Preparation method and application of alkyl chain functionalized azobenzene derivative and composite material thereof

Abstract

The application relates to a preparation method and application of alkyl chain functionalized azobenzene derivatives and composite materials thereof, discloses a series of alkyl chain functionalized azobenzene derivatives and a preparation method thereof, and provides a method for preparing a solar thermal energy fuel film in a photoisomerization type and a ready-to-use type, and a solar thermal energy fuel composite film is prepared. The alkyl chain functionalized azobenzene derivatives and the composite materials thereof have high photoisomerization efficiency, high total energy storage density, a simple and green charging process, and good cycle stability.

Description

Technical Field

[0001] This invention relates to a method for preparing alkyl chain functionalized azobenzene derivatives and their composite materials, as well as their applications, belonging to the fields of clean energy and renewable energy. Background Technology

[0002] Solar energy, as an inexhaustible and powerful energy source, is an ideal clean energy source. Therefore, developing and utilizing solar energy is an effective strategy to solve the current problems of energy scarcity and environmental pollution. Photoresponsive solar thermal fuels have become a research focus in the field of energy storage. Solar thermal fuels refer to materials that utilize changes in molecular structure / bond rearrangement to store light energy in the form of chemical energy, and then release it in the form of thermal energy under thermal stimulation or catalysis, providing a closed-system strategy for storing renewable energy. This energy storage process has the characteristics of high light utilization, recyclability, and no pollution. Azophenyl photoresponsive materials have been widely studied due to their excellent photoinduced cis / trans isomerization ability and good cycle stability. Under ultraviolet light stimulation, azophenyl isomerizes from the trans configuration to the cis configuration, storing energy in the molecular isomer; then, under visible light / thermal stimulation, it isomerizes from the metastable cis configuration to the trans configuration, thus completing a cycle of energy storage and release.

[0003] The low energy density and short half-life of unmodified azobenzene have limited its further development. To apply azophenyl compounds to the field of solar thermal fuels, various azophenyl solar thermal fuels have been developed, such as nano-templated azobenzene derivatives, polymer-templated azobenzene derivatives, and azobenzene composite systems doped with phase change materials. Room-temperature photoinduced solid / liquid conversion azobenzene derivatives, which undergo photoinduced phase transitions at room temperature, do not require solvent pretreatment during the charging process, and the superposition of latent heat of phase transition and isomerization enthalpy greatly improves energy storage performance.

[0004] Although there has been some research on azophenyl solar fuels in existing technologies, it remains essential to find newer and better azophenyl compounds. Summary of the Invention

[0005] The purpose of this invention is to prepare alkyl chain functionalized azobenzene derivatives with fast photoisomerization speed and excellent energy storage performance by designing molecular structures, and to provide a method for preparing solar thermal fuel thin film composite materials by processing them with flexible fabrics, as well as their applications.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] Technical Topic 1

[0008] This invention provides an alkyl-chain functionalized azobenzene derivative, which is liquid in the cis configuration and solid in the trans configuration at room temperature. The azobenzene derivative has the structure shown in Formula I:

[0009]

[0010] Formula I

[0011] Where R 1 When it is methyl, R 2 Selected from C4-C12 straight-chain alkyl groups;

[0012] When R 1 When selected from C2-C16 straight-chain alkyl, C3-C5 branched alkyl, C1-C6 straight-chain alkoxy, or trifluoromethoxy, R 2 Selected from Zhengjiji.

[0013] As a further improvement of the present invention, the alkyl chain functionalized azobenzene derivative is selected from the following structures:

[0014] 1-(4-Butoxyphenyl)-2-(p-Tolyl)diazeline;

[0015] 1-(4-(hexyloxy)phenyl)-2-(p-tolyl)diazeline;

[0016] 1-(4-(octoxy)phenyl)-2-(p-tolyl)diazeline;

[0017] 1-(4-(decoxy)phenyl)-2-(p-tolyl)diazeline;

[0018] 1-(4-(dodecyloxy)phenyl)-2-(p-tolyl)diazeline;

[0019] 1-(4-Ethylphenyl)-2-(4-(Hexoxy)phenyl)diazeline;

[0020] 1-(4-Butylphenyl)-2-(4-(hexyloxy)phenyl)diazeline;

[0021] 1-(4-(hexyloxy)phenyl)-2-(4-hexylphenyl)diazeline;

[0022] 1-(4-Dodecylphenyl)-2-(4-(hexyloxy)phenyl)diazeline;

[0023] 1-(4-Hexadecylphenyl)-2-(4-(hexyloxy)phenyl)diazeline;

[0024] 1-(4-trifluoromethoxyphenyl)-2-(4-(hexyloxy)phenyl)diazeline;

[0025] 1-(4-(hexyloxy)phenyl)-2-(4-methoxyphenyl)diazeline;

[0026] 1-(4-ethoxyphenyl)-2-(4-(hexyloxy)phenyl)diazeline;

[0027] 1-(4-(hexyloxy)phenyl)-2-(4-isopropylphenyl)diazepine.

[0028] Technical Theme Two

[0029] The present invention also provides a method for preparing the above-mentioned alkyl chain functionalized azobenzene derivative, which includes the following steps:

[0030] ;

[0031] S1: Mix aniline derivative a, hydrochloric acid and water, and add NaNO2 solution dropwise to the mixture at 0-5℃, while continuing to stir, to obtain diazonium salt b solution;

[0032] S2: Dissolve phenol, Na2CO3 and NaOH in water and slowly add them dropwise to the diazonium salt b solution. Continue stirring at room temperature to allow the reaction to proceed fully. Adjust the pH to ≤7 with hydrochloric acid, filter the precipitate, wash with water, dry, and purify by column chromatography to obtain the hydroxyl-containing azobenzene intermediate c.

[0033] S3: The hydroxyl-containing azobenzene intermediates c and R 2 -Br reacts in a solvent under heating in the presence of sodium hydroxide. After the reaction is complete, the product d is obtained by purification by column chromatography.

[0034] The R 1 Selected from methyl, C2-C16 straight-chain alkyl, C3-C5 branched alkyl, C1-C6 straight-chain alkoxy, and trifluoromethoxy;

[0035] The R 2 Selected from C4-C12 straight-chain alkyl groups and n-hexyl groups.

[0036] As a further improvement of the present invention, the hydrochloric acid in S1 has a mass percentage of 37%, the molar volume ratio of aniline derivative a to hydrochloric acid is 1 mmol: 0.2-0.5 mL, and the molar ratio of aniline derivative a to NaNO2 is 1: 1.0-1.5.

[0037] As a further improvement of the present invention, the molar ratio of phenol, Na2CO3 and NaOH in S2 is 1:1.0-1.5:1.0-1.3. The column chromatography purification first uses a mixed eluent of dichloromethane and petroleum ether with a volume ratio of 1:1-2 to remove impurities, then uses dichloromethane to elute the product, and rotary evaporation yields the hydroxyl-containing azobenzene intermediate c.

[0038] As a further improvement of the present invention, the solvent in S3 is a mixed solution of water and ethanol with a volume ratio of 1:5-20, and the heating temperature is 50-90℃. The hydroxyl-containing azobenzene intermediates c and R... 2 The molar ratio of Br to NaOH is 1:1.0-5.0:1.0-1.5. Column chromatography purification uses a mixed eluent of dichloromethane and petroleum ether with a volume ratio of 1:1-3.

[0039] Technical Theme 3

[0040] The present invention also provides an azophenyl solar thermal energy fuel thin film composite material, which is composed of the alkyl chain functionalized azophenyl derivative described in Technical Subject 1 and a flexible fabric.

[0041] As a further improvement of the present invention, the material is prepared by the following method: the solid alkyl chain functionalized azobenzene derivative is uniformly spread on a flexible fabric, placed in a dark and enclosed environment, and irradiated with an ultraviolet lamp until the alkyl chain functionalized azobenzene derivative is transformed into a liquid state and immersed into the fabric, thereby obtaining a flexible composite film.

[0042] As a further improvement of the present invention, the thickness of the flexible fabric is 0.5-1.2 mm, and the coating amount of the alkyl chain functionalized azobenzene derivative on the surface of the flexible fabric is 3.2-9.6 mg / cm². 2 .

[0043] The fabrics described in this invention are flat, soft sheets or blocks formed by crossing, knotting, and connecting small, flexible materials. These include, but are not limited to: cotton-type fabrics, commercially known simply as "cotton cloth," which are fabrics woven from cotton yarn or cotton blended with synthetic fibers; wool-type fabrics, commercially known simply as "wool," which are fabrics woven from animal hair and wool-type synthetic fibers; silk-type fabrics, commercially known simply as "silk," with silk fabrics woven from mulberry silk called pure silk and silk fabrics woven from tussah silk called tussah silk; linen-type fabrics, mainly ramie fabrics and flax fabrics; pure synthetic fiber fabrics, mainly medium-length fiber imitation cotton, linen, wool, and silk fabrics, synthetic fiber filament fabrics, artificial deerskin, and artificial fur; nylon; carbon fiber cloth, etc.

[0044] Technical Theme 4

[0045] The final aspect of the invention provides the use of the azophenyl solar thermal fuel thin film composite material described in Technical Subject 3 as a solar thermal energy storage material.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The alkyl chain functionalized azobenzene derivative provided by this invention has a fast photoisomerization rate, a high total energy storage density, a simple and environmentally friendly charging process, and can maintain good cycle stability.

[0048] The solar thermal energy fuel film composite material provided by this invention is made by combining alkyl chain functionalized azobenzene derivatives with flexible fabrics through ultraviolet irradiation to achieve phase change, and has strong solar thermal energy storage characteristics. Attached Figure Description

[0049] Figure 1 The image shows the 1H NMR spectrum of the alkyl chain functionalized azobenzene derivative obtained in Example 3.

[0050] Figure 2 The image shows the 1H NMR spectrum of the alkyl chain functionalized azobenzene derivative obtained in Example 4. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described clearly and completely below in conjunction with specific embodiments.

[0052] Example 1 Preparation of intermediate c

[0053]

[0054] Aniline derivative a (15.0 mmol, 1 equiv), hydrochloric acid (37%, 3.75 mL), and deionized water (15 mL) were added to a 100 mL round-bottom flask, sonicated to obtain solution A, and placed in an ice-water bath. NaNO2 (1.035 g, 15.0 mmol, 1 equiv) was weighed and dissolved in deionized water (5 mL) to obtain solution B. After the temperature of solution A decreased to 0–5 °C, solution B was added dropwise to solution A, and the reaction was stirred at low temperature for 4 h. Phenol (1.41 g, 15.0 mmol, 1 equiv), Na2CO3 (1.608 g, 15.45 mmol, 1.03 equiv), and NaOH (0.60 g, 15.0 mmol, 1 equiv) were dissolved in deionized water (15 mL), sonicated, and then slowly added dropwise to the above reaction system. After the addition was complete, the reaction was stirred at room temperature for another 4 h. After the reaction was completed, the reaction system was acidified with 37% hydrochloric acid. The acidification process required thorough stirring until the pH was ≤7. The acidified mixture was filtered, and the resulting filter cake was washed with a large amount of deionized water and dried under vacuum at 50°C for 24 h to obtain a yellow crude product. The crude product was purified by silica gel column chromatography. The eluent was first a mixture of dichloromethane and petroleum ether (CH2Cl2:PE = 1:1). After the first impurity was eluted, pure dichloromethane was used to elute the product solution. This solution was then concentrated by rotary evaporation to obtain the hydroxyl-containing azobenzene intermediate c. Specific raw materials, products, and yields are shown in Table 1.

[0055] Table 1

[0056]

[0057] Example 2 Preparation of 1-(4-Butoxyphenyl)-2-(p-Tolyl)diazepine

[0058] Weigh 1.06 g (5 mmol, 1 equiv) of 4-(p-tolyldiazenyl)phenol into a 100 mL round-bottom flask, add 45 mL of anhydrous ethanol, and sonicate until fully dissolved. Dissolve 0.4 g (10 mmol, 2 equiv) of NaOH in 5 mL of deionized water and add it to the reaction system. Add 15 mmol (2.055 g, 3 equiv) of bromobutane to the reaction system, purge with nitrogen gas, and degas three times to completely remove oxygen. Under nitrogen protection and reflux, heat and stir at 70 °C for 24 h. After the reaction is complete, concentrate the reaction solution by rotary evaporation. When a small amount of solvent remains, add an appropriate amount of silica gel and continue rotary evaporation to obtain a pale yellow powder. Purify the pale yellow crude product obtained by rotary evaporation by silica gel column chromatography with petroleum ether and dichloromethane in a volume ratio of 2:1 as eluent. After obtaining the product solution, concentrate by rotary evaporation to obtain an orange-yellow solid with a yield of 82%. MS(m / z): 269.2. 1 HNMR (500 MHz, CDCl3) δ(ppm): 7.94-7.85 (d, 2H, Ar-H), 7.83-7.73 (d, 2H, Ar-H), 7.35-7.27 (d, 2H, Ar-H), 7.04-6.95 (d, 2H, Ar-H), 4.09-3.99 (t, 2H, -CH2), 2.43 (s, 3H, -CH3), 1.87-1.77 (m, 2H, -CH2), 1.56-1.43 (m, 2H, -CH2), 1.05-0.92 (t, 3H, -CH3).

[0059] Example 3 Preparation of 1-(4-hexyloxyphenyl)-2-(p-tolyl)diazeline

[0060] Weigh 1.06 g (5 mmol, 1 equiv) of 4-(p-tolyldiazenyl)phenol into a 100 mL round-bottom flask, add 45 mL of anhydrous ethanol, and sonicate until fully dissolved. Dissolve 0.4 g (10 mmol, 2 equiv) of NaOH in 5 mL of deionized water and add it to the reaction system. Add 15 mmol (2.476 g, 3 equiv) of 1-bromohexane to the reaction system, purge with nitrogen gas, and degas three times to completely remove oxygen. Under nitrogen protection and reflux, heat and stir at 70 °C for 24 h. After the reaction is complete, concentrate the reaction solution by rotary evaporation. When a small amount of solvent remains, add an appropriate amount of silica gel and continue rotary evaporation to obtain a pale yellow powder. Purify the pale yellow crude product obtained by rotary evaporation by silica gel column chromatography with petroleum ether and dichloromethane in a volume ratio of 2:1 as eluent. After obtaining the product solution, concentrate by rotary evaporation to obtain a yellow solid with a yield of 75%. MS(m / z): 297.2. 1 HNMR (500 MHz, CDCl3) δ(ppm): 7.92-7.85 (d, 2H, Ar-H), 7.82-7.75 (d, 2H, Ar-H), 7.33-7.27 (d, 2H, Ar-H), 7.03-6.96 (d, 2H, Ar-H), 4.07-4.00 (t, 2H, -CH2), 2.43 (s, 3H, -CH3), 1.88-1.76 (m, 2H, -CH2), 1.53-1.41 (m, 2H, -CH2), 1.40-1.31 (m, 4H, -CH2), 0.96-0.87 (t, 3H, -CH3).

[0061] Example 4 Preparation of 1-(4-octoxyphenyl)-2-(p-tolyl)diazeline

[0062] Weigh 1.06 g (5 mmol, 1 equiv) of 4-(p-tolyldiazenyl)phenol into a 100 mL round-bottom flask, add 45 mL of anhydrous ethanol, and sonicate until fully dissolved. Dissolve 0.4 g (10 mmol, 2 equiv) of NaOH in 5 mL of deionized water and add it to the reaction system. Add 15 mmol (2.896 g, 3 equiv) of bromooctane to the reaction system, purge with nitrogen gas, and degas three times to completely remove oxygen. Under nitrogen protection and reflux, heat and stir at 70 °C for 24 h. After the reaction is complete, concentrate the reaction solution by rotary evaporation. When a small amount of solvent remains, add an appropriate amount of silica gel and continue rotary evaporation to obtain a pale yellow powder. Purify the pale yellow crude product obtained by rotary evaporation by silica gel column chromatography with petroleum ether and dichloromethane in a volume ratio of 2:1 as eluent. After obtaining the product solution, concentrate by rotary evaporation to obtain a yellow solid with a yield of 81%. MS(m / z): 325.2. 1 HNMR (500 MHz, CDCl3) δ(ppm): 7.92-7.85 (d, 2H, Ar-H), 7.81-7.75 (d, 2H, Ar-H), 7.33-7.27 (d, 2H, Ar-H), 7.03-6.96 (d, 2H, Ar-H), 4.07-3.99 (t, 2H, -CH2), 2.43 (s, 3H, -CH3), 1.88-1.77 (m, 2H, -CH2), 1.53-1.41 (m, 2H, -CH2), 1.41-1.23 (m, 8H, -CH2), 0.95-0.84 (t, 3H, -CH3).

[0063] Example 5 Preparation of 1-(4-decoxyphenyl)-2-(p-tolyl)diazeline

[0064] Weigh 1.06 g (5 mmol, 1 equiv) of 4-(p-tolyldiazenyl)phenol into a 100 mL round-bottom flask, add 45 mL of anhydrous ethanol, and sonicate until fully dissolved. Dissolve 0.4 g (10 mmol, 2 equiv) of NaOH in 5 mL of deionized water and add it to the reaction system. Add 15 mmol (3.317 g, 3 equiv) of bromodecane to the reaction system, purge with nitrogen gas, and degas three times to completely remove oxygen. Under nitrogen protection and reflux, heat and stir at 70 °C for 24 h. After the reaction is complete, concentrate the reaction solution by rotary evaporation. When a small amount of solvent remains, add an appropriate amount of silica gel and continue rotary evaporation to obtain a pale yellow powder. Purify the pale yellow crude product obtained by rotary evaporation by silica gel column chromatography with petroleum ether and dichloromethane in a volume ratio of 2:1 as eluent. After obtaining the product solution, concentrate by rotary evaporation to obtain an orange-yellow solid with a yield of 79%. MS(m / z): 353.2. 1 HNMR (500 MHz, CDCl3) δ(ppm): 7.97-7.87 (d, 2H, Ar-H), 7.86-7.77 (d, 2H, Ar-H), 7.36-7.27 (d, 2H, Ar-H), 7.05-6.95 (d, 2H, Ar-H), 4.09-3.97 (t, 2H, -CH2), 2.44 (s, 3H, -CH3), 1.89-1.76 (m, 2H, -CH2), 1.56-1.43 (m, 2H, -CH2), 1.43-1.23 (m, 12H, -CH2), 0.98-0.85 (t, 3H, -CH3).

[0065] Example 6 Preparation of 1-(4-dodecyloxyphenyl)-2-(p-tolyl)diazeline

[0066] Weigh 1.06 g (5 mmol, 1 equiv) of 4-(p-tolyldiazenyl)phenol into a 100 mL round-bottom flask, add 45 mL of anhydrous ethanol, and sonicate until fully dissolved. Dissolve 0.4 g (10 mmol, 2 equiv) of NaOH in 5 mL of deionized water and add it to the reaction system. Add 15 mmol (3.738 g, 3 equiv) of bromododecane to the reaction system, and purge with nitrogen gas three times to remove oxygen completely. Under nitrogen protection and reflux, heat and stir at 70 °C for 24 h. After the reaction is complete, concentrate the reaction solution by rotary evaporation. When a small amount of solvent remains, add an appropriate amount of silica gel and continue rotary evaporation to obtain a pale yellow powder. Purify the pale yellow crude product obtained by rotary evaporation by silica gel column chromatography with petroleum ether and dichloromethane in a volume ratio of 2:1 as eluent. The resulting solution of product is concentrated by rotary evaporation to obtain a yellow solid with a yield of 75%. MS (m / z): 381.3. 1 HNMR (500 MHz, CDCl3) δ(ppm): 7.93-7.85 (d, 2H, Ar-H), 7.83-7.74 (d, 2H, Ar-H), 7.33-7.27 (d, 2H,Ar-H), 7.03-6.96 (d, 2H,Ar-H), 4.07-4.00 (t, 2H, -CH2),2.43 (s, 3H, -CH3), 1.88-1.78 (m, 2H, -CH2), 1.53-1.42 (m, 2H, -CH2), 1.41-1.20 (m, 16H,-CH2), 0.93-0.84 (t, 3H,-CH3).

[0067] Example 7 Preparation of 1-(4-ethylphenyl)-2-(4-(hexyloxy)phenyl)diazeline

[0068] Weigh 1.13 g (5 mmol, 1 equiv) of 4-(p-ethylphenyldiazetenyl)phenol into a 100 mL round-bottom flask, add 45 mL of anhydrous ethanol, and sonicate until fully dissolved. Dissolve 0.4 g (10 mmol, 2 equiv) of NaOH in 5 mL of deionized water and add it to the reaction system. Add 15 mmol (2.476 g, 3 equiv) of 1-bromohexane to the reaction system, and purge with nitrogen gas to degas three times to completely remove oxygen. Under nitrogen protection and reflux, heat and stir at 70 °C for 24 h. After the reaction is complete, concentrate the reaction solution by rotary evaporation. When a small amount of solvent remains, add an appropriate amount of silica gel and continue rotary evaporation to obtain a pale yellow powder. Purify the pale yellow crude product obtained by rotary evaporation by silica gel column chromatography with petroleum ether and dichloromethane in a volume ratio of 2:1 as eluent. After obtaining the product solution, concentrate by rotary evaporation to obtain a yellow solid with a yield of 80%. MS(m / z): 311.2. 1 HNMR (500 MHz, CDCl3) δ(ppm):7.90-7.83 (d, 2H, Ar-H), 7.83-7.77 (d, 2H,Ar-H),7.36-7.29 (d, 2H,Ar-H), 6.97-6.90 (d, 2H,Ar-H), 5.34 (s, 1H, -OH), 2.78-2.66(m, 2H, -CH2), 1.35-1.23 (t, 3H, -CH3).

[0069] Example 8 Preparation of 1-(4-Butylphenyl)-2-(4-(hexyloxy)phenyl)diazeline

[0070] Weigh 1.27 g (p-butyrylphenyldiazenin)phenol into a 100 mL round-bottom flask, add 45 mL of anhydrous ethanol, and sonicate until fully dissolved. Dissolve 0.4 g (10 mmol, 2 equiv) of NaOH in 5 mL of deionized water and add it to the reaction system. Add 15 mmol (2.476 g, 3 equiv) of 1-bromohexane to the reaction system, and purge with nitrogen gas to degas three times to remove oxygen completely. Under nitrogen protection and reflux, heat and stir at 70 °C for 24 h. After the reaction is complete, concentrate the reaction solution by rotary evaporation. When a small amount of solvent remains, add an appropriate amount of silica gel and continue rotary evaporation to obtain a pale yellow powder. Purify the pale yellow crude product obtained by rotary evaporation by silica gel column chromatography with petroleum ether and dichloromethane in a volume ratio of 2:1 as eluent. After obtaining the product solution, concentrate by rotary evaporation to obtain a yellow solid with a yield of 81%. MS(m / z): 339.2. 1HNMR (500 MHz, CDCl3) δ(ppm): 7.93-7.86 (d, 2H,Ar-H), 7.86-7.79 (d, 2H,Ar-H), 7.37-7.31 (d, 2H,Ar-H), 7.00-6.93 (d, 2H,Ar-H), 5.41 (s, 1H, -OH), 2.78-2.65(t, 2H, -CH2), 1.76-1.61 (m, 2H,-CH2), 1.47-1.35 (m, 2H, -CH2), 1.02-0.94 (t,3H,-CH3).

[0071] Example 9 Preparation of 1-(4-(hexyloxy)phenyl)-2-(4-hexylphenyl)diazeline

[0072] Weigh 1.41 g (5 mmol, 1 equiv) of 4-(p-hexylphenyldiazeninyl)phenol into a 100 mL round-bottom flask, add 45 mL of anhydrous ethanol, and sonicate until fully dissolved. Dissolve 0.4 g (10 mmol, 2 equiv) of NaOH in 5 mL of deionized water and add it to the reaction system. Add 15 mmol (2.476 g, 3 equiv) of 1-bromohexane to the reaction system, and purge with nitrogen gas to degas three times to completely remove oxygen. Under nitrogen protection and reflux, heat and stir at 70 °C for 24 h. After the reaction is complete, concentrate the reaction solution by rotary evaporation. When a small amount of solvent remains, add an appropriate amount of silica gel and continue rotary evaporation to obtain a pale yellow powder. Purify the pale yellow crude product obtained by rotary evaporation by silica gel column chromatography with petroleum ether and dichloromethane in a volume ratio of 2:1 as eluent. After obtaining the product solution, concentrate by rotary evaporation to obtain a yellow solid with a yield of 60%. MS (m / z): 367.3. 1 HNMR (500 MHz, CDCl3) δ(ppm):7.89-7.83 (d, 2H, Ar-H), 7.82-7.76 (d, 2H,Ar-H),7.33-7.28 (d, 2H,Ar-H), 6.97-6.91 (d, 2H,Ar-H), 5.17 (s, 1H, -OH), 2.72-2.63(t, 2H,-CH2), 1.70-1.60 (m, 2H, -CH2), 1.40-1.23 (m, 6H, -CH2), 0.93-0.84 (t,3H, -CH3).

[0073] Example 10 Preparation of 1-(4-dodecylphenyl)-2-(4-(hexyloxy)phenyl)diazeline

[0074] Weigh 1.83 g (5 mmol, 1 equiv) of 4-(p-dodecylphenyldiazeninyl)phenol into a 100 mL round-bottom flask, add 45 mL of anhydrous ethanol, and sonicate until fully dissolved. Dissolve 0.4 g (10 mmol, 2 equiv) of NaOH in 5 mL of deionized water and add it to the reaction system. Add 15 mmol (2.476 g, 3 equiv) of 1-bromohexane to the reaction system, and purge with nitrogen gas to degas three times to completely remove oxygen. Under nitrogen protection and reflux, heat and stir at 70 °C for 24 h. After the reaction is complete, concentrate the reaction solution by rotary evaporation. When a small amount of solvent remains, add an appropriate amount of silica gel and continue rotary evaporation to obtain a pale yellow powder. Purify the pale yellow crude product obtained by rotary evaporation by silica gel column chromatography with petroleum ether and dichloromethane in a volume ratio of 2:1 as eluent. After obtaining the product solution, concentrate by rotary evaporation to obtain a yellow solid with a yield of 82%. MS(m / z): 451.4. 1 H NMR (500 MHz, CDCl3) δ(ppm):7.89-7.83 (d, 2H, Ar-H), 7.82-7.76 (d, 2H, Ar-H), 7.33-7.27 (d, 2H,Ar-H), 6.97-6.90 (d, 2H,Ar-H), 5.22 (s, 1H, -OH), 2.71-2.63(t, 2H,-CH2), 1.70-1.60 (m, 2H, -CH2), 1.38-1.20 (m, 18H, -CH2), 0.92-0.83(t, 3H, -CH3).

[0075] Example 11 Preparation of 1-(4-hexadecylphenyl)-2-(4-(hexyloxy)phenyl)diazeline

[0076] Weigh 2.11 g (5 mmol, 1 equiv) of 4-(p-hexadecylphenyldiazeninyl)phenol into a 100 mL round-bottom flask, add 45 mL of anhydrous ethanol, and sonicate until fully dissolved. Dissolve 0.4 g (10 mmol, 2 equiv) of NaOH in 5 mL of deionized water and add it to the reaction system. Add 15 mmol (2.476 g, 3 equiv) of 1-bromohexane to the reaction system, and purge with nitrogen gas to degas three times to completely remove oxygen. Under nitrogen protection and reflux, heat and stir at 70 °C for 24 h. After the reaction is complete, concentrate the reaction solution by rotary evaporation. When a small amount of solvent remains, add an appropriate amount of silica gel and continue rotary evaporation to obtain a pale yellow powder. Purify the pale yellow crude product obtained by rotary evaporation by silica gel column chromatography with petroleum ether and dichloromethane in a volume ratio of 2:1 as eluent. After obtaining the product solution, concentrate by rotary evaporation to obtain a yellow solid with a yield of 70%. MS (m / z): 507.4. 1 H NMR (500 MHz, CDCl3) δ(ppm):7.89-7.82 (d, 2H,Ar-H), 7.82-7.75 (d, 2H,Ar-H), 7.33-7.27 (d, 2H, Ar-H), 6.96-6.90 (d, 2H,Ar-H), 5.16 (s, 1H, -OH), 2.70-2.62(t, 2H,-CH2), 1.70-1.60 (m, 2H, -CH2), 1.39-1.18 (m, 26H, -CH2), 0.92-0.83(t, 3H, -CH3).

[0077] Example 12 Preparation of 1-(4-trifluoromethoxyphenyl)-2-(4-(hexyloxy)phenyl)diazeline

[0078] Weigh 1.41 g (p-trifluoromethoxyphenyldiazenin)phenol into a 100 mL round-bottom flask, add 45 mL of anhydrous ethanol, and sonicate until fully dissolved. Dissolve 0.4 g (10 mmol, 2 equiv) of NaOH in 5 mL of deionized water and add it to the reaction system. Add 15 mmol (2.476 g, 3 equiv) of 1-bromohexane to the reaction system, purge with nitrogen gas, and degas three times to remove oxygen completely. Under nitrogen protection and reflux, heat and stir at 70 °C for 24 h. After the reaction is complete, concentrate the reaction solution by rotary evaporation. When a small amount of solvent remains, add an appropriate amount of silica gel and continue rotary evaporation to obtain a pale yellow powder. Purify the pale yellow crude product obtained by rotary evaporation by silica gel column chromatography with petroleum ether and dichloromethane in a volume ratio of 2:1 as eluent. After obtaining the product solution, concentrate by rotary evaporation to obtain a yellow solid with a yield of 53%. MS(m / z): 367.2. 1 H NMR (500 MHz, CDCl3) δ(ppm):7.96-7.91 (d, 2H,Ar-H), 7.91-7.86 (d, 2H,Ar-H), 7.39-7.31 (d, 2H,Ar-H), 7.00-6.92 (d, 2H,Ar-H), 5.28 (s, 1H, -OH).

[0079] Example 13 Preparation of 1-(4-(hexyloxy)phenyl)-2-(4-methoxyphenyl)diazepine

[0080] Weigh 1.14 g (5 mmol, 1 equiv) of 4-(p-methoxyphenyldiazenin)phenol into a 100 mL round-bottom flask, add 45 mL of anhydrous ethanol, and sonicate until fully dissolved. Dissolve 0.4 g (10 mmol, 2 equiv) of NaOH in 5 mL of deionized water and add it to the reaction system. Add 15 mmol (2.476 g, 3 equiv) of 1-bromohexane to the reaction system, purge with nitrogen gas, and degas three times to completely remove oxygen. Under nitrogen protection and reflux, heat and stir at 70 °C for 24 h. After the reaction is complete, concentrate the reaction solution by rotary evaporation. When a small amount of solvent remains, add an appropriate amount of silica gel and continue rotary evaporation to obtain a pale yellow powder. Purify the pale yellow crude product obtained by rotary evaporation by silica gel column chromatography with petroleum ether and dichloromethane in a volume ratio of 2:1 as eluent. After obtaining the product solution, concentrate by rotary evaporation to obtain a yellow solid with a yield of 71%. MS(m / z): 313.2. 1HNMR (500 MHz, CDCl3) δ(ppm):7.91-7.85 (d, 2H,Ar-H), 7.85-7.80 (d, 2H,Ar-H),7.04-6.97 (d, 2H, Ar-H), 6.96-6.90 (d, 2H,Ar-H), 5.28 (s, 1H, -OH), 3.89 (s,3H, -CH3).

[0081] Example 14 Preparation of 1-(4-ethoxyphenyl)-2-(4-(hexyloxy)phenyl)diazeline

[0082] Weigh 1.21 g (5 mmol, 1 equiv) of 4-(p-ethoxyphenyldiazenin)phenol into a 100 mL round-bottom flask, add 45 mL of anhydrous ethanol, and sonicate until fully dissolved. Dissolve 0.4 g (10 mmol, 2 equiv) of NaOH in 5 mL of deionized water and add it to the reaction system. Add 15 mmol (2.476 g, 3 equiv) of 1-bromohexane to the reaction system, and purge with nitrogen gas three times to remove oxygen completely. Under nitrogen protection and reflux, heat and stir at 70 °C for 24 h. After the reaction is complete, concentrate the reaction solution by rotary evaporation. When a small amount of solvent remains, add an appropriate amount of silica gel and continue rotary evaporation to obtain a pale yellow powder. Purify the pale yellow crude product obtained by rotary evaporation by silica gel column chromatography with petroleum ether and dichloromethane in a volume ratio of 2:1 as eluent. After obtaining the product solution, concentrate by rotary evaporation to obtain a yellow solid with a yield of 73%. MS(m / z): 327.2. 1 HNMR (500 MHz, CDCl3) δ(ppm):7.90-7.80 (m, 4H,Ar-H), 7.02-6.96 (d, 2H,Ar-H), 6.96-6.90 (d, 2H,Ar-H), 5.27 (s, 1H, -OH), 4.17-4.07 (m, 2H,-CH2), 1.50-1.41(t, 3H,-CH3).

[0083] Example 15 Preparation of 1-(4-(hexyloxy)phenyl)-2-(4-isopropylphenyl)diazeline

[0084] Weigh 1.2 g (5 mmol, 1 equiv) of 4-(p-isopropylphenyldiazetenyl)phenol into a 100 mL round-bottom flask, add 45 mL of anhydrous ethanol, and sonicate until fully dissolved. Dissolve 0.4 g (10 mmol, 2 equiv) of NaOH in 5 mL of deionized water and add it to the reaction system. Add 15 mmol (2.476 g, 3 equiv) of 1-bromohexane to the reaction system, purge with nitrogen gas, and degas three times to completely remove oxygen. Under nitrogen protection and reflux, heat and stir at 70 °C for 24 h. After the reaction is complete, concentrate the reaction solution by rotary evaporation. When a small amount of solvent remains, add an appropriate amount of silica gel and continue rotary evaporation to obtain a pale yellow powder. Purify the pale yellow crude product obtained by rotary evaporation by silica gel column chromatography with petroleum ether and dichloromethane in a volume ratio of 2:1 as eluent. After obtaining the product solution, concentrate by rotary evaporation to obtain a yellow solid with a yield of 64%. MS(m / z): 325.2. 1 HNMR (500 MHz, CDCl3) δ(ppm):7.89-7.83 (d, 2H, Ar-H), 7.83-7.77 (d, 2H,Ar-H),7.39-7.32 (d, 2H, Ar-H), 6.97-6.91 (d, 2H,Ar-H), 5.33 (s, 1H, -OH), 3.04-2.93(m, 1H,-CH2), 1.33-1.26 (d, 6H, -CH3).

[0085] Example 16

[0086] Examples 2-15 provide a series of methods for preparing alkyl chain functionalized azobenzene derivatives into solar thermal fuel films, and the detailed steps are as follows:

[0087] Cut a square piece of fabric (cotton cloth, approximately 1 mm thick) with sides of 2.5 cm and place it in a glass disk. Weigh out 45 mg of an alkyl-chain functionalized azobenzene derivative and spread it evenly on the square fabric. Then place the glass disk in a dark, enclosed environment and fix an ultraviolet lamp to an iron stand to irradiate the square fabric. After irradiation for a certain period of time, a flexible composite solar thermal fuel film can be obtained.

[0088] Example 1

[0089] The 1-(4-hexyloxyphenyl)-2-(p-tolyl)diazepine obtained in Example 3 was used to prepare a solar thermal fuel film composite material using the method of Example 16. The energy density of the composite material and the 1-(4-hexyloxyphenyl)-2-(p-tolyl)diazepine obtained in Example 3 were measured. The experimental results showed that the isomerization exothermic reaction of the solar thermal fuel film was significantly higher than that of the 1-(4-hexyloxyphenyl)-2-(p-tolyl)diazepine, indicating that combining it with flexible fabric increased the energy storage capacity. Furthermore, the solar thermal fuel film exhibited excellent total energy storage density. When the solar thermal fuel film composite material was irradiated with 365 nm ultraviolet light, a photoinduced trans-cis conformational transition occurred, storing energy in chemical bonds. The stored energy gradually increased with prolonged irradiation time, and remained unchanged after 40 min. Subsequently, under heating conditions at 70°C, the energy was gradually released as heat, and complete energy release occurred after 80 min.

[0090] By studying the changes in the absorption curve of a photoresponsive molecule, dichloromethane solution, in the UV-Vis absorption spectrum, it was found that this photoresponsive molecule exhibits reversible changes with no significant decay after 10 cycles. DSC testing confirmed that the energy density of the solar thermal fuel shows no significant decay after at least 6 cycles.

[0091] Example 2

[0092] The samples obtained in Examples 2-15 were subjected to ultraviolet light (365nm, 6.7mW / cm²). 2 After irradiation, the sample was observed to show no further color or state change with prolonged UV irradiation. Irradiation was then stopped. The enthalpy of isomerization and latent heat of phase transition from the cis to the trans configuration of the compound were measured using DSC. The compound was then combined with fabrics using the method described in Example 16, and the energy density of the solar thermal fuel was measured. Table 2 shows the energy densities of alkyl chain functionalized azobenzene derivatives and their corresponding solar thermal fuel films, as well as their charging rates and the time required for energy release under natural sunlight.

[0093] Table 2

[0094]

[0095] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An alkyl chain functionalized azobenzene derivative, characterized in that, At room temperature, the cis configuration is liquid and the trans configuration is solid. The structure of the azobenzene derivative is shown in Formula I: ； Specifically, it is selected from one of the following structures: 1-(4-Butoxyphenyl)-2-(p-Tolyl)diazeline; 1-(4-Ethylphenyl)-2-(4-(Hexoxy)phenyl)diazeline; 1-(4-(hexyloxy)phenyl)-2-(4-hexylphenyl)diazeline; 1-(4-Dodecylphenyl)-2-(4-(hexyloxy)phenyl)diazeline; 1-(4-trifluoromethoxyphenyl)-2-(4-(hexyloxy)phenyl)diazeline; 1-(4-(hexyloxy)phenyl)-2-(4-isopropylphenyl)diazepine.

2. A process for the preparation of alkyl chain functionalized azobenzene derivatives as claimed in claim 1, characterized in that, Includes the following steps: ； S1: Mix aniline derivative a, hydrochloric acid and water, and add NaNO2 solution dropwise to the mixture at 0-5℃, while continuing to stir, to obtain diazonium salt b solution; S2: Dissolve phenol, Na2CO3 and NaOH in water and slowly add them dropwise to the diazonium salt b solution. Continue stirring at room temperature to allow the reaction to proceed fully. Adjust the pH to ≤7 with hydrochloric acid, filter the precipitate, wash with water, dry, and purify by column chromatography to obtain the hydroxyl-containing azobenzene intermediate c. S3: reacting the hydroxyl-containing azobenzene intermediate c and R 2 -Br in the presence of sodium hydroxide in a solvent, and after the reaction is completed, purifying by column chromatography to obtain a compound having a structure as shown in Formula I.

3. A process for the preparation of alkyl chain functionalized azobenzene derivatives according to claim 2, characterized in that, The mass percentage of hydrochloric acid in S1 is 37%, the molar volume ratio of aniline derivative a to hydrochloric acid is 1 mmol: 0.2-0.5 mL, and the molar ratio of aniline derivative a to NaNO2 is 1: 1.0-1.

5.

4. The process for the preparation of alkyl chain functionalized azobenzene derivatives according to claim 2, characterized in that, The molar ratio of phenol, Na2CO3 and NaOH in S2 is 1:1.0-1.5:1.0-1.

3. Column chromatography purification first uses a mixed eluent of dichloromethane and petroleum ether with a volume ratio of 1:1-2 to remove impurities, then uses dichloromethane to elute the product, and rotary evaporation yields the hydroxyl-containing azobenzene intermediate c.

5. The method of claim 2, wherein the alkyl chain functionalized azobenzene derivative is prepared by the reaction of the compound of formula (II) with the compound of formula (III) in the presence of a base. The solvent in S3 is a mixed solution of water and ethanol with a volume ratio of 1:5-20, the heating temperature is 50-90℃, the hydroxyl-containing azobenzene intermediate c, R 2 The molar ratio of -Br, NaOH is 1:1.0-5.0:1.0-1.5, and the mixed eluent of dichloromethane and petroleum ether with a volume ratio of 1:1-3 is selected for column chromatography purification.

6. An azobenzene-based solar thermal fuel thin film composite material, characterized by, It is composed of alkyl chain functionalized azobenzene derivatives and flexible fabrics; The structure of the alkyl chain functionalized azobenzene derivative is as described in claim 1 or selected from one of the following: 1-(4-(hexyloxy)phenyl)-2-(p-tolyl)diazeline; 1-(4-(octoxy)phenyl)-2-(p-tolyl)diazeline; 1-(4-(decoxy)phenyl)-2-(p-tolyl)diazeline; 1-(4-(dodecyloxy)phenyl)-2-(p-tolyl)diazeline.

7. The solar thermal fuel thin film composite of claim 6, wherein, It is prepared by the following method: the solid alkyl chain functionalized azobenzene derivative is evenly spread on a flexible fabric, placed in a dark and closed environment, and irradiated with ultraviolet light until the alkyl chain functionalized azobenzene derivative is transformed into a liquid state and immersed into the fabric, thus obtaining a flexible composite film.

8. The azobenzene-based solar thermal fuel thin film composite of claim 7, wherein, The flexible fabric has a thickness of 0.5-1.2 mm, and the alkyl chain functionalized azobenzene derivative is coated on the surface of the flexible fabric at a coating amount of 3.2-9.6 mg / cm 2 .

9. Use of the azophenyl solar thermal fuel thin film composite material as described in claim 6 as a solar thermal energy storage material.

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