A ferulic acid diethyl ester carbon dot with strong ultraviolet absorption and a preparation method and application thereof

Abstract

The application belongs to the technical field of nanomaterials, and discloses a strong ultraviolet absorption ferulic acid diethyl ester carbon dot as well as a preparation method and application thereof. The ferulic acid diethyl ester carbon dot is prepared by using anhydrous sodium citrate, ferulic acid diethyl ester and ethylenediamine monohydrate as raw materials and by using a hydrothermal method. The prepared ferulic acid diethyl ester carbon dot has strong absorption characteristics in the ultraviolet region and can maintain high transparency in the visible light region. The ferulic acid diethyl ester carbon dot prepared by the application is easy to dissolve in water, and the problem of application limitation of the ferulic acid diethyl ester with poor water solubility is overcome. The preparation method of the carbon dot disclosed by the application is simple, the carbon dot has good biocompatibility, and the carbon dot can be mass-produced. The carbon dot can be applied in cosmetics, food packaging, ultraviolet filtering materials, transparent ultraviolet shielding coatings of ultraviolet shielding glass and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nanomaterials, and particularly relates to a ferulic acid diethyl ester carbon dot with strong ultraviolet absorption and a preparation method and application thereof. BACKGROUND

[0002] Ultraviolet radiation is divided into UVA (320-400 nm), UVB (280-320 nm) and UVC (200-280 nm), and the UVC with the highest energy cannot reach the earth's surface, and the main harmful ultraviolet radiation is UVA and UVB radiation. Long-term ultraviolet radiation can accelerate skin aging and cause serious harm to human health; accelerate the degradation and aging of materials and shorten the service life of materials. Moreover, ultraviolet radiation can also promote the oxidation, deterioration and decomposition of food and the generation of some harmful chemical substances in food, so some food also needs to block ultraviolet rays during packaging. The current ultraviolet absorbers include organic ultraviolet absorbers and inorganic ultraviolet absorbers, but both have certain problems. The organic ultraviolet absorber has a narrow ultraviolet shielding range and has an unavoidable toxicity problem, and the inorganic ultraviolet absorber is easy to caking when the content is increased, affecting the transparency. Therefore, it is urgent to develop a non-toxic ultraviolet absorber with strong ultraviolet absorption capacity and high transparency.

[0003] Carbon dots are a new type of carbon nanomaterials, and the size of the carbon dots is generally 1-10 nm. The carbon dots have attracted extensive attention due to their significant fluorescence performance, low cost, green environmental protection, simple synthesis method and the like. More importantly, the ultraviolet absorption performance of the carbon dots can be adjusted, and the light stability is good, so the carbon dots have great potential as an excellent ultraviolet absorber. However, there are few studies on the ultraviolet absorption performance of the carbon dots at present, and the existing carbon dots have problems such as weak ultraviolet absorption intensity and low transparency. Therefore, it is urgent to develop a carbon dot with excellent ultraviolet absorption performance. SUMMARY

[0004] The present application provides a ferulic acid diethyl ester carbon dot with strong ultraviolet absorption and a preparation method and application thereof, solves the application limitation of poor water solubility of the raw material ferulic acid diethyl ester, and the existing carbon dots have problems such as weak ultraviolet absorption intensity and low transparency.

[0005] The present application provides a preparation method of a ferulic acid diethyl ester carbon dot, which comprises: using anhydrous sodium citrate, ferulic acid diethyl ester and ethylenediamine monohydrate as raw materials, and preparing the carbon dot by using a hydrothermal method.

[0006] According to the preparation method of the diethyl ferulate carbon dots, the use amount ratio of diethyl ferulate to ethylenediamine monohydrate is 0.55-0.95 g: 25-40 μL, preferably 0.65-0.85 g: 31-36 μL, further preferably 0.69-0.78 g: 32-35 μL, and more preferably 0.735 g: 33.9 μL. The present application prepares the diethyl ferulate carbon dots with poor water solubility into diethyl ferulate carbon dots which are easily soluble in water, and the prepared carbon dots have strong ultraviolet absorption characteristics at 300-400 nm and are highly transparent in the visible light region.

[0007] According to the preparation method of the diethyl ferulate carbon dots, the use amount ratio of diethyl ferulate to anhydrous sodium citrate is 0.55-0.95 g: 0.8-1.6 g, preferably 0.65-0.85 g: 1-1.5 g, further preferably 0.69-0.78 g: 1.2-1.4 g, and more preferably 0.735 g: 1.2904 g.

[0008] According to the preparation method of the diethyl ferulate carbon dots, a mixed solution including anhydrous sodium citrate, diethyl ferulate and ethylenediamine monohydrate is used as raw material. The mixed solution includes water.

[0009] Preferably, the use amount ratio of diethyl ferulate to water is 0.55-0.95 g: 15-45 ml, preferably 0.65-0.85 g: 20-40 ml, further preferably 0.69-0.78 g: 25-35 ml, and more preferably 0.735 g: 30 ml.

[0010] According to the preparation method of the diethyl ferulate carbon dots, the mixed solution is first ultrasonically treated and then reacted.

[0011] Preferably, the ultrasonic treatment is performed in an ultrasonic bath for 2-5 minutes, preferably 2-4 minutes, and more preferably 3 minutes.

[0012] According to the preparation method of the diethyl ferulate carbon dots, the hydrothermal reaction is performed at 180-220 °C for 6-10 h, preferably 190-210 °C for 7-9 h, and further preferably 200 °C for 8 h.

[0013] According to the preparation method of the diethyl ferulate carbon dots, after the reaction solution is cooled to room temperature, filtration and dialysis are performed to obtain a diethyl ferulate carbon dot solution.

[0014] Preferably, the filtration is performed by using a 0.18-0.24 μm membrane filter, and the dialysis is performed by using a 450-550 Da dialysis bag for 20-30 h.

[0015] Further preferably, the filtration is performed by using a 0.20-0.24 μm membrane filter, and the dialysis is performed by using a 480-520 Da dialysis bag for 24 h.

[0016] More preferably, the filtration is performed using a 0.22 µm membrane filter, and the dialysis is performed using a 500 Da dialysis bag for 24 h.

[0017] The application provides a preparation method of ferulic acid diethyl ester carbon dots, comprising the following steps: weighing 1.29 g of anhydrous sodium citrate and 0.735 g of ferulic acid diethyl ester into 30 ml of ultrapure water, adding 33.9 μL of ethylenediamine monohydrate to obtain a mixed solution. The mixed solution is treated in an ultrasonic bath for 3 minutes to make it more fully diffuse. Then, the obtained mixture is transferred into a high-pressure reaction kettle for reaction at 200 ℃ for 8 h. After the solution obtained by reaction is cooled to room temperature, filtration and dialysis are performed to obtain a strong ultraviolet absorption carbon dot solution.

[0018] The reaction kettle is a polytetrafluoroethylene-lined reaction kettle with a volume of 100 ml; the filtration is performed using a 0.22 µm membrane filter, and the dialysis is performed using a 500 Da dialysis bag for 24 h.

[0019] The application further provides ferulic acid diethyl ester carbon dots prepared by the preparation method of the ferulic acid diethyl ester carbon dots.

[0020] The application further provides ferulic acid diethyl ester carbon dots, which comprise two absorption peaks in the ultraviolet light region, the first absorption peak is located at 275-285 nm, and the second absorption peak is located at 342-352 nm.

[0021] Preferably, the first absorption peak is at 279±1 nm, and the second absorption peak is at 347±1 nm.

[0022] The application further provides applications of the ferulic acid diethyl ester carbon dots in any of the following aspects:

[0023] 1) absorbing ultraviolet light;

[0024] 2) preparing an ultraviolet light absorber;

[0025] 3) preparing cosmetics, food packaging materials, ultraviolet light filtering materials or transparent ultraviolet light-proof coatings.

[0026] Compared with the prior art, the application has the following advantages and beneficial effects:

[0027] (1) The carbon quantum dots prepared by using ferulic acid diethyl ester as a raw material change the poor water solubility of ferulic acid diethyl ester into the water-soluble ferulic acid diethyl ester carbon dots, and the problem of application limitation of ferulic acid diethyl ester is overcome.

[0028] (2) The carbon dots prepared by using ferulic acid diethyl ester as a raw material not only have strong ultraviolet absorption performance at 300-400 nm, but also have high transmittance in the visible light region.

[0029] (3) The preparation method of the carbon dots is simple, has high biocompatibility, and can be prepared in batches.

[0030] (4) The carbon dots prepared by the application can be applied in the fields of cosmetics, food packaging, ultraviolet filtering materials, and transparent ultraviolet shielding coating of ultraviolet shielding glass. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced.

[0032] Figure 1 The physical map of the diethyl ferulate solution provided for the present application example 1 and the diethyl ferulate carbon dot solution prepared in the example.

[0033] Figure 2 The transmission electron microscope image of the diethyl ferulate carbon dots prepared in the present application example 1.

[0034] Figure 3 The fluorescence spectrum of the diethyl ferulate carbon dots prepared in the present application example 1.

[0035] Figure 4 The ultraviolet absorption spectrum of the diethyl ferulate carbon dots prepared in the present application example 1 diluted 200 times.

[0036] Figure 5 The transmission spectrum of the diethyl ferulate carbon dots prepared in the present application example 1 diluted 200 times.

[0037] Note: Pictures 4 and 5 are the ultraviolet absorption and transmission spectra of the carbon dot solution diluted 200 times without dialysis.

[0038] Figure 6 The ultraviolet absorption spectrum of the diethyl ferulate carbon dots prepared in the present application example 1 and comparative example 1.

[0039] Figure 7 The synthesis method diagram of diethyl ferulate provided for the present application. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the present application more clear, the technical solutions in the present application will be described clearly and completely in the following combined with the drawings in the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0041] The anhydrous sodium citrate in the embodiments of the present application is purchased from Innochem with the item number A26822.

[0042] The ethylenediamine monohydrate is purchased from Macklin with the item number: E809066-25ml.

[0043] The preparation method of diethyl ferulate in the embodiments of the present application is as follows: proline mediates the Knoevenagel condensation reaction of vanillin and diethyl malonate to synthesize diethyl ferulate. The specific reference is as follows:

[0044] Mendoza D J, Browne C, Raghuwanshi V S, et al. Phenolic ester-decorated cellulose nanocrystals as UV-absorbing nanoreinforcements in polyvinyl alcohol films [J]. ACS Sustainable Chemistry & Engineering, 2021, 9(18): 6427-6437.

[0045] Example 1:

[0046] The present embodiment provides a preparation method of diethyl ferulate carbon dots with strong ultraviolet absorption, comprising the following steps:

[0047] 1.29 g of anhydrous sodium citrate and 0.735 g of diethyl ferulate were weighed and added to 30 ml of ultrapure water, 33.9 μL of ethylenediamine monohydrate was added to obtain a mixed solution. The mixed solution was treated in an ultrasonic bath for 3 minutes to make it more fully diffuse. Then, the obtained mixture was transferred to a 100 ml high-pressure reaction kettle and reacted at 200℃ for 8h. After the solution obtained by the reaction was cooled to room temperature, it was filtered with a 0.22 μm membrane filter and dialyzed with a 500 Da dialysis bag for 24h to obtain a sample solution.

[0048] The diethyl ferulate carbon dots prepared were subjected to performance testing:

[0049] Figure 1 The physical pictures of the diethyl ferulate solution and the diethyl ferulate carbon dot solution prepared in the embodiment are shown. The left is the diethyl ferulate solution, which can be seen that the diethyl ferulate solution is white and insoluble, indicating that the water solubility of diethyl ferulate is poor. The right is the prepared diethyl ferulate carbon dot solution, which is yellow and well dissolved.

[0050] Figure 2The transmission electron microscope photo of the diethyl ferulate carbon dots prepared in the example shows that the carbon dots are spherical, the crystal lattice is obvious, the lattice spacing is 0.21 nm, and the average particle size is 5.96 nm.

[0051] The sample solution of the example was subjected to fluorescence test at different excitation wavelengths, and the fluorescence spectrum diagram is shown in Figure 3 . Figure 3 It is shown that the maximum emission peak is at 444 nm when the excitation wavelength is 352 nm.

[0052] The prepared carbon dots were diluted 200 times for spectral absorption test, Figure 4 The ultraviolet absorption spectrum diagram of the prepared carbon dot solution diluted 200 times is shown in the figure. Figure 4 It is shown that the prepared carbon dots have strong ultraviolet absorption in the 300-400 nm light wavelength range, i.e. the UVA region.

[0053] Figure 5 The transmission spectrum diagram of the prepared carbon dot solution diluted 200 times is shown in the figure. The prepared carbon dots have two absorption peaks in the ultraviolet light region, absorption peak I: λmax≈279 nm, and the transmittance is about 5.6%; absorption peak II: λmax≈347 nm, and the transmittance is about 0.2%. Figure 5 It is shown that the prepared carbon dot solution has excellent absorption performance in the ultraviolet light region and very low transmittance. By adjusting the carbon dot concentration, the carbon dots can be completely absorbed to ultraviolet light, and have high transmittance in the visible light region. It is shown that the prepared diethyl ferulate carbon dot solution has good ultraviolet resistance.

[0054] Comparative Example 1

[0055] Compared with Example 1, the difference lies in that 0.302 g of diethyl ferulate is added.

[0056] The carbon dots prepared in Comparative Example 1 were diluted 200 times for transmission spectrum test, Figure 6 The ultraviolet transmission spectrum diagram of the carbon dot solution prepared in Example 1 and Comparative Example 1 diluted 200 times is shown in the figure. Figure 6 It is shown that the diethyl ferulate carbon dots prepared in Comparative Example 1 are not as good as the carbon dots prepared in the scheme of the application.

[0057] The application first uses diethyl ferulate as a raw material to prepare carbon dot solution with strong ultraviolet absorption performance, the carbon dots are well dispersed, spherical, and the average particle size is 5.96nm; the strong ultraviolet absorption peak of the carbon dots is 300-400nm. The diethyl ferulate carbon dots disclosed by the application not only have strong absorption characteristics in the ultraviolet region, but also can maintain high transparency in the visible light region; the application prepares the diethyl ferulate carbon dots which are easily soluble in water from the diethyl ferulate which is poor in water solubility, and overcomes the problem of application limitation of the diethyl ferulate; the preparation method of the carbon dots disclosed by the application is simple, has good biocompatibility, and can be mass-produced; the carbon dots can be applied in cosmetics, food packaging, ultraviolet filtering materials, and transparent anti-ultraviolet coating of ultraviolet shielding glass, etc.

[0058] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the application, and not to limit them; although the application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the application.

Claims

1. A method for preparing diethyl ferulate carbon dots, characterized in that, Comprising: Preparation of carbon dots by hydrothermal method using a mixed solution of anhydrous sodium citrate, diethyl ferulate and ethylenediamine monohydrate as raw material, the mixed solution comprising water; The ratio of the amount of diethyl ferulate to ethylenediamine monohydrate is 0.735g:33.9μL; The ratio of the amount of diethyl ferulate to anhydrous sodium citrate is 0.735g:1.29g; The ratio of the amount of diethyl ferulate to water is 0.735g:30ml; The hydrothermal reaction is carried out at 200°C for 8h.

2. The method of claim 1, wherein the diethyl ferulate carbon dots are prepared by the steps of: (a) mixing a diethyl ferulate and a reducing agent to form a mixture; (b) adding a stabilizer to the mixture; and (c) adding a passivation agent to the mixture. The mixed solution of anhydrous sodium citrate, diethyl ferulate and ethylenediamine monohydrate is first treated by ultrasonic and then reacted.

3. The method of claim 2, wherein the diethyl ferulate carbon dots are prepared by the steps of: (a) mixing a diethyl ferulate and a reducing agent to form a mixture; (b) adding a stabilizer to the mixture; and (c) adding a passivation agent to the mixture. Put into the ultrasonic bath for 2-5 minutes.

4. The method of claim 2, wherein the diethyl ferulate carbon dots are prepared by the steps of: (a) mixing a diethyl ferulate and a reducing agent to form a mixture; (b) adding a stabilizer to the mixture; and (c) adding a passivation agent to the mixture. Put into the ultrasonic bath for 2-4 minutes.

5. The method of claim 2, wherein the diethyl ferulate carbon dots are prepared by the steps of: (a) mixing a diethyl ferulate and a reducing agent to form a mixture; (b) adding a stabilizer to the mixture; and (c) adding a passivation agent to the mixture. Put into the ultrasonic bath for 3 minutes.

6. The method of claim 1-5, wherein the diethyl ferulate carbon dots are prepared by the method comprising the steps of: After the solution obtained by reaction is cooled to room temperature, it is filtered and dialyzed to obtain a diethyl ferulate carbon dot solution.

7. The method of claim 6, wherein the diethyl ferulate carbon dots are prepared by the steps of: (a) mixing a diethyl ferulate and a reducing agent to form a mixture; (b) adding a stabilizer to the mixture; and (c) adding a passivation agent to the mixture. Filter with a 0.18-0.24μm membrane filter and dialyze for 20-30h with a 450-550Da dialysis bag.

8. The method of claim 6, wherein the diethyl ferulate carbon dots are prepared by the steps of: (a) mixing a diethyl ferulate and a reducing agent to form a mixture; (b) adding a stabilizer to the mixture; and (c) adding a passivation agent to the mixture. Filter with a 0.20-0.24μm membrane filter and dialyze for 24h with a 480-520Da dialysis bag.

9. The method of claim 6, wherein the diethyl ferulate carbon dots are prepared by the steps of: (a) mixing a diethyl ferulate and a reducing agent to form a mixture; (b) adding a stabilizer to the mixture; and (c) adding a passivation agent to the mixture. Filter with a 0.22μm membrane filter and dialyze for 24h with a 500Da dialysis bag.

10. A diethyl ferulate carbon dot, characterized in that, Prepared by the method of any one of claims 1-9.

11. The diethyl ferulate carbon dots according to claim 10, characterized in that, The diethyl ferulate carbon dots comprise two absorption peaks in the ultraviolet region, the first absorption peak is at 275-285nm and the second absorption peak is at 342-352nm.

12. The diethyl ferulate carbon dots according to claim 10, wherein, The first absorption peak is at 279±1nm and the second absorption peak is at 347±1nm.

13. The diethyl ferulate carbon dots of any one of claims 10-12 are used in any one of the following: 1) Absorbing ultraviolet light; 2) Preparing an ultraviolet light absorber; 3) Preparing a cosmetic, food packaging material, ultraviolet filtering material or transparent ultraviolet-proof coating.

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