Fluorine-containing organic compound test paper and preparation method thereof

Abstract

The invention provides fluorine-containing organic compound test paper and a preparation method thereof. The method comprises the following steps: dissolving a compound DIP in toluene, then immersing filter paper in a DIP toluene solution, taking out the filter paper, and drying the filter paper at room temperature in a dark place to obtain the detection test paper. The detection test paper is dipped in an organic solution mixed with fluorine-containing organic matters, and after irradiation of a 405 nm excitation light source, color change is compared and observed. If the color is inconsistent with the color of the initial picture, the compound has a recognition response effect, namely the compound contains an F element. At present, most chemical reaction detection methods can only detect F-containing ions and cannot detect F-containing organic matters, but the detection test paper provided by the invention can be used for detecting fluorine-containing organic compounds and has a good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of fluorine-containing organic compound detection, specifically relating to a fluorine-containing organic compound detection test strip and its preparation method. Background Technology

[0002] Fluorinated organic compounds are widely used in industrial production and consumer products, but due to their persistence, bioaccumulation and potential toxicity, they pose serious threats to the environment and human health. The main detection methods for fluorinated organic compounds include chromatography, mass spectrometry, spectroscopy and combined techniques.

[0003] While instruments such as gas chromatography, liquid chromatography, high-performance liquid chromatography, and mass spectrometry can be used for precise analysis and detection of halogenated reagents, these devices are costly and time-consuming, requiring highly skilled operators. Furthermore, these instruments only detect specific known components, lacking convenience and universality. Chemical reaction detection methods are limited by the extremely strong bond energy of the CF bond, making reactions difficult to occur and thus limiting detection capabilities. Currently, most chemical reaction detection methods can only detect F-containing ions and cannot detect F-containing organic compounds. Summary of the Invention

[0004] The purpose of this invention is to provide a test strip for detecting fluorinated organic compounds and its preparation method. This method can be used in the fluorochemical field for the detection of fluorinated organic compounds, and the detection method is convenient and efficient.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a test strip for fluorinated organic compounds includes the following steps: dissolving the compound DIP in toluene, then immersing filter paper in the DIP toluene solution, removing it, and drying it at room temperature in the dark to obtain the test strip; The structure of the DIP is as follows: .

[0006] Furthermore, the filter paper was immersed in the DIP toluene solution for 10 minutes.

[0007] Furthermore, the concentration of the DIP toluene solution is 3-25 mg / mL.

[0008] Furthermore, the test strip for fluorinated organic compounds is prepared by the method described above.

[0009] Furthermore, the method of using the fluorine-containing organic compound test strip includes the following steps: dipping the test strip into an organic solution mixed with fluorine-containing organic compounds, irradiating it with a 405 nm excitation light source, and then comparing and observing the color change.

[0010] Furthermore, the illumination time is 10 s.

[0011] Furthermore, the solvents used in the organic solutions containing fluorine-containing organic compounds include, but are not limited to, ethyl acetate, toluene, dimethyl sulfoxide, petroleum ether, benzene, n-hexane, and cyclohexane.

[0012] Detection and Comparison: After 10 seconds of light exposure, the filter paper was observed in different states, including before and after solvent drying, using both naked-eye observation and fluorescence photographs under 365 nm UV light. If the color differs from the initial photograph, it indicates a recognition response, meaning the compound contains F.

[0013] The compound DIP is an organic fluorescent material, and its preparation method includes the following steps: (1) Preparation of Cz-Br: 3,6-di-tert-butylcarbazole was added to dichloromethane and stirred thoroughly to dissolve. Under light-protected conditions, a dichloromethane solution of N-bromosuccinimide was slowly added dropwise. The reaction was carried out at room temperature in the dark for 6 hours. After cooling to room temperature, the product was concentrated and washed with saturated brine and dried with anhydrous magnesium sulfate. The concentrated organic layer was separated and separated by silica gel column chromatography to obtain the product Cz-Br. (2) Preparation of DCz-2Br: Cz-Br was dissolved in acetone, KMnO4 was added, the reaction system was heated to 60℃, and the reaction was refluxed under nitrogen atmosphere for 6 hours. After cooling to room temperature, acetone was removed by vacuum distillation. The product was dissolved in chloroform, filtered and the residue was washed. The resulting solution was washed successively with saturated sodium thiosulfate solution and brine, and dried with anhydrous magnesium sulfate. The concentrated organic layer was separated and separated by silica gel column chromatography to obtain the product DC. Z -2Br; (3) Preparation of DIP: DCz-2Br, palladium chloride, 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl and tetrabutylammonium bromide were added sequentially to the reaction vessel. Nitrogen was purged to remove oxygen, and toluene and K2CO3 solution were injected. The reaction was carried out at 100℃ for 24 hours under a nitrogen atmosphere. After cooling to room temperature, the product was washed with saturated brine, extracted with EA, and dried with anhydrous magnesium sulfate. The organic layer was separated and concentrated and then separated by silica gel column chromatography to obtain the product DIP.

[0014] Furthermore, in step (1), the eluent for silica gel column chromatography is petroleum ether: dichloromethane = 30:1, by volume.

[0015] Furthermore, in step (2), the eluent for silica gel column chromatography is petroleum ether: dichloromethane = 50:1, by volume.

[0016] Furthermore, in step (3), the eluent for silica gel column chromatography is petroleum ether: dichloromethane = 60:1, by volume.

[0017] The advantages of this invention are: (1) The method for synthesizing DIP in this invention is simple, the raw materials are cheap, the yield is high, the post-processing is convenient, and the synthesis and separation costs are saved.

[0018] (2) Existing technologies for the detection of fluorinated organic compounds mainly rely on chromatography, mass spectrometry, and elemental analysis, which require advanced equipment and personnel skills and are costly, making them unsuitable for convenient operation. The sample strips prepared in this invention have the advantages of simple operation, low cost, and wide environmental adaptability.

[0019] (3) The test strip of the present invention can detect fluorinated organic compounds with a content as low as 1 wt%. Attached Figure Description

[0020] Figure 1 This is the UV-Vis absorption spectrum of DIP in toluene; Figure 2 Fluorescence spectra of DIP in different solvents (λ) ex =360 nm). Figure 3 DCM solution for DIP (5×10) -5 Fluorescence spectra of mol / L mixed in the dark for different times (λ) ex =365 nm); Figure 4 The images are of a blank DIP test strip. The orange dashed line represents the image observed in a wet state, the orange solid line represents the image observed in a dry state, the blue dashed line represents the image observed with the naked eye, and the blue solid line represents the image observed under a 365nm UV lamp. Figure 5 Photograph of DIP test strips used to detect 2-fluorophenol; Figure 6 Photograph of DIP test strips used to detect 2,4-difluorophenol; Figure 7 A photo of DIP test strips for detecting ethyl difluoroacetate. Detailed Implementation

[0021] To make the above-mentioned features and advantages of the present invention more apparent and understandable, specific embodiments are described below in detail. Unless otherwise specified, the methods of the present invention are conventional methods in the art.

[0022] The preparation method of organic fluorescent material DIP includes the following steps:

[0023] Preparation of 1-bromo-3,6-di-tert-butylcarbazole (Cz-Br): 3,6-di-tert-butylcarbazole (3000 mg, 10.74 mmol) and 300 mL dichloromethane (DCM) were added to a 1000 mL single-necked flask and stirred thoroughly to dissolve. Under light-protected conditions, 300 mL of DCM solution containing N-bromosuccinimide (2300 mg, 12.92 mmol) was slowly added dropwise. The reaction was carried out at room temperature in the dark for 6 hours, followed by cooling to room temperature. The product was concentrated to 100 mL, washed successively with saturated brine, dried over anhydrous magnesium sulfate, and the concentrated organic layer was separated by silica gel column chromatography to obtain 3200 mg of a pale yellow viscous oil, yielding 83.2% (eluent: PE:DCM = 30:1, volume ratio).

[0024] Preparation of 1,1'-dibromo-3,3',6,6'-tetratert-butyl-9,9'-dicarbazole (DCz-2Br): Cz-Br (2430 mg, 6.78 mmol) was added to a 150 mL two-necked flask and dissolved in 65 mL of acetone. KMnO4 (2680 mg, 16.95 mmol) was added, and the reaction system was heated to 60 °C and refluxed under nitrogen atmosphere for 6 hours. After cooling to room temperature, acetone was removed by vacuum distillation. The product was dissolved in an appropriate amount of chloroform, filtered, and the residue was washed. The resulting solution was washed successively with saturated sodium thiosulfate solution and brine, and dried over anhydrous magnesium sulfate. The concentrated organic layer was separated by silica gel column chromatography to obtain 2071 mg of white solid, yield 85.5%. (Eluent:PE:DCM = 50:1, volume ratio).

[0025] Preparation of 2,5,10,13-tetratert-butyldiindole[3,2,1-de:3',2',1'-kl]phenazine (DIP): DCz-2Br (1000 mg, 1.40 mmol), palladium chloride (PdCl2) (1000 mg, 1.40 mmol), 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl (2297 mg, 5.6 mmol), and tetrabutylammonium bromide (TBAB) (65 mg) were added sequentially to a 150 mL two-necked flask. The mixture was purged with nitrogen to remove oxygen, and TOL (45 mL) and K2CO3 solution (10 mL, 2.0 mol / L) were injected. The reaction was carried out at 100 °C for 24 hours under a nitrogen atmosphere. After cooling to room temperature, the product was washed sequentially with saturated brine, extracted with EA, and dried over anhydrous magnesium sulfate. The concentrated organic layer was separated and purified by silica gel column chromatography to obtain 850 mg of a pale blue solid product, with a yield of 85%. (Eluent PE:DCM = 60:1, volume ratio) NMR data of DIP compounds: 1H NMR (400 MHz, Acetone-d6) δ 8.24 (s, 2H), 8.03 (d, J = 8.8 Hz,2H), 7.72 (s, 2H), 7.68 (d, J= 8.7 Hz, 2H), 7.60 (s, 2H), 1.48 (s, 18H), 1.44(s, 18H). Ultraviolet absorption spectrum: The UV absorption spectrum of the DIP compound in toluene is as follows: Figure 1 As shown, it mainly exhibits strong absorption near 296 nm and 424 nm. Due to the rigid conjugated plane formed by the fusion of two carbazole molecules, the compound has a large degree of conjugation, which extends its absorption sites into the visible light region.

[0026] Fluorescence emission spectrum: The fluorescence spectra of DIP compounds in different solvents are as follows: Figure 2 As shown, its emission peak is mainly located around 425 nm, accompanied by a shoulder peak around 455 nm, and its emission peak is less affected by solvent polarity.

[0027] Further testing was conducted on the dichloromethane solution of DIP (5 × 10⁻⁶). -5 The fluorescence spectrum of the mixture (mol / L) after prolonged mixing in the dark is shown below. Figure 3 As shown, despite prolonged mixing, the DCM solution of compound DIP did not exhibit significant changes, indicating that photoexcitation is a necessary factor for its color change.

[0028] Example 1 A method for preparing and using a test strip for detecting fluorinated organic compounds includes the following steps: Preparation of test strips: 11.0 mg of DIP was completely dissolved in 4.0 mL of toluene by ultrasonic vibration for 1 h. Filter paper of 0.6 cm × 3 cm was cut and immersed in the above solution for 10 min. After removal, it was placed in a watch glass at room temperature to dry in the dark to obtain the test strip.

[0029] Detection method: Dip the prepared test strip into an organic solution containing fluorine-containing organic matter (solvents include, but are not limited to, ethyl acetate, toluene, dimethyl sulfoxide, petroleum ether, benzene, n-hexane, and cyclohexane), and irradiate it with a 405 nm desktop lamp for 10 seconds. Observe the color change. The desktop lamp model is S-10W6868CJG-TD, with a power of 10 W.

[0030] Detection and Comparison: After 10 seconds of light exposure, the filter paper was observed in different states, including before and after solvent drying, using both naked-eye observation and fluorescence photographs under 365 nm UV light. If the color differs from the initial photograph, it indicates a recognition response, meaning the compound contains F.

[0031] Figure 4 The images are of blank DIP test strips. The orange dashed lines represent images observed when the strip is wet with ethyl acetate, the orange solid lines represent images observed when the strip is dry, the blue dashed lines represent images observed with the naked eye, and the blue solid lines represent images observed under a 365 nm UV lamp.

[0032] Figure 5 After being dipped in an ethyl acetate solution (5 wt%) containing 2-fluorophenol, the test paper, observed to be moist and dry, turned dark brown and brown, respectively, with fluorescence of deep blue and sky blue under 365 nm UV light. The colors in all four states differed from those observed with the blank sample, indicating a recognition response. Simultaneously, blank filter paper was dipped in the 2-fluorophenol solution, and after illumination, the colors were observed to be similar to the DIP test paper in both moist and dry states. However, the fluorescence was completely quenched in both states, showing a significant difference from the DIP-containing test paper. These results suggest that the DIP test paper can be used to detect 2-fluorophenol.

[0033] Figure 6 The results showed that after being dipped into an ethyl acetate solution (5 wt%) containing 2,4-difluorophenol, 2,4-difluorophenol exhibited a similar detection effect as 2-fluorophenol.

[0034] Figure 7 The images show four states of the DIP test strip after being exposed to light, with the strip exhibiting similar color changes to 2-fluorophenol and 2,4-difluorophenol, further demonstrating that the DIP test strip has a detection and recognition response behavior for fluorinated organic compounds.

[0035] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A method for preparing a test strip for detecting fluorinated organic compounds, characterized in that, Includes the following steps: The compound DIP is dissolved in toluene, then filter paper is immersed in the DIP toluene solution, removed, and dried at room temperature in the dark to obtain the test paper. The structure of the DIP is as follows: 。 2. The preparation method according to claim 1, characterized in that, The filter paper was immersed in the DIP toluene solution for 10 minutes.

3. The preparation method according to claim 1, characterized in that, The concentration of DIP toluene solution is 3-25 mg / mL.

4. A test strip for detecting fluorinated organic compounds prepared by the preparation method according to any one of claims 1-3.

5. The method of using the fluorine-containing organic compound test strip according to claim 4, characterized in that, Includes the following steps: The test strip is dipped into an organic solution containing fluorine, and after being irradiated by a 405 nm excitation light source, the color change is observed.

6. The method of use according to claim 5, characterized in that, The illumination time was 10 seconds.

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