A condensed ring compound and a reactive vat dye for supercritical co2 fluid dyeing, and a preparation method

Abstract

The application discloses a kind of fused ring type compounds and active vat dyes for supercritical CO2 fluid dyeing, preparation method. Diphenyl bipyrrolequinone halogenated compound, alkyl amine compound is dissolved in organic solvent, and base agent, copper catalyst is added, and a kind of fused ring type compound is obtained by reaction, it has active reaction group and fused ring ketone conjugated structure, used as the precursor of active vat dye, the prepared dye its color parent is fused by six benzene rings, coplanarity is good, and the directness to fiber is better, and color light is stable, suitable for supercritical CO2 fluid dyeing.The active group of fused ring type active vat dye provided in the application is mainly fixed by nucleophilic addition reaction with fiber, avoid the damage caused to equipment or reduce the dyeing rate and bonding stability of cotton in supercritical CO2 fluid by the acid generated in fixing reaction.The dyeing process is green and environmentally friendly, friendly to equipment and environment, and has better application prospect in supercritical CO2 dyeing.

Description

Technical Field

[0001] This invention relates to the field of dye synthesis technology, and in particular to a fused ring compound, a reactive vat dye for supercritical CO2 staining, and a method for preparing the same. Background Technology

[0002] Supercritical CO2 fluid technology uses CO2 instead of water as a medium to dye and functionally finish textiles under the action of various dyes or auxiliaries, solving the problems of high water consumption and difficult wastewater treatment in the dyeing and printing process (see reference: Study on optimizing production scheduling for water-saving in textile dyeing industry [J]. Journal of Cleaner Production, 2017, 141: 721 - 727).

[0003] Compared to water, supercritical CO2 fluid exhibits better diffusivity and lower mass transfer performance, facilitating the penetration of dyes and auxiliaries into textiles and showing promising application prospects (see: Continuous dyeing processes for zipper tape in supercritical carbon dioxide [J]. Journal of Cleaner Production, 2017, 158: 95-100). While dyeing polyester fibers in supercritical CO2 fluid has yielded good results, the application of supercritical CO2 dyeing in nylon and natural fibers is limited due to their inability to swell sufficiently in this fluid and the lack of suitable dyes.

[0004] Providing novel reactive dyes is an effective way to solve the dyeing problem of such fibers in supercritical environments. Especially in the design of novel reactive dye structures, the parent structure and the type of reactive group have a significant impact on the dye's performance. The parent structure determines the color of the dye molecule and its solubility in supercritical CO2 fluid, while selecting suitable reactive groups is crucial for improving the dye uptake, leveling properties, and various fastness properties. Currently, these novel reactive dye systems still suffer from problems such as the parent structure being mainly anthraquinone or azo, resulting in a single structure, incomplete chromatogram, and limited applicability (see references: An ecofriendly dyeing of nylon and cotton fabrics in supercritical CO2 with novel tricyanopyrrolidone reactive disperse dye [J]. Journal of CO2 Utilization, 2022, 60, 102004; Novel sustainable synthesis of dyes for cleandyeing of wool and cotton fibres in supercritical carbon dioxide [J]. Journal of Cleaner Production, 2018, 199, 1-10). To address the aforementioned issues, developing more novel dyes suitable for supercritical CO2 fluid dyeing technology remains one of the most important directions for the technology's development. Summary of the Invention

[0005] This invention addresses the shortcomings of existing specialized dyes in the field of supercritical CO2 dyeing by providing a fused-ring compound and its preparation method. Furthermore, using this compound as a precursor, reactive vat dyes with good coplanarity, good directness to fibers, and stable color can be prepared for water bath dyeing of fibers such as nylon, cotton, wool, and silk, and are particularly suitable for supercritical CO2 dyeing.

[0006] The technical solution to achieve the objective of this invention is to provide a fused-ring compound with the following general structural formula:

[0007] ,

[0008] Where R1 is Cl or Br, and R2 is H or CH3; 0≤n≤6.

[0009] The preferred embodiment is a fused-ring compound, wherein R1 is Br, R2 is CH3, and n=1.

[0010] A method for preparing a fused-ring compound involves dissolving a benzo[a]pyrenequinone halide and an alkylamine compound in an organic solvent at a molar ratio of 1:1.0 to 1:3.5, wherein the concentration of the benzo[a]pyrenequinone halide is 0.00417 mol / L; adding an alkaline agent and a copper-based catalyst; and reacting the mixture for 4 to 12 h under a nitrogen and / or argon protective atmosphere at a temperature of 100–140 °C. After purification, a fused-ring compound is obtained.

[0011] The preferred embodiment is that the dibenzo[a]pyrenequinone halide is dibromodibenzo[a]pyrenequinone; the alkylamine compound is N,N'-dimethylethylenediamine; the organic solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide, xylene, and toluene; the alkaline agent is one or more of potassium hydroxide, sodium hydroxide, triethylamine, sodium carbonate, and potassium carbonate, with a concentration ≤0.01667 mol / L; and the copper-based catalyst is one or more of copper powder, cuprous chloride, cuprous oxide, and cuprous bromide, with a concentration ≤0.00083 mol / L.

[0012] The purification process is carried out using a silica gel column with silica gel powder of 200-300 mesh. The eluent includes petroleum ether and dichloromethane, with a volume ratio of petroleum ether to dichloromethane of 0-1:0-1.

[0013] The technical solution of the present invention also includes a reactive vat dye for staining supercritical CO2 fluids, the general structural formula of which is:

[0014] ,

[0015] Wherein, R1 is Cl or Br, R2 is H or CH3, and R3 is styrene, butene tert-amide, or propylene oxide; 0 ≤ n ≤ 6.

[0016] The preferred embodiment is a reactive vat dye for staining supercritical CO2 fluids, wherein R1 is Br, R2 is CH3, and n=1.

[0017] A method for preparing a reactive vat dye for staining supercritical CO2 fluids includes the following steps:

[0018] (1) Dissolve the halogenated dibenzopyrenequinone and the alkylamine compound in an organic solvent at a molar ratio of 1:1.0 to 1:3.5, with the concentration of the halogenated dibenzopyrenequinone being 0.00417 mol / L; add an alkaline agent and a copper catalyst, and react for 4 to 12 h under a nitrogen and / or argon protective atmosphere at a temperature of 100 to 140 °C. After purification, the dye precursor is obtained.

[0019] (2) Dissolve the precursor and the compound containing active halogen atoms obtained in step (1) in an organic solvent at a molar ratio of 1:1 to 1:3. The compound containing active halogen atoms is one of p-chlorostyrene, butenoyl chloride, and epichlorohydrin. Under the action of a copper catalyst and / or an alkaline agent, stir the reaction. After the reaction stops, purify the product to obtain an active vat dye for supercritical CO2 fluid dyeing.

[0020] The preferred embodiment is that the dibenzo[a]pyrenequinone halide is dibromodibenzo[a]pyrenequinone; the alkylamine compound is N,N'-dimethylethylenediamine; the organic solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide, xylene, and toluene; the alkaline agent is one or more of potassium hydroxide, sodium hydroxide, triethylamine, sodium carbonate, and potassium carbonate, with a concentration ≤0.01667 mol / L; and the copper-based catalyst is one or more of copper powder, cuprous chloride, cuprous oxide, and cuprous bromide, with a concentration ≤0.00083 mol / L.

[0021] The purification process described in step (1) uses a silica gel column for purification. The silica gel powder has a mesh size of 200-300. The eluent includes petroleum ether and dichloromethane, with a volume ratio of petroleum ether to dichloromethane of 0-1:0-1. The purification process described in step (2) uses a silica gel column for purification. The silica gel powder has a mesh size of 200-300. The eluent includes petroleum ether and dichloromethane, with a volume ratio of petroleum ether to dichloromethane of 0-5:1-5.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. The fused-ring compounds provided by this invention have active reactive groups and fused-ring ketone conjugated structures, and can be used as raw materials for the synthesis of other compounds, especially suitable as precursors for the preparation of dyes.

[0024] 2. The reactive vat dye for supercritical CO2 fluid dyeing provided by the present invention uses a low polarity structure as the matrix, and links it to preferred reactive groups through bridging groups, so that it has a certain solubility in supercritical CO2 fluid, and can be bonded and fixed on the fiber by reactive groups on the fiber.

[0025] 3. The reactive vat dye provided by this invention has its reactive groups fixed to the fiber mainly through a nucleophilic addition reaction. The dyeing process is green and environmentally friendly, equipment-friendly, and conducive to improving the dyeing rate of cotton fibers in supercritical CO2 dyeing. It has good application prospects in supercritical CO2 dyeing.

[0026] 4. The preparation method of the present invention is simple to operate, easy to control, has a high reaction conversion rate, and the obtained fused ring reactive vat dye has good coplanarity, good directness to fibers, and stable color. By changing the reactive groups, reactive vat dyes with different structures and similar colors can be obtained, which has strong applicability. Attached Figure Description

[0027] Figure 1 Fourier transform infrared spectrum of the purified fused-ring compound (dye precursor) provided in Example 1 of this invention;

[0028] Figure 2 The purified reactive vat dye II provided in Example 2 of this invention a Fourier infrared spectrum;

[0029] Figure 3 The purified reactive vat dye II provided in Example 3 of this invention b Fourier infrared spectrum;

[0030] Figure 4 The purified reactive vat dye II provided in Example 4 of this invention c Fourier infrared spectrum;

[0031] Figure 5 The UV-Vis absorption spectra of the dye precursor and the reactive vat dye provided in the embodiments of the present invention. Implementation

[0032] The embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. Example 1

[0033] In this embodiment, dibromodibenzopyrenequinone and N,N'-dimethylethylenediamine were used as reactants to prepare a fused-ring compound. The specific steps are as follows:

[0034] 0.12435 g (0.25 mmol) of dibromodibenzo[a]pyrenequinone, 0.0015 g (0.025 mmol) of copper powder, and 40 mL of N,N-dimethylformamide were weighed and placed in a 100 mL four-necked flask and sonicated for 30 min. A reflux condenser was then installed, and the temperature was maintained at 130 °C under nitrogen protection with constant stirring. 0.06615 g (0.75 mmol) of N,N'-dimethylethylenediamine dissolved in 20 mL of N,N-dimethylformamide was slowly added dropwise to the reaction system, and the reaction was allowed to proceed for 8 h. 0.04208 g (0.75 mmol) of potassium hydroxide was weighed and thoroughly ground, and then added in three equal portions at reaction times of 3 h, 4 h, and 5 h. The reaction progress was monitored using TLC. After the reaction was complete, the mixture was cooled to 20 °C, and 30 mL of dichloromethane was added to the reaction solution. The mixture was washed three times with 60 mL of deionized water, and the organic layer was separated and concentrated by rotary evaporation. The concentrated product was purified by column chromatography using silica gel powder of 200–300 mesh (petroleum ether:dichloromethane = 1:1, v / v) to obtain a fused-ring compound with a yield of 68.11%. The prepared fused-ring compound has the following structural formula:

[0035] .

[0036] The fused-ring compound obtained in Example 1 was characterized by Fourier transform infrared spectroscopy, and the results are shown in the appendix. Figure 1 The infrared spectrum shows that at 3472.21 cm⁻¹... -1 The peak at 3415.32 cm⁻¹ represents the water peak formed by the hygroscopic absorption of polar groups such as carbonyl groups. -1 The peak value is the stretching vibration peak of -NH- at 2925.00 cm⁻¹. -1 and 2853.17 cm -1 The peaks at 1734.17 cm⁻¹ represent the antisymmetric and symmetric stretching vibrations of -CH₃ and -CH₂- on the bridge foundation. -1 and 1675.84 cm -1 The peak at 1365.36 cm⁻¹ represents the stretching vibration of two C=O bonds. -1 The peak at 712.09 cm⁻¹ represents the stretching vibration of the CN bond. -1 and 613.73 cm -1 The peak at this point represents the stretching vibration of the C-Br bond on the aromatic ring.

[0037] The fused-ring compound provided in this embodiment has active reactive groups and a fused-ring ketone conjugated structure, and can be used as a raw material for synthesizing other compounds. In this invention, it is used as a precursor for the synthesis of reactive vat dyes. Example 2

[0038] In this embodiment, the fused-ring compound provided in Example 1 was used as a dye precursor to prepare reactive vat dye II. a The specific steps are as follows:

[0039] Weigh 0.06218 g (0.125 mmol) of dye precursor, 0.00075 g (0.0125 mmol) of copper powder, and 15 mL of 1,4-dioxane into a 100 mL four-necked flask and sonicate for 5 min. Then, install a reflux condenser and maintain the temperature at 90 °C under nitrogen protection while stirring at a constant speed. Next, weigh 0.03465 g (0.25 mmol) of p-chlorostyrene and 1.29950 × 10⁻⁶ ppm of copper powder. -5 500 ppm of polymerization inhibitor 701 was dissolved in 5 mL of 1,4-dioxane and added dropwise to the reaction system at a uniform rate. The mixture was stirred for 6 h. 0.01987 g (0.1875 mmol) of ground sodium carbonate was weighed and divided into four equal portions, added to the reaction system at 2, 3, 4, and 5 h. The reaction progress was monitored by TLC. After the reaction was completed, the mixture was cooled to room temperature, diluted with 5 times the amount of deionized water, filtered, and the resulting precipitate was purified by column chromatography using 200–300 mesh silica gel powder (petroleum ether: dichloromethane = 5:1, v / v) to obtain reactive vat dye II. a The separation yield was 62.15%. The prepared dye has the following structural formula:

[0040] .

[0041] Fourier transform infrared spectroscopy was used to analyze the reactive vat dye II obtained in Example 2. a The characterization was performed, and the results are shown in the appendix. Figure 2 The infrared spectrum shows that at 3383.50 cm⁻¹ -1 The peak at 3062.41 cm⁻¹ is due to the hygroscopic absorption of polar groups such as carbonyl groups, resulting in a water peak. -1 The peak at 2924.52 cm⁻¹ corresponds to the =CH₂ stretching vibration in olefins. -1 and 2852.69 cm -1 The peaks at this point represent both antisymmetric and symmetric stretching vibrations of -CH3 and -CH2-. 1735.62 cm⁻¹ -1 and 1653.18 cm -1 The peak at 1631.48 cm⁻¹ represents the stretching vibration of two C=O bonds. -1 The peak value for the stretching vibration of C=C is 1365.84 cm⁻¹. -1 and 1318.59 cm -1The peak at 714.98 cm⁻¹ represents the stretching vibration of the CN bond. -1 and 610.36 cm -1 The peak at this location represents the stretching vibration of the C-Br bond in brominated aromatic hydrocarbons. Example 3

[0042] In this embodiment, the fused-ring compound provided in Example 1 was used as a dye precursor to prepare reactive vat dye II. b The specific steps are as follows:

[0043] 0.02487 g (0.05 mmol) of the dye precursor was weighed and added to 5 mL of dichloromethane in a 100 mL three-necked flask, and dispersed by sonication for 5 min. Under nitrogen protection and with the system temperature controlled at 5 °C, 0.00653 g (0.0625 mmol) of butenoyl chloride was dissolved in 2 mL of dichloromethane and then added dropwise to the reaction system. The reaction was stirred at 5 °C for 4 h. 10.4 μL (0.075 mmol) of triethylamine was weighed and dissolved in 0.2 mL of dichloromethane, and added to the reaction solution in three portions at the 1st, 2nd, and 3rd hours of the reaction. The reaction progress was monitored by TLC. After the reaction was completed, 5% hydrochloric acid aqueous solution was added for quenching. The organic layer was washed with saturated sodium bicarbonate aqueous solution and deionized water until neutral. The organic layer was separated, concentrated under reduced pressure, and purified by column chromatography using silica gel powder with a specification of 200-300 mesh (petroleum ether: dichloromethane = 3:1, v / v) to obtain reactive vat dye II. b The separation yield was 31.74%. The prepared dye has the following structural formula:

[0044] .

[0045] Fourier transform infrared spectroscopy was used to analyze the reactive vat dye II obtained in Example 3. b The characterization was performed, and the results are shown in the appendix. Figure 3 The infrared spectrum shows that at 3427.42 cm⁻¹... -1 The peak at 2931.72 cm⁻¹ is due to the hygroscopic absorption of polar groups such as carbonyl groups, resulting in a water peak. -1 and 2829.50 cm -1 The peaks at 1733.96 cm⁻¹ represent the antisymmetric stretching vibration peaks of -CH₃ and -CH₂-, respectively, and the symmetric stretching vibration peak. -1 1654.88 cm -1 The peak value for the stretching vibration of C=O is 1629.80 cm⁻¹. -1 The peak value for the stretching vibration of C=C is 1363.64 cm⁻¹. -1 and 1311.56 cm -1 The absorption peak at 713.64 cm⁻¹ represents the CN bond.-1 and 609.49 cm -1 The peak at this point represents the C-Br stretching vibration of bromoaromatic hydrocarbons. Example 4

[0046] In this embodiment, the fused-ring compound provided in Example 1 was used as a dye precursor to prepare reactive vat dye II. c The specific steps are as follows:

[0047] Weigh 0.02487 g (0.05 mmol) of the dye precursor and 10 mL of 1,4-dioxane into a 100 mL three-necked flask and sonicate for 5 min. Adjust the solution temperature to 20 °C, add 5 mL of potassium hydroxide aqueous solution (0.00561 g (0.1 mmol)), and add dropwise 0.00578 g (0.0625 mmol) of epichlorohydrin dissolved in 2 mL of 1,4-dioxane to the reaction system. Stir the reaction for 12 h. Then add 2.5 mL of potassium hydroxide aqueous solution (0.25 g (4.5 mmol)), raise the temperature to 40 °C, and continue stirring for 24 h. Monitor the reaction progress using TLC. After the reaction was complete, 42.5 mL of deionized water was added to the reaction solution, and the mixture was stirred thoroughly and filtered. The filtrate was extracted with ethyl acetate. The extract was mixed with the filter cake, concentrated by rotary evaporation, and then purified by column chromatography using silica gel powder with a mesh size of 200–300 (petroleum ether: dichloromethane = 3:1, v / v) to obtain reactive vat dye II. c The separation yield was 42.39%. The prepared dye has the following structural formula:

[0048] .

[0049] Fourier transform infrared spectroscopy was used to analyze the reactive vat dye II obtained in Example 4. c The characterization was performed, and the results are shown in the appendix. Figure 4 The infrared spectrum shows a depth of 3423.56 cm⁻¹. -1 The peak at 2924.01 cm⁻¹ is due to the hygroscopic absorption of water by polar groups such as carbonyl groups. -1 and 2831.43 cm -1 The peaks at 1735.89 cm⁻¹ represent the antisymmetric stretching vibration peaks of -CH₃ and -CH₂-, respectively, and the symmetric stretching vibration peak. -1 and 1652.95 cm -1 The peak value is the stretching vibration peak of C=O, at 1365.56 cm⁻¹. -1 and 1313.49 cm -1 The peak at 1263.34 cm⁻¹ represents the stretching vibration of the CN bond. -1 and 873.73 cm -1The peak at 715.57 cm⁻¹ represents both the antisymmetric and symmetric stretching vibrations of the -O- group on epoxides. -1 and 609.49 cm -1 The peak at this point represents the C-Br stretching vibration of bromoaromatic hydrocarbons. Example 5

[0050] In this embodiment, dichloromethane is used as the solvent, with a concentration range of 5.73 × 10⁻⁶. -5 ~7.43×10 -5 Under conditions of mol / L, the fused-ring compound (dye precursor) provided in Example 1 and the reactive vat dyes provided in Examples 2, 3 and 4 were tested, and the measured UV-Vis absorption spectra are shown in [reference]. Figure 5 As shown in the figure. Curve a represents the UV-Vis absorption spectrum of the dye precursor, with a maximum absorption wavelength of 474 nm and a corresponding molar absorptivity of 5.64 × 10⁻⁶. 3 L / (mol·cm) -1 Curve b represents reactive vat dye II. a The ultraviolet-visible absorption spectrum shows a maximum absorption wavelength of 474 nm, corresponding to a molar absorptivity of 10.7 × 10⁻⁶. 3 L / (mol·cm) -1 Curve c represents reactive vat dye II. b The ultraviolet-visible absorption spectrum shows a maximum absorption wavelength of 473 nm, corresponding to a molar absorptivity of 2.91 × 10⁻⁶. 3 L / (mol·cm) -1 Curve d represents reactive vat dye II. c The ultraviolet-visible absorption spectrum shows a maximum absorption wavelength of 472 nm, corresponding to a molar absorptivity of 8.9 × 10⁻⁶. 3 L / (mol·cm) -1 The above results indicate that the chromophore structure of the reactive vat dye provided by this invention is less affected by the induction of reactive groups, which is beneficial for obtaining reactive vat dyes with different structures but the same color, and further adjusting the dyeing performance of the dye.

Claims

1. A condensed ring type compound, characterized by Its general structure is: ， Wherein, R1 is Cl or Br, R2 is H or CH3; 0≤n≤6.

2. The compound of claim 1, wherein: R1 is Br, R2 is CH3; n=1.

3. The method of claim 1, wherein the method is a method of preparing a fused ring compound, characterized by: The dibenzopyrene halide, the alkyl amine compound are dissolved in an organic solvent according to a molar ratio of 1:1.0-1:3.5, the concentration of the dibenzopyrene halide is 0.00417 mol / L; a base agent and a copper-based catalyst are added, under the conditions of nitrogen and / or argon protection atmosphere and temperature of 100-140 DEG C, reaction for 4-12 h, purification treatment to obtain a fused ring compound.

4. The method of claim 3, wherein the compound is: ###0002### The dibenzopyrene halide is dibromodibenzopyrene; the alkyl amine compound is N, N'-dimethylethylenediamine; the organic solvent is one or several of N, N-dimethylformamide, dimethyl sulfoxide, dimethylbenzene and toluene; the base agent is one or several of potassium hydroxide, sodium hydroxide, triethylamine, sodium carbonate and potassium carbonate, the concentration is ≤0.01667 mol / L; the copper-based catalyst is one or several of copper powder, cuprous chloride, cuprous oxide and cuprous bromide, the concentration is ≤0.00083 mol / L.

5. The method for preparing a fused-ring compound according to claim 3, characterized in that: The purification treatment adopts silica gel chromatographic column purification, the silica gel powder specification is 200-300 mesh, the eluent includes petroleum ether and dichloromethane, the volume ratio of petroleum ether and dichloromethane is 0-1:0-1.

6. A reactive vat dye for supercritical CO2 fluid dyeing, characterized by Its general structure is: ， Wherein, R1 is Cl or Br, R2 is H or CH3, R3 is phenylethylene, butene tertiary amide or propylene oxide; 0≤n≤6.

7. A reactive vat dye for supercritical CO2 fluid dyeing according to claim 6, characterized in that: R1 is Br, R2 is CH3; n=1.

8. A process for the preparation of reactive vat dyes for supercritical CO2 fluid dyeing according to claim 6, characterized in that It comprises the following steps: (1) the dibenzopyrene halide, the alkyl amine compound are dissolved in an organic solvent according to a molar ratio of 1:1.0-1:3.5, the concentration of the dibenzopyrene halide is 0.00417 mol / L; a base agent and a copper-based catalyst are added, under the conditions of nitrogen and / or argon protection atmosphere and temperature of 100-140 DEG C, reaction for 4-12 h, purification treatment to obtain a dye precursor; (2) according to a molar ratio of 1:1-1:3, the precursor obtained in step (1) and a compound containing active halogen atom are dissolved in an organic solvent, the compound containing active halogen atom is one of p-chlorostyrene, butenoyl chloride and epoxy chloropropane, under the action of copper-based catalyst and / or base agent, stirring reaction, after the reaction is stopped, the product is purified to obtain an active vat dye for supercritical CO2 fluid dyeing.

9. A process for the preparation of reactive vat dyes for supercritical CO2 fluid dyeing according to claim 8, characterized in that The dibenzopyrene halide is dibromodibenzopyrene; the alkyl amine compound is N, N'-dimethylethylenediamine; the organic solvent is one or several of N, N-dimethylformamide, dimethyl sulfoxide, dimethylbenzene and toluene; the base agent is one or several of potassium hydroxide, sodium hydroxide, triethylamine, sodium carbonate and potassium carbonate, the concentration is ≤0.01667 mol / L; the copper-based catalyst is one or several of copper powder, cuprous chloride, cuprous oxide and cuprous bromide, the concentration is ≤0.00083 mol / L.

10. A process for the preparation of reactive vat dyes for supercritical CO2 fluid dyeing according to claim 8, characterized in that: The purification treatment in step (1) is carried out by using a silica gel chromatographic column, the silica gel powder has a size of 200-300 mesh, and the eluent includes petroleum ether and dichloromethane, and the volume ratio of petroleum ether to dichloromethane is 0-1:0-1; the purification treatment in step (2) is carried out by using a silica gel chromatographic column, the silica gel powder has a size of 200-300 mesh, and the eluent includes petroleum ether and dichloromethane, and the volume ratio of petroleum ether to dichloromethane is 0-5:1-5.

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