A fluorescent brightener capable of absorbing sunlight ultraviolet rays, and its preparation method and application

Abstract

A fluorescent whitening agent that absorbs sunlight ultraviolet light, as well as its preparation method and application, has the following structural formula: The method comprises: dissolving dimethyl 2,5-dihydroxyterephthalate in N,N-dimethylformamide, adding potassium carbonate and isobutane bromide, heating to 80°C, and stirring for 10 hours; adding ethyl acetate and water as extractants, extracting the organic phase, drying it with a desiccant, filtering it, and concentrating it with vacuum rotary evaporation to obtain a crude product; and subjecting the crude product to column chromatography to obtain fluorescent whitening agent A. This fluorescent whitening agent is used in whitening processes for papermaking, textile printing and dyeing, or plastic processing. The structure is relatively simple, the preparation method is easy, and it exhibits excellent ultraviolet absorption and fluorescence emission properties.

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 brighteners play a key role in improving the appearance of white products. By absorbing ultraviolet light and converting it into visible light, they effectively neutralize the yellowish tint produced by white products' slight absorption of blue light, significantly enhancing their whiteness and brightness. Due to their significant whitening effect and relatively low cost, fluorescent brighteners are widely used in various industries, including printing and dyeing, plastics, papermaking, detergents, coatings, and cosmetics.

[0003] Although existing fluorescent whitening agents have achieved remarkable results in improving the appearance quality of white articles, their structure and synthesis process still have some defects. 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 response to the problems of existing fluorescent whitening agents, it is necessary to develop a new fluorescent whitening agent with a simple structure, simple synthesis process, excellent performance and environmental protection, so as to meet the increasingly high 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 increasingly high 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 its preparation method and application. The fluorescent whitening agent has a relatively simple structure, is easy to prepare, and has 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, whose structure 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), and heat to 80°C with stirring for 10 hours; add ethyl acetate and water as extractants to extract, take the organic phase, 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 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 relates to 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 traditional fluorescent whitening agents, the raw materials used are easily available, the structure is simpler, the synthesis steps are reduced, and it is easy to synthesize, thereby reducing production costs and improving production efficiency.

[0017] (2) This 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-13 NMR 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 This 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 This is a solid fluorescence emission spectrum of the fluorescent whitening agent A of the present invention at an excitation wavelength of 380 nanometers;

[0026] Figure 7 This is a comparison diagram of paper dyed with the fluorescent brightener A of the present invention and undyed paper under 365 nm ultraviolet light. DETAILED DESCRIPTION

[0027] Example 1

[0028] Dissolve 2.26g of dimethyl 2,5-dihydroxyterephthalate in 50ml of N,N-dimethylformamide, then add 4.14g of potassium carbonate and 3.50g of isobutane bromide. Heat to 80°C and stir for 10 hours. Thin layer chromatography monitoring shows that the main raw material dimethyl 2,5-dihydroxyterephthalate has reacted completely. Add 200ml of ethyl acetate and 200ml of water, extract and separate the liquids. Take the organic phase and add anhydrous sodium sulfate to dry. Filter out the desiccant, and concentrate under reduced pressure by rotary evaporation to obtain a crude product. The crude product is subjected to column chromatography to obtain 1.85g of white solid fluorescent brightener A. The nuclear magnetic resonance hydrogen spectrum, carbon spectrum and mass spectrum of fluorescent whitening agent 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 forC 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) 33.8 mg of fluorescent whitening agent A was dissolved in 10 mL of tetrahydrofuran to obtain a 10 mmol / L tetrahydrofuran solution of fluorescent whitening agent A for testing ultraviolet absorption spectrum and fluorescence spectrum.

[0031] (2) The ultraviolet absorption spectrum of fluorescent whitening agent 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 fluorescent brightener A in tetrahydrofuran solution of Example 1 (excitation wavelength 380 nanometers) is shown as Figure 5 As shown, the maximum emission wavelength is 415 nanometers, and the wavelength range covers 400-500 nanometers. It emits strong blue fluorescence, which complements the yellow to achieve a whitening effect.

[0032] (3) The solid fluorescence emission spectrum of fluorescent whitening agent A in Example 1 (excitation wavelength 380 nm) is as follows Figure 6 As shown, this compound still has strong fluorescence emission even in the solid state. When applied to substrates such as paper, it can still emit fluorescence, which 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 it has strong blue fluorescence emission in tetrahydrofuran solution or solid fluorescent whitening agent A, which meets the characteristics of a fluorescent whitening agent.

[0034] 2. Fluorescent Whitening Agent A Fluorescent Whitening Test of the Present Invention

[0035] 0.001 mol of the fluorescent brightener A prepared in Example 1 of the present invention was dissolved in 500 mL of ethyl acetate, and paper was soaked in the solution and immediately taken out. The solution was allowed to stand until the solvent evaporated, thereby obtaining a fluorescent brightened paper sample.

[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 whitening agent, and the paper on the right is a paper sample that has been whitened with fluorescent whitening agent. It can be clearly observed that the blank paper sample has no fluorescent effect, while the paper treated with fluorescent whitening agent has a strong fluorescent whitening effect.

[0037] The above are merely specific embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A fluorescent brightener that absorbs sunlight ultraviolet rays, characterized by: 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 extractants to perform extraction, take the organic phase, dry it with a desiccant, filter it, and concentrate it by rotary evaporation under reduced pressure to obtain a crude product; and subject the crude product to column chromatography to obtain a fluorescent whitening agent.

3. The method for preparing a fluorescent whitening agent that absorbs sunlight ultraviolet rays according to claim 2, wherein: 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 in a whitening process for papermaking, textile printing and dyeing, or plastic processing.

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