A high refractive index benzoxanthene spirofluorene diol and preparation method thereof

Abstract

The invention discloses a benzoxanthene spirofluorene diol with a high refractive index. The structural formula of the benzoxanthene spirofluorene diol is I. The refractive index of the benzoxanthene spirofluorene diol is greater than 1.68 at 589 nm and 25° C. The final product is obtained by subjecting benzoxanthene spirofluorene diol and ethylene carbonate to a hydroxyethylation reaction under alkaline conditions and then recrystallizing the benzoxanthene spirofluorene diol crystal. The benzoxanthene spirofluorene diol crystal has a high refractive index and is used for the preparation of an optical resin material to improve the refractive index of the material. The benzoxanthene spirofluorene diol crystal is a solvent-free complexed non-inclusion body, which is conducive to the manufacture of high-quality optical resin materials.

Description

Technical Field

[0001] The invention relates to a spirofluorene diol derivative and a preparation method thereof, in particular to a benzoxanthene spirofluorene diol with a high refractive index and a preparation method thereof. Background Art

[0002] High-refractive polymer materials have important applications in optical devices, especially polycarbonate optical resins containing fluorene rings, which have replaced optical glass and are widely used as lens materials for mobile phones, tablets, computers, cars, cameras, etc. due to their high refractive index, good transparency, light weight, and easy molding and processing. The refractive index of traditional bisphenol A polycarbonate is only 1.58. Compared with traditional bisphenol A polycarbonate, the refractive index of the diol monomer of the fluorene skeleton and its polycarbonate has been greatly improved. Japanese patent JP2016074644 discloses that the refractive index of 9,9-(4(2-hydroxyethoxy)phenylfluorene (BPEF) monomer is 1.62, and international patent WO2007142149 discloses that the refractive index of the polycarbonate obtained by BPEF copolymerization is 1.62-1.64. Chinese patent CN109456298 discloses that the refractive index of the polycarbonate with spirofluorene diol as monomer is 1.62-1.64. The refractive index of the currently used polycarbonate optical resin is still lower than 1.65. Due to the rapid development of information technology, especially the emergence of 5G and 6G high-frequency communication technology, optoelectronic devices are developing towards light, thin, small and higher heat resistance requirements. Therefore, the diol monomer of the optical resin needs to have a higher refractive index and higher thermal stability. Further improving the refractive index and thermal stability of polycarbonate monomers is a key technical problem that needs to be solved urgently. Summary of the invention

[0003] Purpose of the invention: The present invention aims to increase the refractive index of polycarbonate monomers and provide a high-refractive-index benzoxanthene spirofluorene diol; the second purpose of the present invention is to provide a method for preparing the benzoxanthene spirofluorene diol.

[0004] Technical solution: The high refractive index benzoxanthene spirofluorene diol of the present invention has the structural formula:

[0005]

[0006] The refractive index of the benzoxanthene spirofluorene diol is greater than 1.68 at 589 nm and 25° C.

[0007] The benzoxanthene spirofluorene diol crystal is a non-inclusion body without solvent complexation or inclusion. It is a well-known fact that fluorene derivatives are very easy to form inclusion bodies by inclusion complexation with organic solvents. This solvent inclusion body has a serious adverse effect on the subsequent polymerization reaction to produce polycarbonate. On the one hand, the release of solvent during the polymerization reaction seriously affects the quality of polycarbonate, and on the other hand, the release of solvent has an adverse effect on the environment. Since benzoxanthene spirofluorene diol has a rigid large-plane benzoxanthene ring, a non-inclusion body without solvent complexation can be obtained by recrystallization from an organic solvent.

[0008] The benzoxanthene spirofluorene diol crystal has an endothermic peak measured by a differential scanning calorimeter within a temperature range of 293 to 303°C.

[0009] The preparation method of benzoxanthene spirofluorene diol of the present invention comprises the following steps: subjecting benzoxanthene spirofluorene diol and ethylene carbonate to a hydroxyethylation reaction under alkaline conditions, followed by recrystallization to obtain a final product. The reaction equation is as follows:

[0010]

[0011] Preferably, the temperature of the hydroxyethylation reaction is 110-140° C., and the reaction time is 2-10 h.

[0012] Preferably, the solvent used for the reaction recrystallization is selected from one or more of toluene, xylene, dioxane, acetonitrile, methanol, ethanol, isopropanol, acetone, methyl isobutyl ketone, DMF, ethyl acetate, butyl acetate and the like.

[0013] Preferably, the molar ratio of benzoxanthene spirofluorene diphenol to ethylene carbonate is 1.0:2.0-6.0.

[0014] Preferably, the hydroxyethylation reaction solvent is one or more of polar aprotic solvents or aromatic hydrocarbon solvents such as N,N-dimethylformamide, N,N-diethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, acetonitrile, dioxane, toluene, xylene, ethylbenzene and isopropylbenzene.

[0015] Preferably, the base is one or more of an alkali metal, a carbonate, an alkoxide or an organic base; the molar ratio of the base to the molar ratio of benzoxanthene spirofluorene diphenol is 0.1 to 1.0:1.0. The alkali metal is a hydroxide such as sodium hydroxide, potassium hydroxide, or lithium hydroxide; the carbonate is sodium carbonate, potassium carbonate, sodium bicarbonate, or potassium bicarbonate; the alkoxide is sodium ethoxide, potassium ethoxide, sodium methoxide, potassium methoxide, sodium isopropoxide, potassium isopropoxide, sodium tert-butoxide, or potassium tert-butoxide; the organic base is triethylamine, tripropylamine, triisopropylamine, tributylamine, N-ethyldiisopropylamine, pyridine, piperidine, or tetrahydropyrrole.

[0016] The benzoxanthene spirofluorene diol is obtained by condensation reaction of 1,6-dinaphthol and 9-fluorenone, and the reaction equation is as follows:

[0017]

[0018] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The refractive index of benzoxanthene spirofluorene diol crystals is greater than 1.68 (589nm, 25°C), which can be used in the preparation of optical resin materials to improve the refractive index of the materials; (2) The benzoxanthene spirofluorene diol crystals are solvent-free complexed non-inclusion bodies, which are beneficial to the manufacture of high-quality optical resin materials; (3) The melting endothermic peak of the diol monomer is in the range of 293.0 to 303.0°C, and has good heat resistance; (4) The preparation method is simple and easy to industrialize. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of benzoxanthene spirofluorene diphenol prepared in Example 1;

[0020] Figure 2 The thermal analysis DSC spectrum of benzoxanthene spirofluorene diphenol prepared in Example 1;

[0021] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of benzoxanthene spirofluorene diol prepared in Example 1;

[0022] Figure 4 The thermal analysis DSC spectrum of benzoxanthene spirofluorene diol prepared in Example 1;

[0023] Figure 5 This is the thermal analysis TGA spectrum of benzoxanthene spirofluorene diol prepared in Example 1. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0025] The analytical method adopted in the present invention is as follows:

[0026] 1. Purity determination method (HPLC): instrument: LC-15C (Shimadzu); column type: Kromasil100-5C18 150×4.6 mm; mobile phase: acetonitrile / water; flow rate: 1 mL / min; detection wavelength: 260 nm; injection volume: 2 ul; pump mode: binary high pressure gradient.

[0027] 2. Thermal analysis method: measured by Pyris1 thermal analyzer (Perkin Elemer Company), DSC heating range 45-400°C, 10°C / min; TGA heating range 25-500°C, 10°C / min.

[0028] 3. Chromaticity analysis: Use Transmission colar meter TZ6000 (Nippon Denshoku Industries Co., Ltd.) to test. Add 10 g of sample into 20 g of DMF, stir to dissolve and then test.

[0029] 4. Refractive index (nD): The refractive index was measured at 25°C using a DR-M2 Abbe refractometer manufactured by ATAGO at a wavelength of 589 nm.

[0030] 6. Nuclear magnetic resonance instrument: Bruker AV 400 nuclear magnetic resonance instrument (DMSO-d6 as solvent, TMS as internal standard).

[0031] Example 1

[0032] The preparation method of benzoxanthene spirofluorene diol of the present invention comprises the following steps:

[0033] (1) Preparation of benzoxanthene spirofluorene diphenol:

[0034] In a 1000 ml four-necked flask, add 90 g of 9-fluorenone, 200 g of 1,6-dihydroxynaphthalene, 500 g of toluene, and 3 g of 3-mercaptopropionic acid, stir, heat to dissolve, control the temperature below 30 ° C, then slowly drop 90 g of concentrated sulfuric acid, drip it for about 2 hours, then heat it to 40 ° C, stir and keep it warm for 6 hours. Stop the heating reaction when the HPLC detection of 9-fluorenone residue is less than 0.5%. Cool to room temperature, add 300 g of toluene, then wash with water to neutrality, finally evaporate the solvent under reduced pressure, and the residual solid is recrystallized with methanol. The solid is vacuum dried at 120 ° C for 10 hours to obtain 180 g of benzoxanthene spirofluorene diphenol, a solid white powder with a yield of 77.5% and a purity (HPLC) of 98%.

[0035] like Figure 1 As shown, the H NMR spectrum of benzoxanthene spirofluorene diphenol 1 H NMR (400MHz, DMSO-d6) δ: 9.95 (s, 2H, OH, weighted water disappears), 8.61 (d, 2H, Ar-H), 8.04 (d, 2H, Ar-H), 7.42-7.45 (m, 2H, Ar-H ),7.30-7.33(m,2H,Ar-H),7.23(d,2H,Ar-H),7.15(d,2H,Ar-H),7.07-7.11(m,4H,Ar-H),6.16(d,2H,Ar-H).

[0036] like Figure 2 As shown, the melting endothermic peak of benzoxanthene spirofluorene diphenol is 351.9°C in the DSC spectrum.

[0037] (2) Preparation of benzoxanthene spirofluorene diol:

[0038] In a 500 ml four-necked flask, add 20 g of benzoxanthene spirofluorene diphenol, 40 g of DMF, 15 g of ethylene carbonate, and 1.0 g of anhydrous sodium carbonate, stir and heat, react at 130°C for 5 h, HPLC analysis shows that the residual raw material benzoxanthene spirofluorene diphenol is less than 0.5%, and the reaction conversion rate reaches 95%, then stop the reaction; cool, add 200 g of toluene to dissolve, wash with water 4 times, 100 ml of water each time, then evaporate the solvent under reduced pressure, recrystallize the residual solid with toluene, cool and crystallize, filter and rinse, and dry the solid in vacuum at 120°C for 10 h to obtain 19 g of white crystals with a yield of 82.2% and a purity (HPLC) of 98.5%.

[0039] like Figure 3 As shown, the H NMR spectrum of benzoxanthene spirofluorene diol 1 H NMR(400MHz,DMSO-d6)δ:8.67(d,2H,Ar-H),8.05(d,2H,Ar-H),7.39-7.46(m,4H,Ar-H),7.27-7.20(m,4H,Ar-H),7.20-7.2 4(m,2H,Ar-H), 7.10(d,2H,Ar-H), 6.22(d,2H,Ar-H), 4.96-4.98(m,2H, OH, weighted water disappears), 4.12(dd,4H,2CH2), 3.75(dd,4H,2CH2).

[0040] like Figure 4 As shown, the melting endothermic peak of benzoxanthene spirofluorene diol in the DSC spectrum is in the range of 293.0 to 303.0°C.

[0041] like Figure 5 As shown in the thermal analysis TGA spectrum of benzoxanthene spirofluorene diol, there is no weight loss at 250°C, indicating that the product is a non-inclusion body without solvent complexation or inclusion.

[0042] The refractive index of the benzoxanthene spirofluorene diol prepared in this example is 1.681 (589 nm, 25° C.) and the chromaticity is 20.

[0043] Example 2

[0044] The preparation method of benzoxanthene spirofluorene diol of the present invention comprises the following steps:

[0045] (1) The preparation of benzoxanthene spirofluorene diphenol is the same as in Example 1;

[0046] (2) Preparation of benzoxanthene spirofluorene diol:

[0047] In a 500 ml four-necked flask, add 2g of benzoxanthene spirofluorene diphenol, 40g of DMAC, 11g of ethylene carbonate, and 0.5g of anhydrous potassium carbonate, stir and heat, and react at 140°C for 2h. HPLC analysis shows that the residual benzoxanthene spirofluorene diphenol of the raw material is less than 0.5%, and the reaction conversion rate reaches 96%, and the reaction is stopped; cool down, add 200g of toluene to dissolve, wash with water 4 times, 100 ml of water each time, then evaporate the solvent under reduced pressure, recrystallize the residual solid with toluene, cool and crystallize, filter and rinse, and finally dry the solid at 120°C in vacuum for 10h to obtain 18g of white crystals, with a yield of 80.0% and a purity (HPLC) of 98.0%.

[0048] The refractive index of the benzoxanthene spirofluorene diol prepared in this example is 1.683 (589 nm, 25° C.), and the chromaticity is 15.

[0049] Example 3

[0050] The preparation method of benzoxanthene spirofluorene diol of the present invention comprises the following steps:

[0051] (1) The preparation of benzoxanthene spirofluorene diphenol is the same as in Example 1;

[0052] (2) Preparation of benzoxanthene spirofluorene diol:

[0053] In a 500 ml four-necked flask, add 20 g of benzoxanthene spirofluorene diphenol, 20 g of dioxane, 60 g of toluene, 11 g of ethylene carbonate, and 0.5 g of anhydrous potassium carbonate, stir and heat, react at 120°C for 8 h, HPLC analysis shows that the residual raw material benzoxanthene spirofluorene diphenol is less than 0.5%, and the reaction conversion rate reaches 92%, then stop the reaction; cool, add 200 g of toluene to dissolve, wash with water 4 times, 100 ml of water each time, evaporate the solvent under reduced pressure, recrystallize the residual solid with acetone / toluene solvent, cool and crystallize, filter and rinse, and finally dry the solid in vacuum at 120°C for 10 h to obtain 18 g of white crystals with a yield of 80.0% and a purity (HPLC) of 98.0%.

[0054] The refractive index of the benzoxanthene spirofluorene diol prepared in this example is 1.682 (589 nm, 25° C.), and the chromaticity is 25.

Claims

1. A high refractive index benzoxanthene spirofluorene diol, characterized in that: Its structural formula is: 。 2. The benzoxanthene spirofluorene diol according to claim 1, characterized in that The refractive index of the benzoxanthene spirofluorene diol is greater than 1.68 at 589 nm and 25° C.

3. The benzoxanthene spirofluorene diol according to claim 1, characterized in that: The benzoxanthene spirofluorene diol has an endothermic peak measured by a differential scanning calorimeter within a temperature range of 293-303°C.

4. A method for preparing benzoxanthene spirofluorene diol according to any one of claims 1 to 3, characterized in that: The final product is obtained by hydroxyethylation reaction of benzoxanthene spirofluorene diphenol and ethylene carbonate under alkaline conditions and then recrystallization. The reaction equation is as follows: 。 5. The benzoxanthene spirofluorene diol according to claim 4, characterized in that: The temperature of the hydroxyethylation reaction is 110-140° C., and the reaction time is 2-10 h.

6. The benzoxanthene spirofluorene diol according to claim 4, characterized in that: The solvent used for the reaction recrystallization is selected from one or more of toluene, xylene, dioxane, acetonitrile, methanol, ethanol, isopropanol, acetone, methyl isobutyl ketone, DMF, ethyl acetate, butyl acetate and the like.

7. The benzoxanthene spirofluorene diol according to claim 4, characterized in that: The molar ratio of the benzoxanthene spirofluorene diphenol to ethylene carbonate is 1.0:2.0-6.

0.

8. The benzoxanthene spirofluorene diol according to claim 4, characterized in that: The solvent for the hydroxyethylation reaction is one or more of polar aprotic solvents or aromatic hydrocarbon solvents such as N,N-dimethylformamide, N,N-diethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, acetonitrile, dioxane, toluene, xylene, ethylbenzene and isopropylbenzene.

9. The benzoxanthene spirofluorene diol according to claim 4, characterized in that: The base is one or more of alkali metals, carbonates, alcohol salts or organic bases; the molar ratio of the base to the molar ratio of benzoxanthene spirofluorene diphenol is 0.1-1.0:1.0.

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