Method for jointly degrading 4-ethyl benzoic acid-3-fluoro-4-cyanophenyl ester by using syringol as mediator and laccase

Abstract

The invention discloses a method for jointly degrading 4-ethyl benzoic acid-3-fluoro-4-cyanophenyl ester by taking syringyl alcohol as a mediator and laccase, which specifically comprises the following steps: adding a 4-ethyl benzoic acid-3-fluoro-4-cyanophenyl ester mother solution into a conical flask, and after acetonitrile is volatilized, adding laccase into the conical flask; adding a laccase syringol mediator solution formed by mixing a syringol solution and a laccase mother solution to form a reaction system with the pH value of 5.0, putting the reaction system into an incubator, oscillating at the constant temperature of 40 DEG C for 24 hours, and extracting the 4-ethyl benzoic acid-3-fluoro-4-cyanophenyl ester by using dichloromethane to terminate the reaction; the residual concentration of the 4-ethyl benzoic acid-3-fluoro-4-cyanophenyl ester in a reaction system is determined by adopting a high performance liquid chromatography (HPLC), so that the degradation effect of the 4-ethyl benzoic acid-3-fluoro-4-cyanophenyl ester is analyzed. According to the method disclosed by the invention, a laccase syringyl alcohol mediator reaction system is constructed and is used for degrading the 4-ethyl benzoic acid-3-fluoro-4-cyanophenyl ester, so that the degradation rate of the 4-ethyl benzoic acid-3-fluoro-4-cyanophenyl ester with the initial concentration of 1 mg / L reaches 90% or above; and an efficient method is provided for the degradation of the 4-ethyl benzoic acid-3-fluoro-4-cyanophenyl ester in the environment.

Description

Technical Field

[0001] The invention relates to the technical field of environmental organic pollutant treatment, and in particular to a method for degrading 4-ethylbenzoic acid-3-fluoro-4-cyanophenyl ester by using syringol as a mediator and in combination with laccase. Background Art

[0002] 4-Ethylbenzoic acid-3-fluoro-4-cyanophenyl ester belongs to the benzoic acid phenyl ester liquid crystal monomer. This type of liquid crystal monomer has a wide liquid crystal phase range and good chemical stability. It is one of the commonly used mixed liquid crystal formula components on the market. Due to the widespread use of this type of liquid crystal monomer, benzoic acid phenyl ester liquid crystal monomers including 4-ethylbenzoic acid-3-fluoro-4-cyanophenyl ester have been detected in a variety of environmental media such as indoor dust, rivers, sediments, soils, and leachate from urban solid waste landfills. Relevant experiments and quantitative calculation simulation studies have shown that 4-ethylbenzoic acid-3-fluoro-4-cyanophenyl ester has atmospheric persistence, bioaccumulation and potential acute toxicity. At present, the research on liquid crystal monomers is mainly focused on the synthesis, preparation and performance research of new liquid crystal monomers. There are relatively few studies on the degradation and removal of benzoic acid phenyl ester liquid crystal monomers in the environment. The main method for removing this type of liquid crystal monomer reported is photocatalytic degradation, but the photocatalytic method cannot be the best choice for pollution control of benzoic acid phenyl ester liquid crystal monomers due to its high operating cost and easy secondary pollution.

[0003] Laccase is a polyphenol oxidase containing four copper ions. In the process of catalyzing the redox reaction of the substrate, molecular oxygen is used as an electron acceptor. Laccase exists in mushrooms, fungi and plants, and can remain active in the air. The only product after the reaction is water. Therefore, it is essentially an environmentally friendly enzyme. The unique catalytic properties of laccase make it have a large application potential in environmental pollution remediation. The present invention uses thuja alcohol as a redox mediator and laccase to achieve degradation of 4-ethylbenzoic acid-3-fluoro-4-cyanophenyl ester, and develops a highly efficient, economical and environmentally friendly method for degrading benzoic acid phenyl ester liquid crystal monomers. From the current patent application situation, there is no relevant patent for the degradation method of 4-ethylbenzoic acid-3-fluoro-4-cyanophenyl ester. Summary of the invention

[0004] The primary purpose of the present invention is to provide a method for degrading 4-ethylbenzoic acid-3-fluoro-4-cyanophenyl ester by using syringol as a mediator and laccase.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A method for degrading 4-ethylbenzoic acid-3-fluoro-4-cyanophenyl ester by using syringol as a mediator and laccase, the degradation method comprising the following steps:

[0007] (1) dissolving 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester in acetonitrile to prepare 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester mother solution, dissolving laccase in acetic acid-sodium acetate buffer solution to prepare laccase mother solution, and dissolving syringol in acetic acid-sodium acetate buffer solution to prepare syringol solution;

[0008] (2) Adding 4-ethylbenzoic acid-3-fluoro-4-cyanophenyl ester mother liquor into a conical flask, after acetonitrile evaporates, adding a laccase-syringol mediator solution composed of a mixture of syringol solution and laccase mother liquor into the conical flask to form a reaction system;

[0009] (3) using dichloromethane to extract 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester to terminate the reaction and complete the degradation;

[0010] The mother liquor of 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester was diluted into standard solutions of 0.1 mg / L, 0.3 mg / L, 0.5 mg / L, 0.7 mg / L and 1 mg / L, and the peak area was detected by high performance liquid chromatography (HPLC) to prepare the standard curve of 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester. After the degradation was completed, the concentration of the remaining 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester was detected by HPLC, and the degradation rate was calculated.

[0011] The concentration of the 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester mother liquor in step (1) is 1.0 g / L.

[0012] Furthermore, the concentration of the acetic acid-sodium acetate buffer solution in step (1) is 0.1 mol / L and the pH is 5.0.

[0013] Furthermore, the concentrations of the laccase mother solution and the syringol solution in step (1) are 2.0 mg / mL and 0.01 mol / L, respectively.

[0014] In step (2), the initial concentration of 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester in the reaction system is 1.0 mg / L.

[0015] Furthermore, in step (2), the initial concentration of laccase in the reaction system is 1.0 mg / mL.

[0016] Furthermore, in step (2), the initial concentration of syringol in the reaction system is 5.0 mmol / L.

[0017] Furthermore, in step (2), the temperature of the reaction system is 40° C., the pH is 5.0, and the reaction time is 4-24 h.

[0018] Furthermore, the laccase is produced by Coriolus versicolor, and its activity is ≥0.5 U / mg.

[0019] Furthermore, in step (3), the HPLC detection conditions are as follows: chromatographic column: ZORBAX RX-C18 (250 mm × 4.6 mm × 5 μm); detection conditions are as follows: injection volume 20 μL, mobile phase water: acetonitrile = 25:75 (V / V), flow rate 1.0 mL / min, column temperature: 40°C, ultraviolet detector detects the peak at a wavelength of 244 nm, and records the peak area value.

[0020] In step (3), the degradation rate is calculated as degradation rate = (C0-C) / C0×100%, where C0 is the initial concentration and C is the residual concentration after the reaction.

[0021] Compared with the prior art, the present invention has the following advantages and effects:

[0022] 1. The present invention provides a method for degrading 3-fluoro-4-cyanophenyl 4-ethylbenzoate by using syringol as a mediator and laccase. By using syringol as a redox mediator to rapidly and efficiently degrade 3-fluoro-4-cyanophenyl 4-ethylbenzoate under the catalysis of laccase, a technical method can be provided for the pollution control and remediation of 3-fluoro-4-cyanophenyl 4-ethylbenzoate.

[0023] 2. The laccase-syringol system of the present invention has good degradation effect on 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester, high efficiency, simple operation and low cost, which is beneficial to the rapid treatment of 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester pollution in the environment and has practical application value in the field of environmental organic pollutant treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention.

[0025] Figure 1 is a standard curve diagram of 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester;

[0026] Figure 2 The degradation efficiency of 1 mg / L 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester at different time points;

[0027] Figure 3 This is the effect of different pH on the degradation of 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below in conjunction with examples and drawings, but the embodiments of the present invention are not limited thereto.

[0029] Example 1 Drawing a standard curve of 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester

[0030] Preparation of 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester mother solution: Accurately weigh 0.05 g of 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester, dissolve it in acetonitrile, and dilute it to a 50 mL volumetric flask to obtain 1 g / L 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester mother solution. Dilute the mother solution step by step with acetonitrile to obtain standard solutions of 0.1 mg / L, 0.3 mg / L, 0.5 mg / L, 0.7 mg / L, and 1 mg / L, respectively. Use a sterile syringe to take 1 mL of each concentration standard solution, filter it through a 0.22 μm filter membrane, and then perform HPLC detection. Draw a standard curve for 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester, as shown in the following figure: Figure 1 shown.

[0031] Example 2

[0032] (1) Add 0.01 mL of 1 g / L 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester mother solution into a 50 mL conical flask. After the acetonitrile evaporates, add 5 mL of 2 mg / mL laccase mother solution and 5 mL of 0.01 mol / L syringol solution into the conical flask. The pH of the reaction system is 5.0. Place the system in a shaking incubator at 40°C and 160 rpm for reaction.

[0033] (2) After 4 h of reaction, the reaction system was extracted three times with dichloromethane. The organic phases were combined and extracted and then evaporated to dryness. 10 mL of chromatographic grade acetonitrile was added to make up the volume. 1 mL of the sample was drawn with a sterile syringe, filtered through a 0.22 μm filter membrane, and transferred to a liquid phase injection bottle. Finally, the peak area was detected by HPLC.

[0034] (3) The residual concentration of 4-ethylbenzoic acid-3-fluoro-4-cyanophenyl ester in the reaction system was calculated by substituting the peak area obtained by the detection into the standard curve of 4-ethylbenzoic acid-3-fluoro-4-cyanophenyl ester. The degradation rate was calculated according to the formula: degradation rate = (C0-C) / C0×100%, where C0 is the initial concentration and C is the residual concentration after the reaction. The calculated degradation rate was 17.82%.

[0035] Example 3

[0036] Example 3 is the same as Example 2, except that the reaction time is 8 h. Finally, the measured peak area is substituted into the formula to calculate the degradation rate to be 39.56%.

[0037] Example 4

[0038] Example 4 is the same as Example 2, except that the reaction time is 12 h. Finally, the measured peak area is substituted into the formula to calculate the degradation rate to be 57.44%.

[0039] Example 5

[0040] Example 5 is the same as Example 2, except that the reaction time is 16 h. Finally, the measured peak area is substituted into the formula to calculate the degradation rate to be 73.23%.

[0041] Example 6

[0042] Example 6 is the same as Example 2, except that the reaction time is 20 h. Finally, the measured peak area is substituted into the formula to calculate the degradation rate to be 89.45%.

[0043] Example 7

[0044] Example 7 is the same as Example 2, except that the reaction time is 24 h. Finally, the measured peak area is substituted into the formula to calculate the degradation rate to be 92.72%.

[0045] Example 8

[0046] Example 8 is the same as Example 7, except that the pH of the reaction system is 3.0. Finally, the measured peak area is substituted into the formula to calculate the degradation rate to be 33.57%.

[0047] Example 9

[0048] Example 9 is the same as Example 8, except that the pH of the reaction system is 4.0. Finally, the measured peak area is substituted into the formula to calculate the degradation rate to be 41.88%.

[0049] Example 10

[0050] Example 10 is the same as Example 8, except that the pH of the reaction system is 6.0. Finally, the measured peak area is substituted into the formula to calculate the degradation rate to be 91.98%.

[0051] The present invention studies the degradation effect and trend of 1 mg / L 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester by using syringol as a mediator and laccase under the conditions of temperature of 40°C and pH of 5.0 within 24 hours. The reaction tends to equilibrium in 20 hours and reaches a maximum degradation rate of 92.72% in 24 hours. At the same time, the influence of different pH values ​​on the degradation of 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester is studied. When the pH value of the reaction system is 5-6, the degradation rate of 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester reaches more than 90%, and when the pH value is 3-5, the degradation rate decreases significantly.

[0052] The embodiments described above are only descriptions of the preferred modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement modes and shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for degrading 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester by using syringol as a mediator and laccase, characterized in that: The following steps are involved: (1) dissolving 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester in acetonitrile to prepare 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester mother solution, dissolving laccase in acetic acid-sodium acetate buffer solution to prepare laccase mother solution, and dissolving syringol in acetic acid-sodium acetate buffer solution to prepare syringol solution; (2) Adding 4-ethylbenzoic acid-3-fluoro-4-cyanophenyl ester mother liquor into a conical flask, after acetonitrile evaporates, adding a laccase-syringol mediator solution composed of a mixture of syringol solution and laccase mother liquor into the conical flask to form a reaction system; (3) The reaction was terminated by extracting 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester with dichloromethane to complete the degradation.

2. The method for degrading 4-ethylbenzoic acid-3-fluoro-4-cyanophenyl ester by using syringol as a mediator and laccase according to claim 1, characterized in that: The concentration of the 4-ethylbenzoic acid 3-fluoro-4-cyanophenyl ester mother liquor in step (1) is 1 g / L.

3. The method for degrading 4-ethylbenzoic acid-3-fluoro-4-cyanophenyl ester by using syringol as a mediator and laccase according to claim 1, characterized in that: The concentration of the acetic acid-sodium acetate buffer solution in step (1) is 0.1 mol / L, and the pH is 5-6.

4. The method for degrading 4-ethylbenzoic acid-3-fluoro-4-cyanophenyl ester by using syringol as a mediator and laccase according to claim 1, characterized in that: The concentration of the laccase mother solution in step (1) is 2 mg / mL, and the concentration of the syringol solution is 0.01 mol / L.

5. The method for degrading 4-ethylbenzoic acid-3-fluoro-4-cyanophenyl ester by using syringol as a mediator and laccase according to claim 1, characterized in that: The initial concentration of 4-ethylbenzoic acid-3-fluoro-4-cyanophenyl ester in the reaction system of step (2) is 1 mg / L.

6. The method for degrading 4-ethylbenzoic acid-3-fluoro-4-cyanophenyl ester by using syringol as a mediator and laccase according to claim 1, characterized in that: The initial concentration of laccase in the reaction system described in step (2) is 1 mg / mL.

7. The method for degrading 4-ethylbenzoic acid-3-fluoro-4-cyanophenyl ester by using syringol as a mediator and laccase according to claim 1, characterized in that: The initial concentration of syringol in the reaction system of step (2) is 5 mmol / L.

8. The method for degrading 4-ethylbenzoic acid-3-fluoro-4-cyanophenyl ester by using syringol as a mediator and laccase according to claim 1, characterized in that: The degradation conditions of the reaction system in step (2) are: temperature 40°C, pH 5-6, and time 24 h.

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