Cyclotrisulfide-tri (2-mercaptoethyl) thiol composition and preparation method thereof

Abstract

The invention belongs to the technical field of synthesis and preparation of organic polymer optical materials, and particularly relates to a cyclotrisulfide-tri (2-mercaptoethyl) thiol composition and a preparation method thereof. The preparation method comprises the following three steps: step 1, performing cyclization and vulcanization reaction on S8 and trichloroethane under the catalysis of aluminum chloride to generate 1, 3, 5-trichlorocyclotrisulfide; step 2, carrying out vinylation reaction on the 1, 3, 5-trichlorocyclotrisulfide and a vinyl magnesium bromide Grignard reagent to generate 1, 3, 5-trivinyl cyclotrisulfide; and 3, carrying out a photocatalytic addition reaction on the 1, 3, 5-trivinyl cyclotripolysulfide and 1, 2-ethanedithiol, and finally synthesizing the cyclotripolysulfide-tri (2-mercaptoethyl) thiol composition. The cyclotripolysulfide-tri (2-mercaptoethyl) mercaptan composition disclosed by the invention is high in transmittance and large in refractive index, and can be used for preparing a polythiocarbamate optical material with a high refractive index and high light transmittance.

Description

Technical Field

[0001] The invention belongs to the technical field of synthesis and preparation of organic polymer optical materials, and particularly relates to a cyclotrisulfide-tris(2-mercaptoethyl)thiol composition and a preparation method thereof. Background Art

[0002] With the development of polymer optical materials and functional chemicals, sulfur-containing compounds have attracted significant attention in materials science, medicine, and catalysis due to their unique chemical properties, including high refractive index, high transmittance, and excellent stability. Tris(2-mercaptoethyl)cyclotrisulfide (C3S3(CH2CH2SH)3), a novel multifunctional sulfur heterocyclic compound, possesses a high density of thiol (-SH) groups and a stable cyclotrisulfide backbone (C3S3), making it an ideal candidate for constructing functional optical materials. It is expected to find widespread application in photocurable materials, self-healing polymers, and other fields.

[0003] In recent years, thiol-ene click chemistry has become an important strategy for constructing C-S bonds due to its high efficiency and selectivity. However, existing research has largely focused on linear thioethers, and a systematic approach for the precise construction of cyclic sulfur-containing functional molecules is still lacking. For example, the traditional "nucleophilic substitution method" requires strong base and high temperature conditions, which can easily lead to ring skeleton fracture and make side reactions (such as thiol oxidation and vinyl self-polymerization) difficult to avoid. The current technical bottleneck lies in balancing the high reactivity of the thiol group with the stability of the cyclic structure, as well as developing more environmentally friendly synthetic routes. The controlled synthesis of triazine ring (C3S3) sulfur-containing optical materials remains an industry challenge. Therefore, the development of a mild and highly selective synthetic process to achieve the efficient preparation of cyclotrisulfide-tris(2-mercaptoethyl)thiol compositions is of great significance for promoting the industrial application of sulfur-containing functional optical materials. Summary of the Invention

[0004] The present invention aims to provide a cyclotrisulfide-tris(2-mercaptoethyl)thiol composition and a preparation method thereof. The prepared compound has high transmittance and large refractive index and can be used to prepare polythiocarbamate optical materials with high refractive index and high transmittance.

[0005] The object of the present invention is achieved through the following technical solutions:

[0006] The present invention provides a method for preparing a cyclotrisulfide-tris(2-mercaptoethyl)thiol composition, comprising the following steps:

[0007] (1) Cyclization and sulfidation: add sulfur powder S8 and trichloroethane to a reaction vessel containing a solvent equipped with a stirrer, a vent pipe and a temperature control device. After complete dissolution, cool to 0-7°C in an ice bath. Stir and add a chloroform solution of aluminum chloride with a molar concentration of 1-3M over 20-50 minutes. Heat to 20-30°C and stir to react for 3-6 hours. Add an ice-water mixture to the reaction solution, separate and elute the organic phase, and collect the solvent by vacuum distillation to obtain 1,3,5-trichlorocyclotrisulfide.

[0008] In this step, S8 and trichloroethane are activated by aluminum chloride in a solvent to generate a carbon cation (Cl3C + CH3), the activated carbon cation attacks the S8 sulfur atom, breaks the SS bond to form a -S-CCI3 bond, and finally cyclizes to form 1,3,5-trichlorocyclotrisulfide;

[0009] (2) Vinylation: dissolve the 1,3,5-trichlorocyclotrisulfide prepared in step (1) above in a solvent, cool to 0-9°C in an ice bath, add dropwise a tetrahydrofuran solution of a vinyl magnesium bromide Grignard reagent with a molar concentration of 2-3 M over 40-120 minutes, continue N2 protection, stir and react for 10-24 hours, add dropwise dilute hydrochloric acid to decompose the excess Grignard reagent, and collect the solvent by vacuum rotary evaporation to obtain 1,3,5-trivinylcyclotrisulfide;

[0010] This step involves the reaction of 1,3,5-trichlorocyclotrisulfide with a vinylmagnesium bromide Grignard reagent. The negatively charged vinyl carbon (CH2=CH - ) acts as a strong nucleophile, attacking the electron-deficient carbon (Cl-C=S) connected to the sulfur atom in C3S3Cl3, and the three chlorine atoms of 1,3,5-trichlorocyclotrisulfide are replaced by three vinyl groups to generate 1,3,5-trivinylcyclotrisulfide;

[0011] (3) Photocatalytic addition: Dissolve the photoinitiator in a mixed solvent, add the 1,3,5-trivinyl cyclotrisulfide prepared in step (2) above, and add 50% of the total amount of 1,2-ethanedithiol and mix well. Heat to 15-30°C and irradiate with an intensity of 15-25 mW / cm 2 After irradiation with a blue LED array at a wavelength of 450 nm for 120 minutes, the remaining amount of 1,2-ethanedithiol was added, and irradiation was continued for 18 to 24 hours, after which the power was turned off. The organic phase was separated and eluted, and the solvent was collected by vacuum distillation to obtain a cyclotrisulfide-tris(2-mercaptoethyl)thiol composition.

[0012] In this step, 1,3,5-trivinyl cyclotrisulfide reacts with 1,2-ethanedithiol in a mixed solvent. The thiol group is photocatalytically cleaved into a thiol radical (RS). The thiol radical attacks the vinyl group to form a carbon radical intermediate. The carbon radical then extracts a hydrogen atom from another thiol molecule, completing the addition and regenerating the thiol radical to maintain the chain reaction. Finally, the cyclotrisulfide-tris(2-mercaptoethyl)thiol is precisely synthesized.

[0013] Furthermore, in step (1), the weight ratio of pentaerythritol, thiourea, acrylic acid and solvent is (1-2): (2-5): (2-5): (5-10).

[0014] Furthermore, in step (1), the solvent is selected from at least one of benzene, chloroform, carbon disulfide and carbon tetrachloride.

[0015] Furthermore, in step (2), the weight ratio of the 1,3,5-trichlorocyclotrisulfide, vinylmagnesium bromide Grignard reagent and solvent is (0.5-1): (1-1.5): (5-12), and the solvent is selected from at least one of anhydrous ether and anhydrous tetrahydrofuran.

[0016] Furthermore, in step (3), the weight ratio of the 1,3,5-trivinylcyclotrisulfide, 1,2-ethanedithiol and the mixed solvent is (1-2): (2-3): (50-90); the mixed solvent is a mixture of water and an organic solvent, and the organic solvent is selected from at least one of methanol, ethanol, acetone and acetone; wherein the amount of water accounts for 7-15wt% of the mixed solvent.

[0017] The present invention also provides a cyclotrisulfide-tris(2-mercaptoethyl)thiol composition prepared by the preparation method. The structural formula of the cyclotrisulfide-tris(2-mercaptoethyl)thiol composition is:

[0018] .

[0019] The present invention also provides an application of the cyclotrisulfide-tris(2-mercaptoethyl)thiol composition in the preparation of a polyurethane optical material. The polyurethane optical material has a high refractive index and high light transmittance.

[0020] The present invention also provides a method for preparing the polyurethane optical material, comprising the following steps: adding the cyclotrisulfide-tris(2-mercaptoethyl)thiol composition to a reactor containing 3-iodophenyl isocyanate, adding dibutyltin dilaurate after stirring, and stirring evenly to form a prepolymer; vacuum-debubbling the prepolymer, injecting it into a tempered mold, placing the tempered mold containing the prepolymer in a curing furnace, heating and curing, cooling to room temperature, demoulding, and sampling to obtain the polyurethane optical material.

[0021] Furthermore, the temperature-raising curing is curing at 40° C. for 2.5 hours and curing at 65° C. for 3 hours.

[0022] The invention also provides a polyurethane optical material prepared by the preparation method.

[0023] The beneficial effects of the present invention are:

[0024] (1) High efficiency and precision: Light-driven and photosensitizer-based methods achieve high conversion rates at room temperature, far exceeding traditional thermal initiation methods and avoiding olefin self-polymerization or thiol oxidation side reactions.

[0025] (2) Green and mild: No high temperature or strong oxidants are required, the reaction conditions are close to neutral, there are few by-products in the reaction process, the products are easy to purify, the energy consumption is low, and it complies with the principles of green chemistry.

[0026] (3) Wide application: Stable polysulfide rings, high-density thiol groups and excellent optical properties can be used to prepare polythiocarbamate optical materials with high refractive index and high transmittance, expanding the design space of sulfur-containing functional molecules. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 This is an infrared spectrum of the cyclotrisulfide-tris(2-mercaptoethyl)thiol composition prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0029] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0030] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0031] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0032] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0033] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0034] The preparation method of the cyclotrisulfide-tris(2-mercaptoethyl)thiol composition of the present invention comprises the following steps:

[0035] (1) Cyclization and sulfidation: sulfur powder S8 and trichloroethane are added to a reaction vessel containing a solvent equipped with a stirrer, a vent pipe and a temperature control device. After complete dissolution, the mixture is cooled to 0-7°C in an ice bath. A chloroform solution of aluminum chloride with a molar concentration of 1-3 M is added dropwise with stirring for 20-50 minutes. The mixture is heated to 20-30°C and stirred for 3-6 hours. An ice-water mixture is added to the reaction solution. The organic phase is separated and eluted, and the solvent is collected by vacuum distillation to obtain 1,3,5-trichlorocyclotrisulfide. The reaction process of the above 1,3,5-trichlorocyclotrisulfide is shown in Formula II:

[0036]

[0037] Formula II

[0038] The weight ratio of the aluminum chloride, S8 sulfur powder, trichloroethane and solvent is (0.1-0.5): (1-1.5): (2-5): (12-20), and the solvent is selected from at least one of benzene, chloroform, carbon disulfide and carbon tetrachloride.

[0039] (2) Vinylation: Dissolve an appropriate amount of 1,3,5-trichlorocyclotrisulfide prepared in step (1) above in a solvent, cool to 0-9°C in an ice bath, and add dropwise a tetrahydrofuran solution of a vinyl magnesium bromide Grignard reagent with a molar concentration of 2-3 M over 40-120 minutes, under continuous N2 protection, stir and react for 10-24 hours, add dropwise dilute hydrochloric acid to decompose the excess Grignard reagent, and collect the solvent by vacuum rotary evaporation to obtain 1,3,5-trivinylcyclotrisulfide; the reaction process of the above 1,3,5-trivinylcyclotrisulfide is shown in Formula III:

[0040]

[0041] Formula III

[0042] The weight ratio of 1,3,5-trichlorocyclotrisulfide (II), vinylmagnesium bromide Grignard reagent and solvent is (0.5-1): (1-1.5): (5-12), and the solvent is selected from at least one of anhydrous ether and anhydrous tetrahydrofuran.

[0043] (3) Photocatalytic addition: Dissolve the photoinitiator in a mixed solvent, add the 1,3,5-trivinyl cyclotrisulfide prepared in step (2) above, and add 50% of the total amount of 1,2-ethanedithiol and mix well. Heat to 15-30°C and irradiate with an intensity of 15-25 mW / cm 2 After irradiation with a blue LED array at a wavelength of 450 nm for 120 minutes, the remaining amount of 1,2-ethanedithiol was added, and irradiation was continued for 18 to 24 hours, after which the power was turned off. The organic phase was separated and eluted, and the solvent was collected by vacuum distillation to obtain a cyclotrisulfide-tris(2-mercaptoethyl)thiol composition. The reaction process of the cyclotrisulfide-tris(2-mercaptoethyl)thiol is shown in Formula I:

[0044]

[0045] Formula I

[0046] The weight ratio of 1,3,5-trivinylcyclotrisulfide, 1,2-ethanedithiol and the mixed solvent is (1-2): (2-3): (50-90);

[0047] The mixed solvent is a mixture of water and an organic solvent, wherein the organic solvent is selected from at least one of methanol, ethanol, acetone and acetone; wherein the amount of water accounts for 7-15wt% of the mixed solvent;

[0048] The photoinitiator is selected from one of 2,2-dimethoxy-2-phenylacetophenone, pentaerythritol tetramercaptocarboxylate, LA-C640 and EH-310; wherein the amount of the photoinitiator is 0.05-0.2wt% of 1,2-ethanedithiol.

[0049] The present invention will be further described below by way of examples.

[0050] Example 1

[0051] The specific preparation method of the cyclotrisulfide-tris(2-mercaptoethyl)thiol composition in this embodiment is as follows:

[0052] (1) Add 55 g of sulfur powder S8 and 185 g of trichloroethane to a reaction vessel containing 850 g of carbon disulfide equipped with a stirrer, a vent pipe and a temperature control device. After complete dissolution, cool to 2 °C in an ice bath. Stir and add 94 g of chloroform solution of aluminum chloride (14 g / 80 g) dropwise over 30 minutes. Heat to 22 °C and stir for 5 hours. Add ice water to the reaction solution, separate and elute the organic phase, and collect the solvent by vacuum distillation to obtain 73.2 g of 1,3,5-trichlorocyclotrisulfide.

[0053] (2) Take 60g of 1,3,5-trichlorocyclotrisulfide prepared in step (1) above and dissolve it in 450g of tetrahydrofuran solvent, cool it to 5°C in an ice bath, and add 500g of tetrahydrofuran solution of vinylmagnesium bromide Grignard reagent (120g / 380g) dropwise within 100 minutes, and continue for N 2 The mixture was stirred for 20 hours, 10 g of 9% dilute hydrochloric acid was added dropwise to decompose the excess Grignard reagent, and the solvent was collected by rotary evaporation under reduced pressure to obtain 57.3 g of 1,3,5-trivinyl cyclotrisulfide.

[0054] (3) Dissolve 0.15g of Japan Toray LA-C 640 photoinitiator in a mixed solvent of 300g of water and 2700g of ethanol, add 50g of 1,3,5-trivinyl cyclotrisulfide prepared in the above step (2) with N2 protection, add 36g of 1,2-ethanedithiol and mix well, heat to 20℃, and irradiate with an intensity of 20mW / cm 2 After irradiation with a blue LED array at a wavelength of 450 nm for 120 minutes, 36 g of 1,2-ethanedithiol was added. Irradiation was continued for 20 hours, and then the power was turned off. The organic phase was separated and eluted, and the solvent was collected by vacuum distillation to obtain 74.4 g of a colorless, transparent, oily cyclotrisulfide-tris(2-mercaptoethyl)thiol composition with a yield of 88.2%.

[0055] Infrared spectrum FT-IR test: The product prepared in Example 1 was subjected to Fourier transform infrared spectrum FT-IR) test, and the results are as follows: Figure 1 As shown, 2934~2857cm -1 The strong absorption peaks at 2567~2593cm are the asymmetric and symmetric stretching vibrations of methylene (-CH2-). -1 The absorption peak at 1012~1195 cm is the characteristic peak of -SH stretching vibration. -1The absorption peak is CC stretching vibration, 906~947cm -1 The absorption peak is the bending vibration of -SH, 611-702 cm -1 The absorption peak at ‌ is the vibration coupling between the CS bond and the cyclic sulfur skeleton (S3), 552~503cm -1 The absorption peak at ‌ is the SS stretching vibration of the ring S3.

[0056] H NMR nuclear magnetic resonance hydrogen spectrum analysis: δ = 2.67~2.77 ppm (t, 6H, -S-CH2, α-methylene), δ = 2.81~2.96 ppm (t, 6H, -CH2-SH, β-methylene), δ = 1.78~2.45 ppm (s, 3H, -SH).

[0057] Example 2

[0058] The specific preparation method of the cyclotrisulfide-tris(2-mercaptoethyl)thiol composition in this embodiment is as follows:

[0059] (1) Add 55 g of sulfur powder S8 and 150 g of trichloroethane to a reaction vessel containing 680 g of carbon disulfide equipped with a stirrer, a vent pipe and a temperature control device. After complete dissolution, cool to 2 °C in an ice bath. Stir and add 77 g of chloroform solution of aluminum chloride (12 g / 75 g) dropwise over 30 minutes. Heat to 22 °C and stir for 5 hours. Add ice water to the reaction solution, separate and elute the organic phase, and collect the solvent by vacuum distillation to obtain 61.2 g of 1,3,5-trichlorocyclotrisulfide.

[0060] (2) Take 60g of 1,3,5-trichlorocyclotrisulfide prepared in step (1) above and dissolve it in 400g of tetrahydrofuran solvent, cool it to 3°C in an ice bath, and add 570g of tetrahydrofuran solution of vinylmagnesium bromide Grignard reagent (120g / 450g) dropwise. The solution is added within 90 minutes and the temperature is kept constant for N 2 The mixture was stirred for 21 hours, 10 g of 9% dilute hydrochloric acid was added dropwise to decompose the excess Grignard reagent, and the solvent was collected by rotary evaporation under reduced pressure to obtain 58.6 g of 1,3,5-trivinyl cyclotrisulfide.

[0061] (3) Dissolve 0.15g of Japan Toray LA-C 640 photoinitiator in 300g of water and 2700g of acetonitrile mixed solvent, add 50g of 1,3,5-trivinyl cyclotrisulfide prepared in the above step (2) with N2 protection, add 35g of 1,2-ethanedithiol and mix well, heat to 20℃, and irradiate with an intensity of 20mW / cm 2After irradiation with a blue LED array at a wavelength of 450 nm for 120 minutes, 35 g of 1,2-ethanedithiol was added. Irradiation was continued for 20 hours, and then the power was turned off. The organic phase was separated and eluted, and the solvent was collected by vacuum distillation to obtain 74.7 g of a colorless, transparent, oily cyclotrisulfide-tris(2-mercaptoethyl)thiol composition with a yield of 90.1%.

[0062] The cyclotrisulfide-tris(2-mercaptoethyl)thiol composition prepared in Example 2 was subjected to infrared spectroscopy FT-IR and HNMR nuclear magnetic resonance hydrogen spectrum tests, and the test results were basically the same as those in Example 1.

[0063] Example 3

[0064] The specific preparation method of the cyclotrisulfide-tris(2-mercaptoethyl)thiol composition in this embodiment is as follows:

[0065] (1) Add 55 g of sulfur powder S8 and 200 g of trichloroethane to a reaction vessel containing 900 g of carbon disulfide equipped with a stirrer, a vent pipe and a temperature control device. After complete dissolution, cool to 2 °C in an ice bath. Stir and add 99 g of chloroform solution of aluminum chloride (14 g / 80 g) dropwise. Add the solution dropwise over 30 minutes. Heat to 22 °C and stir for 5 hours. Add ice water to the reaction solution, separate and elute the organic phase, and collect the solvent by vacuum distillation to obtain 73.6 g of 1,3,5-trichlorocyclotrisulfide.

[0066] (2) Take 60g of 1,3,5-trichlorocyclotrisulfide prepared in step (1) above and dissolve it in 430g of tetrahydrofuran solvent, cool it to 4°C in an ice bath, and add 520g of tetrahydrofuran solution of vinylmagnesium bromide Grignard reagent (120g / 400g) dropwise. The solution is added within 90 minutes and the temperature is kept constant for N 2 The reaction was stirred for 21 hours, 10 g of 9% dilute hydrochloric acid was added dropwise to decompose the excess Grignard reagent, and the solvent was collected by rotary evaporation under reduced pressure to obtain 58.9 g of 1,3,5-trivinyl cyclotrisulfide.

[0067] (3) Dissolve 0.15g of Japan Toray LA-C 640 photoinitiator in 350g of water and 2650g of acetonitrile mixed solvent, add 50g of 1,3,5-trivinyl cyclotrisulfide prepared in step (2) above, N2 protected, add 37g of 1,2-ethanedithiol and mix well, heat to 20℃, and irradiate with an intensity of 20mW / cm 2 After irradiation with a blue LED array at a wavelength of 450 nm for 120 minutes, 37 g of 1,2-ethanedithiol was added. Irradiation was continued for 20 hours, then the power was turned off. The organic phase was separated and eluted, and the solvent was collected by vacuum distillation to obtain 74.0 g of a colorless, transparent, oily cyclotrisulfide-tris(2-mercaptoethyl)thiol composition with a yield of 89.7%.

[0068] Example 4

[0069] The specific preparation method of the cyclotrisulfide-tris(2-mercaptoethyl)thiol composition in this embodiment is as follows:

[0070] (1) Add 55 g of sulfur powder S8 and 165 g of trichloroethane to a reaction vessel containing 750 g of carbon disulfide equipped with a stirrer, a vent pipe and a temperature control device. After complete dissolution, cool to 2 °C in an ice bath. Stir and add 77 g of chloroform solution of aluminum chloride (12 g / 75 g) dropwise. Add the solution over a period of 30 minutes. Heat the solution to 22 °C and stir for 5 hours. Add ice water to the reaction solution, separate and elute the organic phase, and collect the solvent by vacuum distillation to obtain 63.5 g of 1,3,5-trichlorocyclotrisulfide.

[0071] (2) Take 60g of 1,3,5-trichlorocyclotrisulfide prepared in step (1) above and dissolve it in 500g of tetrahydrofuran solvent, cool it to 1°C in an ice bath, and add 475g of tetrahydrofuran solution of vinyl magnesium bromide Grignard reagent (125g / 350g) dropwise within 120 minutes, and continue N 2 The mixture was stirred for 20 hours, 10 g of 9% dilute hydrochloric acid was added dropwise to decompose the excess Grignard reagent, and the solvent was collected by rotary evaporation under reduced pressure to obtain 57.7 g of 1,3,5-trivinyl cyclotrisulfide.

[0072] (3) Dissolve 0.15g of Japan Toray LA-C 640 photoinitiator in a mixed solvent of 350g of water and 2650g of ethanol, add 50g of 1,3,5-trivinyl cyclotrisulfide prepared in the above step (2) with stirring, and add 40g of 1,2-ethanedithiol and mix well. Heat to 20℃ and irradiate with an intensity of 20mW / cm 2 After irradiation with a blue LED array at a wavelength of 450 nm for 120 minutes, 40 g of 1,2-ethanedithiol was added. Irradiation was continued for 20 hours, then the power was turned off. The organic phase was separated and eluted, and the solvent was collected by vacuum distillation to obtain 73.9 g of a colorless, transparent, oily cyclotrisulfide-tris(2-mercaptoethyl)thiol composition with a yield of 87.4%.

[0073] Example 5

[0074] This example is used to prepare a polyurethane optical material containing cyclotrisulfide-tris(2-mercaptoethyl)thiol, and the specific steps are as follows:

[0075] 70 g of cyclotrisulfide-tris(2-mercaptoethyl)mercaptan prepared in Example 1 was added to a reactor containing 70 g of 3-iodophenyl isocyanate and stirred at 80 rpm for 35 minutes. 0.2 g of dibutyltin dilaurate was added and stirred uniformly to form a prepolymer. The prepolymer was vacuum-degassing and injected into a tempered mold. The tempered mold containing the prepolymer was placed in a curing oven, heated to 40° C. for curing for 2.5 hours, then heated to 65° C. for curing for 3 hours, cooled to room temperature, demolded, and sampled to obtain a polyurethane optical material.

[0076] Experimental Example 1 Optical Performance Test of Cyclotrisulfide-Tris(2-Mercaptoethyl)thiol Composition

[0077] The transmittance and refractive index of the cyclotrisulfide-tris(2-mercaptoethyl)thiol compositions prepared in Examples 1-4 were tested, respectively. The transmittance was tested using a UV-8000 UV-visible photometer from Shanghai Yuanxi Instrument Co., Ltd., and the refractive index was tested using a WZS1 refractometer from Shanghai Optical Instrument Equipment Co., Ltd.

[0078] Detection method: Directly apply the compound monomer on the prism of the UV-visible photometer or the prism of the refractometer for detection.

[0079] The test results are shown in Table 1.

[0080] Table 1 Optical properties of cyclotrithiodiphenyltris(2-mercaptoethyl)thiol

[0081] sample Transmittance (T%) Refractive index (nd) Example 1 89.7 1.687 Example 2 89.6 1.688 Example 3 89.7 1.687 Example 4 89.7 1.687

[0082] Experimental Example 2

[0083] The transmittance and refractive index test experiments were conducted on the optical material containing cyclotrisulfide-tris(2-mercaptoethyl)thiol polymer prepared in Example 5;

[0084] Detection method: Place the optical material directly in the area to be tested for measurement.

[0085] The test results are shown in Table 2.

[0086] Table 2 Optical properties of cyclotrisulfide-tris(2-mercaptoethyl)thiol polymers

[0087] sample Transmittance (T%) Refractive index (nd) Application Example 1 90.2 1.696

[0088] The test results show that the polythiocarbamate optical material prepared from the cyclotrisulfide-tris(2-mercaptoethyl)thiol composition of the present invention has a high refractive index and high transmittance.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be covered by the scope of the claims of the present invention.

Claims

1. A method for preparing a cyclotrisulfide-tris(2-mercaptoethyl)thiol composition, characterized in that: The following steps are involved: (1) Cyclization and sulfidation: add sulfur powder S8 and trichloroethane to a reaction vessel containing a solvent equipped with a stirrer, a vent pipe and a temperature control device. After complete dissolution, cool to 0-7°C in an ice bath. Stir and add a chloroform solution of aluminum chloride with a molar concentration of 1-3M over 20-50 minutes. Heat to 20-30°C and stir to react for 3-6 hours. Add an ice-water mixture to the reaction solution, separate and elute the organic phase, and collect the solvent by vacuum distillation to obtain 1,3,5-trichlorocyclotrisulfide. (2) Vinylation: dissolve the 1,3,5-trichlorocyclotrisulfide prepared in step (1) above in a solvent, cool to 0-9°C in an ice bath, add dropwise a tetrahydrofuran solution of a vinyl magnesium bromide Grignard reagent with a molar concentration of 2-3 M over 40-120 minutes, continue N2 protection, stir and react for 10-24 hours, add dropwise dilute hydrochloric acid to decompose the excess Grignard reagent, and collect the solvent by vacuum rotary evaporation to obtain 1,3,5-trivinylcyclotrisulfide; (3) Photocatalytic addition: Dissolve the photoinitiator in a mixed solvent, add the 1,3,5-trivinyl cyclotrisulfide prepared in step (2) above, and add 50% of the total amount of 1,2-ethanedithiol and mix well. Heat to 15-30°C and irradiate with an intensity of 15-25 mW / cm 2 After irradiation with a blue LED array at a wavelength of 450 nm for 120 minutes, the remaining amount of 1,2-ethanedithiol was added. After continuous irradiation for 18 to 24 hours, the power was turned off, the organic phase was separated and eluted, and the solvent was collected by vacuum distillation to obtain a cyclotrisulfide-tris(2-mercaptoethyl)thiol composition.

2. The method for preparing the cyclotrisulfide-tris(2-mercaptoethyl)thiol composition according to claim 1, characterized in that: In step (1), the weight ratio of pentaerythritol, thiourea, acrylic acid and solvent is (1-2): (2-5): (2-5): (5-10).

3. The method for preparing the cyclotrisulfide-tris(2-mercaptoethyl)thiol composition according to claim 1, characterized in that: In step (1), the solvent is selected from at least one of benzene, chloroform, carbon disulfide and carbon tetrachloride.

4. The method for preparing the cyclotrisulfide-tris(2-mercaptoethyl)thiol composition according to claim 1, characterized in that: In step (2), the weight ratio of the 1,3,5-trichlorocyclotrisulfide, vinylmagnesium bromide Grignard reagent and solvent is (0.5-1): (1-1.5): (5-12), and the solvent is selected from at least one of anhydrous ether and anhydrous tetrahydrofuran.

5. The method for preparing the cyclotrisulfide-tris(2-mercaptoethyl)thiol composition according to claim 1, characterized in that: In step (3), the weight ratio of the 1,3,5-trivinylcyclotrisulfide, 1,2-ethanedithiol and the mixed solvent is (1-2): (2-3): (50-90); the mixed solvent is a mixture of water and an organic solvent, and the organic solvent is selected from at least one of methanol, ethanol, acetone and acetone; wherein the amount of water accounts for 7-15wt% of the mixed solvent.

6. A cyclotrisulfide-tris(2-mercaptoethyl)thiol composition prepared by the preparation method according to any one of claims 1 to 5, characterized in that: The structural formula of the cyclotrisulfide-tris(2-mercaptoethyl)thiol composition is: 。 7. Use of the cyclotrisulfide-tris(2-mercaptoethyl)thiol composition according to claim 6 in the preparation of polyurethane optical materials, characterized in that: The polyurethane optical material has high refractive index and high light transmittance.

8. The method for preparing a polyurethane optical material according to claim 7, wherein: The method comprises the following steps: adding the cyclotrisulfide-tris(2-mercaptoethyl)thiol composition described in claim 6 into a reactor containing 3-iodophenyl isocyanate, adding dibutyltin dilaurate after stirring, and stirring evenly to form a prepolymer; vacuum-debubbling the prepolymer, injecting the prepolymer into a tempered mold, placing the tempered mold containing the prepolymer in a curing furnace, heating and curing, cooling to room temperature, demoulding, and sampling, thereby obtaining the polyurethane optical material.

9. The preparation method according to claim 8, wherein The temperature-raising curing is performed by heating the temperature to 40° C. for curing for 2.5 hours and heating the temperature to 65° C. for curing for 3 hours.

10. A polyurethane optical material prepared by the preparation method according to any one of claims 8 to 9.

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