A high-refractive bifunctional optical resin monomer and preparation method thereof

Abstract

The present invention discloses a high-refractive bifunctional optical resin monomer and a preparation method thereof, which has the following chemical structure: wherein X 1 and X 2 The monomer of the present invention not only contains a vinyl functional group that can be free radical polymerized, but also has an epoxy functional group that can be post-heat cured after the vinyl polymerization is completed to enhance the strength of the resin. At the same time, sulfur elements and benzene ring structures that have the effect of increasing the refractive index are introduced. After free radical polymerization, the benzene ring and sulfur elements that provide a high refractive index are retained on the main chain of the polymer, so that its refractive index reaches above 1.65.

Description

Technical Field

[0001] The invention relates to the technical field of molecular structure design and organic compound synthesis, and in particular to a method for preparing a high-refractive bifunctional optical resin monomer. Background Art

[0002] Optical resins made of optical monomers have a wide range of applications in real life. For example, they can be used in optical lenses, precision instrument lenses, photoresists, diffraction gratings and other fields. At present, traditional glass materials are showing a decline in these application fields and will be replaced by optical resins. Therefore, it is very important to find optical resin monomers with extremely high refractive index, high strength and good heat resistance.

[0003] At present, the high-refractive optical resins used in the market are mostly polymerized by acrylate monofunctional monomers or glycidyl ether monofunctional monomers, and the refractive index of most products is difficult to exceed 1.58. Patent CN115636803A discloses a sulfur-containing high-refractive epoxy resin monomer, which is obtained by replacing p-vinylphenol and 1,4-cyclohexanedithiol and then replacing with epichlorohydrin, but the refractive index only reaches 1.601. The more commonly used product that can simultaneously meet free radical polymerization and cationic polymerization in the market is GMA epoxy, but its refractive index is only, which greatly limits its application, and because it does not contain benzene rings in the structure, its strength and thermal stability are also insufficient. Therefore, it is particularly important to design and synthesize a bifunctional high-refractive monomer. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] The present invention proposes a new type of bifunctional high refractive monomer, which aims to solve the problems of low refractive index and low strength of existing products.

[0006] (II) Technical Solution The present invention is implemented by the following technical solution: The present invention proposes a high-refractive bifunctional optical resin monomer having the following chemical structure:

[0007] Among them, X1 and X2 are O or S.

[0008] A method for preparing a high-refractive bifunctional optical resin monomer comprises the following steps:

[0009]

[0010] Step 1: dissolving 1 equivalent of benzene diphenol (hydroxythiophenol, dithiobenzene, diphenol can be any of the three structures of o-, m-, and p-) in a solvent, adding 2 equivalents of anhydrous potassium carbonate in sequence, adding 1 equivalent of fluorobenzaldehyde (fluorobenzaldehyde can be any of the three structures of o-, m-, and p-) at 0-5°C, reacting at 80°C-150°C, quenching the reaction solution into water, extracting, washing with saturated brine, drying, concentrating, and recrystallizing to obtain compound b;

[0011] Step 2: Dissolve 1.2 equivalents of methyltriphenylphosphonium bromide in a solvent, add 1.5 equivalents of a base and then 1 equivalent of compound b under a temperature control of 0-5°C, warm the reaction to room temperature and continue the reaction for 16-48T, quench the reaction solution in ice water, extract with a solvent, add a desiccant and dry, and separate by column chromatography to obtain the target compound c;

[0012] Step 3: Dissolve 1 equivalent of compound c in 1 equivalent of epichlorohydrin at room temperature, add an appropriate amount of base, react at room temperature for 16 hours, monitor the completion of the reaction, filter the reaction solution and wash it with a small amount of organic solvent several times, then wash the filtrate with clean water and extract, spin dry the organic solvent containing the product and separate it by column chromatography to obtain compound d.

[0013] (III) Beneficial effects

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention discloses a method for preparing a high-refractive bifunctional optical resin monomer. The monomer in the present invention not only contains a vinyl functional group that can be polymerized by free radicals, but also is designed with an epoxy functional group that can be post-heat cured to enhance the resin strength after the vinyl polymerization is completed. At the same time, sulfur elements and benzene ring structures that have the effect of increasing the refractive index are introduced. After free radical polymerization, the benzene ring and sulfur elements that provide a high refractive index will be retained on the polymer main chain, so that its refractive index reaches more than 1.65. Secondly, the cross-linked heat curing of the epoxy functional group provides the resin with very high strength, thermal stability and corrosion resistance, which can be maintained for a long time in microprisms and precision instruments. This structural design fills the gap in domestic bifunctional high-refractive monomers, and its excellent performance makes it have excellent application potential in various fields. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0017] Embodiment 1: Preparation of compound 1

[0018]

[0019] In the first step, hydroquinone (10 g, 0.091 mol) was dissolved in N, N-dimethylformamide (50 mL), and anhydrous potassium carbonate (18.95 g, 0.137 mol) and p-fluorobenzaldehyde (11.29 g, 0.091 mol) were added in sequence at room temperature. After the addition was completed, the mixture was reacted at 80°C for 4 h. The reaction solution was quenched into water (150 mL), and intermediate 1-i (17.2 g, yield 88.6%) was obtained after extraction, washing, drying of the organic phase, concentration under reduced pressure and column chromatography.

[0020] In the second step, methyl triphenylphosphonium bromide (27.76 g, 0.077 mol) was dissolved in anhydrous tetrahydrofuran (150 ml), and NaH (3.64 g, 0.091 mol) was added under the condition of controlling the temperature at 0°C in a salt ice bath, and then 4-(4-hydroxyphenoxy)benzaldehyde (15 g, 0.070 mol) was added under the condition of controlling the temperature. After the addition, the system was heated to room temperature and reacted for 20 hours, and the reaction was monitored to be complete. The reaction solution was quenched into ice water and extracted with tert-butyl methyl ether, and dried with anhydrous sodium sulfate, and then separated by column chromatography to obtain the target intermediate compound 1-ii (12.4 g, yield 83%).

[0021] The third step is to put the intermediate compound 1-ii (10 g, 0.047 mol) into epichlorohydrin (40 g, 0.43 mol) at room temperature, add potassium hydroxide (5.27 g, 0.094 mol) and react at room temperature for 16 hours. The reaction solution is filtered and washed with a small amount of organic solvent for multiple times, and then the filtrate is washed with clean water and extracted. The organic solvent containing the product is dried and separated by column chromatography to obtain the target product 1 (9.2 g, yield 72%), the refractive index of which is 1.63.

[0022] The NMR characterization of the target product 1 is as follows:

[0023] 1 H NMR (400MHz, CDCl3) δ7.59–7.51(m,2H),7.37–7.30(m,2H),7.02–7.01(m,2H),6.96–6.93(m,2H),6.5 9(m,1H),5.69(d,1H),5.19(d,1H),4.23(m,1H),3.94(m,1H),3.35(m,1H),2.91(m,1H),2.75(m,1H).

[0024] Embodiment 2: Preparation of 4-(4-vinylphenylmercapto)phenyl glycidyl ether

[0025]

[0026] In the first step, p-hydroxythiophenol (10 g, 0.079 mol) was dissolved in N, N-dimethylformamide (50 mL), and anhydrous potassium carbonate powder (16.4 g, 0.119 mol) and p-fluorobenzaldehyde (9.80 g, 0.079 mol) were added in sequence at room temperature. After the addition was completed, the mixture was reacted at 80° C. for 4 h. The reaction solution was quenched into water (150 mL), extracted with ethyl acetate, and the organic phase was washed and dried. The crude product was separated by column chromatography to obtain intermediate 2-i (17.2 g, yield 95%).

[0027] In the second step, methyl triphenylphosphonium bromide (25.6 g, 0.071 mol) was dissolved in anhydrous tetrahydrofuran (200 mL), and NaH (3.92 g, 0.098 mol, 60%) was added under the condition of controlling the temperature at 0-5°C in a salt ice bath, and 4-(4-hydroxyphenylthio)benzaldehyde (15 g, 0.065 mol) was added after 0.5 h of temperature control. After the addition was completed and reacted at room temperature for 20 h, the reaction solution was quenched in ice water and extracted with tert-butyl methyl ether, and dried by adding anhydrous sodium sulfate, and then separated by column chromatography to obtain the target intermediate 2-ii (11.7 g, yield 78%).

[0028] The third step is to put the intermediate 1-vinyl-4-phenylthiophenol (10g, 0.043mol) into epichlorohydrin (40g, 0.43mol) at room temperature, add potassium hydroxide (4.6g, 0.086mol) and continue to react at room temperature for 16h. The reaction solution is filtered and washed with an organic solvent in small amounts for multiple times, and then the filtrate is washed with clean water and extracted. The organic solvent containing the product is spin-dried and separated by column chromatography to obtain the target product 2 (7.7g, yield 63%), whose refractive index is 1.66.

[0029] The NMR characterization of the target product 2 is as follows:

[0030] 1 H NMR (400MHz, CDCl3) δ7.47–7.39(m,2H),7.36–7.29(m,2H),7.21–7.16(m,2H),6.95–6.84(m,2H),6.6 7(m,1H),5.71(m,1H),5.25(m,1H),4.18(m,1H),3.86(m,1H),3.29(m,1H),2.88(m,1H),2.71(m,1H).

[0031] Embodiment 3: Preparation of compound 3

[0032]

[0033] In the first step, p-dithiophenol (10 g, 0.070 mol) was dissolved in N, N-dimethylformamide (30 mL), anhydrous potassium carbonate powder (19.68 g, 0.142 mol) was added, the temperature was raised to 80°C, and a solution of p-fluorobenzaldehyde (8.69 g, 0.070 mol) in N, N-dimethylformamide (50 mL) was slowly added dropwise. After the addition was completed, the reaction was continued at 80°C for 4 hours. The reaction solution was quenched into water (150 mL), extracted with ethyl acetate, and the organic phase was washed and dried. The crude product was separated by column chromatography to obtain intermediate 3-i (16.2 g, yield 93%).

[0034] In the second step, methyl triphenylphosphonium bromide (24.00 g, 0.067 mol) was dissolved in tetrahydrofuran, and NaH (3.48 g, 0.087 mol, 60%) was added under the condition of controlling the temperature at 0°C in a salt ice bath, and then the intermediate compound 3-i (15 g, 0.060 mol) was added under the temperature control, and the temperature was raised to room temperature and stirred for 24 hours. The reaction solution was quenched in ice water and extracted with tert-butyl methyl ether, and dried by adding anhydrous sodium sulfate, and then separated by column chromatography to obtain the target intermediate compound 3-ii (11.7 g, yield 85%).

[0035] In the third step, the intermediate compound 3-ii (10 g, 0.041 mol) was added to epichlorohydrin (40 g, 0.43 mol) at room temperature, and potassium hydroxide (4.6 g, 0.082 mol) was added to react at room temperature for 16 hours. The reaction solution was quenched into water and extracted with methyl tert-butyl ether. The organic phases were combined, washed, and concentrated, and the crude product was separated by column chromatography to obtain the target product compound 3 (6.1 g, yield 50%), whose refractive index was 1.69.

[0036] The NMR characterization of the target product compound 3 is as follows:

[0037] 1 H NMR (400MHz, CDCl3) δ7.32–7.30(m,2H),7.28–7.26(m,2H),7.19–7.16(m,2H),6.74–6.65( m,2H),6.76(m,1H),5.45(m,1H),4.16(m,1H),3.02(m,2H),2.91(m,1H),2.60–2.35(m,2H).

[0038] Embodiment 4: Preparation of compound 4

[0039]

[0040] In the first step, p-methylmercaptophenol (10 g, 0.071 mol) was dissolved in N, N-dimethylformamide (50 mL), anhydrous potassium carbonate (14.58 g, 0.105 mol) was added, o-fluorobenzaldehyde (8.79 g, 0.071 mol) was added under temperature control, and the mixture was reacted at 100°C for 4 h. The reaction solution was quenched into water and extracted with methyl tert-butyl ether. The organic phases were combined, washed, and concentrated, and the crude product was separated by column chromatography to obtain the target product compound 4-i (16.5 g, 0.063 mol).

[0041] In the second step, compound 4-i (15 g, 0.057 mol) was dissolved in dichloromethane, and boron tribromide (28.5 g, 0.114 mol) was added at 0-5°C, and the reaction was carried out at room temperature overnight for 12 hours. After the raw materials were completely consumed, the reaction solution was poured into a saturated sodium bicarbonate aqueous solution and extracted with tert-butyl methyl ether for 3 times. The organic phase was washed with saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to obtain compound 4-ii (11.3 g, 0.045 mol).

[0042] In the third step, methyltriphenylphosphonium bromide (20 g, 0.052 mol) was dissolved in tetrahydrofuran, and NaH (1.44 g, 0.06 mol) was added under the condition of controlling the temperature at 0°C in a salt ice bath, and then the compound 4-ii (10 g, 0.040 mol) was added under the condition of controlling the temperature. After the addition, the reaction temperature was raised to room temperature and reacted for 24 hours. The reaction solution was quenched in ice water and extracted with tert-butyl methyl ether. The organic phase was washed with saturated brine, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and separated by column chromatography to obtain the target compound 4-iii (7.6 g, 0.031 mol).

[0043] The fourth step is to put compound 4-iii (5 g, 0.020 mol) into epichlorohydrin (40 g, 0.43 mol) at room temperature, add potassium hydroxide (2.24 g, 0.040 mol) and react at room temperature for 16 hours. The reaction solution is filtered and washed with a small amount of organic solvent for multiple times, and then the filtrate is washed with clean water and extracted. The organic solvent containing the product is dried and separated by column chromatography to obtain the target product compound 4 (2.2 g, 0.007 mol).

[0044] The NMR characterization of the target product compound 4 is as follows:

[0045] 1 H NMR(400MHz, CDCl3)δ7.29–7.26(d,1H),7.13–7.10(m,3H),6.95–6.91(m,4H),6.68(m,1H) ,5.77–5.75(d,1H),5.55–5.53(d,1H),3.11(m,1H),2.91(m,1H),2.71(m,1H),2.49(m,2H).

[0046] Taking compound 2 as an example, free radical polymerization and photoinduced cationic polymerization were carried out respectively. The specific operations are as follows:

[0047] Free radical polymerization: 100 parts of the product of the present invention were dissolved in 10 parts of ethyl acetate, 1 part of initiator AIBN was added, and the reaction was carried out at 80°C for 5 hours. After the reaction was completed, the reaction solution was concentrated to obtain a high refractive index optical resin. After testing, the refractive index of the resin was 1.67.

[0048] Photoinitiated cationic polymerization:

[0049] 100 parts of the product of the present invention are dissolved in 10 parts of ethyl acetate, 1 part of cationic photoinitiator 6976 is added, the mixture is evenly mixed and then the solvent is evaporated to obtain a film of a certain thickness. A photopolymerized photocurable film of compound 2 is obtained by irradiation with a high-pressure mercury lamp (lamp distance 5 cm, light intensity I365nm=1mW / cm2), and the refractive index is 1.68.

[0050] The structure of the compounds obtained by the above examples can be derived: the monomers described in the present invention not only contain vinyl functional groups that can be free radical polymerized, but also are designed with epoxy functional groups that can be post-heat cured after the vinyl polymerization is completed to enhance the strength of the resin. The sulfur element and benzene ring structure that have the effect of increasing the refractive index are introduced. After free radical polymerization, the benzene ring and sulfur element that provide a high refractive index will be retained on the main chain of the polymer, so that its refractive index reaches above 1.65.

[0051] The above-described embodiments are merely descriptions of preferred implementations of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made by ordinary persons in the art to the technical solution of the present invention should fall within the protection scope of the present invention, and the technical contents for which protection is sought in the present invention have been fully recorded in the claims.

Claims

1. A high-refractive bifunctional optical resin monomer, characterized in that: It has the following chemical structure: Among them, X1 and X2 are O or S.

2. A method for preparing a high-refractive bifunctional optical resin monomer as claimed in claim 1, characterized in that: The steps include: Step 1: dissolving 1 equivalent of hydroquinone in a solvent, adding 2 equivalents of anhydrous potassium carbonate in sequence, adding 1 equivalent of fluorobenzaldehyde at 0-5°C, reacting at 80°C-150°C, quenching the reaction solution into water, extracting, washing with saturated brine, drying, concentrating, and recrystallizing to obtain compound b, wherein hydroquinone is hydroxythiophenol and dithiobenzene, wherein hydroxythiophenol and dithiobenzene can be any three structures of o-, m-, and p-, and the fluorobenzaldehyde can be any three structures of o-, m-, and p-; Step 2: Dissolve 1.2 equivalents of methyltriphenylphosphonium bromide in a solvent, add 1.5 equivalents of a base and then 1 equivalent of compound b under the condition of temperature control of 0-5°C, warm the reaction to room temperature and continue the reaction for 16-48T, quench the reaction solution in ice water, extract with a solvent, add a desiccant and dry, and separate by column chromatography to obtain the target compound c; Step 3: Dissolve 1 equivalent of compound c in 1 equivalent of epichlorohydrin at room temperature, add an appropriate amount of base, react at room temperature for 16 hours, monitor the completion of the reaction, filter the reaction solution and wash it with a small amount of organic solvent several times, then wash the filtrate with clean water and extract, spin dry the organic solvent containing the product and separate it by column chromatography to obtain compound d.

Images