Application and method of fluorescent ionic liquid in detection of nitrophenol isomer

Abstract

The invention relates to application of fluorescent ionic liquid in detection of nitrophenol isomers and a method, the fluorescent ionic liquid is (poly) 1, 3-bis (N-methylimidazolyl) propane 1, 4-naphthalic acid salt, and the structure of the compound is as shown in the following formula: # imgabs0 #. The preparation method comprises the following steps: firstly, sequentially adding 30mL of NaOH solution (3mol / L) and 9.47 g of 1, 4-naphthalic acid into a single-mouth bottle, carrying out reflux reaction at 30 DEG C for 24 hours, filtering, washing, and drying to obtain the fluorescent ionic liquid. The brown clear solution is the 1, 4-sodium naphthalate solution. Secondly, 1, 3-dibromopropane (8mL), N-methylimidazole (12mL) and acetone (50mL) are sequentially added into the three-neck flask; stirring and refluxing at 45 DEG C for 20 hours, washing with acetone for three times, 50mL each time, and carrying out suction filtration to obtain white solid powder; and finally, sequentially adding the prepared sodium 1, 4-naphthalate solution and 8.3 g of the white solid product obtained in the step 2 into a single-mouth flask, and stirring and reacting at 50 DEG C for 24 hours. And carrying out rotary evaporation, drying, absolute ethyl alcohol dilution, suction filtration and drying on the prepared solution to obtain the target product (poly) 1, 3-bis (N-methylimidazolyl) propane 1, 4-naphthalic acid salt. The method is simple and convenient to operate, has relatively high fluorescence intensity and sensitivity, and can be used for fluorescence analysis and analysis and identification of nitrophenol isomers.

Description

Technical Field

[0001] The invention relates to a method for preparing a fluorescent ionic liquid. The compound can be used as a fluorescent probe to identify nitrophenol isomers in living environments such as the atmosphere, water bodies, soil and the like. Background Art

[0002] Nitrophenol compounds, as an important class of organic chemical raw materials and intermediates, are widely used in the fields of pesticides, dyes, medicines and explosives. However, these compounds are often toxic and pose a potential threat to the environment and human health. The United Nations Environmental Protection Agency has included them in the "Priority Control Pollutants List". As the two main isomers of nitrophenol, p-nitrophenol and o-nitrophenol have similar physical and chemical properties and are difficult to be directly identified by chemical methods. The prior art discloses a method for preparing a fluorescent ionic liquid containing a binaphthalene ring structure, and the obtained fluorescent ionic liquid has the advantages of good stability, high fluorescence intensity, high sensitivity, etc. The prior art provides a method for identifying isomers of p-nitrophenol and o-nitrophenol contained in water. Compared with reported technologies such as high performance liquid chromatography and electrochemical methods, this method has the advantages of low detection cost, simple operation, short response time, high stability, etc. Summary of the invention

[0003] One of the purposes of the present invention is to provide a fluorescent ionic liquid which is a high molecular polymer, and the anion structure of which contains a naphthalene ring structure and is relatively stable. The present invention is suitable for analyzing and identifying isomers of p-nitrophenol and o-nitrophenol in water, and has the characteristics of short response time and simple operation.

[0004] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0005] Step 1: Add 30 mL of NaOH solution (3 mol / L) and 9.47 g of 1,4-naphthalenedicarboxylic acid into a single-necked bottle in sequence, and reflux for 24 h at 30° C. to obtain a brown clear solution, which is a sodium 1,4-naphthalenedicarboxylate solution.

[0006] Step 2: Add 1,3-dibromopropane (8 mL), N-methylimidazole (12 mL) and acetone (50 mL) to a three-necked flask in sequence, stir and reflux at 45°C for 20 h, wash with acetone 3 times, 50 mL each time, and filter to obtain a white solid powder.

[0007] Step 3: Add the prepared sodium 1,4-naphthalene dicarboxylate solution and 8.3 g of the white solid product obtained in step 2 to a single-necked flask in sequence, and stir and react at 50° C. for 24 hours. The prepared solution is rotary evaporated, dried, diluted with anhydrous ethanol, filtered, and dried to obtain the target product (poly) 1,3-di(N-methylimidazolyl)propane 1,4-naphthalene dicarboxylate, with a yield of 97.4%.

[0008] The ionic liquid (poly) 1,3-di(N-methylimidazolyl) propane 1,4-naphthalene dicarboxylate compound of the present invention is a brown viscous liquid. It provides a new idea for detecting and identifying the isomers of nitrophenol, p-nitrophenol and o-nitrophenol of water pollutants by fluorescence spectroscopy. The preparation principle of the fluorescent ionic liquid (poly) 1,3-di(N-methylimidazolyl) propane 1,4-naphthalene dicarboxylate compound is as follows:

[0009] Step 1: Synthesis principle of 1,4-naphthalene dicarboxylate solution:

[0010]

[0011] Step 2 Synthesis principle of 1,3-di(N-methylimidazolyl)propane:

[0012]

[0013] Step 3: Principle of synthesis of final product:

[0014]

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] ① The present invention discloses a fluorescent ionic liquid, which is named (poly) 1,3-di(N-methylimidazolyl)propane 1,4-naphthalenedicarboxylate, and has a simple synthesis method. In addition, the present invention has higher fluorescence than commonly used ionic liquids such as halogenated imidazoles, imidazole hexafluorophosphates, and imidazole tetrafluoroborates.

[0017] ② The present invention has strong fluorescence performance. The aqueous solution of the fluorescent ionic liquid of the present invention (4mmol / L) has an excitation wavelength of 330nm and a maximum fluorescence intensity of about 3.5×10 4 au, the emission wavelength is 370nm.

[0018] ③ The present invention is a novel fluorescent ionic liquid, the preparation method of which is simple to operate, requires little equipment investment, and is easy to scale up and produce.

[0019] ④ The fluorescent ionic liquid of the present invention has good environmental performance, "zero" volatility, no odor, and can be recycled.

[0020] The preparation of the fluorescent ionic liquid (poly) 1,3-di(N-methylimidazolyl) propane 1,4-naphthalene dicarboxylate compound of the present invention can identify p-nitrophenol and o-nitrophenol according to the quenching degree, and provides a new idea for detecting pollutants in water by using fluorescence spectroscopy. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to further illustrate the structure and performance of the product, the following drawings are given.

[0022] Figure 1 The H NMR spectrum of (poly) 1,3-di(N-methylimidazolyl)propane 1,4-naphthalenedicarboxylate compound is as follows:

[0023] 1 H NMR (400MHz, DMSO) δ=2.56-2.61(2H), δ=3.85(6H), δ=4.23-4.26(4H), δ=7.37-7 .40(1H), δ=7.67(1H), δ=7.74(2H), δ=7.85(2H), δ=8.73-8.75(1H), δ=9.37(2H).

[0024] Figure 2 The fluorescence spectrum of (poly) 1,3-di(N-methylimidazolyl)propane 1,4-naphthalene dicarboxylate compound is as follows:

[0025] Figure 2 The results show that when the excitation wavelength is 330 nm, the fluorescence intensity of (poly) 1,3-di(N-methylimidazolyl)propane 1,4-naphthalene dicarboxylate is the highest, reaching about 3.5×10 4 . Specific embodiments

[0026] The raw materials involved in the present invention are all existing products, and the specific preparation operations and testing methods are all conventional methods. The technical solution of the present invention is further described below in conjunction with specific implementation methods.

[0027] Synthesis example

[0028] Embodiment 1 First, add 30mL NaOH solution (3mol / L) and 9.47g 1,4-naphthalenedicarboxylic acid to a single-necked flask in sequence, and reflux for 24 hours at 30°C to obtain a brown clear solution, which is a 1,4-naphthalenedicarboxylic acid sodium solution. Secondly, add 1,3-dibromopropane (8mL), N-methylimidazole (12mL) and acetone (50mL) to a three-necked flask in sequence. Stir and reflux for 20h at 45°C, wash with acetone 3 times, 50mL each time, and filter to obtain a white solid powder. Finally, add the prepared 1,4-naphthalenedicarboxylic acid sodium solution and 8.3g of the white solid product obtained in the previous step to a single-necked flask in sequence, and stir and react for 24h at 50°C. The prepared solution is rotary evaporated, dried, diluted with anhydrous ethanol, filtered, and dried to obtain the target product (poly) 1,3-di(N-methylimidazolyl)propane 1,4-naphthalenedicarboxylic acid salt, with a yield of 97.4%.

[0029] Example 2 First, 30mL NaOH solution (3mol / L) and 9.47g of 1,4-naphthalenedicarboxylic acid were added to a single-necked flask in sequence, and refluxed at 30°C for 24 hours to obtain a brown clear solution, which is a sodium 1,4-naphthalenedicarboxylate solution. Secondly, 1,3-dibromopropane (8mL), N-methylimidazole (12mL) and acetone (50mL) were added to a three-necked flask in sequence. Stir and reflux at 45°C for 20h, wash with acetone 3 times, 50mL each time, and filter to obtain a white solid powder. Finally, the prepared sodium 1,4-naphthalenedicarboxylate solution and 8.3g of the white solid product obtained in the previous step were added to a single-necked flask in sequence, and stirred for reaction at 40°C for 12h. The prepared solution was rotary evaporated, dried, diluted with anhydrous ethanol, filtered, and dried to obtain the target product (poly) 1,3-di(N-methylimidazolyl)propane 1,4-naphthalenedicarboxylate, with a yield of 57.8%.

[0030] Example 3 First, add 30mL NaOH solution (3mol / L) and 9.47g 1,4-naphthalenedicarboxylic acid to a single-necked flask in sequence, and reflux for 24 hours at 30°C to obtain a brown clear solution, which is a 1,4-naphthalenedicarboxylic acid sodium solution. Secondly, add 1,3-dibromopropane (8mL), N-methylimidazole (12mL) and acetone (50mL) to a three-necked flask in sequence. Stir and reflux at 45°C for 20h, wash with acetone 3 times, 50mL each time, and filter to obtain a white solid powder. Finally, add the prepared 1,4- The sodium diformate solution and 8.3 g of the white solid product obtained in the previous step were stirred and reacted at 30° C. for 36 h. The prepared solution was rotary evaporated, dried, diluted with anhydrous ethanol, filtered, and dried to obtain the target product (poly) 1,3-di(N-methylimidazolyl)propane 1,4-naphthalenedicarboxylate, with a yield of 45.2%.

[0031] Embodiment 4 First, add 30mL NaOH solution (3mol / L) and 9.47g 1,4-naphthalenedicarboxylic acid to a single-necked flask, and reflux for 24 hours at 30°C to obtain a brown clear solution, which is a 1,4-naphthalenedicarboxylic acid sodium solution. Secondly, add 1,3-dibromopropane (8mL), N-methylimidazole (12mL) and acetone (50mL) to a three-necked flask in sequence. Stir and reflux for 20h at 45°C, wash with acetone 3 times, 50mL each time, and filter to obtain a white solid powder. Finally, add the prepared 1,4-naphthalenedicarboxylic acid sodium solution and 8.3g of the white solid product obtained in the previous step to a single-necked flask in sequence, and stir and react for 48h at 25°C. The prepared solution is rotary evaporated, dried, diluted with anhydrous ethanol, filtered, and dried to obtain the target product (poly) 1,3-di(N-methylimidazolyl)propane 1,4-naphthalenedicarboxylic acid salt, with a yield of 37.2%.

[0032] Fluorescence test example

[0033] Example 7: A 4 mmol / L aqueous solution of (poly) 1,3-di(N-methylimidazolyl)propane 1,4-naphthalenedicarboxylate was prepared. Fluorescence was measured at an excitation wavelength of 330 nm, and the fluorescence intensity was about 3.5×10 4 au, the emission wavelength is 375nm.

[0034] Example 8: A 4 mmol / L aqueous solution of (poly) 1,3-di(N-methylimidazolyl)propane 1,4-naphthalenedicarboxylate was prepared. Fluorescence was measured at an excitation wavelength of 310 nm, and the fluorescence intensity was almost 0, with no emission wavelength.

[0035] Example 9: A 6 mmol / L aqueous solution of (poly) 1,3-di(N-methylimidazolyl)propane 1,4-naphthalenedicarboxylate was prepared. Fluorescence was measured at an excitation wavelength of 330 nm, and the fluorescence intensity was about 3.0×10 4 au, the emission wavelength is 375nm.

[0036] Example 10: A 2 mmol / L aqueous solution of (poly) 1,3-di(N-methylimidazolyl)propane 1,4-naphthalenedicarboxylate was prepared. Fluorescence was measured at an excitation wavelength of 330 nm, and the fluorescence intensity was about 2.8×10 4 au, the emission wavelength is 375nm.

[0037] Example 11: A 10 mmol / L aqueous solution of (poly) 1,3-di(N-methylimidazolyl)propane 1,4-naphthalenedicarboxylate was prepared. Fluorescence was measured at an excitation wavelength of 330 nm, and the fluorescence intensity was about 2.0×10 4au, the emission wavelength is 375nm.

[0038] Example 12 Prepare a 1 mmol / L (poly) 1,3-di(N-methylimidazolyl)propane 1,4- The fluorescence intensity of the solution was about 1.6×10 4 au, the emission wavelength is 360nm.

[0039] Analysis and Identification Examples of Nitrophenols

[0040] Example 13: In an aqueous solution of (poly)1,3-di(N-methylimidazolyl)propane 1,4-naphthalene dicarboxylate at a concentration of 4 mmol / L, p-nitrophenol at a concentration of 0.01 mmol / L was added, the pH was adjusted to 7, the excitation wavelength was 330 nm, the emission wavelength was 375 nm, and the fluorescence was quenched by about 14.3%.

[0041] Example 14 In the presence of 4 mmol / L (poly) 1,3-di(N-methylimidazolyl)propane 1,4- In the aqueous solution of diformate, 0.01 mmol / L o-phenol was added, the pH was adjusted to 7, the excitation wavelength was 330 nm, the emission wavelength was 375 nm, and the fluorescence intensity was reduced by about 7.1%.

[0042] Example 15: In an aqueous solution of (poly)1,3-di(N-methylimidazolyl)propane 1,4-naphthalene dicarboxylate at a concentration of 4 mmol / L, p-nitrophenol at a concentration of 0.05 mmol / L was added, the pH was adjusted to 7, the excitation wavelength was 330 nm, the emission wavelength was 375 nm, and the fluorescence intensity was reduced by about 42.9%.

[0043] Example 16: In an aqueous solution of (poly)1,3-di(N-methylimidazolyl)propane 1,4-naphthalene dicarboxylate at a concentration of 4 mmol / L, o-nitrophenol at a concentration of 0.05 mmol / L was added, the pH was adjusted to 7, the excitation wavelength was 330 nm, the emission wavelength was 375 nm, and the fluorescence intensity was reduced by about 28.6%.

[0044] Example 17: In an aqueous solution of (poly)1,3-di(N-methylimidazolyl)propane 1,4-naphthalene dicarboxylate at a concentration of 4 mmol / L, p-nitrophenol at a concentration of 0.1 mmol / L was added, the pH was adjusted to 7, the excitation wavelength was 330 nm, the emission wavelength was 375 nm, and the fluorescence intensity was reduced by about 71.4%.

[0045] Example 18: In an aqueous solution of (poly)1,3-di(N-methylimidazolyl)propane 1,4-naphthalene dicarboxylate at a concentration of 4 mmol / L, o-nitrophenol at a concentration of 0.1 mmol / L was added, the pH was adjusted to 7, the excitation wavelength was 330 nm, the emission wavelength was 375 nm, and the fluorescence intensity was reduced by about 35.7%.

[0046] Example 19 In the presence of 4 mmol / L (poly) 1,3-di(N-methylimidazolyl)propane 1,4- In the aqueous solution of diformate, p-nitrophenol with a concentration of 0.5 mmol / L was added, pH was adjusted to 7, the excitation wavelength was 330 nm, and the emission wavelength was 375 nm. The fluorescence intensity was reduced by about 100%.

[0047] Example 20: In an aqueous solution of (poly)1,3-di(N-methylimidazolyl)propane 1,4-naphthalene dicarboxylate at a concentration of 4 mmol / L, 0.5 mmol / L of o-nitrophenol was added, the pH was adjusted to 7, the excitation wavelength was 330 nm, the emission wavelength was 375 nm, and the fluorescence intensity was reduced by about 82.3%.

[0048] Example 21: In an aqueous solution of (poly)1,3-di(N-methylimidazolyl)propane 1,4-naphthalene dicarboxylate at a concentration of 4 mmol / L, p-nitrophenol at a concentration of 0.1 mmol / L was added, the pH was adjusted to 4, the excitation wavelength was 330 nm, the emission wavelength was 375 nm, and the fluorescence intensity was reduced by about 60%.

[0049] Example 22: In an aqueous solution of (poly)1,3-di(N-methylimidazolyl)propane 1,4-naphthalene dicarboxylate at a concentration of 4 mmol / L, o-nitrophenol at a concentration of 0.1 mmol / L was added, the pH was adjusted to 4, the excitation wavelength was 330 nm, the emission wavelength was 375 nm, and the fluorescence intensity was reduced by about 34.2%.

[0050] Example 23: In an aqueous solution of (poly)1,3-di(N-methylimidazolyl)propane 1,4-naphthalene dicarboxylate at a concentration of 4 mmol / L, p-nitrophenol at a concentration of 0.1 mmol / L was added, the pH was adjusted to 6, the excitation wavelength was 330 nm, the emission wavelength was 375 nm, and the fluorescence intensity was reduced by about 71.4%.

[0051] Example 24: In an aqueous solution of (poly)1,3-di(N-methylimidazolyl)propane 1,4-naphthalene dicarboxylate at a concentration of 4 mmol / L, o-nitrophenol at a concentration of 0.1 mmol / L was added, the pH was adjusted to 6, the excitation wavelength was 330 nm, the emission wavelength was 375 nm, and the fluorescence intensity was reduced by about 38.6%.

[0052] Example 25: In an aqueous solution of (poly)1,3-di(N-methylimidazolyl)propane 1,4-naphthalene dicarboxylate at a concentration of 4 mmol / L, p-nitrophenol at a concentration of 0.1 mmol / L was added, the pH was adjusted to 8, the excitation wavelength was 330 nm, the emission wavelength was 375 nm, and the fluorescence intensity was reduced by about 82.9%.

[0053] Example 26: In an aqueous solution of (poly)1,3-di(N-methylimidazolyl)propane 1,4-naphthalene dicarboxylate at a concentration of 4 mmol / L, o-nitrophenol at a concentration of 0.1 mmol / L was added, the pH was adjusted to 8, the excitation wavelength was 330 nm, the emission wavelength was 375 nm, and the fluorescence intensity was reduced by about 38.5%.

[0054] Example 27: In an aqueous solution of (poly)1,3-di(N-methylimidazolyl)propane 1,4-naphthalene dicarboxylate at a concentration of 4 mmol / L, p-nitrophenol at a concentration of 0.1 mmol / L was added, the pH was adjusted to 10, the excitation wavelength was 330 nm, the emission wavelength was 375 nm, and the fluorescence intensity was reduced by about 82.9%.

[0055] Example 28: In an aqueous solution of (poly)1,3-di(N-methylimidazolyl)propane 1,4-naphthalene dicarboxylate at a concentration of 4 mmol / L, o-nitrophenol at a concentration of 0.1 mmol / L was added, the pH was adjusted to 10, the excitation wavelength was 330 nm, the emission wavelength was 375 nm, and the fluorescence intensity was reduced by about 28.6%.

[0056] Example 29: In an aqueous solution of (poly)1,3-di(N-methylimidazolyl)propane 1,4-naphthalene dicarboxylate at a concentration of 4 mmol / L, p-nitrophenol at a concentration of 0.1 mmol / L was added, the pH was adjusted to 12, the excitation wavelength was 330 nm, the emission wavelength was 375 nm, and the fluorescence intensity was reduced by about 85.7%.

[0057] Example 30: In an aqueous solution of (poly)1,3-di(N-methylimidazolyl)propane 1,4-naphthalene dicarboxylate at a concentration of 4 mmol / L, o-nitrophenol at a concentration of 0.1 mmol / L was added, the pH was adjusted to 12, the excitation wavelength was 330 nm, the emission wavelength was 375 nm, and the fluorescence intensity was reduced by about 25.7%.

Claims

1. An application and method of a fluorescent ionic liquid in detecting nitrophenol isomers, characterized in that: The compound is named (poly) 1,3-di(N-methylimidazolyl)propane 1,4-naphthalene dicarboxylate, and its structure is shown below:

2. The method for preparing a fluorescent ionic liquid according to claim 1, wherein The method is as follows: first, 30 mL of NaOH solution (3 mol / L) and 9.47 g of 1,4-naphthalenedicarboxylic acid are sequentially added to a single-mouth bottle, and the mixture is refluxed at 30°C for 24 hours to obtain a brown clear solution, and a sodium 1,4-naphthalenedicarboxylate solution is obtained. Secondly, 1,3-dibromopropane (8 mL), N-methylimidazole (12 mL) and acetone (50 mL) are sequentially added to a three-mouth bottle. The mixture is stirred and refluxed at 45°C for 20 hours, washed with acetone 3 times, 50 mL each time, and filtered to obtain a white solid powder. Finally, the prepared sodium 1,4-naphthalenedicarboxylate solution and 8.3 g of the obtained white solid product are sequentially added to a single-mouth flask, and the mixture is stirred and reacted at 25-50°C for 12-48 hours. The prepared solution is rotary evaporated, dried, diluted with anhydrous ethanol, filtered, and dried to obtain the target product (poly) 1,3-di(N-methylimidazolyl)propane 1,4-naphthalenedicarboxylate.

3. A fluorescent ionic liquid containing a binaphthalene ring structure as claimed in claim 1 as a fluorescent probe for analyzing and identifying isomers of p-nitrophenol and o-nitrophenol.

4. The method for analyzing and identifying nitrophenol isomers as claimed in claim 3, characterized in that: When it is added into the aqueous solution containing fluorescent ionic liquid as claimed in claim 1, its fluorescence will be quenched.

5. The method for analyzing and identifying nitrophenol isomers as claimed in claim 3, characterized in that The excitation wavelength is 310nm-340nm, and the emission wavelength is 360-375nm.

6. The method for analyzing and identifying nitrophenol isomers as claimed in claim 3, characterized in that The concentration of the fluorescent ionic liquid aqueous solution is 1-10 mmol / L, pH=4-12, and the concentration of nitrophenol is 0.01-0.5 mmol / / L.

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