield and purity of SPS. (3) Sodium sulfide and sulfur powder are used to generate sodium persulfide, which is then reacted with propane sultone to prepare SPS; this method is prone to generate polysulfide side reaction products, and an additional by-product removal step is required to improve the product purity.

[0040] In the related art, there is another preparation method with the following steps: (I) thiourea and propane sultone are reacted to form isothiourea propane sulfonate; (II) 3-mercaptopropane sulfonate ammonium is obtained by alkaline hydrolysis in aqueous ammonia; (III) 3-mercaptopropane sulfonate ammonium is then recrystallized in a solvent of chloroform and alcohol; (IV) the purified ammonium salt is then subjected to ion exchange to obtain 3-mercaptopropane sulfonic acid, and finally oxidized under alkaline conditions to obtain SPS. In this preparation method, due to the use of excessive thiourea in step (I), the residual thiourea reacts with the aqueous ammonia in step (II). Side reactions occur, and isothiourea propanesulfonic acid inner salt and thiourea also have side reactions such as urea and excess ammonia produced by hydrolysis in concentrated ammonia. Due to the occurrence of the above side reactions, resins are needed for impurity removal and ion replacement, but the ion exchange step requires a large amount of water, and the subsequent evaporation of water consumes a lot of energy; and the used resins also need to be post-processed (such as discarding or recycling and regenerating with acid, etc.). In addition, the use of chloroform for recrystallization in step (IV) also has certain risks.

[0041] The above preparation method has the problems of low purity, complicated process and unsafe and environmentally unfriendly poly(sodium disulfide dipropane sulfonate).

[0042] See also Figure 1 In the first aspect of the present application, a method for preparing polydipropane disulfide sulfonate is provided, comprising the following steps:

[0043] S10, mixing a thiourea source, propane sultone and a solvent at a temperature of 35° C. to 65° C., and performing a ring-opening reaction to prepare isothiourea propane sulfonic acid inner salt;

[0044] S20, mixing the isothioureapropanesulfonic acid inner salt and an alkali metal hydroxide solution, and performing an alkaline hydrolysis reaction at a temperature of 40° C. to 100° C. to prepare an alkali metal salt of 3-mercaptopropanesulfonic acid;

[0045] S30, adding an oxidant to the alkali metal salt of 3-mercaptopropane sulfonic acid, and performing an oxidation reaction at a temperature of 15° C. to 35° C. to prepare the polydisulfide propane sulfonate.

[0046] It can be understood that in step S10, the temperature of the mixing and the ring-opening reaction is independently selected from any value of 35° C. to 65° C. Further, the temperature of the mixing and the ring-opening reaction includes but is not limited to 35° C., 38° C., 40° C., 43° C., 45° C., 48° C., 49° C., 50° C., 51° C., 52° C., 53° C., 54° C., 58° C., 60° C., 63° C. or 65° C.

[0047] Furthermore, the temperature of the mixing and the ring-opening reaction is independently selected from any value of 45° C. to 55° C. Based on a lot of creative work, the inventors of the present application found that the thiourea source and propane sultone have high requirements for the reaction temperature, and the temperature of the mixing and the ring-opening reaction is further limited to 45° C. to 55° C. At this time, the collision frequency between the reactant molecules is high, which is conducive to the formation of isothiourea propane sulfonic acid inner salt and can improve the conversion rate of isothiourea propane sulfonic acid inner salt.

[0048] In one example, in step S10, the molar ratio of the thiourea source to the propane sultone is 1:(1~1.15). In the present application, the moles of the thiourea source and the propane sultone are limited, wherein the mole number of propane sultone is ≥ the mole number of the thiourea source, which can maximize the use of reactants, avoid the excess of thiourea source as much as possible, and thus reduce the side reactions caused by the thiourea source in subsequent steps. It can be understood that in step S10, the molar ratio of the thiourea source to the propane sultone includes but is not limited to 1:1, 1:1.02, 1:1.04, 1:1.05, 1:1.07, 1:1.09, 1:1.1, 1:1.11, 1:1.12, 1:1.13, 1:1.14 or 1:1.15.

[0049] In one example, in step S10, the molar volume ratio of the thiourea source and the solvent is 1 mol: (300-400) mL. Further, in step S10, the molar volume ratio of the thiourea source and the solvent includes but is not limited to 1 mol: 300 mL, 1 mol: 310 mL, 1 mol: 320 mL, 1 mol: 330 mL, 1 mol: 340 mL, 1 mol: 350 mL, 1 mol: 360 mL, 1 mol: 370 mL, 1 mol: 380 mL, 1 mol: 390 mL or 1 mol: 400 mL.

[0050] In one example, in step S10, the solvent includes one or more of methanol, ethanol, isopropanol and tert-butanol.

[0051] In one example, in step S10, the step of mixing the thiourea source, propane sultone and the solvent at a temperature of 35° C. to 65° C. and performing a ring-opening reaction includes:

[0052] a1. Dissolving the thiourea source in the solvent at a temperature of 35° C. to 65° C. to prepare an intermediate solution;

[0053] a2. Adding the propane sultone into the intermediate solution in batches, carrying out a ring-opening reaction at a temperature of 35° C. to 65° C., to prepare the isothiourea propane sulfonic acid inner salt.

[0054] Wherein, in step a1, the batch addition time of the propane sultone is 1.5h~2.5h. For example, the batch addition method includes but is not limited to dripping. By controlling the time of batch addition, propane sultone can be gradually added to the solution of the thiourea source, thereby ensuring that the reactants are evenly mixed. This can avoid the one-time addition of a large amount of propane sultone causing the local reaction to be too intense, thereby controlling the reaction rate and making it more uniform. Further, the batch addition time of the propane sultone includes but is not limited to 1.5h, 1.6h, 1.7h, 1.8h, 1.9h, 2h, 2.1h, 2.2h, 2.3h, 2.4h or 2.5h.

[0055] Wherein, in step a1, the time of the ring-opening reaction is 4 h to 6 h. It can be understood that the time of the ring-opening reaction includes but is not limited to 4 h, 4.1 h, 4.5 h, 4.7 h, 4.9 h, 5 h, 5.2 h, 5.5 h, 5.8 h or 6 h.

[0056] For example, in step S10, the thiourea source includes thiourea ( )、Tetramethylthiourea( )、1,3-diethylthiourea( ) and guanidine thiourea ( )

[0057] For example, in step S10, the isothiourea propane sulfonic acid inner salt comprises , , and One or more of .

[0058] For example, when the thiourea source is thiourea, the isothiourea propane sulfonic acid inner salt is At this time, the reaction formula of step S10 is

[0059] .

[0060] For example, when the thiourea source is tetramethylthiourea, the isothiourea propane sulfonic acid inner salt is At this time, the reaction formula of step S10 is

[0061] .

[0062] For example, when the thiourea source is 1,3-diethylthiourea, the isothiourea propane sulfonic acid inner salt is At this time, the reaction formula of step S10 is

[0063] .

[0064] For example, when the thiourea source is guanidine thiourea, the isothiourea propane sulfonic acid inner salt is At this time, the reaction formula of step S10 is .

[0065] In one example, in step S20, the alkali metal hydroxide solution includes one or more of a sodium hydroxide solution and a potassium hydroxide solution.

[0066] In one example, in step S20, the molar ratio of the alkali metal hydroxide in the alkali metal hydroxide solution to the isothiourea propane sulfonic acid inner salt is (1.5-2.5):1. Alkali metal hydroxides within this molar ratio range can effectively hydrolyze -SC(=N)- groups to -SH. In step S20, the molar ratio of the alkali metal hydroxide in the alkali metal hydroxide solution to the isothiourea propane sulfonic acid inner salt includes but is not limited to 1.5:1, 1.6:1, 1.7:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.23:1, 2.25:1, 2.28:1, 2.3:1, 2.4:1 or 2.5:1.

[0067] In one example, in step S20, the alkaline hydrolysis reaction time is 1 h to 4 h. Further, the alkaline hydrolysis reaction time includes but is not limited to 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h or 4 h.

[0068] In one example, in step S20, the isothiourea propane sulfonic acid inner salt and the alkali metal hydroxide solution are mixed and subjected to alkaline hydrolysis reaction at a temperature of 40° C. to 100° C. The step of preparing the alkali metal salt of 3-mercaptopropane sulfonic acid includes:

[0069] b1, mixing the alkali metal hydroxide in an aqueous solution to prepare an alkali metal hydroxide solution;

[0070] b2. Adding the isothiourea propane sulfonic acid inner salt to the alkali metal hydroxide solution at a temperature of 30° C. to 50° C. to prepare a mixed solution;

[0071] b3. subjecting the mixed solution to alkaline hydrolysis at a temperature of 40° C. to 100° C. to prepare an alkali metal salt of 3-mercaptopropane sulfonic acid.

[0072] It can be understood that in step S30, the temperature for the oxidation reaction can be selected from any value between 15° C. and 35° C. Further, the temperature for the oxidation reaction includes but is not limited to 15° C., 18° C., 20° C., 25° C., 28° C., 30° C., 33° C. or 35° C.

[0073] In the present application, the oxidation reaction is carried out at 15°C to 35°C, which is close to room temperature, which is conducive to simplifying the preparation process, reducing energy consumption, and facilitating the industrial production of polydipropane disulfide sulfonate.

[0074] It is understandable that the anion of the alkali metal salt of 3-mercaptopropane sulfonic acid is When the alkali metal hydroxide solution is sodium hydroxide, the cation of the alkali metal salt of 3-mercaptopropane sulfonic acid is Na + At this time, the alkali metal salt of 3-mercaptopropane sulfonic acid is sodium 3-mercaptopropane sulfonate.

[0075] When the alkali metal hydroxide solution selected is potassium hydroxide, the cation of the alkali metal salt of 3-mercaptopropane sulfonic acid is K + At this time, the alkali metal salt of 3-mercaptopropane sulfonic acid is potassium 3-mercaptopropane sulfonate.

[0076] In one example, in step S30, the oxidant includes one or more of air, oxygen and hydrogen peroxide.

[0077] Preferably, in step S30, the oxidant includes hydrogen peroxide.

[0078] More preferably, in step S30, the oxidant includes hydrogen peroxide with a mass concentration of 8% to 20%.

[0079] In one example, in step S30, the oxidation reaction time is 2h~4h. Further, the oxidation reaction time includes but is not limited to 2h, 2.2h, 2.h, 2.7h, 3h, 3.2h, 3.5h, 3.8h or 4h.

[0080] In one example, in step S30, an oxidant is added to the alkali metal salt of 3-mercaptopropane sulfonic acid, and an oxidation reaction is carried out at a temperature of 15° C. to 35° C. The steps of preparing the polydisulfide dipropane sulfonate include:

[0081] c1. Adding the oxidant to the alkali metal salt of 3-mercaptopropane sulfonic acid in batches at a temperature of 15° C. to 35° C., and then performing an oxidation reaction at a temperature of 15° C. to 35° C. for 2 h to 4 h to prepare the polydisulfide propane sulfonate.

[0082] In step c1, the oxidant is added in batches at a temperature of 15°C to 35°C for a period of 0.8h to 1.5h. For example, the manner of adding in batches includes, but is not limited to, dropwise addition. Further, the oxidant is added in batches at a temperature of 15°C to 35°C for a period of, but is not limited to, 0.8h, 0.9h, 1h, 1.1h, 1.2h, 1.3h, 1.4h or 1.5h.

[0083] In one example, after the oxidation reaction is completed, the preparation method further comprises:

[0084] S40, mixing the crude product obtained by the oxidation reaction with a recrystallization solvent at a temperature of 50° C. to 70° C., cooling to room temperature, and collecting the precipitated solid to prepare the poly(dipropane disulfide sulfonate).

[0085] It is understandable that in step S40, due to the oxidant added in the aforementioned step S30, or the product is not dried in the aforementioned step, the polydipropane disulfide sulfonate will be present in the solution. At this time, if the concentration of the polydipropane disulfide sulfonate in the polydipropane disulfide sulfonate solution is low, the polydipropane disulfide sulfonate solution can be concentrated before step S40. Preferably, the mass concentration of the polydipropane disulfide sulfonate in the polydipropane disulfide sulfonate solution is 45% to 50%. The way of concentration includes but is not limited to evaporation under reduced pressure.

[0086] In one example, in step S40, the recrystallization reagent includes one or more of methanol, ethanol, isopropanol, acetonitrile, N,N-dimethylformamide and dimethyl sulfoxide.

[0087] In one example, in step S40, the recrystallization reagent is added in batches to the crude product obtained by the oxidation reaction at a temperature of 50° C. to 70° C., stirred for 1.5 h to 2.5 h, cooled to room temperature, and filtered to obtain the polydisulfide dipropane sulfonate.

[0088] It can be understood that in step S40, the temperature for mixing can be selected from any value between 50° C. and 70° C. Further, in step S40, the temperature for mixing includes but is not limited to 50° C., 52° C., 55° C., 58° C., 60° C., 62° C., 65° C., 68° C. or 70° C.

[0089] In one specific example, the preparation method of polydipropane disulfide sulfonate comprises the following steps:

[0090] (1) Dissolving the thiourea source in the solvent at a temperature of 35° C. to 65° C., wherein the molar volume ratio of the thiourea source to the solvent is 1 mol: (300-400) mL, to prepare an intermediate solution.

[0091] (2) Adding the propane sultone to the intermediate solution in batches so that the molar ratio of the thiourea source to the propane sultone is 1:(1-1.15), and the batch addition time is 1.5h-2.5h; performing a ring-opening reaction at a temperature of 35°C-65°C for 4h-6h to prepare the isothiourea propane sulfonic acid salt.

[0092] (3) The alkali metal hydroxide is mixed with an aqueous solution to prepare an alkali metal hydroxide solution.

[0093] (4) adding the isothiourea propane sulfonic acid inner salt to the alkali metal hydroxide solution at a temperature of 30° C. to 50° C. so that the molar ratio of the alkali metal hydroxide in the alkali metal hydroxide solution to the molar ratio of the isothiourea propane sulfonic acid inner salt is (1.5 to 2.5):1, to prepare a mixed solution.

[0094] (5) subjecting the mixed solution to an alkaline hydrolysis reaction at a temperature of 40° C. to 100° C. for 1 h to 4 h to prepare an alkali metal salt of 3-mercaptopropane sulfonic acid.

[0095] (6) The oxidant is added to the alkali metal salt of 3-mercaptopropane sulfonic acid in batches at a temperature of 15° C. to 35° C., and then an oxidation reaction is carried out at a temperature of 15° C. to 35° C. for 2 h to 4 h to prepare a crude product.

[0096] (7) Adding the recrystallization reagent to the crude product in batches at a temperature of 50° C. to 70° C., stirring for 1.5 h to 2.5 h, cooling to room temperature, and filtering to obtain the poly(disulfide dipropane sulfonate).

[0097] In one example, the polydipropane disulfide sulfonate includes one or more of sodium polydipropane disulfide sulfonate and potassium polydipropane disulfide sulfonate.

[0098] It can be understood that in the present application, when the alkali metal hydroxide solution selected is sodium hydroxide solution, the alkali metal salt of 3-mercaptopropane sulfonic acid is sodium 3-mercaptopropane sulfonate, and the corresponding polydisulfide propane sulfonate is sodium polydisulfide propane sulfonate.

[0099] For example, the preparation method of the poly(sodium disulfide dipropane sulfonate) comprises the following steps:

[0100] (1) Dissolving the thiourea source in the solvent at a temperature of 35° C. to 65° C., wherein the molar volume ratio of the thiourea source to the solvent is 1 mol: (300-400) mL, to prepare an intermediate solution.

[0101] (2) Adding the propane sultone to the intermediate solution in batches so that the molar ratio of the thiourea source to the propane sultone is 1:(1-1.15), and the batch addition time is 1.5h-2.5h; performing a ring-opening reaction at a temperature of 35°C-65°C for 4h-6h to prepare the isothiourea propane sulfonic acid salt.

[0102] (3) Mix sodium hydroxide with an aqueous solution to prepare a sodium hydroxide solution.

[0103] (4) adding the isothiourea propane sulfonic acid inner salt to the sodium hydroxide solution at a temperature of 30° C. to 50° C. so that the molar ratio of the sodium hydroxide in the sodium hydroxide solution to the molar ratio of the isothiourea propane sulfonic acid inner salt is (1.5 to 2.5):1, to prepare a mixed solution.

[0104] (5) subjecting the mixed solution to an alkaline hydrolysis reaction at a temperature of 40° C. to 100° C. for 1 h to 4 h to prepare sodium 3-mercaptopropane sulfonate.

[0105] (6) The oxidant is added to the sodium 3-mercaptopropane sulfonate in batches at a temperature of 15° C. to 35° C., and then an oxidation reaction is carried out at a temperature of 15° C. to 35° C. for 2 h to 4 h to prepare a crude product.

[0106] (7) Adding the recrystallization reagent to the crude product in batches at a temperature of 50° C. to 70° C., stirring for 1.5 h to 2.5 h, cooling to room temperature, and filtering to obtain the sodium polydisulfide dipropane sulfonate.

[0107] It can be understood that in the present application, when the alkali metal hydroxide solution selected is potassium hydroxide solution, the alkali metal salt of 3-mercaptopropane sulfonic acid is potassium 3-mercaptopropane sulfonate, and the corresponding polydisulfide propane sulfonate is potassium polydisulfide propane sulfonate.

[0108] For example, the preparation method of the poly (disulfide dipropane sulfonate potassium) comprises the following steps:

[0109] (1) Dissolving the thiourea source in the solvent at a temperature of 35° C. to 65° C., wherein the molar volume ratio of the thiourea source to the solvent is 1 mol: (300-400) mL, to prepare an intermediate solution.

[0110] (2) Adding the propane sultone to the intermediate solution in batches so that the molar ratio of the thiourea source to the propane sultone is 1:(1-1.15), and the batch addition time is 1.5h-2.5h; performing a ring-opening reaction at a temperature of 35°C-65°C for 4h-6h to prepare the isothiourea propane sulfonic acid salt.

[0111] (3) Potassium hydroxide is mixed with an aqueous solution to prepare a potassium hydroxide solution.

[0112] (4) adding the isothiourea propane sulfonic acid inner salt to the potassium hydroxide solution at a temperature of 30° C. to 50° C. so that the molar ratio of potassium hydroxide in the potassium hydroxide solution to the molar ratio of the isothiourea propane sulfonic acid inner salt is (1.5 to 2.5):1, to prepare a mixed solution.

[0113] (5) subjecting the mixed solution to an alkaline hydrolysis reaction at a temperature of 40° C. to 100° C. for 1 h to 4 h to prepare potassium 3-mercaptopropane sulfonate.

[0114] (6) The oxidant is added to the potassium 3-mercaptopropane sulfonate in batches at a temperature of 15° C. to 35° C., and then an oxidation reaction is carried out at a temperature of 15° C. to 35° C. for 2 h to 4 h to prepare a crude product.

[0115] (7) Adding the recrystallization reagent to the crude product in batches at a temperature of 50° C. to 70° C., stirring for 1.5 h to 2.5 h, cooling to room temperature, and filtering to obtain the potassium polydisulfide dipropane sulfonate.

[0116] In a second aspect of the present application, there is provided a polydipropane disulfide sulfonate, which is prepared by the preparation method described in any example of the first aspect of the present application.

[0117] The sodium polydipropane disulfide sulfonate prepared by the preparation method of the present application has a high purity of ≥98.5%. Furthermore, the sodium polydipropane disulfide sulfonate has a purity of ≥99%.

[0118] In one example, the polydipropane disulfide sulfonate includes one or more of sodium polydipropane disulfide sulfonate and potassium polydipropane disulfide sulfonate.

[0119] It can be understood that in the present application, when the alkali metal hydroxide solution selected is sodium hydroxide solution, the alkali metal salt of 3-mercaptopropane sulfonic acid is sodium 3-mercaptopropane sulfonate, and the corresponding polydisulfide propane sulfonate is sodium polydisulfide propane sulfonate. It can be understood that in the present application, when the alkali metal hydroxide solution selected is potassium hydroxide solution, the alkali metal salt of 3-mercaptopropane sulfonic acid is potassium 3-mercaptopropane sulfonate, and the corresponding polydisulfide propane sulfonate is potassium polydisulfide propane sulfonate.

[0120] The third aspect of the present application provides a brightener, comprising the sodium polydisulfide dipropane sulfonate described in the second aspect of the present application.

[0121] The following further specific examples are provided to explain the present application in detail. It should also be understood that the following examples are only used to further explain the present application and cannot be understood as limiting the scope of protection of the present application. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present application belong to the scope of protection of the present application. The specific process parameters of the following embodiments are also only examples within a suitable range, that is, those skilled in the art can make a selection within a suitable range through the description herein, and are not necessarily limited to the specific values ​​of the embodiments below.

[0122] Example 1

[0123] The preparation method of poly sodium disulfide propane sulfonate comprises the following steps:

[0124] (1) Preparation of isothiourea propane sulfonic acid inner salt:

[0125] In a four-necked round-bottom flask equipped with a dropping funnel, a reflux condenser, and a thermometer, thiourea (114 g, 1.50 mol) and 500 mL of methanol were added to the round-bottom flask, heated and stirred at 50 ° C to completely dissolve the thiourea solid and prepare an intermediate solution; propane sultone (192 g, 1.57 mol) was added to the dropping funnel, and the dripping speed was controlled to slowly drip propane sultone for about 2 hours, and the ring-opening reaction was continued at 50 ° C for 5 hours, during which white solids were observed to precipitate continuously. The reaction was completed and cooled to room temperature, and then filtered to obtain a white solid, which was dried to obtain isothiourea propane sulfonic acid salt (280.0 g, yield 94.3%), which can be carried out without further purification.

[0126] (2) Preparation of sodium 3-mercaptopropane sulfonate:

[0127] In a four-necked round-bottom flask equipped with a dropping funnel, a reflux condenser, and a thermometer, sodium hydroxide (90 g, 2.25 mol) and 300 mL are added to the round-bottom flask to completely dissolve the sodium hydroxide to prepare a sodium hydroxide solution. At a temperature of about 40° C., the isothiourea propane sulfonic acid inner salt (198 g, 1 mol) prepared in step (1) is added to the sodium hydroxide solution to prepare a mixed solution. The mixed solution is subjected to an alkaline hydrolysis reaction at a temperature of 70° C. for 3 h to prepare a sodium 3-mercaptopropane sulfonate solution.

[0128] (3) Preparation of sodium polydisulfide propane sulfonate solution:

[0129] The sodium 3-mercaptopropane sulfonate solution prepared in step (2) was cooled to 25° C., 170 g of 10% hydrogen peroxide was added to the dropping funnel, the dropping speed was controlled to be slow, the dropping was completed in 1 hour, and then an oxidation reaction was carried out at a temperature of 25° C. for 2 hours to prepare the sodium polydisulfide propane sulfonate solution.

[0130] (4) Purification of sodium polydisulfide propane sulfonate:

[0131] The sodium polydisulfide dipropane sulfonate solution of step (3) was evaporated under reduced pressure to remove part of the water and concentrated into an aqueous solution of about 50%, and then heated to 60°C, 900 mL of ethanol was gradually added dropwise, stirred for 2 hours after the addition was completed, cooled to room temperature, filtered, and the purified sodium polydisulfide dipropane sulfonate was prepared; the structure of the sodium polydisulfide dipropane sulfonate was shown by nuclear magnetic hydrogen spectrum: ( 1 H NMR (400 MHz, Deuterium Oxide) δ 3.13 –3.06 (m, 4H), 2.93 (t, J = 7.0 Hz, 4H), 2.27 – 2.16 (m, 4H). The mass of the purified poly(sodium disulfide bispropane sulfonate) was (168.7 g, yield 95.2%), and the purity was 99.53%.

[0132] Example 2

[0133] The preparation method of poly sodium disulfide propane sulfonate comprises the following steps:

[0134] (1) Preparation of isothiourea propane sulfonic acid inner salt:

[0135] In a four-necked round-bottom flask equipped with a dropping funnel, a reflux condenser, and a thermometer, thiourea (114 g, 1.50 mol) and 500 mL of methanol were added to the round-bottom flask, heated and stirred at 50 ° C to completely dissolve the thiourea solid and prepare an intermediate solution; propane sultone (201 g, 1.65 mol) was added to the dropping funnel, and propane sultone was slowly added dropwise at a controlled dripping speed for about 2 hours, and the ring-opening reaction was continued at 50 ° C for 5 hours, during which white solids were observed to precipitate continuously. The reaction was completed and cooled to room temperature, and then filtered to obtain a white solid, which was dried to obtain isothiourea propanesulfonic acid salt (285.4 g, yield 96.1%), which can be carried out without further purification.

[0136] (2) Preparation of sodium 3-mercaptopropane sulfonate:

[0137] In a four-necked round-bottom flask equipped with a dropping funnel, a reflux condenser, and a thermometer, sodium hydroxide (90 g, 2.25 mol) and 300 mL are added to the round-bottom flask to completely dissolve the sodium hydroxide to prepare a sodium hydroxide solution. At a temperature of about 40° C., the isothiourea propane sulfonic acid inner salt (198 g, 1 mol) prepared in step (1) is added to the sodium hydroxide solution to prepare a mixed solution. The mixed solution is subjected to an alkaline hydrolysis reaction at a temperature of 70° C. for 3 h to prepare a sodium 3-mercaptopropane sulfonate solution.

[0138] (3) Preparation of sodium polydisulfide propane sulfonate solution:

[0139] The sodium 3-mercaptopropane sulfonate solution prepared in step (2) was cooled to 25° C., 170 g of 10% hydrogen peroxide was added to the dropping funnel, the dropping speed was controlled to be slow, the dropping was completed in 1 hour, and then an oxidation reaction was carried out at a temperature of 25° C. for 2 hours to prepare the sodium polydisulfide propane sulfonate solution.

[0140] (4) Purification of sodium polydisulfide dipropane sulfonate:

[0141] The sodium polydisulfide dipropane sulfonate solution of step (3) was evaporated under reduced pressure to remove part of the water and concentrated into an aqueous solution of about 50%, and then heated to 60°C, 900 mL of ethanol was gradually added dropwise, stirred for 2 hours after the addition was completed, cooled to room temperature, filtered, and the purified sodium polydisulfide dipropane sulfonate was prepared; the structure of the sodium polydisulfide dipropane sulfonate was shown by nuclear magnetic hydrogen spectrum: ( 1H NMR (400 MHz, Deuterium Oxide) δ 3.13 –3.04 (m, 4H), 2.92 (t, J = 7.0 Hz, 4H), 2.26 – 2.16 (m, 4H). The mass of the purified poly(sodium disulfide bispropane sulfonate) was (170.8 g, yield 96.4%), and the purity was 99.47%.

[0142] Example 3

[0143] The preparation method of poly sodium disulfide propane sulfonate comprises the following steps:

[0144] (1) Preparation of isothiourea propane sulfonic acid inner salt:

[0145] In a four-necked round-bottom flask equipped with a dropping funnel, a reflux condenser, and a thermometer, thiourea (114 g, 1.50 mol) and 500 mL of methanol were added to the round-bottom flask, heated and stirred at 50 ° C to completely dissolve the thiourea solid and prepare an intermediate solution; propane sultone (210 g, 1.72 mol) was added to the dropping funnel, and the dripping speed was controlled to slowly drip propane sultone for about 2 hours, and the ring-opening reaction was continued at 50 ° C for 5 hours, during which white solids were observed to precipitate continuously. The reaction was completed and cooled to room temperature, and then filtered to obtain a white solid, which was dried to obtain isothiourea propanesulfonic acid salt (289.3 g, yield 97.4%), which can be carried out without further purification.

[0146] (2) Preparation of sodium 3-mercaptopropane sulfonate:

[0147] In a four-necked round-bottom flask equipped with a dropping funnel, a reflux condenser, and a thermometer, sodium hydroxide (90 g, 2.25 mol) and 300 mL are added to the round-bottom flask to completely dissolve the sodium hydroxide to prepare a sodium hydroxide solution. At a temperature of about 40° C., the isothiourea propane sulfonic acid inner salt (198 g, 1 mol) prepared in step (1) is added to the sodium hydroxide solution to prepare a mixed solution. The mixed solution is subjected to an alkaline hydrolysis reaction at a temperature of 70° C. for 3 h to prepare a sodium 3-mercaptopropane sulfonate solution.

[0148] (3) Preparation of sodium polydisulfide propane sulfonate solution:

[0149] The sodium 3-mercaptopropane sulfonate solution prepared in step (2) was cooled to 25° C., 170 g of 10% hydrogen peroxide was added to the dropping funnel, the dropping speed was controlled to be slow, the dropping was completed in 1 hour, and then an oxidation reaction was carried out at a temperature of 25° C. for 2 hours to prepare the sodium polydisulfide propane sulfonate solution.

[0150] (4) Purification of sodium polydisulfide dipropane sulfonate:

[0151] The sodium polydisulfide dipropane sulfonate solution of step (3) was evaporated under reduced pressure to remove part of the water and concentrated into an aqueous solution of about 50%, and then heated to 60°C, 900 mL of ethanol was gradually added dropwise, stirred for 2 hours after the addition was completed, cooled to room temperature, filtered, and the purified sodium polydisulfide dipropane sulfonate was prepared; the structure of the sodium polydisulfide dipropane sulfonate was shown by nuclear magnetic hydrogen spectrum: ( 1 H NMR (400 MHz, Deuterium Oxide) δ 3.16 –3.06 (m, 4H), 2.94 (t, J = 7.0 Hz, 4H), 2.28 – 2.17 (m, 4H). The mass of the purified poly(sodium disulfide bispropane sulfonate) was (169.7 g, yield 95.8%), and the purity was 99.69%.

[0152] Example 4

[0153] The preparation method of poly sodium disulfide propane sulfonate comprises the following steps:

[0154] (1) Preparation of isothiourea propane sulfonic acid inner salt:

[0155] In a four-necked round-bottom flask equipped with a dropping funnel, a reflux condenser, and a thermometer, thiourea (114 g, 1.50 mol) and 500 mL of methanol were added to the round-bottom flask, heated and stirred at 50 ° C to completely dissolve the thiourea solid and prepare an intermediate solution; propane sultone (174 g, 1.42 mol) was added to the dropping funnel, and the dripping speed was controlled to slowly drip propane sultone for about 2 hours, and the ring-opening reaction was continued at 50 ° C for 5 hours, during which white solids were observed to precipitate continuously. The reaction was completed and cooled to room temperature, and then filtered to obtain a white solid, which was dried to obtain isothiourea propane sulfonic acid salt (271.6 g, yield 96.6%), which can be carried out without further purification.

[0156] (2) Preparation of sodium 3-mercaptopropane sulfonate:

[0157] In a four-necked round-bottom flask equipped with a dropping funnel, a reflux condenser, and a thermometer, sodium hydroxide (90 g, 2.25 mol) and 300 mL are added to the round-bottom flask to completely dissolve the sodium hydroxide to prepare a sodium hydroxide solution. At a temperature of about 40° C., the isothiourea propane sulfonic acid inner salt (198 g, 1 mol) prepared in step (1) is added to the sodium hydroxide solution to prepare a mixed solution. The mixed solution is subjected to an alkaline hydrolysis reaction at a temperature of 70° C. for 3 h to prepare a sodium 3-mercaptopropane sulfonate solution.

[0158] (3) Preparation of sodium polydisulfide propane sulfonate solution:

[0159] The sodium 3-mercaptopropane sulfonate solution prepared in step (2) was cooled to 25° C., 170 g of 10% hydrogen peroxide was added to the dropping funnel, the dropping speed was controlled to be slow, the dropping was completed in 1 hour, and then an oxidation reaction was carried out at a temperature of 25° C. for 2 hours to prepare the sodium polydisulfide propane sulfonate solution.

[0160] (4) Purification of sodium polydisulfide dipropane sulfonate:

[0161] The sodium polydisulfide dipropane sulfonate solution of step (3) was evaporated under reduced pressure to remove part of the water and concentrated into an aqueous solution of about 50%, and then heated to 60°C, 900 mL of ethanol was gradually added dropwise, stirred for 2 hours after the addition was completed, cooled to room temperature, filtered, and the purified sodium polydisulfide dipropane sulfonate was prepared; the structure of the sodium polydisulfide dipropane sulfonate was shown by nuclear magnetic hydrogen spectrum: ( 1 H NMR (400 MHz, Deuterium Oxide) δ 3.14 –3.07 (m, 4H), 2.94 (t, J = 7.0 Hz, 4H), 2.28 – 2.18 (m, 4H). The mass of the purified poly(sodium disulfide bispropane sulfonate) was (167.8 g, yield 94.7%), and the purity was 98.70%.

[0162] Example 5

[0163] (1) Preparation of isothiourea propane sulfonic acid inner salt:

[0164] In a four-necked round-bottom flask equipped with a dropping funnel, a reflux condenser, and a thermometer, thiourea (114 g, 1.50 mol) and 500 mL of methanol were added to the round-bottom flask, heated and stirred at 35 ° C to completely dissolve the thiourea solid and prepare an intermediate solution; propane sultone (192 g, 1.57 mol) was added to the dropping funnel, and the propane sultone was slowly added dropwise at a controlled dripping speed for about 2 hours, and the ring-opening reaction was continued at 35 ° C for 5 hours, during which white solids were observed to precipitate continuously. The reaction was completed and cooled to room temperature, and then filtered to obtain a white solid, which was dried to obtain isothiourea propanesulfonic acid salt (228.7 g, yield 81.3%), which can be carried out without further purification.

[0165] (2) Preparation of sodium 3-mercaptopropane sulfonate:

[0166] In a four-necked round-bottom flask equipped with a dropping funnel, a reflux condenser, and a thermometer, sodium hydroxide (90 g, 2.25 mol) and 300 mL are added to the round-bottom flask to completely dissolve the sodium hydroxide to prepare a sodium hydroxide solution. At a temperature of about 40° C., the isothiourea propane sulfonic acid inner salt (198 g, 1 mol) prepared in step (1) is added to the sodium hydroxide solution to prepare a mixed solution. The mixed solution is subjected to an alkaline hydrolysis reaction at a temperature of 70° C. for 3 h to prepare a sodium 3-mercaptopropane sulfonate solution.

[0167] (3) Preparation of sodium polydisulfide propane sulfonate solution:

[0168] The sodium 3-mercaptopropane sulfonate solution prepared in step (2) was cooled to 25° C., 170 g of 10% hydrogen peroxide was added to the dropping funnel, the dropping speed was controlled to be slow, the dropping was completed in 1 hour, and then an oxidation reaction was carried out at a temperature of 25° C. for 2 hours to prepare the sodium polydisulfide propane sulfonate solution.

[0169] (4) Purification of sodium polydisulfide dipropane sulfonate:

[0170] The sodium polydisulfide dipropane sulfonate solution of step (3) was evaporated under reduced pressure to remove part of the water and concentrated into an aqueous solution of about 50%, and then heated to 60°C, 900 mL of ethanol was gradually added dropwise, stirred for 2 hours after the addition was completed, cooled to room temperature, filtered, and the purified sodium polydisulfide dipropane sulfonate was prepared; the structure of the sodium polydisulfide dipropane sulfonate was shown by nuclear magnetic hydrogen spectrum: ( 1 H NMR (400 MHz, Deuterium Oxide) δ 3.13 –3.05 (m, 4H), 2.92 (t, J = 7.1 Hz, 4H), 2.27 – 2.16 (m, 4H). The mass of the purified poly(sodium disulfide bispropane sulfonate) was (163.4 g, yield 92.2%), and the purity was 99.21%.

[0171] Comparative Example 1

[0172] The preparation method of poly sodium disulfide propane sulfonate comprises the following steps:

[0173] (1) Preparation of isothiourea propane sulfonic acid inner salt:

[0174] In a four-necked round-bottom flask equipped with a dropping funnel, a reflux condenser, and a thermometer, thiourea (114 g, 1.50 mol) and 500 mL of methanol were added to the round-bottom flask, heated and stirred at 50 ° C to completely dissolve the thiourea solid and prepare an intermediate solution; propane sultone (192 g, 1.57 mol) was added to the dropping funnel, and the dripping speed was controlled to slowly drip propane sultone for about 2 hours, and the ring-opening reaction was continued at 50 ° C for 5 hours, during which white solids were observed to precipitate continuously. The reaction was completed and cooled to room temperature, and then filtered to obtain a white solid, which was dried to obtain isothiourea propane sulfonic acid salt (280.0 g, yield 94.3%), which can be carried out without further purification.

[0175] (2) Preparation of sodium 3-mercaptopropane sulfonate:

[0176] In a four-necked round-bottom flask equipped with a dropping funnel, a reflux condenser, and a thermometer, sodium hydroxide (90 g, 2.0 mol) and 300 mL are added to the round-bottom flask to completely dissolve the sodium hydroxide to prepare a sodium hydroxide solution. At a temperature of about 40° C., the isothiourea propane sulfonic acid inner salt (198 g, 1 mol) prepared in step (1) is added to the sodium hydroxide solution to prepare a mixed solution. The mixed solution is subjected to an alkaline hydrolysis reaction at a temperature of 70° C. for 3 h to prepare a sodium 3-mercaptopropane sulfonate solution.

[0177] (3) Preparation of sodium polydisulfide propane sulfonate solution:

[0178] The sodium 3-mercaptopropane sulfonate solution prepared in step (2) was cooled to 25° C., 170 g of 10% hydrogen peroxide was added to the dropping funnel, the dropping speed was controlled to be slow, the dropping was completed in 1 hour, and then an oxidation reaction was carried out at a temperature of 25° C. for 2 hours to prepare the sodium polydisulfide propane sulfonate solution.

[0179] (4) Purification of sodium polydisulfide dipropane sulfonate:

[0180] The sodium polydisulfide dipropane sulfonate solution of step (3) was evaporated under reduced pressure to remove part of the water and concentrated into an aqueous solution of about 50%, and then heated to 60°C, 900 mL of ethanol was gradually added dropwise, stirred for 2 hours after the addition was completed, cooled to room temperature, filtered, and the purified sodium polydisulfide dipropane sulfonate was prepared; the structure of the sodium polydisulfide dipropane sulfonate was shown by nuclear magnetic hydrogen spectrum: ( 1H NMR (400 MHz, Deuterium Oxide) δ 3.14 –3.06 (m, 4H), 2.94 (t, J = 7.0 Hz, 4H), 2.28 – 2.17 (m, 4H). The mass of the purified poly(sodium disulfide bispropane sulfonate) was (156.3 g, yield 88.2%), and the purity was 99.13%.

[0181] In the above examples and comparative examples, the synthesis steps of polydipropane disulfide sodium sulfonate are as follows: .

[0182] In Examples 1 to 3, the molar ratio of propane sultone to thiourea is slightly greater than 1, and the yield and purity of the obtained SPS are very high and close. In Example 4, the molar ratio of propane sultone to thiourea is slightly less than 1, and the yield and purity of the obtained SPS are both reduced. At this time, the excess unreacted thiourea is adsorbed in the solid of isothiourea propanesulfonic acid salt. In step (2), the thiourea is first hydrolyzed into sulfur anions, and then oxidized into sodium sulfate, and finally mixed in the SPS. In Example 5, the temperature for the ring-opening reaction is slightly lower than that of the example, resulting in a slightly lower yield of isothiourea propanesulfonic acid salt generated in step (1); the yield of the final polydisulfide sodium propane sulfonate is also slightly lower.

[0183] The difference between Comparative Example 1 and Example 1 lies in the molar ratio of isothiourea propanesulfonic acid inner salt to sodium hydroxide in step (2). In this step, one molecule of isothiourea propanesulfonic acid inner salt first undergoes a neutralization reaction with one molecule of sodium hydroxide to become sodium isothiourea propanesulfonate, and then reacts with another molecule of sodium hydroxide to form sodium 3-mercaptopropanesulfonate. Therefore, when the molar ratio of isothiourea propanesulfonic acid inner salt to sodium hydroxide in Comparative Example 1 is less than 2, part of the sodium isothiourea propanesulfonate cannot be hydrolyzed into sodium 3-mercaptopropanesulfonate, and then cannot be converted into SPS; and because sodium isothiourea propanesulfonate can be removed during the recrystallization process in step (3), although the amount of SPS finally obtained is reduced, the purity is not affected.

[0184] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0185] The above-described embodiments only express several implementation methods of the present application, which is convenient for understanding the technical solution of the present application in detail, but it cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the scope of protection of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the scope of protection of the claims attached to the present application. Therefore, the scope of protection of the patent of this application shall be based on the content of the attached claims, and the description can be used to interpret the content of the claims.

Claims

1. A method for preparing polydipropane disulfide sulfonate, characterized in that: The following steps are involved: The thiourea source, propane sultone and a solvent are mixed at a temperature of 35°C to 65°C to carry out a ring-opening reaction to prepare isothiourea propane sultone; The isothiourea propane sulfonic acid inner salt and an alkali metal hydroxide solution are mixed, and an alkaline hydrolysis reaction is carried out at a temperature of 40° C. to 100° C. to prepare an alkali metal salt of 3-mercaptopropane sulfonic acid; the molar ratio of the alkali metal hydroxide in the alkali metal hydroxide solution to the molar ratio of the isothiourea propane sulfonic acid inner salt is (2.1 to 2.5): 1; An oxidant is added to the alkali metal salt of 3-mercaptopropane sulfonic acid, and an oxidation reaction is carried out at a temperature of 15° C. to 35° C. to prepare the polydisulfide dipropane sulfonate.

2. The method for preparing polydipropane disulfide sulfonate according to claim 1, characterized in that: After the oxidation reaction is completed, the preparation method further comprises: The crude product obtained by the oxidation reaction is mixed with a recrystallization solvent at a temperature of 50° C. to 70° C., cooled to room temperature, and the precipitated solid is collected to prepare the polydisulfide dipropane sulfonate.

3. The method for preparing polydipropane disulfide sulfonate according to claim 1 or 2, characterized in that: The steps for preparing isothiourea propane sulfonic acid inner salt have one or more of the following characteristics: (1) The molar ratio of the thiourea source to the propane sultone is 1:(1-1.15); (2) The solvent includes one or more of methanol, ethanol, isopropanol and tert-butanol.

4. The method for preparing polydipropane disulfide sulfonate according to claim 1 or 2, characterized in that: The steps of mixing a thiourea source, propane sultone and a solvent at a temperature of 35° C. to 65° C. and performing a ring-opening reaction include: Dissolving the thiourea source in the solvent at a temperature of 35° C. to 65° C. to prepare an intermediate solution; Adding the propane sultone into the intermediate solution in batches, and performing a ring-opening reaction at a temperature of 35° C. to 65° C. to prepare the isothiourea propane sulfonic acid inner salt; The batch addition time of the propane sultone is 1.5 h to 2.5 h, and the ring-opening reaction time is 4 h to 6 h.

5. The method for preparing polydipropane disulfide sulfonate according to claim 1 or 2, characterized in that: The steps for preparing the alkali metal salt of 3-mercaptopropane sulfonic acid have one or more of the following characteristics: (1) The alkali metal hydroxide solution includes one or more of a sodium hydroxide solution and a potassium hydroxide solution; (2) The alkaline hydrolysis reaction time is 1h~4h.

6. The method for preparing polydipropane disulfide sulfonate according to claim 5, characterized in that: The step of adding an oxidant to the alkali metal salt of 3-mercaptopropane sulfonic acid and performing an oxidation reaction at a temperature of 15° C. to 35° C. to prepare the polydisulfide dipropane sulfonate has one or more of the following characteristics: (1) The oxidant includes one or more of air, oxygen and hydrogen peroxide; (2) The oxidation reaction time is 2h~4h; (3) The poly(dipropane disulfide sulfonate) comprises one or more of sodium poly(dipropane disulfide sulfonate) and potassium poly(dipropane disulfide sulfonate).

7. The method for preparing polydipropane disulfide sulfonate according to claim 2, characterized in that: The preparation method has one or more of the following characteristics: (1) The recrystallization reagent includes one or more of methanol, ethanol, isopropanol, acetonitrile, N,N-dimethylformamide and dimethyl sulfoxide; (2) The step of mixing the crude product obtained from the oxidation reaction with a recrystallization solvent at a temperature of 50° C. to 70° C. comprises: adding the recrystallization reagent to the crude product obtained from the oxidation reaction in batches at a temperature of 50° C. to 70° C., mixing, and stirring for 1.5 h to 2.5 h.

8. The method for preparing polydipropane disulfide sulfonate according to claim 1, 2 or 7, characterized in that: The thiourea source includes one or more of thiourea, tetramethylthiourea, 1,3-diethylthiourea and guanylthiourea.

9. The method for preparing polydipropane disulfide sulfonate according to claim 8, characterized in that: The preparation method has one or more of the following characteristics: (1) The isothiourea propane sulfonic acid inner salt comprises , , and One or more of; (2) The anion of the alkali metal salt of 3-mercaptopropane sulfonic acid is .

10. A polydipropane disulfide sulfonate, characterized in that: The polydipropane disulfide sulfonate is prepared by the preparation method according to any one of claims 1 to 9, and the purity of the polydipropane disulfide sulfonate is ≥ 98.5%.

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