A method for producing a polyphenylene sulfide
By using an oxidative polymerization method with diphenyl disulfide, dichloromethane, and manganese-Lewis acid catalyst, the problems of large catalyst usage and high cost in polyphenylene sulfide synthesis have been solved, achieving efficient and low-cost polyphenylene sulfide production with excellent product quality and environmental friendliness.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DALIAN INSTITUTE OF CHEMICAL PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2024-11-29
- Publication Date
- 2026-05-29
AI Technical Summary
Existing methods for synthesizing polyphenylene sulfide suffer from problems such as large amounts of catalysts and auxiliaries, high costs, serious environmental pollution, and immature processes, resulting in high production costs and unstable product quality.
Using diphenyl disulfide as the reactant, dichloromethane as the solvent, a mixture of manganese-based and Lewis acid as the catalyst, and air as the oxidant, the catalyst was prepared in two steps and carried out an oxidative polymerization reaction under normal pressure. The catalyst can be recovered for use in the next batch of reaction after simple post-treatment.
It has achieved low-cost and high-efficiency production of polyphenylene sulfide with a yield of up to 99%. The product has excellent chemical stability and mechanical properties. The process is simple and the reaction conditions are mild, making it valuable for industrial applications.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of oxidative polymerization technology, specifically relating to a method for efficiently synthesizing polyphenylene sulfide via oxidative polymerization. Background Technology
[0002] Polyphenylene sulfide (PPS) is composed of alternating benzene rings and sulfur atoms, giving it a regular structure and high crystallinity. The benzene rings provide PPS with good rigidity and heat resistance, while the sulfide bonds impart a degree of flexibility. Therefore, PPS possesses excellent comprehensive properties and is considered the sixth largest engineering plastic after polycarbonate (PC), polyester (PET), polyoxymethylene (POM), nylon (PA), and polyphenylene oxide (PPO). It is also one of the eight major aerospace materials. PPS is composed of alternating phenylene rings and sulfur atoms. It is a white or off-white, hard, brittle, highly crystalline (60%–80%) polymer with excellent chemical resistance, good mechanical properties, good thermal stability, and is a cost-effective semi-crystalline high-performance thermoplastic material. It is widely used in environmental protection, automotive, electronics, machinery, chemical, and pharmaceutical fields.
[0003] Polyphenylene sulfide (PPS) is a high-performance thermoplastic. Its excellent properties, unique characteristics, high rigidity, excellent heat resistance, flame retardancy, dimensional stability, chemical corrosion resistance, and adhesive properties make it the leading variety of specialty engineering plastics, widely used in various fields. To provide a better reaction environment, strongly polar solvents should be selected, such as NMP, hexamethylphosphoric triamine (HMPA), N,N-dimethylacetamide, N-methylcaprolactam, and pyridine. Catalysts and additives can increase the residence time of macromolecular chains in solution, effectively increasing the molecular weight and improving the yield and selectivity of PPS. However, excessive amounts of catalysts and additives can cause polymer precipitation. Currently, lithium chloride (LiCl), magnesium chloride (MgCl2), aluminum chloride (AlCl3), lithium benzoate, lithium stearate, lithium acetate, and caprolactam are commonly used as catalysts in industrial production. Commonly used additives are alkali metal salts of inorganic or organic acids, including sodium carbonate (Na2CO3), sodium hydroxide (NaOH), benzoates, and phosphates. Because catalysts and additives are used in large quantities and are relatively expensive, and some are quite toxic, to effectively reduce the cost of PPS synthesis and mitigate environmental pollution and resource waste, the selection of catalysts and additives should consider process recycling design. That is, after use, catalysts, additives, and solvents can be recycled for the next batch of PPS synthesis reactions after simple treatment.
[0004] The synthesis methods of polyphenylene sulfide (PPS) have been extensively studied, primarily including the sodium sulfide method, sulfur method, hydrogen sulfide method, Focke catalysis method, Maxwell method, melt or solution self-condensation polymerization of p-halothiophenol salts, and oxidative polymerization. Each method has its advantages. However, due to drawbacks such as numerous byproducts leading to poor quality or immature technology, their industrial applications are limited. Furthermore, with advancements in science and technology and rapid economic development, PPS products are finding increasingly wider applications across various fields, indicating a huge market potential. Compared to countries like Japan and the United States, the quality of domestic PPS products and the stability of production processes need further improvement, particularly in catalysts and additives, desalination processes, and recycling technologies. Additionally, domestic PPS manufacturers should enhance their independent innovation capabilities and accelerate research and development efforts in the synthesis, processing, and modification of PPS into composite materials. Summary of the Invention
[0005] This invention relates to a highly efficient method for synthesizing polyphenylene sulfide (PPS), belonging to the field of oxidative polymers. The main technical problem addressed by this invention is to provide a reaction method with low production cost, fewer side reactions, low equipment requirements, a short reaction process, and simple post-processing. This method primarily uses diphenyl disulfide as the reactant, dichloromethane as the reaction solvent, a mixture of manganese-based and Lewis acids as the catalyst, and air as the oxidant. The amounts of diphenyl disulfide (0.05-0.3 mol), the manganese-based and Lewis acid mixture (0.15-0.3 mol), and the dichloromethane solvent (7-15 mol) are used. A two-step process is employed: first, the catalyst is prepared; then, the reactants, solvent, and the prepared catalyst mixture are added to the reaction vessel.
[0006] The preparation process of polyphenylene sulfide is as follows:
[0007] a. Weigh a measured amount of diphenyl disulfide and the prepared manganese-based and Lewis acid mixture catalyst into a single-necked bottom flask, add a measured amount of dichloromethane solvent, and stir for 30-60 minutes until the mixture is homogeneous.
[0008] b. Stopper the round-bottom flask, place it in an oil bath, turn on the stirrer, and react at 15-35℃ for 16-24 hours. After the reaction is complete, a gray powder will be separated out, and the dark black color of the solution will gradually disappear.
[0009] c. Pour the reaction mixture into a large amount of hydrochloric acid and methanol, collect the precipitated white powder, and wash it repeatedly with methanol and potassium hydroxide aqueous solution.
[0010] d. Wash the product with hot water for 8-12 hours, dissolve it completely in hot N-methyl-2-pyrrolidone, and then precipitate it again with methanol. After filtration and washing with methanol, the product is dried under vacuum at 70-100℃ to obtain the polyphenylene sulfide product.
[0011] The preferred components are 0.05-0.3 mol of diphenyl disulfide, 0.15-0.3 mol of a mixture of manganese-based and Lewis acid, and 7-15 mol of dichloromethane as the solvent.
[0012] In an oil bath, start stirring at a preferred speed of 500-600 r / min and react at 15-35℃ for 16-24 hours.
[0013] Preferably, the reaction mixture is poured into a large amount of 4%-8% hydrochloric acid-methanol solution, the precipitated white powder is collected, and the mixture is repeatedly washed with methanol and potassium hydroxide aqueous solution.
[0014] Preferably, the product is washed with hot water for 8-12 hours, completely dissolved in hot N-methyl-2-pyrrolidone, reprecipitated with methanol, filtered and washed with methanol, and then vacuum dried at 70-100°C to obtain the polyphenylene sulfide product.
[0015] The raw materials of this invention are readily available, the product quality is good, the yield is high, and the production process is short.
[0016] The selection of catalyst takes into account process recovery design; that is, after use, the catalyst can be recycled for the next batch of polyphenylene sulfide synthesis reaction after simple treatment, which has great industrial application value. Compared with the prior art, the advantages of this invention are:
[0017] (1) The method for synthesizing polyphenylene sulfide of the present invention firstly prepared a mixture catalyst of manganese-based and Lewis acid by co-precipitation, and then added the prepared catalyst into the reaction to improve the efficiency of oxidative polymerization.
[0018] (2) The method for synthesizing polyphenylene sulfide in this invention uses air as an oxidant, and the yield is as high as 99%, which is not only more convenient than other methods but also has a higher yield.
[0019] (3) The method for synthesizing polyphenylene sulfide in this invention yields a product with high chemical stability, good mechanical properties, and high purity. It can be reacted under normal pressure conditions and has the advantages of simple process flow, mild reaction conditions, and high yield.
[0020] (4) The synthesis method of polyphenylene sulfide in this invention takes into account the process recycling design when selecting the catalyst. That is, after the catalyst is used, it can be recycled for the next batch of polyphenylene sulfide synthesis reaction after only simple treatment. Detailed Implementation
[0021] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto:
[0022] The following examples or comparative examples describe the preparation process of a mixture of manganese-based and Lewis acids.
[0023] 1 g of manganese-based solution was dissolved in 20 mL of aqueous solution, heated to 60 °C, Lewis acid was added, and the mixture was stirred at 60 °C for 12 hours. After centrifugation, the mixture was dried at 80 °C for 12 hours to obtain a mixture of manganese-based solution and Lewis acid.
[0024] In this composition, the manganese-based component is manganese nitrate, the Lewis acid is aluminum trichloride, and the mass ratio of Lewis acid to manganese-based component is 10:1.
[0025] Example 1
[0026] The preparation process of polyphenylene sulfide is as follows:
[0027] a. 0.05 mol of diphenyl disulfide, 0.15 mol of a mixture of manganese-based and Lewis acid (calculated as manganese), and 7 mol of dichloromethane as solvent. Stir in a reactor for 60 min until homogeneous. The reactor should be filled to 12% of its volume.
[0028] b. After stirring evenly, seal the reaction vessel and place it in an oil bath. Turn on the stirring and react for 16 hours at 15-35℃ (specifically 30℃ in this case).
[0029] c. After the reaction is complete, pour the reaction mixture into 150 ml of 5% hydrochloric acid-methanol solution (prepared by preparing 138.9 g of 36% hydrochloric acid solution and adding it to 861.1 g of methanol for later use), collect the precipitated white powder, and wash it successively with methanol and potassium hydroxide aqueous solution.
[0030] d. The product was washed with hot water at 80°C for 12 hours, completely dissolved in 15 ml of N-methyl-2-pyrrolidone at 80°C, and then precipitated again with 15 ml of methanol. After filtration and washing with methanol, the product was vacuum dried to obtain the polyphenylene sulfide product.
[0031] The obtained polyphenylene sulfide yield was 99%, the average molecular weight was 10,000, and the viscosity at 25°C was 1 Pa·s.
[0032] Example 2
[0033] The operation steps of Example 1 were followed (the process and conditions were the same as in Example 1, hereinafter the same), except that the molar proportions of the feed were changed to 0.07 mol of diphenyl disulfide and 0.15 mol of manganese-based Lewis acid catalyst, the molar amount of dichloromethane solvent was 7 mol, the reaction time was 17 h, and the yield of the high-purity polyphenylene sulfide product was 99.1%, the average molecular weight was 9000, and the viscosity at 25 °C was 0.95 Pa·s.
[0034] Example 3
[0035] The operation steps of Example 1 were followed (the process and conditions were the same as in Example 1), except that the molar proportions of the feed were changed to a mixture of 0.09 mol of diphenyl disulfide and 0.2 mol of manganese-based Lewis acid catalyst, the molar amount of dichloromethane solvent was 7 mol, the reaction time was 17 h, and the yield of the high-purity polyphenylene sulfide product was 99.2%, the average molecular weight was 9500, and the viscosity at 25 °C was 0.89 Pa·s.
[0036] Example 4
[0037] The operation steps of Example 1 were followed (the process and conditions were the same as in Example 1), except that the molar proportions of the feed were changed to 0.11 mol of diphenyl disulfide and 0.2 mol of manganese-based Lewis acid catalyst, the molar amount of dichloromethane solvent was 9 mol, the reaction time was 17 h, and the yield of the high-purity polyphenylene sulfide product was 99.4%, the average molecular weight was 10500, and the viscosity at 25 °C was 1.02 Pa·s.
[0038] Example 5
[0039] The procedure and conditions are the same as in Example 1, except that the molar proportions of the feed are changed to 0.13 mol of diphenyl disulfide and 0.25 mol of manganese-based Lewisite.
[0040] Using an acid-catalyst mixture with 11 mol of dichloromethane as the solvent and a reaction time of 18 h, a high-purity polyphenylene sulfide product was obtained with a yield of 99.42%, an average molecular weight of 111,000, and a viscosity of 1.1 Pa·s at 25 °C.
[0041] Example 6
[0042] The procedure is the same as in Example 1 (the process and conditions are the same as in Example 1), except that the molar proportions of the ingredients are changed to 0.15 mol of diphenyl disulfide and 0.25 mol of manganese-based Lewisite.
[0043] Using an acid-catalyst mixture with 11 mol of dichloromethane as the solvent and a reaction time of 18 h, a high-purity polyphenylene sulfide product was obtained with a yield of 99.44%, an average molecular weight of 9700, and a viscosity of 0.95 Pa·s at 25 °C.
[0044] Example 7
[0045] The procedure and conditions are the same as in Example 1, except that the molar proportions of the feed are changed to 0.2 mol of diphenyl disulfide and 0.25 mol of manganese-based Lewisite.
[0046] Using an acid-catalyst mixture with 11 mol of dichloromethane as the solvent and a reaction time of 18 h, a high-purity polyphenylene sulfide product was obtained with a yield of 99.46%, an average molecular weight of 10,000, and a viscosity of 1.1 Pa·s at 25 °C.
[0047] Example 8
[0048] The operation steps of Example 1 were followed (the process and conditions were the same as in Example 1), except that the molar proportions of the feed were changed to 0.2 mol of diphenyl disulfide and 0.15 mol of manganese-based Lewis acid catalyst, the molar amount of dichloromethane solvent was 11 mol, the reaction time was 20 h, and the yield of the high-purity polyphenylene sulfide product was 99.48%, the average molecular weight was 10800, and the viscosity at 25 °C was 1.09 Pa·s.
[0049] Comparative Example 1
[0050] The operation steps of Example 1 were followed (the process and conditions were the same as in Example 1), except that the molar amounts of the feed were changed to 0.2 mol of diphenyl disulfide, 0.15 mol of manganese-based solid catalyst manganese nitrate, and the molar amount of dichloromethane solvent was 11 mol. The reaction time was 20 h. The high-purity polyphenylene sulfide product obtained had a yield of 80%, an average molecular weight of 7500, and a viscosity of 0.97 Pa·s at 25 °C.
[0051] Comparative Example 2
[0052] The operation steps of Example 1 were followed (the process and conditions were the same as in Example 1), except that the molar amounts of the feed were changed to 0.2 mol of diphenyl disulfide, 0.15 mol of Lewis acid catalyst aluminum trichloride, 11 mol of dichloromethane solvent, and the reaction time was 20 h. The high-purity polyphenylene sulfide product obtained had a yield of 85%, an average molecular weight of 6900, and a viscosity of 0.89 Pa·s at 25 °C.
[0053] Comparative Example 3
[0054] The operation steps of Example 1 were followed (the process and conditions were the same as in Example 1), except that the molar amounts of the feed were changed to 0.2 mol of diphenyl disulfide, 0.15 mol of Lewis acid catalyst, and 11 mol of sulfoxide solvent. The reaction time was 20 h. The yield of the high-purity polyphenylene sulfide product was 76%, the average molecular weight was 5500, and the viscosity at 25 °C was 0.79 Pa·s.
[0055] Comparative Example 4
[0056] The operation steps of Example 1 were followed (the process and conditions were the same as in Example 1), except that the molar amounts of the feed were changed to 0.2 mol of diphenyl disulfide, 0.15 mol of Lewis acid catalyst, and 11 mol of dimethyl furan solvent. The reaction time was 20 h. The yield of the high-purity polyphenylene sulfide product was 72%, the average molecular weight was 5600, and the viscosity at 25 °C was 0.78 Pa·s.
[0057] Table 1 compares the polyphenylene sulfide yields in different examples and comparative examples.
[0058]
[0059] As shown in the above examples, the yield of the product is as high as 99%, and the product has high chemical stability, good mechanical properties, and high purity. This invention uses air as an oxidant and operates under normal pressure, offering advantages such as a simple process flow, mild reaction conditions, and high yield. It has significant industrial application value.
[0060] Compared with existing processes, it has the advantages of simple process flow, mild reaction conditions and high yield.
[0061] The method for synthesizing polyphenylene sulfide (PPS) utilizes air as an oxidant, achieving a yield of up to 99%, which is not only more convenient but also yields a higher output than other methods. The resulting product exhibits high chemical stability, good mechanical properties, and high purity, and the reaction can proceed under normal pressure. The catalyst selection incorporates process recovery design, meaning that after use, the catalyst can be recycled for reuse in the next batch of PPS synthesis reactions with only simple treatment. This method has significant industrial application value.
Claims
1. A method for preparing polyphenylene sulfide, characterized in that: Using diphenyl disulfide as the reactant, dichloromethane as the solvent, and a mixture of manganese-based and Lewis acids as the catalyst, the molar amounts of each component are as follows: diphenyl disulfide 0.05-0.3 mol, the mixture of manganese-based and Lewis acids 0.15-0.3 mol (calculated as manganese), and the solvent dichloromethane 7-15 mol. A two-step method is adopted: first, the catalyst is prepared, and then the reactant diphenyl disulfide, solvent dichloromethane, and the prepared mixed catalyst are added to the reaction vessel.
2. The preparation method according to claim 1, characterized in that: The specific process is as follows: a. Weigh out diphenyl disulfide and the prepared manganese-based and Lewis acid mixture catalyst and put them into the reaction vessel. Add dichloromethane solvent and stir for 30-60 minutes until the mixture is homogeneous. b. With the reactor either unsealed or sealed, turn on the stirrer and react at 15-35℃ for 16-24 hours; c. After the reaction is complete, pour the reaction mixture into a 4-15% hydrochloric acid-methanol solution, collect the precipitated white powder, and wash it with methanol and a 0.1-0.3N potassium hydroxide aqueous solution; d. Wash the product with hot water at 60-90℃ for 8-12 hours, dissolve it completely in hot N-methyl-2-pyrrolidone at 60-90℃, and precipitate it again with methanol; after filtration and washing with methanol, the product is dried under vacuum at 70-100℃ to obtain the polyphenylene sulfide product.
3. The preparation method according to claim 1, characterized in that: First, a mixture catalyst of manganese-based and Lewis acid was prepared by co-precipitation. Then, the prepared catalyst was added to the reactor to improve the efficiency of oxidative polymerization. The preparation process of the mixture of manganese-based and Lewis acid is as follows: dissolve 1g of manganese-based solution in 10-50mL of aqueous solution, heat to 50-80℃, add Lewis acid, stir at 50-80℃ for 8-24 hours, centrifuge, and dry at 40-90℃ for 2-24 hours to obtain the mixture of manganese-based and Lewis acid. The manganese group is one or more of manganese bromide, manganese nitrate, manganese silicide, manganese sulfide, manganese sulfate, manganese citrate, manganese molybdate, and manganese carbonate; the Lewis acid is one or more of aluminum trichloride, sulfur trioxide, boron trifluoride, and tin dichloride; the mass ratio of Lewis acid to manganese group is 20:1 to 1:1, preferably 10:1 to 3:
1.
4. The preparation method according to claim 1, characterized in that: Unlike other oxidative polymerization methods, air is used as the oxidant in the reaction, and the amount of material loaded into the reactor during the reaction process is 5-30% of the reactor volume.
5. The preparation method according to claim 1, characterized in that: In step a, 0.05-0.3 mol of diphenyl disulfide is used; Step c. After the reaction is complete, pour the reaction mixture into 80-300 ml of 4-15% hydrochloric acid-methanol mixture and collect the precipitated white powder. Step d. Wash the product with hot water, dissolve it completely in 5-30 ml of N-methyl-2-pyrrolidone, and then precipitate it again with methanol.