Fluorescent whitening agent capable of absorbing sunlight ultraviolet rays as well as preparation method and application of fluorescent whitening agent

Abstract

The invention relates to a fluorescent whitening agent for absorbing sunlight ultraviolet rays and a preparation method and application thereof, and the structural formula is as follows: # imgabs0: a method for dissolving 2, 5-dihydroxy dimethyl terephthalate in N, N-dimethylformamide, adding potassium carbonate and bromo-isobutane, heating to 80 DEG C, and stirring to react for 10 hours; adding an extracting solution ethyl acetate and water, extracting, drying an organic phase by using a drying agent, filtering, and carrying out reduced-pressure rotary evaporation concentration to obtain a crude product; and performing column chromatography on the crude product to obtain the fluorescent whitening agent A. The fluorescent whitening agent is applied to a whitening process for papermaking, textile printing and dyeing or plastic processing. The structure is relatively simple, the preparation method is easy, and the material has excellent ultraviolet absorption and fluorescence emission performance.

Description

Technical Field

[0001] The invention relates to a fluorescent whitening agent capable of absorbing sunlight ultraviolet rays and a preparation method and application thereof. Background Art

[0002] As an important fine chemical product, fluorescent whitening agents play a key role in improving the appearance quality of white objects. They absorb ultraviolet light and convert it into visible light, effectively neutralizing the yellow hue caused by the slight absorption of blue light by white objects, thereby significantly enhancing the whiteness and brightness of the objects. In many industries such as printing and dyeing, plastics, papermaking, detergents, coatings and cosmetics, fluorescent whitening agents have been widely used due to their significant whitening effect and relatively low cost.

[0003] Although existing fluorescent whitening agents have achieved remarkable results in improving the appearance quality of white articles, there are still some defects in their structure and synthesis process. Most fluorescent whitening agents are organic compounds with complex chemical structures and require multiple chemical reactions to synthesize. This not only increases production costs and limits production efficiency, but may also cause environmental pollution and safety hazards. In addition, the complex chemical structure may also affect the stability and durability of the fluorescent whitening agent, reducing its performance in different application scenarios. Therefore, in view of the problems existing in existing fluorescent whitening agents, it is necessary to develop a new type of fluorescent whitening agent with a simple structure, simple synthesis process, excellent performance and environmental protection, so as to meet the increasing requirements of different industries for the appearance quality of white articles and promote the further development of fluorescent whitening agent technology.

[0004] With the continuous advancement of science and technology, the types of fluorescent whitening agents are also constantly increasing and improving. Traditional fluorescent whitening agents are mostly organic compounds, such as diphenylethylene, coumarin, pyrazoline, benzoxazole and phthalimide fluorescent whitening agents. However, most of the existing fluorescent whitening agents have complex structures and complex chemical structures. They require multiple steps of chemical reactions to synthesize, which increases production costs and limits production efficiency. In addition, the complex chemical structure may also affect the stability and durability of the fluorescent whitening agent, reducing its performance in different application scenarios. Therefore, it is urgent to develop a new type of fluorescent whitening agent with a simple structure, simple synthesis process, excellent performance and environmental protection to meet the increasing requirements of different industries for the appearance quality of white products and promote the further development of fluorescent whitening agent technology. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a fluorescent whitening agent that absorbs sunlight ultraviolet rays, and a preparation method and application thereof. The fluorescent whitening agent has a relatively simple structure, an easy preparation method, and excellent ultraviolet absorption and fluorescence emission properties.

[0006] The technical solution of the present invention is:

[0007] A fluorescent brightener that absorbs sunlight ultraviolet rays, the structure of which is shown in Formula A:

[0008]

[0009] A method for preparing the above-mentioned fluorescent whitening agent that absorbs sunlight ultraviolet rays, the specific process is as follows:

[0010] 1) Dissolve dimethyl 2,5-dihydroxyterephthalate (2.26 g, 0.010 mol) in N,N-dimethylformamide, add potassium carbonate (4.14 g, 0.030 mol) and isobutane bromide (3.5 g, 0.026 mol), heat to 80°C and stir to react for 10 hours; add ethyl acetate and water as extracting liquid to extract, take the organic phase and dry it with a desiccant, filter it, and concentrate it by rotary evaporation under reduced pressure to obtain a crude product; the crude product is subjected to column chromatography to obtain a fluorescent brightener A.

[0011] Furthermore, the molar volume ratio of dimethyl 2,5-dihydroxyterephthalate to N,N-dimethylformamide is 0.2 mol / L.

[0012] Furthermore, during extraction, the volume ratio of ethyl acetate to water in the extract is 1:1.

[0013] A use of the above-mentioned fluorescent whitening agent that absorbs sunlight ultraviolet rays as a whitening agent.

[0014] The invention discloses an application of the fluorescent brightener for absorbing sunlight ultraviolet rays in the whitening process of papermaking, textile printing and dyeing or plastic processing.

[0015] Beneficial effects of the present invention:

[0016] (1) The fluorescent whitening agent provided by the present invention has a brand-new chemical structure. Compared with the traditional fluorescent whitening agent, the raw materials used are easily available, the structure is simpler, the synthesis steps are reduced, and it is easy to synthesize, thereby reducing the production cost and improving the production efficiency.

[0017] (2) The fluorescent whitening agent can effectively absorb ultraviolet rays in sunlight and convert them into visible light. It has excellent ultraviolet absorption and fluorescent emission properties, significantly improving the whiteness and brightness of white objects, and its performance is stable and long-lasting.

[0018] (3) The raw materials used in the preparation process are easily available and environmentally friendly. Due to its excellent performance and environmental protection characteristics, this fluorescent brightener can be widely used in many fields such as papermaking, textile printing and dyeing, and plastic processing.

[0019] In summary, the present invention provides a novel fluorescent whitening agent with simple structure, easy synthesis, excellent performance and environmental protection and a preparation method thereof, which has broad application prospects and market value. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is the hydrogen nuclear magnetic resonance spectrum of the fluorescent whitening agent A of the present invention;

[0021] Figure 2 is the carbon nuclear magnetic resonance spectrum of the fluorescent whitening agent A of the present invention;

[0022] Figure 3 is a high-resolution mass spectrum of the fluorescent whitening agent A of the present invention;

[0023] Figure 4 is the ultraviolet absorption spectrum of the fluorescent brightener A of the present invention in tetrahydrofuran solution;

[0024] Figure 5 It is a fluorescence emission spectrum of the fluorescent brightener A of the present invention in a tetrahydrofuran solution at an excitation wavelength of 380 nanometers;

[0025] Figure 6 It is a solid fluorescence emission spectrum of the fluorescent brightener A of the present invention at an excitation wavelength of 380 nanometers;

[0026] Figure 7 It is a comparison diagram of paper impregnated with the fluorescent brightener A of the present invention and unimpregnated paper under 365 nanometer ultraviolet light. DETAILED DESCRIPTION

[0027] Example 1

[0028] Dissolve 2.26 g of dimethyl 2,5-dihydroxyterephthalate in 50 ml of N,N-dimethylformamide, then add 4.14 g of potassium carbonate and 3.50 g of isobutyl bromide, heat to 80°C and stir for 10 hours. TLC monitoring shows that the main raw material dimethyl 2,5-dihydroxyterephthalate has reacted completely; add 200 ml of ethyl acetate and 200 ml of water, extract and separate, take the organic phase and add anhydrous sodium sulfate to dry. Filter out the desiccant, concentrate under reduced pressure and rotary evaporation to obtain a crude product; the crude product is subjected to column chromatography to obtain 1.85 g of white solid fluorescent brightener A The nuclear magnetic resonance hydrogen spectrum, carbon spectrum and mass spectrum of fluorescent brightener A are as follows Figure 1-3 As shown, 1 H NMR (400MHz, Chloroform-d) δ7.35 (s, 2H), 3.91 (s, 6H), 3.77 (d, J = 6.46Hz, 4H), 2.11 (m, 2H), 1.04 (d, J = 6.62Hz, 12H). 13C NMR(101MHz,Chloroform-d)δ166.4,151.8,124.2,116.5,76.0,52.3,28.4,19.2.HRMS(ESI + )Calcd for C 18 H 27 O6 + [M+H] + :339.1808,found:339.1800

[0029] 1. Ultraviolet absorption spectrum and fluorescence spectrum test of the present invention

[0030] (1) Take 33.8 mg of fluorescent brightener A and dissolve it in 10 mL of tetrahydrofuran to obtain a 10 mmol / L tetrahydrofuran solution of fluorescent brightener A for testing ultraviolet absorption spectrum and fluorescence spectrum.

[0031] (2) The ultraviolet absorption spectrum of fluorescent brightener A in tetrahydrofuran solution of Example 1 of the present invention is as follows Figure 4 As shown, the maximum absorption wavelength is 380 nanometers, and it has strong absorption in the ultraviolet region of sunlight, which is conducive to absorbing ultraviolet rays; the fluorescence emission spectrum of the fluorescent brightener A in tetrahydrofuran solution of Example 1 (excitation wavelength 380 nanometers) is shown in Figure 5 As shown, the maximum emission wavelength is 415 nanometers, and the wavelength range covers 400-500 nanometers, emitting strong blue fluorescence, which complements the yellow to achieve a whitening effect;

[0032] (3) The solid fluorescence emission spectrum (excitation wavelength 380 nanometers) of the fluorescent brightener A in Example 1 is as follows Figure 6 As shown, it shows that even in the solid state, the compound still has strong fluorescence emission. When applied to substrates such as paper, it can still emit fluorescence and has a wide range of application scenarios.

[0033] Therefore, the maximum ultraviolet absorption peak of the fluorescent whitening agent A compound of the present invention is at 380 nanometers, the maximum fluorescence emission peak is at 415 nanometers, and there is strong blue fluorescence emission in tetrahydrofuran solution or solid fluorescent whitening agent A, which meets the characteristics of fluorescent whitening agent.

[0034] 2. Fluorescent whitening test of fluorescent whitening agent A of the present invention

[0035] 0.001 mol of the fluorescent brightener A prepared in Example 1 of the present invention was taken and dissolved in 500 mL of ethyl acetate. Paper was soaked in the solution and immediately taken out. After the solvent was allowed to evaporate, a fluorescent brightened paper sample was obtained.

[0036] The fluorescent whitening paper sample was placed under ultraviolet light with a wavelength of 365nm for observation. Figure 7It can be seen that the paper on the left is a blank paper sample that has not been treated with fluorescent brightener, and the paper on the right is a paper sample that has been whitened with a fluorescent brightener. It can be clearly observed that the blank paper sample has no fluorescent effect, while the paper treated with a fluorescent brightener has a strong fluorescent whitening effect.

[0037] The above are only specific embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A fluorescent brightener that absorbs sunlight ultraviolet rays, characterized in that: The structural formula is as follows:

2. A method for preparing a fluorescent whitening agent that absorbs sunlight ultraviolet rays as claimed in claim 1, characterized in that: The specific process is as follows: Dissolve dimethyl 2,5-dihydroxyterephthalate in N,N-dimethylformamide, add potassium carbonate and isobutane bromide in a molar ratio of 1:3:2.6, raise the temperature to 80°C and stir to react for 10 hours; add ethyl acetate and water as extracting solution to extract, take the organic phase and dry it with a desiccant, filter it, and concentrate it by rotary evaporation under reduced pressure to obtain a crude product; subject the crude product to column chromatography to obtain fluorescent brightener A.

3. The method for preparing a fluorescent whitening agent that absorbs sunlight ultraviolet rays according to claim 2, characterized in that: The molar volume ratio of the dimethyl 2,5-dihydroxyterephthalate to N,N-dimethylformamide is 0.2 mol / L.

4. The method for preparing a fluorescent whitening agent that absorbs sunlight ultraviolet rays according to claim 2, wherein: During extraction, the volume ratio of ethyl acetate to water in the extract is 1:

1.

5. Use of the fluorescent whitening agent that absorbs sunlight ultraviolet rays as claimed in claim 1 as a whitening agent.

6. Use of the fluorescent brightener that absorbs sunlight ultraviolet rays as claimed in claim 1 in a whitening process for papermaking, textile printing and dyeing or plastic processing.

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