A method for preparing dihydroxysulfonic acid amine salt

Abstract

The invention discloses a method for preparing a dihydroxy sulfonic acid amine salt, and belongs to the technical field of aqueous chain extender synthesis of organic compounds. The method for preparing the dihydroxy sulfonic acid amine salt comprises the following steps: S1, acidifying a 2,3-dihydroxy-1-propane sulfonic acid sodium solution using a sodium-type strongly acidic cation exchange resin, and then concentrating to obtain an acidified concentrated solution; S2, adding triethylamine to the acidified concentrated solution obtained in step S1 to obtain 2,3-dihydroxy-1-propane sulfonic acid triethylamine salt. This method can relatively simply prepare 2,3-dihydroxy-1-propane sulfonic acid triethylamine salt.

Description

Technical Field

[0001] The invention relates to the technical field of synthesis of water-based chain extenders for organic compounds, and in particular to a method for preparing a dihydroxysulfonic acid amine salt. Background Art

[0002] Waterborne polyurethane is an environmentally friendly material that complies with the country's green development concept. It also has many excellent properties, such as mechanical strength, cold resistance, safety and environmental protection, low VOC, and easy modification. It is widely used in water-based coatings, adhesives, textile coatings, leather finishing, and high-end wood coatings.

[0003] Waterborne chain extenders are a key raw material for the preparation of waterborne polyurethanes. They introduce hydrophilic groups into the polyurethane molecular chain, providing hydrophilic components during the emulsification process, thereby forming a stable emulsion. Based on the type of hydrophilic group, waterborne chain extenders can be divided into three categories: anionic, cationic, tertiary amine, and nonionic ethoxy groups. Anionic chain extenders primarily contain carboxylic acid and sulfonic acid groups, with carboxylic acid-based DMPA (2,2-dihydroxymethylpropionic acid) and DMBA (2,2-dihydroxymethylbutyric acid) being the mainstream hydrophilic chain extenders for waterborne polyurethanes. Cationic chain extenders primarily contain tertiary amine groups, such as N-methyldiethanolamine and triethanolamine. Nonionic chain extenders primarily contain ethoxy groups, such as trimethylolpropane polyethylene glycol monomethyl ether. Waterborne polyurethanes prepared using carboxylic acid-based chain extenders have relatively low solids content due to the poor water solubility of the carboxylic acid, limiting their application in certain applications. Sulfonic acid groups, on the other hand, are highly hydrophilic, resulting in relatively high solids content in the resulting waterborne polyurethanes, making them suitable for applications such as adhesives.

[0004] 2,3-Dihydroxy-1-propanesulfonic acid triethylamine salt, abbreviated as DHPS-TEA, is a dihydroxy-type sulfonic acid amine salt aqueous polyurethane chain extender. It is a yellow transparent liquid and can be used as a pre-chain extension additive to prepare waterborne polyurethane. Its properties allow it to be well dispersed in isocyanate systems and participate in isocyanate grafting reactions.

[0005] For the preparation method of 2,3-dihydroxy-1-propanesulfonic acid triethylamine salt, prior art research is not much. In patent CN113666850A, sodium carbonate and 3-chloro-2-hydroxy-propanesulfonic acid sodium are used to reflux at 85 DEG C for 5h, after the reaction is completed, hydrogen chloride gas is passed through to acidify, and after filtering salt, thin film evaporation is purified, and short-path distillation removes water to obtain 2,3-dihydroxy-1-propanesulfonic acid (DHPS) finished product. Although this invention can obtain low-moisture DHPS, this process temperature is higher, and the reaction time is longer, and sodium carbonate is used to synthesize, and subsequent hydrogen chloride acidification produces a large amount of carbon dioxide, and is prone to problems such as material expansion and spraying in actual production, and atom economy is poor, and the actual production operation difficulty of hydrogen chloride gas acidification is large. Summary of the Invention

[0006] The purpose of the present invention is to overcome the above technical deficiencies, provide a method for preparing dihydroxysulfonic acid amine salt, and solve the technical problem of how to relatively simply prepare 2,3-dihydroxy-1-propanesulfonic acid triethylamine salt in the prior art.

[0007] In order to achieve the above technical objectives, the technical solution of the present invention provides a method for preparing a dihydroxysulfonic acid amine salt, comprising the following steps:

[0008] S1, acidifying the sodium 2,3-dihydroxy-1-propane sulfonate solution using a sodium-type strongly acidic cation exchange resin, and then concentrating it to obtain an acidified concentrate;

[0009] S2. Add triethylamine to the acidified concentrated solution obtained in step S1 to obtain 2,3-dihydroxy-1-propanesulfonic acid triethylamine salt.

[0010] Furthermore, in step S1, the mass concentration of the sodium 2,3-dihydroxy-1-propane sulfonate solution is 15-30%.

[0011] Furthermore, in step S1, the concentration is reduced-pressure concentration, and the solid content of the acidified concentrated liquid is above 98%.

[0012] Furthermore, in step S1, the sodium 2,3-dihydroxy-1-propane sulfonate solution is prepared by the following steps:

[0013] A strong base solution is added dropwise to the sodium 3-chloro-2-hydroxypropane sulfonate solution for reaction, and then diluted to obtain the sodium 2,3-dihydroxy-1-propane sulfonate solution.

[0014] Furthermore, the mass concentration of the sodium 3-chloro-2-hydroxypropane sulfonate solution is 20-50%.

[0015] Furthermore, the strong base in the strong base solution is sodium hydroxide, potassium hydroxide or sodium methoxide.

[0016] Furthermore, the molar ratio of the sodium 3-chloro-2-hydroxypropane sulfonate in the sodium 3-chloro-2-hydroxypropane sulfonate solution to the strong base in the strong base solution is 1:1-1.2.

[0017] Furthermore, the reaction temperature is 30-50° C., and the reaction time is 2-3 hours.

[0018] Furthermore, in step S2, the molar ratio of the triethylamine to the sodium 3-chloro-2-hydroxypropane sulfonate in the sodium 3-chloro-2-hydroxypropane sulfonate solution is 0.5-1:1.

[0019] Furthermore, when the strong base solution is a sodium methoxide methanol solution, after the strong base solution is added dropwise for reaction, the method further comprises: filtering to obtain a filtrate, concentrating the filtrate under reduced pressure, and then diluting to obtain the sodium 2,3-dihydroxy-1-propane sulfonate solution.

[0020] Compared with the prior art, the present invention has the following beneficial effects: a sodium 2,3-dihydroxy-1-propane sulfonate sodium solution is acidified using a sodium-type strongly acidic cation exchange resin; after the acidification is completed, the solution is concentrated to obtain an acidified concentrated solution; the acidification is performed using the sodium-type strongly acidic cation exchange resin, thereby improving the acidification efficiency, reducing the amount of acidifying acid used, controlling the sodium ions and chloride ions at a relatively low level, and reducing the difficulty of post-processing; and a concentration-before-neutralization process is subsequently adopted. The concentration-before-neutralization process can remove volatile acidic substances, thereby preventing the volatile acidic substances from affecting the finished product after neutralization, thereby obtaining a dihydroxysulfonic acid amine salt with good quality. The method is easy to operate and relatively simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the H NMR spectrum of 2,3-dihydroxy-1-propanesulfonic acid triethylamine salt prepared in Example 1.

[0022] Figure 2 This is the C-NMR spectrum of 2,3-dihydroxy-1-propanesulfonic acid triethylamine salt prepared in Example 1. DETAILED DESCRIPTION

[0023] This specific embodiment provides a method for preparing a dihydroxysulfonic acid amine salt, comprising the following steps:

[0024] S1, acidifying the sodium 2,3-dihydroxy-1-propane sulfonate solution with a sodium-type strongly acidic cation exchange resin, and after the acidification is completed, concentrating under reduced pressure to obtain an acidified concentrate, wherein the solid content of the acidified concentrate is more than 98%; the mass concentration of the sodium 2,3-dihydroxy-1-propane sulfonate solution is 15-30%;

[0025] S2. Add triethylamine to the acidified concentrated solution obtained in step S1 to obtain 2,3-dihydroxy-1-propanesulfonic acid triethylamine salt.

[0026] In this specific embodiment, in step S1, the sodium 2,3-dihydroxy-1-propane sulfonate solution is prepared by the following steps:

[0027] A strong alkali aqueous solution is added dropwise to a 3-chloro-2-hydroxypropane sodium sulfonate solution, reacted at 30-50° C. for 2-3 hours, and then diluted to obtain a 2,3-dihydroxy-1-propane sodium sulfonate solution with a mass concentration of 15-30%. The mass concentration of the 3-chloro-2-hydroxypropane sodium sulfonate solution is 20-50%. The strong alkali in the strong alkali aqueous solution is sodium hydroxide, potassium hydroxide, or sodium methoxide. The molar ratio of the sodium 3-chloro-2-hydroxypropane sodium sulfonate in the 3-chloro-2-hydroxypropane sodium sulfonate solution to the strong alkali in the strong alkali aqueous solution is 1:1-1.2.

[0028] In certain embodiments, when the strong base solution is a sodium methoxide methanol solution, the step of adding the strong base solution for reaction further comprises: filtering to obtain a filtrate, concentrating the filtrate under reduced pressure, and then diluting the filtrate to obtain the sodium 2,3-dihydroxy-1-propane sulfonate solution.

[0029] In certain embodiments, the molar ratio of the triethylamine to the sodium 3-chloro-2-hydroxypropane sulfonate in the sodium 3-chloro-2-hydroxypropane sulfonate solution is 0.5-1:1.

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0031] Example 1

[0032] This embodiment provides a method for preparing a dihydroxysulfonic acid amine salt liquid chain extender, comprising the following steps:

[0033] T1. 393.2g of sodium 3-chloro-2-hydroxypropane sulfonate was added to a 1000ml four-necked flask with a thermometer and a tetrafluoroethylene mechanical stirrer, 393.2 deionized water was added and stirred to give a solution of sodium 3-chloro-2-hydroxypropane sulfonate, and 192g of a 50% aqueous sodium hydroxide solution was added dropwise. The temperature was controlled at 45-50 ° C. The addition time was 3h. After completion of the reaction, a solution of sodium 2,3-dihydroxy-1-propane sulfonate was obtained. The solution was a light yellow liquid, and the free chlorine content was detected to be 7.09%, and the reaction conversion rate was 97.70%;

[0034] T2. The sodium 2,3-dihydroxy-1-propane sulfonate solution obtained in step T1 was diluted to a mass concentration of 30%, and acidified using a sodium-type strongly acidic cation exchange resin. After acidification, the sodium ion content was 500ug / mL, and then entered a concentration device for reduced pressure concentration to obtain an acidified concentrate; wherein the solid content was 98.94%, sodium ions were 1600ug / ml, and chloride ions were 0.06%. The mass of the acidified concentrate was 292g, and the yield was 93.59%;

[0035] T3. To the acidified concentrate obtained in step T2, 189 g of triethylamine was added and neutralized, and the mixture was stirred evenly to obtain 2,3-dihydroxy-1-propanesulfonic acid triethylamine salt, which was a light yellow transparent fluid.

[0036] The reaction route is as follows:

[0037]

[0038] like Figure 1 and Figure 2 As shown in the figure, respectively, are the H NMR spectrum and C NMR spectrum of the 2,3-dihydroxy-1-propanesulfonic acid triethylamine salt prepared in Example 1. Through the analysis of the H NMR spectrum and C NMR spectrum, the corresponding hydrogen number ratio in the H spectrum after removing the hydrogen carried by the hydroxyl group is consistent with the hydrogen in the finished product structure, and the carbon number and ratio in the C NMR spectrum are consistent with the finished product structure, further verifying that the method of the present invention successfully prepared 2,3-dihydroxy-1-propanesulfonic acid triethylamine salt.

[0039] Example 2

[0040] This embodiment provides a method for preparing a dihydroxysulfonic acid amine salt liquid chain extender, comprising the following steps:

[0041] T1. 393.2g of sodium 3-chloro-2-hydroxypropane sulfonate was added to a 2000ml four-necked flask with a thermometer and a PTFE mechanical stirrer, 393.2 deionized water was added and stirred to give a solution of sodium 3-chloro-2-hydroxypropane sulfonate, and 750g of a 15% aqueous potassium hydroxide solution was added dropwise. The temperature was controlled at 30-35 ° C. The addition time was 2h. After completion of the reaction, a solution of sodium 2,3-dihydroxy-1-propane sulfonate was obtained. The solution was a light yellow liquid with a free chlorine content of 4.54% and a reaction conversion rate of 98.43%;

[0042] T2. The sodium 2,3-dihydroxy-1-propane sulfonate solution obtained in step T1 was diluted to a mass concentration of 15%, and acidified using a strongly acidic cation exchange resin. After acidification, the sodium ion content was 100ug / mL and the potassium ion content was 120ug / mL. The solution was then concentrated under reduced pressure in a concentrator to obtain an acidified concentrate; wherein the solid content was 99.1%, sodium ions were 700ug / ml, potassium ions were 800ug / ml, and chloride ions were 0.04%. The mass of the acidified concentrate was 299g, and the yield was 95.83%;

[0043] T3. To the acidified concentrate obtained in step T2, 98 g of triethylamine was added and neutralized, and the mixture was stirred evenly to obtain 2,3-dihydroxy-1-propanesulfonic acid triethylamine salt, which was a light yellow transparent fluid.

[0044] Example 3

[0045] This embodiment provides a method for preparing a dihydroxysulfonic acid amine salt liquid chain extender, comprising the following steps:

[0046] T1. 393.2g of sodium 3-chloro-2-hydroxypropane sulfonate was added to a 2000ml four-necked flask with a thermometer and a PTFE mechanical stirrer, 393.2 deionized water was added and stirred evenly, and 360g of a 30% sodium methoxide methanol solution was added dropwise. The temperature was controlled at 30-35 ° C. The addition time was 2h. After completion of the reaction, a sodium 2,3-dihydroxy-1-propane sulfonate solution was obtained. The solution was a light yellow liquid, and the free chlorine content was detected to be 6.11%, and the reaction conversion rate was 98.65%;

[0047] T2. The sodium 2,3-dihydroxy-1-propanesulfonate solution obtained in step T1 was filtered and concentrated under reduced pressure to remove methanol. The solution was then diluted to a mass concentration of 15% and acidified using a strongly acidic cation exchange resin. After acidification, the sodium ion content was 120 μg / ml. The solution was then concentrated under reduced pressure in a concentrator to obtain an acidified concentrate; wherein the solid content was 98.7%, sodium ions were 800 μg / ml, and chloride ions were 0.02%. The mass of the acidified concentrate was 296 g, and the yield was 94.87%.

[0048] T3. To the acidified concentrate obtained in step T2, 153g of triethylamine was added and neutralized, and the mixture was stirred evenly to obtain 2,3-dihydroxy-1-propanesulfonic acid triethylamine salt, which was a light yellow transparent fluid.

[0049] Comparative Example 1

[0050] The difference between this comparative example and Example 1 is that in step T1, the sodium hydroxide aqueous solution is not added dropwise but added all at once, as follows:

[0051] This comparative example proposes a method for preparing a dihydroxysulfonic acid amine salt liquid chain extender, comprising the following steps:

[0052] T1. 393.2g of sodium 3-chloro-2-hydroxypropane sulfonate was added to a 1000ml four-necked flask with a thermometer and a PTFE mechanical stirrer, 393.2 deionized water was added and stirred evenly, 192g of a 50% aqueous sodium hydroxide solution was added at once, the temperature was controlled at 45-50 ° C, and the reaction was kept warm for three hours. After completion of the reaction, a solution of sodium 2,3-dihydroxy-1-propane sulfonate was obtained. The reaction solution had a dark red appearance, and the free chlorine content was detected to be 6.83%, and the reaction conversion rate was 94.12%;

[0053] T2. The sodium 2,3-dihydroxy-1-propane sulfonate solution was diluted to a mass concentration of 30% and acidified using a sodium-type strongly acidic cation exchange resin. After acidification, the sodium ion content was 650ug / ml, and then the solution was concentrated under reduced pressure in a concentrator to obtain an acidified concentrate; wherein the solid content was 99.01%, sodium ions were 2000ug / ml, and chloride ions were 0.08%. The mass of the acidified concentrate was 275g, and the yield was 88.14%;

[0054] T3. To the acidified concentrate in step T2, 178 g of triethylamine was added and neutralized, and the mixture was stirred evenly to obtain the finished product of 2,3-dihydroxy-1-propanesulfonic acid triethylamine salt, which was a dark brown fluid in appearance.

[0055] In this comparative example, the product of 2,3-dihydroxy-1-propanesulfonic acid triethylamine salt is a dark brown fluid. The main reason is that the sodium hydroxide is added at one time, resulting in a strong alkaline system. The raw materials form dark groups under strong alkaline conditions, resulting in the final product being dark brown.

[0056] Comparative Example 2

[0057] The difference between this comparative example and Example 1 is that, in step T2, no concentration treatment is performed after the acidification is completed, but instead, triethylamine is added for neutralization and then the product is concentrated under reduced pressure, as follows:

[0058] This comparative example proposes a method for preparing a dihydroxysulfonic acid amine salt liquid chain extender, comprising the following steps:

[0059] T1. 393.2g of sodium 3-chloro-2-hydroxypropane sulfonate was added to a 1000ml four-necked flask with a thermometer and a PTFE mechanical stirrer, 393.2 deionized water was added and stirred evenly, 192g of 50% aqueous sodium hydroxide solution was added dropwise, the temperature was controlled at 45-50 ° C, the addition time was 3h, and after completion of the reaction, a solution of sodium 2,3-dihydroxy-1-propane sulfonate was obtained, which was a light yellow liquid. The free chlorine content was detected to be 7.07%, and the reaction conversion rate was 97.43%;

[0060] T2. The sodium 2,3-dihydroxy-1-propane sulfonate solution was diluted to a concentration of 30% by mass and acidified using a sodium-type strongly acidic cation exchange resin. After acidification, the acidified solution was obtained, and the sodium ion content in the acidified solution was 500ug / ml;

[0061] T3. To the acidified solution obtained in step T2, 189 g of triethylamine was added for neutralization, and after stirring, the mixture was concentrated under reduced pressure to obtain a yellow-green turbid fluid containing a large amount of precipitate.

[0062] The 2,3-dihydroxy-1-propanesulfonic acid triethylamine salt product obtained in this comparative example is a yellow-green turbid fluid containing a large amount of precipitate. The main reason is that the acidified liquid is not concentrated before adding triethylamine, resulting in volatile acidic substances in the acidified liquid, which affects the subsequent neutralization reaction.

[0063] The present invention uses a strong base as the raw material, which is the most atom-economical from a reaction perspective. Furthermore, the reaction temperature is reduced, the reaction time is shortened, the reaction energy consumption is low, the production cycle is short, the production safety factor is high, and the process has practical economic value. Acidification is performed using a cation exchange resin, which improves acidification efficiency, reduces the amount of acidifying acid used, controls sodium ions and chloride ions at low levels, and reduces the difficulty of post-processing. A concentration-before-neutralization process is adopted to prevent volatile acidic substances from affecting the neutralized finished product.

[0064] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a dihydroxysulfonic acid amine salt, characterized in that: The following steps are involved: S0, adding a strong base solution to the sodium 3-chloro-2-hydroxypropane sulfonate solution and reacting at 30-50° C. for 2-3 hours, and then diluting to obtain the sodium 2,3-dihydroxy-1-propane sulfonate solution; the strong base in the strong base solution is sodium hydroxide, potassium hydroxide or sodium methoxide; S1. Acidifying a sodium 2,3-dihydroxy-1-propane sulfonate solution with a sodium-type strongly acidic cation exchange resin, and then concentrating the solution to obtain an acidified concentrate; the concentration is concentrated under reduced pressure, and the solid content of the acidified concentrate is greater than 98%; the mass concentration of the sodium 2,3-dihydroxy-1-propane sulfonate solution is 15-30%; S2. Add triethylamine to the acidified concentrated solution obtained in step S1 to obtain 2,3-dihydroxy-1-propanesulfonic acid triethylamine salt.

2. The method for preparing dihydroxysulfonic acid amine salt according to claim 1, wherein The mass concentration of the sodium 3-chloro-2-hydroxypropane sulfonate solution is 20-50%.

3. The method for preparing dihydroxysulfonic acid amine salt according to claim 1, wherein The molar ratio of the sodium 3-chloro-2-hydroxypropane sulfonate in the sodium 3-chloro-2-hydroxypropane sulfonate solution to the strong base in the strong base solution is 1:1-1.

2.

4. The method for preparing dihydroxysulfonic acid amine salt according to claim 1, wherein In step S2, the molar ratio of the triethylamine to the sodium 3-chloro-2-hydroxypropane sulfonate in the sodium 3-chloro-2-hydroxypropane sulfonate solution is 0.5-1:

1.

5. The method for preparing dihydroxysulfonic acid amine salt according to claim 1, characterized in that: When the strong base solution is a sodium methoxide methanol solution, the method further comprises the following steps after the strong base solution is dropped: filtering to obtain a filtrate, concentrating the filtrate under reduced pressure, and then diluting the filtrate to obtain the sodium 2,3-dihydroxy-1-propane sulfonate solution.

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