Synthesis method of polythioester

Abstract

The invention discloses a synthesis method of polythioester, and relates to the technical field of polymer chemistry. The synthesis method comprises the following steps: in a solvent system and an inert gas atmosphere, under the action of a catalyst, carrying out dehydrogenation polymerization on a diol compound I and a dithiol compound II or a mercapto alcohol compound V to generate polythioester III or polythioester VI. The reaction raw materials used in the synthesis method are cheap and easy to obtain, the reaction conditions are mild, the by-product hydrogen can be used as clean energy, the requirement of the reaction on equipment is low, the green, efficient and safe production principle is met, and the method has high commercial application value.

Description

Technical Field

[0001] The invention relates to the technical field of polymer chemistry, and in particular to a method for synthesizing polythioester. Background Art

[0002] As one of the most commonly used plastics, polyester is widely used in packaging, agriculture, medical and other fields. However, the service life of plastic is short, and the accumulation of plastic after a large amount of use will cause serious environmental pollution. Therefore, based on practicality and environmental protection, it is of great significance to synthesize polymers with good properties and recyclability to replace polyester.

[0003] Polythioesters, as common heteroatom polymers, have received extensive attention in recent years. The introduction of sulfur atoms into compounds can give polymers unique properties, including optical properties, chemical resistance, self-healing ability, and heavy metal capture ability, whether in the synthesis of new active pharmaceutical ingredients or in the synthesis of new polymers with enhanced mechanical, electrical, and physicochemical properties. At the same time, polythioesters, as a new type of material, have high research value. However, sulfur atoms easily deactivate common catalysts, so the synthesis of polythioesters is currently a difficulty.

[0004] The traditional method for synthesizing polythioesters is mainly to react thiols and acylating agents under strong acid or strong base, but this method will produce unnecessary by-products, and this type of polycondensation reaction needs to be carried out under harsh conditions such as high temperature and vacuum, with high energy consumption and low molecular weight of the resulting polymer and uncontrollable molecular weight distribution, which does not meet the requirements of the currently advocated green chemistry. In addition, ring-opening polymerization has also been widely studied as a method for synthesizing polythioesters, which improves the atomic utilization rate by ring-opening of thiolactones and obtains polythioesters by controlled polymerization. Professor Lu Hua synthesized thiolactones from 4-hydroxyproline to complete ring-opening polymerization; Hong Miao's team used succinic acid to prepare five-membered ring thiolactones (TnBL) and synthesized PTBL by ring opening; Tao Youhua's research group prepared thiolactones and further prepared polythioesters by ring opening. However, ring-opening polymerization requires complex cyclic thiolactone monomers, which have cumbersome steps for the synthesis of monomers and are difficult to commercialize. At the same time, due to the single structure of the cyclic thiolactone monomer, the synthesized polythioester has a single structure and cannot meet the current complex real-time environment. Therefore, it is urgent to develop a green, efficient and widely applicable polymerization method to realize industrial large-scale production of polythioester. Summary of the invention

[0005] The present invention aims to provide a method for synthesizing polythioesters, which utilizes diol compounds I and dithiol compounds II or mercapto alcohol compounds V to generate polythioesters III or polythioesters VI through dehydrogenation polymerization. The reaction raw materials used in the method are cheap and readily available, and the required catalyst is reduced compared with the traditional method, which can effectively reduce the synthesis cost, and no other additives are required. The only byproduct hydrogen can also be used as clean energy. Compared with the traditional polymerization method, it is more efficient and green, and is conducive to large-scale industrial production.

[0006] The present invention provides a method for synthesizing polythioesters. In a solvent system and an inert gas atmosphere, under the action of a catalyst, a diol compound I and a dithiol compound II are dehydrogenated and polymerized to generate polythioester III.

[0007]

[0008] Among them, R 1 , R 2 The groups are independently C2-C 30 Aliphatic alkyl, C3-C 30 Cycloalkyl and heterocycloalkyl with C5-C 30 Any one of an aromatic group and a heteroaromatic group; n is any integer from 1 to 300; and the molecular weight of the polythioester is 5,000 to 500,000.

[0009] The synthesis method provided by the present invention can fully circulate the entire reaction system, and the reaction by-product is only hydrogen, and no harmful acylating agent needs to be added, so that thioesters can be synthesized efficiently and greenly under relatively mild conditions.

[0010] Optionally, the solvent system includes at least one of cyclohexane, benzene, toluene, bromobenzene, chlorobenzene, p-xylene, m-xylene, o-xylene, anisole, mesitylene, tetrahydrofuran, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, dimethylformamide, dimethyl sulfoxide and hexamethyldisiloxane.

[0011] Optionally, the inert gas atmosphere includes at least one of argon and nitrogen.

[0012] Optionally, the catalyst is an acridinium-based ruthenium catalyst, the structure of which is shown in Formula IV:

[0013]

[0014] Optionally, the diol compound I includes any one of 1,2-ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,15-pentadecanediol, 1,16-hexadecanediol, 4-phenylenediol, 2,5-furan dimethanol and 2,5-methanol.

[0015] Optionally, the dithiol compound II includes any one of 1,2-ethanedithiol, 1,3-propanedithiol, 1,4-butanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 1,7-heptanedithiol, 1,8-octanedithiol, 1,9-nonanedithiol, 1,10-decanedithiol, 1,11-undecanedithiol, 1,12-dodecanedithiol, 1,13-tridecanedithiol, 1,14-tetradecanedithiol, 1,15-pentadecanedithiol, 1,16-hexadecanedithiol, 4-methylenedithiol and 5-methylenedithiol.

[0016] Optionally, the molar ratio of the diol compound I to the dithiol compound II is 1:1.

[0017] Optionally, the molar ratio of the catalyst to the diol compound I is 1:(20-1000).

[0018] Optionally, the concentration of the diol compound I and the dithiol compound II is 0.01 mol / L-0.50 mol / L.

[0019] Optionally, the dehydrogenation polymerization of the diol compound I and the dithiol compound II comprises: reacting the diol compound I and the dithiol compound II at 80° C.-240° C. for 1 h-80 h to generate polythioester III.

[0020] Optionally, a mercapto alcohol compound V may be used to replace the diol compound I and the dithiol compound II to carry out dehydrogenation polymerization to generate polythioester VI;

[0021]

[0022] Among them, R 3 The group is C1-C 30 Aliphatic alkyl, C3-C 30 Cycloalkyl and heterocycloalkyl with C5-C 30 Any one of an aromatic group and a heteroaromatic group; n is any integer from 1 to 300. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly introduce the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments.

[0024] Figure 1 The reaction formula for synthesizing polythioester III by dehydrogenation polymerization of diol compound I and dithiol compound II provided by the present invention;

[0025] Figure 2 The reaction formula for synthesizing polythioester VI by dehydrogenation polymerization of mercapto alcohol compound V provided by the present invention;

[0026] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of the polythioester synthesized in Example 1 of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with general skills in the field to which the present invention belongs.

[0028] As described in the Summary of the Invention, the embodiments of the present invention include any other embodiments described herein, which can be combined in any manner, and the description of the variables in the embodiments is not only for the method of the present invention but also for the polythioester prepared therefrom. If no specific conditions are specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are followed, and the reagents or instruments used without the manufacturer specified are all conventional products that can be purchased commercially.

[0029] The present invention provides a method for synthesizing polythioesters. In a solvent system and an inert gas atmosphere, under the action of a catalyst, a diol compound I and a dithiol compound II are dehydrogenated and polymerized to generate polythioester III.

[0030]

[0031] Among them, R 1 , R 2 The groups are independently C2-C 30 Aliphatic alkyl, C3-C 30 Cycloalkyl and heterocycloalkyl with C5-C 30 Any one of an aromatic group and a heteroaromatic group; n is any integer from 1 to 300, and the molecular weight of the polythioester is 5,000 to 500,000.

[0032] In some embodiments, the solvent system includes at least one of cyclohexane, benzene, toluene, bromobenzene, chlorobenzene, p-xylene, m-xylene, o-xylene, anisole, mesitylene, tetrahydrofuran, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, dimethylformamide, dimethyl sulfoxide and hexamethyldisiloxane.

[0033] In some embodiments, the inert gas atmosphere includes at least one of argon and nitrogen.

[0034] In some embodiments, the catalyst is an acridinium-based ruthenium catalyst, the structure of which is shown in Formula IV:

[0035]

[0036] In some embodiments, the diol compound I includes any one of 1,2-ethanediol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,15-pentadecanediol, 1,16-hexadecanediol, 4-phenylenediol, 2,5-furan dimethanol and 2,5-methanol.

[0037] In some embodiments, the dithiol compound II includes any one of 1,2-ethanedithiol, 1,3-propanedithiol, 1,4-butanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 1,7-heptanedithiol, 1,8-octanedithiol, 1,9-nonanedithiol, 1,10-decanedithiol, 1,11-undecanedithiol, 1,12-dodecanedithiol, 1,13-tridecanedithiol, 1,14-tetradecanedithiol, 1,15-pentadecanedithiol, 1,16-hexadecanedithiol, 4-methylenedithiol and 2-methylenedithiol.

[0038] In some embodiments, the molar ratio of the diol compound I to the dithiol compound II is 1:1.

[0039] In some embodiments, the molar ratio of the catalyst to the diol compound I is 1:(20-1000).

[0040] In some embodiments, the concentration of the diol compound I and the dithiol compound II is 0.01 mol / L-0.50 mol / L.

[0041] In some embodiments, the synthesis method comprises the following steps:

[0042] S1. In a solvent system, a catalyst, a diol compound I and a dithiol compound II are mixed;

[0043] S2. In an inert gas atmosphere, react at 80°C-240°C for 1h-80h, and separate and purify to obtain polythioester III.

[0044] In some embodiments, the thiol alcohol compound V can be used to replace the diol compound I and the dithiol compound II for dehydrogenation polymerization to generate polythioester VI;

[0045]

[0046] Among them, R 3 The group is C1-C 30 Aliphatic alkyl, C3-C 30 Cycloalkyl and heterocycloalkyl with C5-C 30 Any one of an aromatic group and a heteroaromatic group; n is any integer from 1 to 300.

[0047] In actual operation, the product needs to be repeatedly dissolved and precipitated with an organic solvent at least three times. Specifically, the organic solvent used for dissolution includes at least one of tetrahydrofuran, dichloromethane and chloroform, and the organic solvent used for precipitation includes at least one of methanol, ethanol and petroleum ether.

[0048] Example 1

[0049] Embodiment 1 of the present invention provides a method for synthesizing polythioester, comprising the following steps:

[0050] S1. In a glove box, add 1 mL of toluene and 1 mL of water to a 100 mL Schlenk bottle to dissolve 5.7 mg (0.01 mmol) of acridinium ruthenium catalyst (CAS: 1254107-28-2), then add 1 mmol of 1,6-hexanedithiol (CAS: 1191-43-1) and 1 mmol of 1,6-hexanediol (CAS: 629-11-8), seal the Schlenk bottle and remove it from the glove box;

[0051] S2. In a nitrogen atmosphere, heat the container in an oil bath to 150°C. After reacting for 5 hours, evacuate the container and react for 2 days. After the Schlenk flask is cooled to room temperature, take out the product, dissolve it in tetrahydrofuran and precipitate it in methanol. Repeat the dissolution-precipitation three times, collect the solid product, and vacuum dry it to obtain polythioester.

[0052] NMR, GPC, and DSC characterize polythioesters. The NMR hydrogen spectrum is shown in Figure 3 As shown, the calculated yield was 78.3%.

[0053] Table 1 Synthesis results in Example 1

[0054]

[0055] Example 2 to Example 11

[0056] Embodiments 2 to 11 of the present invention respectively provide a method for synthesizing polythioester, which is different from Embodiment 1 in that the solvent and reaction temperature used in step S1 are specifically shown in Table 2.

[0057] Table 2 Solvents, reaction temperatures and yields in Examples 2 to 11

[0058] serial number Solvent Temperature / ℃ Yield / % Example 2 Toluene 120 14.2 Example 3 Dioxane 150 50.3 Example 4 Toluene: water = 1:1 150 78.3 Example 5 Hexamethyldisiloxane 150 22.6 Example 6 Anisole 150 16.1 Example 7 Tetrahydrofuran 150 70.4 Example 8 1,2-Dimethoxyethane:water=1:1 120 54.3 Example 9 1,2-Dimethoxyethane 100 69.7 Example 10 Toluene: Hexamethyldisiloxane = 1:1 80 17.4 Embodiment 11 Dichloromethane 150 56.8

[0059] Example 12 to Example 17

[0060] Embodiments 12 to 17 of the present invention respectively provide a method for synthesizing polythioester, which is different from Embodiment 1 in that the content of the catalyst added in step S1 and the reaction time are specifically shown in Table 3.

[0061] Table 3 Catalyst content, reaction time and yield of Examples 12 to 17

[0062] serial number Catalyst content Reaction time / h Yield / % Example 12 0.005mmol 12 23.5 Example 13 0.01mmol 24 74.3 Embodiment 14 0.015mmol 24 76.9 Embodiment 15 0.02mmol 36 77.3 Example 16 0.025mmol 24 78.8 Embodiment 17 0.03mmol 36 79.4

[0063] Example 18 to Example 27

[0064] Embodiments 18 to 27 of the present invention respectively provide a method for synthesizing polythioesters, which are different from Embodiment 1 in that the types of diol compounds and dithiol compounds added in step S1 are specifically shown in Table 4.

[0065] Table 4 Diol compounds and dithiol compounds and synthesis results in Examples 18 to 27

[0066]

[0067]

[0068] Example 28 to Example 33

[0069] Examples 28 to 33 of the present invention respectively provide a method for synthesizing polythioesters, which are different from Example 1 in that mercapto alcohol compounds are used instead of diol compounds and dithiol compounds as reaction substrates in step S1, as shown in Table 5.

[0070] Table 5 Mercapto alcohol compounds and synthesis results in Examples 28 to 33

[0071]

[0072] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as described in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.

Claims

1. A method for synthesizing polythioester, characterized in that: In a solvent system and an inert gas atmosphere, under the action of a catalyst, diol compound I and dithiol compound II undergo dehydrogenation polymerization to generate polythioester III; Among them, R 1 , R 2 The groups are independently C2-C 30 Aliphatic alkyl, C3-C 30 Cycloalkyl and heterocycloalkyl with C5-C 30 Any one of an aromatic group and a heteroaromatic group; n is any integer from 1 to 300; and the molecular weight of the polythioester is 5,000 to 500,000.

2. The synthesis method according to claim 1, characterized in that The solvent system includes at least one of cyclohexane, benzene, toluene, bromobenzene, chlorobenzene, p-xylene, m-xylene, o-xylene, anisole, mesitylene, tetrahydrofuran, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, dimethylformamide, dimethyl sulfoxide and hexamethyldisiloxane.

3. The synthesis method according to claim 1, characterized in that The inert gas atmosphere includes at least one of argon and nitrogen.

4. The synthesis method according to claim 1, characterized in that The catalyst is an acridinium-based ruthenium catalyst, and its structure is shown in Formula IV:

5. The synthesis method according to claim 1, characterized in that The diol compound I includes any one of 1,2-ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,15-pentadecanediol, 1,16-hexadecanediol, 4-phenylenediol, 2,5-furan dimethanol.

6. The synthesis method according to claim 1, characterized in that The dithiol compound II includes any one of 1,2-ethanedithiol, 1,3-propanedithiol, 1,4-butanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 1,7-heptanedithiol, 1,8-octanedithiol, 1,9-nonanedithiol, 1,10-decanedithiol, 1,11-undecanedithiol, 1,12-dodecanedithiol, 1,13-tridecanedithiol, 1,14-tetradecanedithiol, 1,15-pentadecanedithiol, 1,16-hexadecanedithiol, 4-phenylenediol and 5-phenylenediol.

7. The synthesis method according to claim 1, characterized in that The molar ratio of the diol compound I to the dithiol compound II is 1:1; the molar ratio of the catalyst to the diol compound I is 1:(20-1000).

8. The synthesis method according to claim 1, characterized in that The concentrations of the diol compound I and the dithiol compound II are 0.01 mol / L-0.50 mol / L.

9. The synthesis method according to claim 1, characterized in that The dehydrogenation polymerization of the diol compound I and the dithiol compound II comprises: reacting at 80° C.-240° C. for 1 h-80 h.

10. The synthesis method according to claim 1, characterized in that The mercapto alcohol compound V can be used to replace the diol compound I and the dithiol compound II to carry out dehydrogenation polymerization to generate polythioester VI; Among them, R 3 The group is C1-C 30 Aliphatic alkyl, C3-C 30 Cycloalkyl and heterocycloalkyl with C5-C 30 Any one of an aromatic group and a heteroaromatic group; n is any integer from 1 to 300.

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