A method for rapid detection of acetonitrile in gas

Abstract

This invention relates to a method for rapid detection of acetonitrile in gases, belonging to the technical field of environmental pollutant detection technology. The method involves placing a test strip in the environment of the gas to be detected, observing the color change of the test strip, and qualitatively or quantitatively determining the acetonitrile concentration based on the color change. The test strip is prepared as follows: Step 1, dissolving 1.0-3.0 mmol of N,N-diphenyl-4-(quinoline-5-yl)aniline in 1.0-3.0 mL of N,N-dimethylacetamide, and adding 40.0-50.0 μL of hydroiodic acid aqueous solution to form solution A; dissolving 1.0-3.0 mmol of silver iodide in 1.0-3.0 mL of saturated potassium iodide aqueous solution to form solution B; mixing solutions A and B, and allowing them to stand to produce yellow crystals, forming the target analyte; Step 2, uniformly distributing the target analyte onto filter paper using a dispersion liquid, and then air-drying or baking to form the test strip. This invention enables rapid qualitative or quantitative detection of acetonitrile in gases.

Description

Technical Field

[0001] This invention relates to a method for rapid detection of acetonitrile in a gas. Background Technology

[0002] Acetonitrile, as an important organic solvent and chemical raw material, is widely used in industrial production and scientific research. Its widespread use means that there are risks of leakage and human exposure in the production, transportation, use, and waste disposal of acetonitrile. The volatility and potential high toxicity of acetonitrile pose a serious threat to occupational health and public safety. Studies have shown that long-term exposure to low concentrations of acetonitrile vapor may lead to chronic poisoning, damaging the nervous system, liver function, and kidney function. The National Institute for Occupational Safety and Health (NIOSH) recommends a time-weighted average exposure limit of 20 ppm for a 10-hour work shift over a 40-hour work week. Furthermore, acetonitrile is flammable, and its vapor can form explosive mixtures with air, easily igniting or exploding upon contact with open flames or high heat. Therefore, real-time and effective monitoring of acetonitrile vapor in the environment is a crucial step in preventing poisoning incidents and ensuring personnel safety.

[0003] Chinese invention patent application CN112014503A, entitled "A Method for Detecting Acetonitrile in Organized Waste Gas," discloses a method for detecting acetonitrile in organized waste gas, comprising the following steps: S1, determination of the desorption efficiency of sampling tubes: determining the desorption efficiency of activated carbon sampling tubes used in the same batch; S2, sample collection: collecting organized waste gas in the test environment using activated carbon sampling tubes, and measuring the temperature and atmospheric pressure at the sampling point; S3, acetonitrile desorption: transferring the activated carbon from the sampling tube to a desorption bottle, adding desorption solution for acetonitrile desorption; S4, preparation of standard solution: taking multiple volumetric flasks, and separately filling them with... Add a certain amount of acetonitrile and desorption solution to prepare multiple sets of acetonitrile standard solutions with a concentration range of 0-400 μg / mL; S5, Standard curve preparation: Take 1.0 μL of the acetonitrile standard solutions of different concentrations prepared in step S4, place them in a gas chromatograph to determine the peak area corresponding to different acetonitrile concentrations, and plot the standard acetonitrile standard curve or calculate the regression equation; S6, Sample determination: Detect the sample using the same operating conditions of the gas chromatograph in S4, and obtain the peak area value by referring to the standard curve or regression equation to obtain the acetonitrile concentration of the sample; S7, Concentration calculation: Calculate the acetonitrile concentration of the sampled organized waste gas based on the obtained acetonitrile concentration of the sample.

[0004] For example, Chinese invention patent application CN119310213A, entitled "A Method for Detecting Ethylene Oxide and Acetonitrile in Stationary Source Exhaust Gas," discloses a method for detecting ethylene oxide and acetonitrile in stationary source exhaust gas, comprising the following steps: collecting stationary source exhaust gas using an exhaust gas sampling device and studying the motion direction of the stationary source exhaust gas to obtain motion characteristics; using gas chromatography to detect ethylene oxide and acetonitrile in the stationary source exhaust gas based on the motion characteristics to obtain first detection data; using electrochemical analysis to detect ethylene oxide in the stationary source exhaust gas and using liquid chromatography to detect acetonitrile to obtain second detection data; fusing the first detection data and the second detection data to obtain a comprehensive quantity, and outputting the comprehensive quantity as the detection result.

[0005] Currently, the main technologies used for acetonitrile detection include gas chromatography and its coupled techniques, Fourier transform infrared spectroscopy, photoionization detection, and chemical colorimetry. However, all of them have limitations to varying degrees and cannot meet the needs of rapid on-site detection.

[0006] Based on the above issues, the applicant conducted research on these issues and thus this case came into being. Summary of the Invention

[0007] The purpose of this invention is to provide a simple method for the rapid detection of acetonitrile in gases.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A method for rapid detection of acetonitrile in a gas involves placing a test strip in the environment of the gas to be detected, observing the color change of the test strip, and qualitatively or quantitatively determining the acetonitrile concentration based on the color change. The test strip is prepared using the following method:

[0010] Step 1: Dissolve 1.0-3.0 mmol of N,N-diphenyl-4-(quinolin-5-yl)aniline in 1.0-3.0 mL of N,N-dimethylacetamide, and add 40.0-50.0 μL of hydroiodic acid aqueous solution to form solution A; dissolve 1.0-3.0 mmol of silver iodide in 1.0-3.0 mL of saturated potassium iodide aqueous solution to form solution B; mix solutions A and B, and allow to stand to produce yellow crystals, forming the target substance;

[0011] Step 2: Take 2.0-4.0 mg of the target substance from Step 1, disperse it in 0.5-1.5 mL of n-hexane, and sonicate it to form a uniformly mixed dispersion. Immerse a filter paper in the dispersion and sonicate it to ensure that the dispersion is evenly distributed on the filter paper. Air dry or bake dry to form the test paper.

[0012] In a preferred embodiment of the present invention, the hydroiodic acid aqueous solution contains 57% hydroiodic acid by weight.

[0013] In a preferred embodiment of the present invention, in step one, the settling time is 68 to 74 hours.

[0014] In a preferred embodiment of the present invention, the target substance is dispersed in n-hexane and ultrasonically treated for 5 minutes at a frequency of 35 kHz. Filter paper is then immersed in the dispersion and ultrasonically treated for 1 minute at a frequency of 35 kHz.

[0015] In a preferred embodiment of the present invention, a filter paper is immersed in the above-mentioned dispersion, ultrasonically treated to make the dispersion evenly distributed on the filter paper, and then air-dried or oven-dried at room temperature. This process is repeated three times to form the test paper.

[0016] As a preferred embodiment of the present invention, the test strip is exposed to the gas for 3-8 minutes during detection.

[0017] As a preferred embodiment of the present invention, the qualitative determination of acetonitrile concentration is performed by pre-preparing a color card. The color card is prepared in the following manner: acetonitrile is injected into the gas to form air with different acetonitrile concentrations, and test strips are placed in air with different acetonitrile concentrations for 5 minutes. The colors corresponding to the test strips are then made on the color card. During the test, the color changes of the test strips are compared with the color card.

[0018] In a preferred embodiment of the present invention, the quantitative determination of acetonitrile concentration involves injecting acetonitrile into a gas to form gases with different acetonitrile concentrations, placing the test strip in these gases for 5 minutes, irradiating it with a 365 nm handheld UV lamp, taking a picture to acquire an image, extracting the RGB values ​​of the image using a colorimetric app, selecting the ratio of the green channel to the red channel (G / R) as the ordinate, and the acetonitrile concentration as the abscissa to plot a standard curve of the linear correlation model. During detection, the test strip image is captured by taking a picture, and the RGB values ​​of the image are extracted using the colorimetric app. The ratio of the green channel to the red channel is calculated as the ordinate value, and the corresponding abscissa value on the standard curve of the linear correlation model is found as the acetonitrile concentration.

[0019] In a preferred embodiment of the present invention, the diameter of the test strip is 0.7-0.9 cm, and the loading of the target analyte in the test strip is 2.3 mg to 2.7 mg.

[0020] As a preferred embodiment of the present invention, the N,N-diphenyl-4-(quinoline-5-yl)aniline is synthesized as follows: 4.00-6.00 mmol of 5-bromoquinoline and 4.00-6.00 mmol of triphenylamine 4-borate are added to a container containing 15-20.0 mL of tetrahydrofuran. 0.40-0.50 g of potassium carbonate or sodium carbonate is dissolved in 4.0-5.0 mL of water and added to the container. Then, 0.08-0.12 mmol of tetra(triphenylphosphine)palladium is added to the container. The mixture is stirred and reacted at 70-80 °C for 42 to 54 hours under nitrogen protection. After the reaction is completed, the mixture is diluted with water, the organic layer is separated, and the crude product is concentrated under reduced pressure. The crude product is purified to obtain N,N-diphenyl-4-(quinoline-5-yl)aniline.

[0021] Using the technical solution of the present invention, Ag2I3 - Using a metal halide center, protonated N,N-diphenyl-4-(quinolino5-yl)aniline (5-DQL) as the organic cation, and N,N-dimethylacetamide (DMA) as the solvent, a one-dimensional OIMH, namely (5-DQL-H)-Ag₂I₃·DMA, was prepared. A simple ultrasonic method was used to load (5-DQL-H)-Ag₂I₃·DMA onto filter paper, preparing a test strip for real-time monitoring of acetonitrile content in gases. As the acetonitrile concentration increased, the fluorescence color of the paper-based sensor changed from yellow to deep red. Within the range of 10-500 ppm, the green channel ratio (G / R) showed a good linear relationship with the acetonitrile concentration. The detection limit for acetonitrile vapor of this paper-based sensor was calculated to be 6.4 ppm using 3σ / K, which is lower than the permissible exposure limit of 20 ppm defined by the National Institute for Occupational Safety and Health (NIOHS). The beneficial effects of this invention are: by placing the test strip in the gas environment to be detected, observing the color change of the test strip, and qualitatively or quantitatively determining the acetonitrile concentration through the color change of the test strip, the acetonitrile concentration can be detected quickly in the gas, which has the advantage of convenient operation. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the molecular structure of the target substance in this invention.

[0023] Figure 2 This is a graph showing the fluorescence intensity wavelength of the test strip of the present invention when exposed to different volatile organic compounds.

[0024] Figure 3 This is a comparison of the fluorescence intensity of the test paper in this invention when exposed to different mixed gases (acetonitrile and volatile organic compounds).

[0025] Figure 4 This is a schematic diagram of the color card in this invention.

[0026] Figure 5 This is a standard curve diagram of the linear correlation model in this invention (the horizontal axis represents the acetonitrile concentration in ppm, and the vertical axis represents the ratio of the green channel to the red channel, i.e., the G / R value). Detailed Implementation

[0027] To better understand the technical solution of the present invention, such as Figures 1-5 As shown, the following is a more detailed explanation with reference to the embodiments.

[0028] (1) Synthesis of N,N-diphenyl-4-(quinolin-5-yl)aniline (i.e., 5-DQL)

[0029] 4.00-6.00 mmol of 5-bromoquinoline (CAS No.: 4964-71-0) and 4.00-6.00 mmol of triphenylamine 4-borate (CAS No.: 201802-67-7) were added to a flask containing 15-20.0 mL (20.0 mL in the example) of tetrahydrofuran (THF). Separately, 0.40-0.50 g of potassium carbonate or sodium carbonate (potassium carbonate was used in the example, 0.50 g) was dissolved in 4.0-5.0 mL (5 mL in the example) of water, and the two solutions were then mixed. Next, 0.08-0.12 mmol (0.10 mmol in the example) of tetrakis(triphenylphosphine)palladium (CAS No.: 14221-01-3) was added to the mixture. The reaction was carried out under nitrogen protection at 70-80 °C with stirring for 42 to 54 hours (75 °C, 48 hours in the example). After the reaction was complete, the mixture was diluted with water and extracted with ethyl acetate. The organic layer was separated and retained. An equal volume of water was added, the mixture was shaken, allowed to stand for separation, the aqueous layer was discarded, and the organic layer was separated and retained. An equal volume of saturated brine was added, the mixture was shaken, allowed to stand for separation, the brine layer was discarded, and the organic layer was separated and retained. The obtained organic layer was transferred to an Erlenmeyer flask, dried with sufficient anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure to obtain the crude product. The crude product was purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 5 / 1, v / v). Finally, a colorless powdery intermediate product 5-DQL was obtained.

[0030] Under otherwise identical conditions, the yield of 5-DQL obtained from the reaction of 5-bromoquinoline (4.00 mmol) and triphenylamine 4-boronate (6.00 mmol) was 86.7%; the yield from the reaction of 5-bromoquinoline (5.00 mmol) and triphenylamine 4-boronate (4.00 mmol) was 79.6%; and the yield from the reaction of 5-bromoquinoline (6.00 mmol) and triphenylamine 4-boronate (5.00 mmol) was 95.3%. The reaction of 5-bromoquinoline (6.00 mmol) and triphenylamine 4-boronate (5.00 mmol) yielded the highest product yield.

[0031] (2) Synthesis of silver-based organic-inorganic hybrid halides (OIMHs) ((5-DQL-H)-Ag2I3·DMA)

[0032] 1.0–3.0 mmol of 5-DQL was dissolved in 1.0–3.0 mL (2.0 mL in the example) of N,N-dimethylacetamide (DMA), followed by the addition of 40.0–50.0 μL (50.0 μL in the example) of hydroiodic acid (57 wt% aqueous hydroiodic acid solution). Separately, 1.0–3.0 mmol (2.0 mmol in the example) of silver iodide (AgI) was dissolved in 1.0–3.0 mL (1.0 mL in the example) of saturated potassium iodide (KI) aqueous solution. The two solutions were mixed and allowed to stand for 72 hours. The resulting yellow needle-like crystals were the target compound (5-DQL-H)-Ag₂I₃·DMA. The yellow needle-like crystals were ground into powder for later use.

[0033] Under the same conditions, the yield of the product (i.e., the target analyte) obtained by the reaction of 5-DQL (2.0 mmol) and silver iodide (1.0 mmol) was 33.7%; the yield of the product obtained by the reaction of 5-DQL (3.0 mmol) and silver iodide (2.0 mmol) was 40.2%; and the yield of the product obtained by the reaction of 5-DQL (1.0 mmol) and silver iodide (2.0 mmol) was 46.2%.

[0034] The resulting target compound (5-DQL-H)-Ag₂I₃·DMA is a one-dimensional organic-inorganic hybrid metal halide. Each asymmetric unit contains two silver ions, three iodide ions, one protonated (5-DQL-H) cation, and one solvent molecule. Figure 1 In DMA, the oxygen atom acts as a hydrogen bond acceptor. Each Ag(I) center forms an AgI4 tetrahedron with three μ3-I atoms and one μ2-I atom. Four tetrahedra assemble into an Ag4I8 unit, which extends into [Ag2I3] by sharing edges. - It is a chain, and is bounded by four (5-DQL-H) chains. + Cations and solvent molecules surround ( Figure 1 ).

[0035] (3) Preparation of filter paper-based test paper discs

[0036] Disperse 2.0-4.0 mg (3 mg in the example) of (5-DQL-H)-Ag2I3·DMA in 0.5-1.5 mL (0.5 mL in the example) of n-hexane, and sonicate for 5 minutes (working frequency is 35 kHz) to ensure uniform distribution of the hybrid material. Then immerse a circular filter paper disc with a diameter of 0.7 to 0.9 cm (0.8 cm in the example) into the above dispersion, sonicate for 1 minute (working frequency is 35 kHz), remove it, and air dry or oven dry at room temperature. Repeat the above immersion-drying process 3 times. Under the same conditions, (5-DQL-H)-Ag2I3·DMA (1.0 mg) dispersed in 1.5 mL of n-hexane yielded a single filter paper loading of 0.78 ± 0.15 mg; (5-DQL-H)-Ag2I3·DMA (2.0 mg) dispersed in 1.0 mL of n-hexane yielded a single filter paper loading of 1.4 ± 0.3 mg; and (5-DQL-H)-Ag2I3·DMA (3.0 mg) dispersed in 0.5 mL of n-hexane yielded a single filter paper loading of 2.5 ± 0.2 mg. The filter paper (i.e., the test paper) obtained by dispersing (5-DQL-H)-Ag2I3·DMA 3.0 mg in 0.5 mL of n-hexane was the most uniform, with a single sheet loading of 2.5 ± 0.2 mg.

[0037] Selectivity test: The prepared paper-based sensor (test strip) was exposed to 100.0 ppm of common volatile organic compounds (including methanol (MeOH), ethanol (EtOH), ethyl acetate (EtOAc), acetone (Ac.), dichloromethane (DCM), chloroform (CF), pyridine (Py), tetrahydrofuran (THF), and acetonitrile (ACN)) for 5.0 minutes, followed by fluorescence measurement. The paper-based sensor showed a significant fluorescence response only after 5.0 minutes of exposure to acetonitrile (ACN) vapor. This indicates that the paper-based sensor has high selectivity for acetonitrile (ACN).

[0038] Interference resistance test: The prepared paper-based sensor (test strip) was exposed to a mixture of vapors containing 100.0 ppm acetonitrile and 300.0 ppm common volatile organic compounds (i.e., 100.0 ppm acetonitrile + 300.0 ppm methanol, 100.0 ppm acetonitrile + 300.0 ppm ethanol, 100.0 ppm acetonitrile + 300.0 ppm ethyl acetate, 100.0 ppm acetonitrile + 300.0 ppm acetone, 100.0 ppm acetonitrile + 300.0 ppm dichloromethane, 100.0 ppm acetonitrile + 300.0 ppm trichloromethane, 100.0 ppm acetonitrile + 300.0 ppm pyridine, and 100.0 ppm acetonitrile + 300.0 ppm tetrahydrofuran) for 5.0 minutes, and then fluorescence was measured. Using exposure to 100.0 ppm acetonitrile vapor for 5.0 minutes as a blank control, the results show that the paper-based sensor still maintains excellent selectivity and strong anti-interference ability under interference from other volatile organic compounds.

[0039] Actual sample testing: Expose the sample to air (air containing acetonitrile) for 3 to 8 minutes (5 minutes in this example), then take a picture after illuminating it with a 365nm flashlight. Use the Color Grab color picking app (an existing color picking tool) to pick the color, or other color picking software can be used. Select the central area of ​​the test strip (diameter ≥ 0.5 cm) to obtain the RGB value, calculate the green / red channel ratio (G / R), compare it with the color chart, and read the corresponding acetonitrile concentration, or compare it with the vertical axis of the standard curve of the linear correlation model to find the corresponding horizontal axis. This horizontal axis value is the acetonitrile concentration.

[0040] The process of creating a standard color chart is as follows:

[0041] Different concentrations (10.0, 50.0, 100.0, 200.0, 300.0, 400.0, 500.0 ppm) of acetonitrile-n-pentane solution were injected into the flask of the experimental apparatus using a syringe. After the solvent completely evaporated and formed vapor, the vapor was diffused to another flask containing the test strip, and timing was started. The test strip was exposed to acetonitrile gas for 5 minutes, then removed and immediately irradiated with a 365 nm handheld ultraviolet lamp. An image of the test strip was then captured using a smartphone camera.

[0042] Each concentration corresponds to a separate image of the test strip, and the corresponding color is plotted on a color chart. Then, a color-picking app is used to extract the RGB values ​​of the images. The ratio of the green channel to the red channel (G / R) is selected as the ordinate, and the acetonitrile concentration (calculated by converting the acetonitrile injection volume and the flask volume) is used as the abscissa to construct a standard curve of the linear correlation model, achieving visualized semi-quantitative detection of acetonitrile levels.

[0043] The color-changing mechanism of this invention is explained as follows:

[0044] DMA: N,N-dimethylacetamide

[0045] ACN: Acetonitrile

[0046] MLCT: Metal-to-Ligand Charge Transfer.

[0047] XLCT: Halide-to-Ligand Charge Transfer (HATCT)

[0048] ICT: Intra-ligand Charge Transfer

[0049] The core of the color change mechanism of (5-DQL-H)-Ag2I3·DMA detection of acetonitrile is: the irreversible single-crystal to single-crystal transformation induced by solvent molecules, which leads to a significant change in photophysical properties.

[0050] Summary: ACN (vapor / liquid) contact → DMA is replaced by ACN molecules → Irreversible change in crystal structure ([Ag2I3]) - Increased distance from organic cations → Changes in electronic structure (weakened XLCT / MLCT, enhanced ICT, narrowed band gap) → Suppression of nonradiative transitions, changes in excited-state properties → Macroscopic manifestation: color changes from yellow to red, luminescence changes from non-existent to present (producing deep red fluorescence).

[0051] Specific steps:

[0052] (1) Structural transformation: DMA molecules in (5-DQL-H)-Ag2I3·DMA crystals are replaced by ACN molecules in the environment.

[0053] (2) Structural changes lead to changes in electronic structure: The insertion of ACN increases the size of the inorganic anion cluster [Ag2I3]. - With organic cations (5-DQL-H) + The increased distance between them causes the band gap of the material to narrow (from 1.34 eV to 1.19 eV).

[0054] (3) Changes in electronic structure lead to changes in optical properties:

[0055] Primitive state (DMA form): At room temperature, luminescence is quenched (no luminescence or very weak luminescence) due to nonradiative transitions caused by silver-silver interactions.

[0056] After the transition (ACN form): the increased distance weakens the silver-silver interaction and suppresses nonradiative transitions. At the same time, the ICT-dominated excited state produces deep red / near-infrared fluorescence (peak at 666 nm) through radiative recombination of the self-trapped exciton.

[0057] The narrowing of the band gap causes the ACN-type material to exhibit characteristic absorption in the visible light region (585 nm), thus changing the crystal color from yellow to deep red.

[0058] Of course, the scope of protection of this invention is not limited to this embodiment. Any similar modifications made to it are considered to be within the scope of patent protection of this invention.

Claims

1. A method for rapid detection of acetonitrile in a gas, characterized by: The test paper sheet is placed in the gas environment to be detected, the color change of the test paper sheet is observed, and the acetonitrile concentration is qualitatively judged or quantitatively judged according to the color change of the test paper sheet, wherein the test paper sheet is prepared in the following manner: Step one, 1.0-3.0 mmol of N,N-diphenyl-4-(quinolin-5-yl) aniline is dissolved in 1.0-3.0 mL of N,N-dimethylacetamide, 40.0-50.0 μL of hydroiodic acid aqueous solution is added to form solution A; 1.0-3.0 mmol of silver iodide is dissolved in 1.0-3.0 mL of saturated potassium iodide aqueous solution to form solution B, and the solutions A and B are mixed to generate yellow crystals, and the target product is formed; Step two, 2.0-4.0 mg of the target product of step one is dispersed in 0.5-1.5 mL of n-hexane, and ultrasonic treatment is performed to form a uniformly mixed dispersion liquid, a filter paper sheet is immersed in the above dispersion liquid, ultrasonic treatment is performed to uniformly distribute the dispersion liquid on the filter paper sheet, and air drying or oven drying is performed to form the test paper sheet; The quantitative judgment of the acetonitrile concentration is to inject acetonitrile into the gas to form gas with different acetonitrile concentrations, and the test paper sheet is placed in the gas with different acetonitrile concentrations for 5 minutes, a 365 nm wavelength handheld ultraviolet lamp is used for irradiation, an image is obtained by photographing, the RGB value of the image is extracted by a color picking APP software, the ratio of the green channel to the red channel (G / R) is selected as the ordinate, and the acetonitrile concentration is selected as the abscissa to draw a linear correlation model standard curve graph, during detection, the image of the test paper sheet is obtained by photographing, the RGB value of the image is extracted by the color picking APP software, the ratio of the green channel to the red channel is calculated as the ordinate value, and the corresponding abscissa value is found on the linear correlation model standard curve graph as the concentration of acetonitrile.

2. The method for rapid detection of acetonitrile in a gas according to claim 1, characterized in that: The weight percentage of hydroiodic acid in the hydroiodic acid aqueous solution is 57%.

3. The method for rapid detection of acetonitrile in a gas according to claim 1, characterized in that: In step one, the standing time is 68-74 hours.

4. The method for rapid detection of acetonitrile in a gas according to claim 1, characterized in that: The target product is dispersed in n-hexane, ultrasonic treatment is performed for 5 minutes at a frequency of 35 kHz, the filter paper sheet is immersed in the above dispersion liquid, and ultrasonic treatment is performed for 1 minute at a frequency of 35 kHz.

5. A method for rapid detection of acetonitrile in a gas as claimed in claim 4, characterized in that: The filter paper sheet is immersed in the above dispersion liquid, ultrasonic treatment is performed to uniformly distribute the dispersion liquid on the filter paper sheet, and air drying or oven drying is performed at room temperature, and the process is repeated three times to form the test paper sheet.

6. The method for rapid detection of acetonitrile in a gas as claimed in claim 1, wherein: During detection, the test paper sheet is exposed to the gas for 3-8 minutes.

7. The method for rapid detection of acetonitrile in a gas as claimed in claim 1, wherein: The qualitative judgment of the acetonitrile concentration is to prepare a color card in advance, and the color card is prepared in the following manner: acetonitrile is injected into the gas to form air with different acetonitrile concentrations, and the test paper sheet is placed in the air with different acetonitrile concentrations for 5 minutes, and the corresponding color of the test paper sheet is prepared on the color card, and during testing, the color card is compared according to the color change of the test paper sheet.

8. The method for rapid detection of acetonitrile in a gas as claimed in claim 1, wherein: The diameter of the test paper sheet is 0.7-0.9 cm, and the loading amount of the target final product in the test paper sheet is 2.3-2.7 mg.

9. The method of claim 1, wherein the gas is selected from the group consisting of air, nitrogen, and helium. The N,N-diphenyl-4-(quinolin-5-yl)aniline is synthesized as follows: 4.00-6.00 mmol of 5-bromoquinoline and 4.00-6.00 mmol of 4-boronic acid triphenylamine are added to a container containing 15-20.0 mL of tetrahydrofuran, 0.40-0.50 g of potassium carbonate or sodium carbonate is dissolved in 4.0-5.0 mL of water and added to the above container, then 0.08-0.12 mmol of tetrakis(triphenylphosphine)palladium is added to the container, and the reaction is stirred at 70-80°C for 42 to 54 hours under nitrogen protection; after the reaction is completed, water is added for dilution, the organic layer is separated, and the crude product is obtained by concentration under reduced pressure, and the obtained crude product is purified to obtain N,N-diphenyl-4-(quinolin-5-yl)aniline.

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