A method for preparing sodium propylene sulfonate using a composite catalyst

Abstract

This application discloses a method for preparing sodium propylene sulfonate using a composite catalyst, belonging to the technical field of sodium propylene sulfonate preparation. The method includes the following steps: uniformly mixing sodium sulfite with recycled water to obtain a sodium sulfite solution; adding a composite catalyst to 3-chloropropylene, followed by dropwise addition of the sodium sulfite solution, heating to 45-55°C to initiate the reaction, then controlling the temperature at 45-50°C for 0.5-1.5 hours, allowing the mixture to settle, and condensing and recovering the tail gas during the reaction; subjecting the reaction solution obtained from the reaction step to coarse dehydration and refined dehydration sequentially to obtain dehydrated material, and condensing and recovering the water vapor generated during the two dehydration processes; centrifuging the dehydrated material to obtain sodium chloride solid and centrifugal mother liquor; and post-processing the centrifugal mother liquor to obtain sodium propylene sulfonate. This method achieves efficient, low-consumption, and clean production of sodium propylene sulfonate, improving its yield and purity, and meeting the synthesis requirements of acrylic fibers.

Description

Technical Field

[0001] This application relates to a method for preparing sodium propylene sulfonate using a composite catalyst, belonging to the technical field of sodium propylene sulfonate preparation. Background Technology

[0002] Acrylic fiber, as one of the three major synthetic fibers of our time, has undergone continuous innovation in its production process. Among these innovations, the introduction of an optimal third monomer for copolymerization has successfully solved the dyeing problem. Currently, domestically produced acrylic fiber possesses excellent light resistance, weather resistance, and aging resistance, while also exhibiting good resilience and warmth retention, making it highly favored by the market. With the continuous growth in demand for acrylic fiber, the consumption of sodium propylene sulfonate (sodium allyl sulfonate), a key third monomer, is also increasing year by year. Therefore, conducting research on the synthesis of sodium propylene sulfonate has significant practical implications.

[0003] Currently, most sodium propylene sulfonate is produced using an aqueous phase method, which involves reacting allyl chloride with an aqueous solution of sodium sulfite, followed by dehydration, filtration, concentration, and drying to obtain the product. However, the yield is not high and it is difficult to meet the synthesis requirements of acrylonitrile fiber. Summary of the Invention

[0004] To address the aforementioned issues, a method for preparing sodium propylene sulfonate using a composite catalyst is provided. This method achieves efficient, low-consumption, and clean production of sodium propylene sulfonate, improving its yield and purity, and meeting the synthesis requirements of acrylic fibers.

[0005] The technical solution adopted in this invention is as follows: A method for preparing sodium propylene sulfonate using a composite catalyst includes the following steps: (1) Dissolution process: Sodium sulfite is mixed evenly with recycled water to obtain a sodium sulfite solution; (2) Reaction process: Add composite catalyst to 3-chloropropene, then add sodium sulfite solution dropwise, raise the temperature to 45-55℃ to initiate the reaction, then control the temperature at 45-50℃ for 0.5-1.5h, let it stand to precipitate, and condense and recover the tail gas during the reaction process; (3) Dehydration process: The reaction liquid obtained from the reaction process is subjected to coarse dehydration and fine dehydration in sequence to obtain dehydrated material, and the water vapor generated in the two dehydration processes is condensed and recovered; (4) Separation process: The dehydrated material is centrifuged to obtain sodium chloride solid and centrifugal mother liquor; (5) Post-processing step: The centrifuged mother liquor is post-processed to obtain sodium propylene sulfonate.

[0006] Optionally, in step (2), the molar ratio of 3-chloropropene to sodium sulfite is 1:(1.05-1.1). And / or, the amount of composite catalyst added is 0.8-1.5 wt% of 3-chloropropene.

[0007] Optionally, in step (3), the temperature for coarse dehydration and fine dehydration is 60-70℃ and the time is 0.5-1.5h.

[0008] Optionally, the 3-chloropropene in the tail gas recovered by condensation in step (2) is returned to the reaction process, and the water and the water vapor recovered by condensation in step (3) are combined as recycled water, which is then treated with activated carbon and returned to the dissolution process.

[0009] Optionally, in step (4), the centrifugation speed is 1500-2500 rpm and the time is 10-20 min.

[0010] Optionally, in step (2), the composite catalyst is a quaternary ammonium salt phase transfer catalyst, fatty alcohol polyoxyethylene ether AEO-10, and sodium styrene-maleate in a weight ratio of (2.5-4):(1.3-2):1.

[0011] Optionally, the preparation method of the quaternary ammonium salt phase transfer catalyst includes the following steps: Tripentylamine, 1-bromohexane, and an organic solvent were mixed and heated under reflux at 72-85°C for 10-20 h. The solvent was removed by rotary evaporation, and then ethyl acetate was added. After cooling and crystallization, the mixture was filtered, washed, and dried to obtain a quaternary ammonium salt phase transfer catalyst.

[0012] Optionally, the molar ratio of tripentylamine to 1-bromohexane is 1:(1.05-1.1). And / or, the organic solvent is at least one of methanol, ethanol, acetonitrile and acetone.

[0013] Optionally, in step (5), the post-processing is a drying process, wherein the drying process is spray drying, and the inlet air temperature of the spray drying is 50-60℃ and the outlet air temperature is 45-55℃.

[0014] Optionally, in step (5), the post-processing is crystallization treatment, which includes: cooling and crystallizing the centrifuged mother liquor to 20-30℃ and keeping it at that temperature for 1.5-2.5h; the crystallized material is then filtered by pressure to obtain filter cake and filtrate; the filter cake is then crushed, dried, and naturally cooled before being packaged; and the filtrate is returned to the dehydration process.

[0015] The beneficial effects of this application include, but are not limited to: 1. The method for preparing sodium propylene sulfonate using a composite catalyst of this application first prepares a feed solution by mixing sodium sulfite with recycled water, then adds the composite catalyst and drops 3-chloropropylene. The reaction can be initiated and maintained under mild temperature conditions, effectively reducing energy consumption, improving reaction conversion rate and selectivity, and reducing side reactions. At the same time, by condensing and recovering the reaction tail gas, the unreacted 3-chloropropylene is directly returned to the reaction process, which greatly improves the utilization rate of raw materials and product yield. The condensate from the dehydration process and the tail gas condensate are combined, treated with activated carbon, and reused for dissolving sodium sulfite, realizing a closed-loop recycling of process water. This reduces the amount of fresh water replenishment and avoids the discharge of high-concentration organic wastewater, significantly reducing the wastewater treatment burden. In addition, through coarse dehydration, refined dehydration, centrifugal separation, and post-treatment processes, not only is the by-product sodium chloride effectively separated, but the purity of sodium propylene sulfonate is also ensured. The entire process flow is reasonably designed, combining resource recycling and environmental protection advantages, and is suitable for large-scale production.

[0016] 2. The method for preparing sodium propylene sulfonate using a composite catalyst in this application utilizes a quaternary ammonium salt phase transfer catalyst that is oil-soluble. This catalyst can carry sulfite ions from the aqueous phase to the organic phase in the form of ion pairs. In the organic phase, the sulfite ions are freed from hydration, resulting in significantly enhanced reactivity. It can rapidly undergo a nucleophilic substitution reaction with 3-chloropropylene to generate the target product, sodium propylene sulfonate. After the reaction, the quaternary ammonium salt phase transfer catalyst combines with the generated chloride ions and returns to the aqueous phase for the next catalytic cycle. Fatty alcohol polyoxyethylene ether (AEO-10) significantly reduces the interfacial tension between the aqueous and organic phases, creating a more stable emulsion with a larger contact area. This provides a larger platform for the quaternary ammonium salt phase transfer catalyst, thereby improving ion exchange and transfer efficiency and further accelerating the reaction process. Sodium styrene-maleate is amphiphilic and can adsorb onto the droplet surface, stabilizing the emulsion and preventing droplet aggregation. This creates a more efficient microenvironment for the quaternary ammonium salt phase transfer catalyst and fatty alcohol polyoxyethylene ether (AEO-10), thereby enhancing the stability and catalytic activity of the entire catalytic system. The synergistic effect of these three factors helps to form a stable reaction system, thereby greatly increasing the effective contact between reactants, enabling the reaction to proceed rapidly under mild conditions, and thus improving the yield and purity of sodium propylene sulfonate.

[0017] 3. The method for preparing sodium propylene sulfonate using a composite catalyst in this application has a quaternary ammonium salt phase transfer catalyst with an alkyl chain of suitable length, a balanced oil solubility and ion exchange capacity, and excellent lipophilic and hydrophobic properties of the cationic catalyst. When used in a two-phase system for the synthesis of sodium propylene sulfonate from 3-chloropropylene and sodium sulfite, it can not only efficiently combine sulfite ions to form ion pairs, cross the water-oil interface, enhance the migration of anions to the organic phase, significantly improve the main reaction rate, and suppress hydrolysis and polymerization side reactions, but also reduce catalyst deactivation caused by salting out during the reaction, allowing the reaction to proceed rapidly and thoroughly under mild conditions, thereby improving the yield and purity of sodium propylene sulfonate. Detailed Implementation

[0018] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0019] Unless otherwise specified in the examples, the procedures shall be performed under standard conditions or conditions recommended by the manufacturer. Raw materials or instruments whose manufacturers are not specified are all commercially available products.

[0020] The number-average molecular weight of sodium styrene-maleate mentioned below is 12,000.

[0021] Example 1 A method for preparing sodium propylene sulfonate using a composite catalyst includes the following steps: (1) Dissolution process: Sodium sulfite is mixed evenly with recycled water to obtain a sodium sulfite solution; (2) Reaction process: Add 0.8wt% composite catalyst to 3-chloropropene, then add sodium sulfite solution dropwise. The molar ratio of 3-chloropropene to sodium sulfite is 1:1.05. Heat to 45℃ to initiate the reaction, and then control the temperature at 45℃ for 1.5h. Let it stand to precipitate. During the reaction, the tail gas is condensed and recovered. 3-chloropropene is returned to the reaction process. Water and water vapor condensed and recovered in step (3) are combined as recycled water. After being treated with activated carbon, it is returned to the dissolution process. (3) Dehydration process: The reaction liquid obtained from the reaction process is subjected to coarse dehydration and fine dehydration in sequence. The temperature of coarse dehydration is 60℃ and the time is 0.5h. The temperature of fine dehydration is 60℃ and the time is 1h. Dehydrated material is obtained, and the water vapor generated in the two dehydration processes is condensed and recovered. (4) Separation process: The dehydrated material is centrifuged at a speed of 1500 rpm for 20 min to obtain sodium chloride solid and centrifuged mother liquor; (5) Post-processing step: The centrifuged mother liquor is spray-dried with an inlet air temperature of 50°C and an outlet air temperature of 45°C to obtain sodium propylene sulfonate; The composite catalyst was obtained by uniformly mixing a quaternary ammonium salt phase transfer catalyst, fatty alcohol polyoxyethylene ether AEO-10, and sodium styrene maleate in a weight ratio of 2.5:1.3:1. The preparation method of the quaternary ammonium salt phase transfer catalyst includes the following steps: Tripentylamine, 1-bromohexane, and methanol were mixed at a molar ratio of 1:1.05. The mixture was heated under reflux at 72°C for 20 h, the solvent was removed by rotary evaporation, ethyl acetate was added, and the mixture was cooled to crystallize. The resulting product was then filtered, washed, and dried to obtain a quaternary ammonium salt phase transfer catalyst.

[0022] Example 2 A method for preparing sodium propylene sulfonate using a composite catalyst includes the following steps: (1) Dissolution process: Sodium sulfite is mixed evenly with recycled water to obtain a sodium sulfite solution; (2) Reaction process: Add 1.2wt% composite catalyst to 3-chloropropene, then add sodium sulfite solution dropwise. The molar ratio of 3-chloropropene to sodium sulfite is 1:1.08. Heat to 50℃ to initiate the reaction, then control the temperature at 48℃ for 1 hour, let it stand to precipitate. During the reaction, the tail gas is condensed and recovered. 3-chloropropene is returned to the reaction process. Water and water vapor recovered by condensation in step (3) are combined as recycled water. After being treated with activated carbon, it is returned to the dissolution process. (3) Dehydration process: The reaction liquid obtained from the reaction process is subjected to coarse dehydration and fine dehydration in sequence. The temperature of coarse dehydration is 65℃ and the time is 1h. The temperature of fine dehydration is 65℃ and the time is 1.5h to obtain dehydrated material. The water vapor generated in the two dehydration processes is condensed and recovered. (4) Separation process: The dehydrated material is centrifuged at a speed of 2000 rpm for 15 min to obtain sodium chloride solid and centrifuged mother liquor; (5) Post-processing steps: The centrifuged mother liquor is cooled and crystallized, and kept at 25°C for 2 hours. The crystallized material is filtered by pressure to obtain filter cake and filtrate. The filtrate is returned to the dehydration process. The filter cake is crushed, dried and cooled naturally before being packaged to obtain sodium propylene sulfonate. The composite catalyst was obtained by uniformly mixing a quaternary ammonium salt phase transfer catalyst, fatty alcohol polyoxyethylene ether AEO-10, and sodium styrene maleate in a weight ratio of 3.2:1.6:1. The preparation method of the quaternary ammonium salt phase transfer catalyst includes the following steps: Tripentylamine, 1-bromohexane, and acetonitrile were mixed with a molar ratio of tripentylamine to 1-bromohexane of 1:1.08. The mixture was heated under reflux at 78 °C for 15 h, the solvent was removed by rotary evaporation, ethyl acetate was added, and the mixture was cooled to crystallize. The mixture was then filtered, washed, and dried to obtain a quaternary ammonium salt phase transfer catalyst.

[0023] Example 3 A method for preparing sodium propylene sulfonate using a composite catalyst includes the following steps: (1) Dissolution process: Sodium sulfite is mixed evenly with recycled water to obtain a sodium sulfite solution; (2) Reaction process: Add 1.5wt% composite catalyst to 3-chloropropene, then add sodium sulfite solution dropwise. The molar ratio of 3-chloropropene to sodium sulfite is 1:1.1. Heat to 55℃ to initiate the reaction, then control the temperature at 50℃ for 0.5h, let it stand to precipitate. During the reaction, the tail gas is condensed and recovered. 3-chloropropene is returned to the reaction process. Water and water vapor recovered by condensation in step (3) are combined as recycled water. After being treated with activated carbon, it is returned to the dissolution process. (3) Dehydration process: The reaction liquid obtained from the reaction process is subjected to coarse dehydration and fine dehydration in sequence. The temperature of coarse dehydration is 70℃ and the time is 1h. The temperature of fine dehydration is 70℃ and the time is 1.5h to obtain dehydrated material. The water vapor generated in the two dehydration processes is condensed and recovered. (4) Separation process: The dehydrated material is centrifuged at a speed of 2500 rpm for 10 min to obtain sodium chloride solid and centrifuged mother liquor; (5) Post-processing step: Spray dry the centrifuged mother liquor with an inlet air temperature of 60°C and an outlet air temperature of 55°C to obtain sodium propylene sulfonate; In this process, a composite catalyst is obtained by uniformly mixing a quaternary ammonium salt phase transfer catalyst, fatty alcohol polyoxyethylene ether AEO-10, and sodium styrene maleate in a weight ratio of 4:2:1. The preparation method of the quaternary ammonium salt phase transfer catalyst includes the following steps: Tripentylamine, 1-bromohexane, ethanol, and acetone were mixed with a volume ratio of ethanol to acetone of 1:1 and a molar ratio of tripentylamine to 1-bromohexane of 1:1.1. The mixture was heated under reflux at 85°C for 10 h, the solvent was removed by rotary evaporation, ethyl acetate was added, and the mixture was cooled to crystallize. The resulting product was then filtered, washed, and dried to obtain a quaternary ammonium salt phase transfer catalyst.

[0024] Comparative Example 1 The difference from Example 2 is that no composite catalyst was added.

[0025] Comparative Example 2 The difference from Example 2 is that the exhaust gas during the reaction process was not condensed and recovered.

[0026] Comparative Example 3 The difference from Example 2 is that the recycled water is not treated with activated carbon and is directly returned to the dissolution process.

[0027] Comparative Example 4 The difference from Example 2 is that the weight ratio of the quaternary ammonium salt phase transfer catalyst, fatty alcohol polyoxyethylene ether AEO-10, and sodium styrene maleate is 1:1:1.

[0028] Comparative Example 5 The difference from Example 2 is that no quaternary ammonium salt phase transfer catalyst was added.

[0029] Comparative Example 6 The difference from Example 2 is that fatty alcohol polyoxyethylene ether AEO-10 ​​was not added.

[0030] Comparative Example 7 The difference from Example 2 is that sodium styrene-maleate was not added.

[0031] Comparative Example 8 The difference from Example 2 is that the quaternary ammonium salt phase transfer catalyst is replaced with hexadecyltrimethylammonium bromide.

[0032] Comparative Example 9 The difference from Example 2 is that fatty alcohol polyoxyethylene ether AEO-10 ​​is replaced with fatty alcohol polyoxyethylene ether AEO-7.

[0033] Comparative Example 10 The difference from Example 2 is that sodium styrene maleate is replaced with sodium polyacrylate.

[0034] Comparative Example 11 The difference from Example 2 is that triammonium is replaced with triethylamine.

[0035] Comparative Example 12 The difference from Example 2 is that 1-bromohexane is replaced with bromooctane.

[0036] Effect evaluation The sodium propylene sulfonate prepared by the methods of Examples 1-3 and Comparative Examples 1-12 was subjected to quality testing. The yield was calculated based on the ratio of actual yield to theoretical yield. The results are shown in Table 1 below.

[0037] Table 1

[0038] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for preparing sodium propylene sulfonate using a composite catalyst, characterized in that, Includes the following steps: (1) Dissolution process: Sodium sulfite is mixed evenly with recycled water to obtain a sodium sulfite solution; (2) Reaction process: Add composite catalyst to 3-chloropropene, then add sodium sulfite solution dropwise, raise the temperature to 45-55℃ to initiate the reaction, then control the temperature at 45-50℃ for 0.5-1.5h, let it stand to precipitate, and condense and recover the tail gas during the reaction process; (3) Dehydration process: The reaction liquid obtained from the reaction process is subjected to coarse dehydration and fine dehydration in sequence to obtain dehydrated material, and the water vapor generated in the two dehydration processes is condensed and recovered; (4) Separation process: The dehydrated material is centrifuged to obtain sodium chloride solid and centrifugal mother liquor; (5) Post-processing step: The centrifuged mother liquor is post-processed to obtain sodium propylene sulfonate.

2. The method for preparing sodium propylene sulfonate using a composite catalyst according to claim 1, characterized in that, In step (2), the molar ratio of 3-chloropropene to sodium sulfite is 1:(1.05-1.1). And / or, the amount of composite catalyst added is 0.8-1.5 wt% of 3-chloropropene.

3. The method for preparing sodium propylene sulfonate using a composite catalyst according to claim 1, characterized in that, In step (3), the temperature for coarse dehydration and fine dehydration is 60-70℃ and the time is 0.5-1.5h.

4. The method for preparing sodium propylene sulfonate using a composite catalyst according to claim 1, characterized in that, In step (2), the 3-chloropropene in the condensed and recovered tail gas is returned to the reaction process. The water and the water vapor recovered in step (3) are combined as recycled water, which is then treated with activated carbon and returned to the dissolution process.

5. The method for preparing sodium propylene sulfonate using a composite catalyst according to claim 1, characterized in that, In step (4), the centrifugation speed is 1500-2500 rpm and the time is 10-20 min.

6. The method for preparing sodium propylene sulfonate using a composite catalyst according to claim 1, characterized in that, In step (2), the composite catalyst is a quaternary ammonium salt phase transfer catalyst with a weight ratio of (2.5-4):(1.3-2):1, fatty alcohol polyoxyethylene ether AEO-10, and sodium styrene maleate.

7. The method for preparing sodium propylene sulfonate using a composite catalyst according to claim 6, characterized in that, The preparation method of the quaternary ammonium salt phase transfer catalyst includes the following steps: Tripentylamine, 1-bromohexane, and an organic solvent were mixed and heated under reflux at 72-85°C for 10-20 h. The solvent was removed by rotary evaporation, and then ethyl acetate was added. After cooling and crystallization, the mixture was filtered, washed, and dried to obtain a quaternary ammonium salt phase transfer catalyst.

8. The method for preparing sodium propylene sulfonate using a composite catalyst according to claim 7, characterized in that, The molar ratio of tripentylamine to 1-bromohexane is 1:(1.05-1.1). And / or, the organic solvent is at least one of methanol, ethanol, acetonitrile and acetone.

9. The method for preparing sodium propylene sulfonate using a composite catalyst according to claim 1, characterized in that, In step (5), the post-processing is drying, which is spray drying. The inlet air temperature of the spray drying is 50-60℃ and the outlet air temperature is 45-55℃.

10. The method for preparing sodium propylene sulfonate using a composite catalyst according to claim 1, characterized in that, In step (5), the post-processing is crystallization treatment, which includes: cooling and crystallizing the centrifuged mother liquor to 20-30℃ and keeping it at that temperature for 1.5-2.5h. The crystallized material is then filtered to obtain filter cake and filtrate. The filter cake is then crushed, dried, and naturally cooled before being packaged. The filtrate is returned to the dehydration process.

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