Preparation method of siloxane-based fluorescent material for detecting trifluralin under sunlight
The prepared siloxane-based fluorescent material for detecting trifluralin under sunlight solves the problem of difficult detection under sunlight in existing technologies, achieving high sensitivity and simple trifluralin detection. The raw materials are readily available, the operation is simple, and it is not limited by ultraviolet light sources.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-23
- Publication Date
- 2026-04-07
AI Technical Summary
Existing methods for detecting fluroxypyr rely on ultraviolet light excitation, which cannot achieve efficient and accurate detection under sunlight. Furthermore, these methods are costly, complex to operate, and lack portability.
Siloxane-based fluorescent materials were prepared by reacting vinylsiloxanes with halogenated aromatic compounds via the Heck reaction. The materials were then used for the detection of trifluralin using sunlight excitation. The materials exhibited high fluorescence quantum yield and visible fluorescence.
It achieves high sensitivity, low detection limit and rapid response for the detection of fluroxypyr under sunlight. The raw materials are readily available, the operation is simple and not limited by ultraviolet light source.
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Figure CN121801094A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of polymer materials, specifically relating to a method for preparing a siloxane-based fluorescent material for detecting trifluralin under sunlight. Background Technology
[0002] The residues resulting from the excessive use of highly toxic pesticides remain a major threat to human health and the ecological environment. Among these highly toxic pesticides, trifluralin is particularly representative due to its resistance to degradation and bioaccumulation, which severely impacts human organs and the endocrine system. In recent years, trifluralin has not only been listed as a carcinogen and endocrine disruptor by the U.S. Environmental Protection Agency but also as an organic water pollutant by the European Union guidelines. Therefore, establishing efficient and accurate methods for detecting trifluralin residues is of significant practical importance.
[0003] Currently, the main methods for detecting trifluralin are chromatographic analysis coupled with mass spectrometry, including gas chromatography-ECD (GC-ECD), high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS), electrochemical techniques, and enzyme biosensors. However, these detection techniques mostly suffer from drawbacks such as reliance on large, sophisticated instruments, high equipment costs, complex operation, and poor portability, hindering their use in real-time detection. Compared with the above methods, fluorescence detection technology, due to its advantages of simple operation, rapid response, and high sensitivity, is an ideal candidate for real-time and on-site detection and has been successfully applied in the detection of pesticide residues such as carbendazim and acetamiprid. However, this fluorescence imaging mostly relies on ultraviolet light excitation and can only be observed under ultraviolet (365 nm) or visible light (405 nm) because fluorescence emission requires a certain amount of energy, which sunlight cannot provide. Therefore, sunlight visualization for trifluralin detection remains a significant challenge.
[0004] Therefore, there is an urgent need to develop a fluorescent probe for fluroxypyr detection that utilizes sunlight as an excitation source and is easy to operate, highly sensitive, and highly selective. Summary of the Invention
[0005] The present invention addresses the limitations of existing technologies by providing a method for preparing siloxane-based fluorescent materials and their application in the detection of trifluralin under sunlight. This invention utilizes vinyl-containing siloxanes and various halogenated aromatic compounds as raw materials, and, under the action of a catalyst, prepares siloxane-based fluorescent materials via the Heck reaction. The siloxane-based fluorescent materials synthesized in this invention exhibit high fluorescence quantum yields, up to 90%, and emit visible blue-violet light under sunlight. This invention enables the detection of trifluralin under sunlight, characterized by low detection limits, high sensitivity, good selectivity, and rapid response.
[0006] To achieve the above objectives, the present invention adopts the following technical solution.
[0007] The first objective of this invention is to provide a method for preparing a siloxane-based fluorescent material for detecting trifluralin under sunlight. The material is a vinylsiloxane-containing fluorescent material, specifically prepared by reacting vinylsiloxane with a halogenated aromatic compound via a Heck reaction. The specific steps are as follows: Under inert gas protection, vinylsiloxane monomer, catalyst, and acid absorbent are added to an organic solvent, followed by the addition of a halogenated aromatic compound. The mixture is heated under reflux with stirring, filtered, rotary evaporated, precipitated with methanol, and dried under vacuum to remove the solvent, yielding a siloxane fluorescent material. The reaction temperature is 80–130 °C, and the reaction time is 24–72 h; the vacuum drying temperature is 50–150 °C, and the drying time is 18–48 h; the best results are achieved when the reaction temperature is 100 °C, the reaction time is 24 h, and the vacuum drying temperature is 75 °C, and the drying time is 48 h.
[0008] Preferably, the molar ratio of vinyl groups in the vinyl siloxane to halogen groups in the halogenated aromatic compound is 1:1 to 1:3; the vinyl siloxane is a disiloxane, trisiloxane, or tetrasiloxane; the halogenated aromatic compound is a mono- or poly-substituted iodo or bromo group; and the aromatic unit is phenyl, biphenyl, 1,3,5-triphenyl-substituted benzene, stilbene, fluorene, spirodifluorene, pyrene, triphenylamine, 1,3,5-triphenyl-2,4,6-triazine, 1,2,3,4,5,6-hexaphenyl-substituted benzene, fluorenone, carbazole, or tetraphenylethylene.
[0009] Preferably, the structural formula of the siloxane fluorescent material is shown in Formula I, Formula II, Formula III, or Formula IV.
[0010] Formula I
[0011] Formula II
[0012] Formula III
[0013] Formula IV In Equations I, II, III, and IV, n is a number greater than 0 and less than 4, and R1 and R2 are selected from C1 to C2. 18The hydrocarbon group can be a straight-chain or branched saturated or unsaturated hydrocarbon group, or a hydrocarbon group with O, S, or N heteroatoms, or a cycloalkanes or aromatic hydrocarbons, with R1 and R2 being the same or different; R is an aromatic unit phenyl, biphenyl, 1,3,5-triphenyl-substituted benzene, stilbene, fluorene, spirofluorene, pyrene, triphenylamine, 1,3,5-triphenyl-2,4,6-triazine, 1,2,3,4,5,6-hexaphenyl-substituted benzene, fluorenone, carbazole, or tetraphenylethylene.
[0014] Preferably, the molar ratio of the catalyst to vinylsiloxane is (0.01-0.1):1, the molar volume ratio of the vinylsiloxane to the organic solvent is (1-3) mmol:50 mL, the molar ratio of the absorbent to vinylsiloxane is (10-50):1, and the molar ratio of vinyl groups in the vinylsiloxane to halogen groups in the halogenated aromatic compounds is 1:1 to 1:3.
[0015] Preferably, the optimal ratio of vinyl groups in the vinyl siloxane to halogens in the halogenated aromatic compounds is 1:1.
[0016] Preferably, the catalyst is a palladium-based catalyst, specifically one or a mixture of any two or more of palladium chloride, palladium acetate, tetra(triphenylphosphine)palladium, bis(triphenylphosphine)palladium dichloride, [1,1'-bis(diphenylphosphine)ferrocene]palladium dichloride, bisacetonitrile palladium(II) chloride, and tris(dibenzylacetone)palladium.
[0017] Preferably, the halogenated aromatic compound is halogenated by mono- or poly-substituted iodide or bromine, and the aromatic unit is phenyl, biphenyl, 1,3,5-triphenyl-substituted benzene, stilbene, fluorene, spirodifluorene, pyrene, triphenylamine, 1,3,5-triphenyl-2,4,6-triazine, 1,2,3,4,5,6-hexaphenyl-substituted benzene, fluorenone, carbazole, or tetraphenylethylene.
[0018] Preferably, the absorbent is an organic amine or an inorganic base; the organic amine is selected from diethylamine, triethylamine, diisopropylamine, tripropylamine or tri-n-butylamine, and the inorganic base is sodium carbonate, potassium carbonate or cesium carbonate.
[0019] Preferably, when the reaction is carried out in an organic solvent, the organic solvent is selected from one or a mixture of two or more of acetonitrile, tetrahydrofuran, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide, and the method is carried out in the presence of an organic solvent or in the absence of a solvent.
[0020] A second objective of this invention is to prepare a siloxane fluorescent material with high quantum yield according to the above method, wherein the siloxane fluorescent material is used for pesticide detection under sunlight, and the pesticide is trifluralin.
[0021] Compared with the prior art, the present invention has the following beneficial effects: 1. The raw materials of this invention are readily available and the preparation method is simple. It uses vinyl-containing siloxanes and various halogenated compounds as reaction raw materials and prepares siloxane fluorescent materials based on the Heck reaction.
[0022] 2. This invention utilizes the dynamic regulation of siloxanes to increase the degree of spatial conjugation, thereby emitting fluorescence, and the fluorescence quantum yield is as high as 90%.
[0023] 3. This invention can synthesize siloxane fluorescent materials of different colors by controlling different halogenated aromatic ring monomers. The materials emit blue light visible to the naked eye under sunlight and emit blue, green, yellow and red fluorescence under ultraviolet light.
[0024] 4. The siloxane-based fluorescent material prepared by this invention can achieve trace detection of fluroxypyr under sunlight, without being limited by the requirement of an external ultraviolet lamp source for fluorescent materials. Attached Figure Description
[0025] Figure 1 Structural formula and 1H NMR spectrum of the siloxane-based fluorescent material prepared in Example 1; Figure 2 Fluorescence emission patterns of siloxane-based fluorescent materials at different concentrations in Example 1; Figure 3 The structural formula and 1H NMR spectrum of the siloxane-based fluorescent material prepared in Example 2; Figure 4 Fluorescence emission patterns of siloxane-based fluorescent materials at different concentrations in Example 2; Figure 5 Structural formula and 1H NMR spectrum of the siloxane-based fluorescent material prepared in Example 3; Figure 6 Fluorescence emission patterns of siloxane-based fluorescent materials at different concentrations in Example 3; Figure 7 The structural formula and 1H NMR spectrum of the siloxane-based fluorescent material prepared in Example 4; Figure 8 Fluorescence emission patterns of siloxane-based fluorescent materials at different concentrations in Example 4; Figure 9 The structural formula and 1H NMR spectrum of the siloxane-based fluorescent material prepared in Example 5; Figure 10 Fluorescence emission patterns of siloxane-based fluorescent materials at different concentrations in Example 5; Figure 11 Structural formula and 1H NMR spectrum of the siloxane-based fluorescent material prepared in Example 6; Figure 12Fluorescence emission patterns of siloxane-based fluorescent materials at different concentrations in Example 6; Figure 13 Fluorescence images of the siloxane-based fluorescent materials prepared in Examples 1 and 2 under sunlight and ultraviolet light irradiation; Figure 14 Example 1: Fluoroxon detection image of the siloxane-based fluorescent material prepared under sunlight; Figure 15 Response time of the siloxane-based fluorescent material prepared in Example 1 to the detection of trifluralin; Figure 16 Example 1: Fluorescence quenching rate of siloxane-based fluorescent materials to trifluralin and linear fitting graph; Figure 17 Example 2: Fluoroxon detection image of the siloxane-based fluorescent material prepared under sunlight; Figure 18 Example 2: Fluorescence quenching rate of the siloxane-based fluorescent material prepared for fluroxypyridine and linear fitting graph. Detailed Implementation
[0026] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.
[0027] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.
[0028] The experimental materials used in the embodiments of this invention are all conventional experimental materials in the art and can be purchased through commercial channels.
[0029] Example 1 0.5 g of 1,5-divinyl-1,1,3,3,5,5-hexamethyltrisiloxane was stirred with 50 mg of palladium acetate and 1.5 g of potassium phosphate at room temperature for 0.5 h. Then, 1 g of 2,7-dibromo-9,9'-spirodifluorene was added, and the mixture was reacted at 120 °C for 24 h. After the reaction was complete, the mixture was filtered, the filtrate was extracted, rotary evaporated, dissolved in THF, precipitated in methanol, filtered, and dried to give a gray-green solid with a yield of 48.6%.
[0030] The structure of the siloxane fluorescent material obtained by this invention is shown below:
[0031] The structure of the siloxane-based fluorescent material prepared in this embodiment was characterized, and the results are as follows: Figure 1 As shown.
[0032] After the Heck reaction, the product of Example 1 simultaneously exhibited characteristic peaks of both aromatic ring and vinyl groups. The peaks in the 5.0-5.6 ppm region were attributed to carbon-carbon double bonds, and the multiple peaks in the 6.55-7.86 ppm region were characteristic peaks of H in the aromatic ring, indicating that the target product structure was correct.
[0033] In addition, using tetrahydrofuran as a solvent, the quantum yield was measured to be 91.72% using an integrating sphere. Solutions of siloxane fluorescent materials with different concentrations were prepared, and the fluorescence emission spectra of the siloxane solutions at different concentrations were detected. The results are as follows: Figure 2 As shown.
[0034] Example 2 0.5 g of 1,7-divinyl-1,1,3,3,5,5,7,7-octamethyltetrasiloxane was stirred with 50 mg of palladium acetate and 1.2 g of potassium phosphate at room temperature for 0.5 h. Then, 2,2'-dibromo-9,9'-spirodifluorene (2.5 g) was added, and the mixture was reacted at 120 °C for 24 h. After the reaction was complete, the mixture was filtered, the filtrate was extracted, rotary evaporated, dissolved in THF, precipitated in methanol, filtered, and dried to give a pale yellow solid in 45.5% yield.
[0035] The structure of the siloxane-based fluorescent material obtained by this invention is shown below.
[0036] The structure of the siloxane fluorescent probe prepared in this embodiment was characterized, and the results are as follows: Figure 3 As shown.
[0037] After the Heck reaction, the product of Example 2 simultaneously exhibited characteristic peaks of both aromatic ring and vinyl groups. The peaks in the 5.0-6.5 ppm region were attributed to carbon-carbon double bonds, and the multiple peaks in the 6.4-8 ppm region were characteristic peaks of H in the aromatic ring, indicating that the target product structure was correct.
[0038] In addition, using tetrahydrofuran as a solvent, the quantum yield was measured to be 92.71% using an integrating sphere. Solutions of siloxane fluorescent materials with different concentrations were prepared, and the fluorescence emission spectra of the siloxane solutions at different concentrations were detected. The results are as follows: Figure 4 As shown.
[0039] Example 3 1,5-Divinyl-1,1,3,3,5,5-hexamethyltrisiloxane (0.5 g) was reacted with palladium acetate (50 mg) and potassium phosphate (1.2 g) at room temperature for 0.5 h, followed by the addition of 4,4'-dibromobiphenyl (1.3 g), and the reaction was carried out at 120 °C for 24 h. After the reaction was complete, the mixture was filtered, the filtrate was extracted, rotary evaporated, dissolved in THF, precipitated in methanol, filtered, and dried to give a pale yellow solid in 57.6% yield.
[0040] The structure of the siloxane-based fluorescent material obtained by this invention is shown below.
[0041] The structure of the siloxane fluorescent probe prepared in this embodiment was characterized, and the results are as follows: Figure 5 As shown.
[0042] After the Heck reaction, the product of Example 3 simultaneously exhibited characteristic peaks of both aromatic ring and vinyl groups. The peaks in the 5.2-5.8 ppm region were attributed to carbon-carbon double bonds, and the multiple peaks in the 6.4-7.8 ppm region were characteristic peaks of H in the aromatic ring, indicating that the target product structure was correct.
[0043] In addition, using tetrahydrofuran as a solvent, the quantum yield was measured to be 73.11% using an integrating sphere. Solutions of siloxane fluorescent materials with different concentrations were prepared, and the fluorescence emission spectra of the siloxane solutions at different concentrations were detected. The results are as follows: Figure 6 As shown.
[0044] Example 4 0.5 g of 1,7-divinyl-1,1,3,3,5,5,7,7-octamethyltetrasiloxane was reacted with 50 mg of palladium acetate and 1.2 g of potassium phosphate at room temperature for 0.5 h. Then, 1.3 g of tris(4-bromophenyl)amine was added, and the mixture was reacted at 120 °C for 24 h. After the reaction was complete, the mixture was filtered, the filtrate was extracted, rotary evaporated, dissolved in THF, precipitated in methanol, filtered, and dried to give a yellow-green solid in 60.9% yield.
[0045] The structure of the siloxane-based fluorescent material obtained by this invention is shown below.
[0046] The structure of the siloxane fluorescent probe prepared in this embodiment was characterized, and the results are as follows: Figure 7 As shown.
[0047] After the Heck reaction, the product of Example 4 simultaneously exhibited characteristic peaks of both aromatic ring and vinyl groups. The peaks in the 5.2-6.1 ppm region were attributed to carbon-carbon double bonds, and the multiple peaks in the 6.6-7.7 ppm region were characteristic peaks of H in the aromatic ring, indicating that the target product structure was correct.
[0048] In addition, using tetrahydrofuran as a solvent, the quantum yield was tested using an integrating sphere and found to be 52.58%. Solutions of siloxane-based fluorescent materials with different concentrations were prepared, and the fluorescence emission spectra of these solutions were detected. The results are as follows: Figure 8 As shown.
[0049] Example 5 0.5 g of 1,7-divinyl-1,1,3,3,5,5,7,7-octamethyltetrasiloxane was reacted with 50 mg of palladium acetate and 1.2 g of potassium phosphate at room temperature for 0.5 h. Then, 1.3 g of tetra-(4-bromophenyl)ethylene was added, and the mixture was reacted at 120 °C for 24 h. After the reaction was complete, the mixture was filtered, the filtrate was extracted, rotary evaporated, dissolved in THF, precipitated in methanol, filtered, and dried to give a yellow solid with a yield of 64.7%.
[0050] The structure of the siloxane-based fluorescent material obtained by this invention is shown below.
[0051] The structure of the siloxane fluorescent probe prepared in this embodiment was characterized, and the results are as follows: Figure 9 As shown.
[0052] After the Heck reaction, the product of Example 5 simultaneously exhibited characteristic peaks of both aromatic ring and vinyl groups. The peaks in the 5.2-5.8 ppm region were attributed to carbon-carbon double bonds, and the multiple peaks in the 6.6-7.8 ppm region were characteristic peaks of H in the aromatic ring, indicating that the target product structure was correct.
[0053] In addition, using tetrahydrofuran as a solvent, an integrating sphere was used to test a quantum yield of 2.26%. Solutions of siloxane-based fluorescent materials with different concentrations were prepared, and the fluorescence emission spectra of the siloxane solutions at different concentrations were detected. The results are as follows: Figure 10 As shown.
[0054] Example 6 0.5 g of 1,5-divinyl-1,1,3,3,5,5-hexamethyltrisiloxane was stirred with 50 mg of palladium acetate and 1.2 g of potassium phosphate at room temperature for 0.5 h. Then, 1 g of 1,3,6,8-tetrabromopyrene was added, and the mixture was reacted at 120 °C for 24 h. After the reaction was complete, the mixture was filtered, the filtrate was extracted, rotary evaporated, dissolved in THF, precipitated in methanol, filtered, and dried to give a red solid in 59.8% yield.
[0055] The structure of the siloxane-based fluorescent material obtained by this invention is shown below.
[0056] The structure of the siloxane fluorescent probe prepared in this embodiment was characterized, and the results are as follows: Figure 11 As shown.
[0057] After the Heck reaction, the product of Example 6 simultaneously exhibited characteristic peaks of both aromatic ring and vinyl groups. The peaks in the 5.6-6.4 ppm region were attributed to carbon-carbon double bonds, and the multiple peaks in the 7.1-8.5 ppm region were characteristic peaks of H in the aromatic ring, indicating that the target product structure was correct.
[0058] In addition, using tetrahydrofuran as a solvent, an integrating sphere was used to test the quantum yield of 2%. Solutions of siloxane-based fluorescent materials with different concentrations were prepared, and the fluorescence emission spectra of the siloxane solutions at different concentrations were detected. The results are as follows: Figure 12 As shown.
[0059] Different concentrations of siloxane-based fluorescent material solutions from Examples 1 and 2 were placed under sunlight and ultraviolet light irradiation, and the luminescence phenomenon was observed. The results are as follows: Figure 13 As shown.
[0060] Application Example 1 The blue fluorescent siloxane-based fluorescent material prepared in Example 1 was mixed with tetrahydrofuran to obtain a solution with a concentration of 1 mg / mL. Mixing 0.001 mg / mL trifluralin solution and 1 mg / mL siloxane-based fluorescent solution at different volume ratios yielded mixed solutions. Images of the above mixed solutions were taken under sunlight, and the results are as follows. Figure 14 As shown. From Figure 14 As can be seen, the siloxane fluorescent material prepared in Example 1 can detect as low as 0.7 ppm of trifluralin under sunlight alone, which means that the siloxane fluorescent material synthesized in this invention exhibits high sensitivity to trifluralin at low concentrations (<1 ppm).
[0061] Adding 0.7 ppm of trifluralin to a 1 mg / mL solution from Example 1 resulted in 85% quenching of fluorescence intensity within 10 seconds, followed by stability over the next 600 seconds. Figure 15 As shown in the figure. This result demonstrates that the siloxane-based fluorescent material synthesized in this invention exhibits a rapid response when detecting fluroxypyr.
[0062] Take a 1 mg / mL tetrahydrofuran solution from Example 1 and record its fluorescence spectrum. Also record the fluorescence spectra after adding different concentrations (0.1–10 mg / L) of trifluralin solution sequentially. Figure 16 As shown in (a). The fluorescence quenching rate of Example 1 caused by different concentrations of trifluralin was calculated. The fluorescence quenching rate of Example 1 was linearly fitted with the trifluralin concentration, and the results are shown in (a). Figure 16 As shown in (b).
[0063] from Figure 16 As can be seen in (a), the fluorescence intensity of Example 1 gradually decreased as the concentration of trifluralin increased. When the concentration of trifluralin was 200 μM, the fluorescence quenching rate of Example 1 reached its maximum of 90%. By linearly fitting the fluorescence quenching rate of Example 1 with the concentration of trifluralin, it can be calculated that the detection limit of Example 1 for trifluralin is 0.313 μM.
[0064] Application Example 2 The blue fluorescent siloxane-based fluorescent material obtained in Example 2 was mixed with tetrahydrofuran to prepare a solution with a concentration of 1 mg / mL. Mixing 0.001 mg / mL trifluralin solution and 1 mg / mL siloxane-based fluorescent solution at different volume ratios yielded mixed solutions. Images of the above mixed solutions were taken under sunlight, and the results are as follows. Figure 17 As shown.
[0065] Take a 1 mg / mL tetrahydrofuran solution from Example 2 and record its fluorescence spectrum. Also record the fluorescence spectra after adding different concentrations (0.1–10 mg / L) of trifluralin solution sequentially. Figure 18 As shown in (a). The fluorescence quenching rate of Example 1 caused by different concentrations of trifluralin was calculated, and the fluorescence quenching rate of Example 2 was linearly fitted with the trifluralin concentration. The results are shown in (a). Figure 18 As shown in (b).
[0066] from Figure 18 As can be seen in (a), in Example 2, the fluorescence intensity gradually decreased as the concentration of trifluralin increased. By linearly fitting the fluorescence quenching rate of Example 2 with the trifluralin concentration, the detection limit for trifluralin in Example 2 was calculated to be 0.427 μM.
[0067] The siloxane-based fluorescent material provided by this invention can achieve the detection of trifluralin under sunlight and even quantitative fluorescence detection. It can detect trifluralin as low as 0.7 ppm under sunlight alone. It has the characteristics of low detection limit, high sensitivity, good selectivity and rapid response. In particular, it can achieve instantaneous detection of trace amounts of trifluralin.
[0068] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A method for preparing a siloxane-based fluorescent material for detecting trifluralin under sunlight, characterized in that, The material is a fluorescent material containing vinylsiloxane, specifically prepared by reacting vinylsiloxane with a halogenated aromatic compound via the Heck reaction. The specific procedure is as follows: Under inert gas protection, vinylsiloxane monomer, catalyst, and acid absorbent are added to an organic solvent, followed by the addition of a halogenated aromatic compound. The mixture is heated under reflux with stirring, filtered, rotary evaporated, precipitated with methanol, and dried under vacuum to remove the solvent, yielding a siloxane fluorescent material. The reaction temperature is 80–130 °C, and the reaction time is 24–72 h; the vacuum drying temperature is 50–150 °C, and the drying time is 18–48 h; the best results are achieved when the reaction temperature is 100 °C, the reaction time is 24 h, and the vacuum drying temperature is 75 °C, and the drying time is 48 h.
2. The method for preparing the siloxane-based fluorescent material for detecting trifluralin under sunlight according to claim 1, characterized in that, The molar ratio of vinyl groups in the vinyl siloxane to halogen groups in the halogenated aromatic compound is 1:1 to 1:3; the vinyl siloxane is a disiloxane, trisiloxane, or tetrasiloxane; the halogenated aromatic compound is a mono- or poly-substituted iodo or bromo group; and the aromatic unit is phenyl, biphenyl, 1,3,5-triphenyl-substituted benzene, stilbene, fluorene, spirodifluorene, pyrene, triphenylamine, 1,3,5-triphenyl-2,4,6-triazine, 1,2,3,4,5,6-hexaphenyl-substituted benzene, fluorenone, carbazole, or tetraphenylethylene.
3. The method for preparing the siloxane-based fluorescent material for detecting trifluralin under sunlight according to claim 1, characterized in that, The structural formula of the siloxane-based fluorescent material is shown in Formula I, Formula II, Formula III, or Formula IV. ； Formula I ； Formula II ； Formula III ； Formula IV In Equations I, II, III, and IV, n is a number greater than 0 and less than 4, and R1 and R2 are selected from C1 to C2. 18 The hydrocarbon group can be a straight-chain or branched saturated or unsaturated hydrocarbon group, or a hydrocarbon group with O, S, or N heteroatoms, or a cycloalkanes or aromatic hydrocarbons, with R1 and R2 being the same or different; R is an aromatic unit phenyl, biphenyl, 1,3,5-triphenyl-substituted benzene, stilbene, fluorene, spirofluorene, pyrene, triphenylamine, 1,3,5-triphenyl-2,4,6-triazine, 1,2,3,4,5,6-hexaphenyl-substituted benzene, fluorenone, carbazole, or tetraphenylethylene.
4. The method for preparing the siloxane-based fluorescent material for detecting trifluralin under sunlight according to claim 1, characterized in that, The molar ratio of the catalyst to vinylsiloxane is (0.01-0.1):1, the molar volume ratio of the vinylsiloxane to the organic solvent is (1-3) mmol:50 mL, the molar ratio of the absorbent to vinylsiloxane is (10-50):1, and the molar ratio of vinyl groups in the vinylsiloxane to halogen groups in the halogenated aromatic compounds is 1:1-1:
3.
5. The method for preparing the siloxane-based fluorescent material for detecting trifluralin under sunlight according to claim 4, characterized in that, The optimal ratio of vinyl groups in the vinyl siloxane to halogens in the halogenated aromatic compounds is 1:
1.
6. The method for preparing the siloxane-based fluorescent material for detecting trifluralin under sunlight according to claim 1, characterized in that, The catalyst is a palladium-based catalyst, specifically one or a mixture of two or more of the following: palladium chloride, palladium acetate, tetra(triphenylphosphine)palladium, bis(triphenylphosphine)palladium dichloride, [1,1'-bis(diphenylphosphine)ferrocene]palladium dichloride, bisacetonitrile palladium(II) chloride, and tris(dibenzylideneacetone)palladium.
7. The method for preparing a siloxane-based fluorescent material for detecting trifluralin under sunlight according to claim 1, characterized in that, The halogenated aromatic compounds are halogenated by mono- or poly-substituted iodide or bromine, and the aromatic unit is phenyl, biphenyl, 1,3,5-triphenyl-substituted benzene, stilbene, fluorene, spirofluorene, pyrene, triphenylamine, 1,3,5-triphenyl-2,4,6-triazine, 1,2,3,4,5,6-hexaphenyl-substituted benzene, fluorenone, carbazole, or tetraphenylethylene.
8. The method for preparing a siloxane-based fluorescent material for detecting trifluralin under sunlight according to claim 1, characterized in that, The absorbent is an organic amine or an inorganic base; the organic amine is selected from diethylamine, triethylamine, diisopropylamine, tripropylamine or tri-n-butylamine, and the inorganic base is sodium carbonate, potassium carbonate or cesium carbonate.
9. The method for preparing a siloxane-based fluorescent material for detecting trifluralin under sunlight according to claim 1, characterized in that, When the reaction is carried out in an organic solvent, the organic solvent is selected from one or any mixture of two or more of acetonitrile, tetrahydrofuran, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide, and the method is carried out in the presence of an organic solvent or in the absence of a solvent.
10. The siloxane-based fluorescent material with high quantum yield prepared by the method according to any one of claims 1-9, characterized in that, The siloxane-based fluorescent material is used for pesticide detection under sunlight, and the pesticide is trifluralin.