A method for the synthesis of polythioethers based on the insertion polymerization of sulfhydryl groups

Abstract

The application discloses a method for synthesizing polythiaether based on sulfur-hydrogen insertion polymerization. The method can obtain high-molecular-weight polythiaether in high yield without catalyst. The application has the advantages of simple operation, mild reaction condition, low energy consumption, environmental friendliness, high yield and high molecular weight.

Description

Technical Field

[0001] This invention belongs to the field of polymer synthesis and relates to a method for synthesizing polysulfides based on sulfur-hydrogen insertion polymerization, providing a method for synthesizing polysulfides with high yield and high molecular weight. Technical Background

[0002] Carbene insertion reactions, as an efficient method for constructing carbon-carbon bonds and carbon-heterobonds, have been widely used in organic synthesis. (Reference 1: (a) Ford, A.; Miel, H.; Ring, A.; Slattery, CN; Maguire, AR; McKervey, MA. Modern organic synthesis with α-diazocarbonyl compounds[J]. Chem. Rev. 2015, 115, 9981-10080. (b) Xia, Y.; Qiu, D.; Wang, J. Transition-metal-catalyzed cross-couplings through carbene migratory insertion[J]. Chem. Rev. 2017, 117, 13810-13889. (c) Zhu, S.-F.; Zhou, Q.-L. Iron-catalyzed transformations of diazocarbonyl compounds[J]. Chem. Rev. 2017, 117, 13810-13889.) Compounds[J].Natl.Sci.Rev.2014,1,580-603.(d)Zhu,S.-F.;Zhou,Q.-L.Transition-metal-catalyzed enantioselective heteroatom-hydrogenbond insertion reactions[J].Acc.Chem.Res.2012,45,1365-1377.). Considering the high reactivity of diazocarbonyl compounds and the high efficiency of insertion reactions, this method has been increasingly used in the synthesis of polymers with novel main chain structures. In 2010, the Ihara group first reported the insertion polymerization of carbene to oxygen-hydrogen bonds. In this work, they used Rh2(OAc)4 as a catalyst to achieve a three-component polycondensation reaction of diazocarbonyl compounds, phenols, and tetrahydrofuran to obtain a novel polyetherketone.(Reference 2: (a) Ihara, E.; Saiki, K.; Goto, Y.; Itoh, T.; Inoue, K. Polycondensation of bis(diazo-carbonyl) compounds with aromatic diols and cyclic ethers: synthesis of new type of polyetherketones[J]. Macromolecules 2010, 43, 4589-4598. (b) Ihara, E.; Hara, Y.; Itoh, T.; Inoue, K. Three-component polycondensation of bis(diazoketone) with dicarboxylic acids and cyclic ethers: synthesis of new types of poly(ester ether ketone)s[J]. Macromolecules 2011, 44, 5955-5960.). This polycondensation reaction involves the ring-opening reaction of tetrahydrofuran and the oxygen-hydrogen bond insertion reaction of carbene. Subsequently, dicarboxylic acids were also applied to this three-component polycondensation reaction to achieve the synthesis of polyester ether ketones. Furthermore, Yan's group reported Rh-catalyzed oxygen-hydrogen bond insertion polymerization of diazo compounds with carboxylic acids, synthesizing a series of polyesters with diverse structures (Reference 3: Wang, X.; Ding, Y.; Tao, Y.; Wang, Z.; Wang, Z.; Yan, J. Polycondensation of bis(α-diazo-1,3-dicarbonyl) compounds with dicarboxylic acids: an efficient access to functionalized alternating polyesters[J]. Polym. Chem. 2020, 11, 1708-1712.). Recently, Ihara's group successfully achieved nitrogen-hydrogen bond insertion polymerization of diazo compounds with aromatic amines using a Ru catalyst.(Reference 4: Shimomoto, H.; Mukai, H.; Bekku, H.; Itoh, T.; Ihara, E. Ru-Catalyzed polycondensation of dialkyl1,4-phenylenebis-(diazoacetate) with dianiline:synthesis of well-defined aromatic polyamines bearing an alkoxycarbonyl group at the adjacent carbon of each nitrogen in the main chain framework[J]. Macromolecules 2017, 50, 9233-9238.). This year, Zhou's group achieved silicon-hydrogen bond insertion polymerization using an inexpensive copper system (Reference 5: Zhai, X.-Y.; Wang, X.-Q.; Wu, B.; Zhou, Y.-G. Copper-Catalyzed Si-H Bond Insertion Polymerization for Synthesis of Optically Active Polyesters Containing Silicon. Chin. J. Chem. 2022, 40, 21.).

[0003] Although the sulfhydryl-hydrogen insertion reactions of carbenes have been well developed (Reference 6: (a) Momo, PB; Leveille, AN; Farrar, EHE; Grayson, MN; Mattson, AE; Burtoloso, ACBenantioselective SH Insertion Reactions of α-Carbonyl Sulfoxonium Ylides. Angew. Chem. Int. Ed. 2020, 59, 15554-15559 (b) Keipour, H.; Jalba, A.; Delage-Laurin, L.; Olevier, T. Copper-Catalyzed Carbenoid Insertion Reactions of α-Diazoesters and α-Diazoketones into Si-H and SH Bonds. J. Org. Chem. 2017, 82, 3000-3010. (c) Guo, W.;Wang, M.;Han, Z.;Huang, H.;Sun, J. Organocatalytic asymmetric synthesis of α-amino esters from sulfoxonium ylides. Chem. Sci. 2021, 12, 11191-11196. (d) Keipour, H.;Jalba, A.;Tanbouza, N.;Carreras, V.;Ollevier, T. α-Thiocarbonyl synthesis via the FeII-catalyzed insertion reaction of α-diazocarbonyls into S–H bonds. Org. Biomol. Chem. 2019, 17, 3098-3102.), but this method has not yet been applied to polymer synthesis.

[0004] Therefore, developing a method for synthesizing polysulfides through sulfur-hydrogen intercalation polymerization is of great significance. Based on this, the present invention provides a method for synthesizing polysulfides through sulfur-hydrogen intercalation polymerization, which can yield a series of high-yield, high-molecular-weight polysulfides. Summary of the Invention

[0005] The purpose of this invention is to provide a method for synthesizing polysulfides based on sulfur-hydrogen insertion polymerization. This invention is simple and practical to operate, uses readily available raw materials, has high molecular weight, high yield, and the reaction has the advantages of being green, atom-economical, and environmentally friendly.

[0006] The technical solution of the present invention is as follows:

[0007] This invention provides a method for synthesizing polysulfides based on hydrogen sulfide insertion polymerization. The method uses diarylthiophenol and thioyl ylide as monomers, and without a catalyst, synthesizes high-yield, high-molecular-weight polysulfides through hydrogen sulfide insertion polymerization at a certain temperature. The reaction formula of the method is as follows:

[0008]

[0009] In the formula:

[0010] One of them;

[0011] for Where n = 1 - 10;

[0012] or for

[0013] or for Ar' is a benzene ring or an aromatic ring containing a substituent, wherein the substituent is one of methyl, methoxy, naphthyl, or chlorine.

[0014] Based on the above technical solutions, preferably, the reaction system can be solvent-free, or the reaction system can be solvent-added, wherein the solvent is an organic solvent, and the organic solvent is one of cyclohexane, n-hexane, dichloromethane, chloroform, toluene, and ethyl acetate, preferably cyclohexane.

[0015] Based on the above technical solutions, the preferred one is the aggregation process. The molar ratio is 1:1 to 1:1.5, preferably 1:1.05.

[0016] Based on the above technical solutions, preferably, the reaction can be carried out in air.

[0017] Based on the above technical solutions, preferably, the reaction time is 24-72 hours, more preferably 24-48 hours, and even more preferably 24 hours.

[0018] Based on the above technical solutions, the preferred reaction temperature is 80-120℃, and more preferably 80℃.

[0019] Based on the above technical solution, preferably, the specific reaction steps of the method are as follows:

[0020] Will The solvent is added to the reaction flask, and the reaction is carried out at 80-120℃ for 24-72 hours. After purification, a pure product is obtained.

[0021] Based on the above technical solution, preferably, the purification step is as follows: after the reaction is completed, the solvent is removed under reduced pressure, 1-2 mL of dichloromethane is added to the system, then 20-25 mL of ice-cold methanol is added, the upper liquid is discarded, and pure polysulfide is obtained by precipitation.

[0022] Based on the above technical solutions, preferably, the... The ratio of solvent to solvent is 0.2 mmol: 0.5-1 mL.

[0023] Based on the above technical solutions, preferably, in the air, Add cyclohexane (0.5 mL) to a reaction flask and react at 80-120℃ for 24-72 hours. After the reaction is complete, remove the solvent under reduced pressure, add 1-2 mL of dichloromethane to the system, and then add 20-25 mL of ice-cold methanol. Discard the upper liquid and precipitate to obtain pure polysulfide. The molecular weight of polysulfide is determined by GPC.

[0024] The method of this invention enables the synthesis of polysulfides in high yield and with high molecular weight through hydrogen sulfide insertion polymerization. This invention offers advantages such as simple and practical operation, readily available raw materials, mild reaction conditions, low energy consumption, environmental friendliness, and high yield.

[0025] Beneficial effects

[0026] 1. The raw materials are simple and readily available, no catalyst is required, and the reaction operation is simple and practical.

[0027] 2. It has high reactivity, is easy to separate, and can obtain products with high purity.

[0028] 3. The polymer has a high molecular weight and good thermal stability.

[0029] 4. The reaction conditions are mild and environmentally friendly. Detailed Implementation

[0030] The present invention is described in detail below through embodiments, but the present invention is not limited to the embodiments described below.

[0031] The following examples illustrate the synthesis of sulfoxonium ylides 2, with references to: (a) Guo, W.; Wang, M.; Han, Z.; Huang, H.; Sun, J. Organocatalytic asymmetric synthesis of α-amino esters from sulfoxonium ylides. Chem. Sci. 2021, 12, 11191-11196. (b) Dias, RMP; Burtoloso, ACB Catalyst-Free Insertion of Sulfoxonium Ylides into Aryl Thiols. A Direct Preparation of β-Keto Thioethers. Org. Lett. 2016, 18, 3034-3037.

[0032] Examples 1-14

[0033] Condition optimization: changing the type of organic solvent, temperature, and monomer ratio.

[0034] Diarylthiophenol monomer 1a (0.2 x mmol), thioyl ylide monomer 2a (0.2 x mmol), and solvent (0.5 mL) were added to a reaction flask and reacted at 80 °C for 24 hours. The solvent was removed under reduced pressure, 1-2 mL of dichloromethane was added, followed by 20-25 mL of ice-cold methanol. The supernatant was discarded, and pure polysulfide 3a was precipitated.

[0035] The types of organic solvents, temperatures, and monomer ratios are detailed in Table 1.

[0036]

[0037] Table 1. Optimization of reaction conditions for the synthesis of polysulfides via sulfur-hydrogen intercalation polymerization

[0038]

[0039] Examples 15-27

[0040] A method for synthesizing polysulfides based on sulfur-hydrogen insertion polymerization.

[0041] Diarylthiophenol monomer 1 (0.2 mmol) and thioyl ylide monomer 2 (0.21 mmol) were added to a reaction flask and reacted at 80 °C for 24 hours. After the reaction was completed, 1-2 mL of dichloromethane was added, followed by 20-25 mL of ice-cold methanol. The supernatant was discarded, and the precipitate was used to obtain pure polysulfide 3.

[0042] The diarylthiophenol monomer was 1. By changing the type of 1 in the reaction, five different examples of polysulfide 3 were obtained. The specific types of changes are as follows:

[0043]

[0044] The reaction time for 1a-1e was 24 hours, and the reaction was carried out at 80℃ without the need for solvent.

[0045] To broaden the substrate scope for the synthesis of polysulfides via sulfur-hydrogen insertion polymerization, eight different examples of polysulfides 3 were obtained by changing the type of sulfur ylide monomer 2 in the reaction. The specific types of monomers changed are as follows:

[0046]

[0047]

[0048] The reaction time for 2a-2c was 24 h, and the reaction was carried out at 80 °C with 0.5 mL of cyclohexane.

[0049] The reaction time for 2d-2h was 48h, and the reaction was carried out at 80℃ with 0.5mL of cyclohexane.

[0050]

[0051]

[0052]

Claims

1. A method for synthesizing polysulfides based on sulfur-hydrogen intercalation polymerization, characterized in that, The method does not require a catalyst and uses diarylthiophenol and thioyl ylide as monomers to synthesize polysulfides. The reaction formula is as follows: In the formula: for One of them; for Where m = 1 - 10; or for or for Ar is a benzene ring or an aromatic ring containing a substituent, wherein the substituent is one of methyl, methoxy, naphthyl, or chlorine.

2. The method according to claim 1, characterized in that, The reaction system can be solvent-free or solvent-added, wherein the solvent is an organic solvent, and the organic solvent is one of cyclohexane, n-hexane, dichloromethane, chloroform, toluene, and ethyl acetate.

3. The method according to claim 1, characterized in that: In the reaction The molar ratio is 1:1 to 1:1.

5.

4. The method according to claim 1, characterized in that: Reaction time: 24-72 hours; Reaction temperature: 80-120℃.

5. The method according to claim 1, characterized in that: The reaction can take place in air.

6. The method according to claim 1, characterized in that, The specific reaction steps of the method are as follows: Will The solvent is added to the reaction flask, and the reaction is carried out at 80-120℃ for 24-72 hours. After purification, a pure product is obtained.

7. The method according to claim 6, characterized in that, The purification steps are as follows: after the reaction is completed, the solvent is removed under reduced pressure, dichloromethane is added to the system, followed by ice-cold methanol, the upper liquid is discarded, and pure polysulfide is obtained by precipitation.

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