Sulfide-supported dispersion reducing agent, benzotriazole-based ultraviolet absorber, and method for producing same

Abstract

The application belongs to the technical field of chemical synthesis, and particularly relates to a sulfide-loaded dispersion reductant, a benzotriazole ultraviolet absorber and a preparation method. The preparation method of the sulfide-loaded dispersion reductant comprises the following steps: under stirring, suspending a sulfur-containing compound raw material in a solvent, then adding a dispersion carrier, heating and stirring under an air atmosphere, filtering and drying after the reaction is completed, and obtaining the sulfide-loaded dispersion reductant. The sulfide-loaded dispersion reductant is used as a single reductant, a blank in the catalytic effect research field of sulfides in azo body reduction cyclization reactions is filled, and a high-efficiency, environmentally-friendly and economical production process route of the benzotriazole ultraviolet absorber is constructed.

Description

Technical Field

[0001] This invention belongs to the field of chemical synthesis technology, specifically relating to a sulfide-supported dispersion reducing agent, a benzotriazole ultraviolet absorber, and a preparation method thereof. Background Technology

[0002] Benzotriazole UV absorbers are an important class of polymer material modifiers, widely used in plastics, rubber, paints, and fibers. Their core function is to effectively inhibit photo-oxidative aging of materials during outdoor use, thereby significantly extending the lifespan of products. They are indispensable additives, especially for outdoor products exposed to sunlight for extended periods. It is well known that polymer materials such as plastics, under sunlight or strong fluorescent light, will undergo photo-aging reactions due to the absorption of ultraviolet light, leading to fading, surface cracking, and significant deterioration of physical and mechanical properties (such as strength and toughness). Adding light stabilizers to materials can effectively prevent this process. UV absorbers play the most direct role—they selectively absorb ultraviolet light with wavelengths between 290 nm and 400 nm and convert it into harmless heat or lower-energy light, thus preventing the polymer chains from being photo-oxidized and decomposed. The light stabilizer family, besides UV absorbers, also includes quenchers, free radical scavengers, and light shielding agents. UV absorbers are the most widely used class, with common varieties including benzotriazoles, benzophenones, triazines, hindered amines, and substituted acrylonitriles. Among these, benzotriazole compounds, due to their excellent UV absorption efficiency and photostability, have become the most produced and diverse series of UV absorbers, especially considered one of the most effective and commonly used UV absorbers in polymer plastics and automotive coatings. Currently, global consumption of benzotriazole UV absorbers is second only to hindered amine light stabilizers, with major consumer markets concentrated in the United States, European countries, China, and Japan. However, the existing production processes for these products present serious environmental problems: they typically use aromatic amines as raw materials, first generating diazonium salts through a diazotization reaction, then coupling them with phenolic compounds to obtain an azo intermediate, and finally reducing and cyclizing to obtain the target product. This traditional route generates a large amount of "three wastes" (wastewater, waste gas, and waste residue), and the post-treatment process is extremely difficult, leading to serious environmental pollution. This has become a key bottleneck restricting the sustainable development of the benzotriazole UV absorber industry. Therefore, developing a clean, low-waste, and easily post-treatment synthesis process is of great practical significance for the future development of this type of light stabilizer.

[0003] Several reduction processes have been explored for the preparation of benzotriazole UV absorbers. Among them, the zinc powder-based reducing agent (patent US3230194) is currently the most common industrial choice. Although it achieves a reasonable product yield, it generates a large amount of waste residue and wastewater, posing significant environmental pressure and has been gradually phased out in recent years. Another route (patent US4001266) attempts to use hydrazine hydrate as a reducing agent and reacts in ethylene glycol diethyl ether. However, this process not only releases water and a large amount of nitrogen gas but also fails to achieve industrial-scale adoption due to the high toxicity of hydrazine hydrate. An improved process (patent US4224451) employs a two-step reduction method combining sodium sulfide and zinc powder: first, in an alkaline medium, the azo dye is reduced to a nitrogen-oxygen intermediate using sodium sulfide. After washing with water, the intermediate is further reduced to benzotriazole using zinc powder under alkaline conditions. This method significantly improves the yield and purity of the product, but the operation steps are more complex, and the most fundamental drawback is that it still does not fundamentally solve the pollution problem, as a large amount of wastewater, waste residue, and other environmentally harmful substances are still generated during the reaction. In recent years, there have been numerous reports on research into the synthesis of benzotriazole UV absorbers via catalytic hydrogenation. Patent EP0380840A1 reports the synthesis of UV-328 in a toluene-isopropanol-water-sodium hydroxide system using Raney nickel as a catalyst, with a yield of 90.3%; CIBA GEIGY's patent US5276161 uses 5% Pt / C as a catalyst to synthesize UV-P, achieving a yield of 92%; patent US5104992 uses 5% Pd / C to synthesize UV-320, with a yield of 87.3%; and patent EP0794179A1 uses a composite catalyst of 4% Pd / C and 1% Pt / C to synthesize UV-328, adding hypophosphoric acid or sulfuric acid to the reduction system to improve the product yield. Although the catalytic hydrogenation reduction method has low wastewater discharge and high atom economy, and hydrogen as a reducing agent does not cause environmental pollution, the non-precious metal catalysts represented by Raney nickel in the above-mentioned catalytic system are spontaneously combustible and easily oxidize and release heat in the air, posing a risk of fire or even explosion. Although precious metal catalysts such as platinum (Pt) and palladium (Pd) have better safety, they are expensive, leading to a significant increase in raw material costs and limiting their application in large-scale low-cost synthesis. At the same time, the catalytic hydrogenation process usually requires the use of high-pressure hydrogen, which is flammable and explosive, placing stringent requirements on the safety design and operation specifications of the reaction equipment and increasing the risks of equipment investment and safe operation.

[0004] To address the aforementioned issues, there is an urgent need to provide a safe and efficient reducing agent that can be used as a single reducing agent in the preparation of benzotriazole UV absorbers, thereby reducing them in one step to produce benzotriazole UV absorbers. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing a sulfide-supported dispersion reducing agent, a benzotriazole-based ultraviolet absorber, and a preparation method thereof. By using a sulfide-supported dispersion reducing agent as a single reducing agent, it fills a gap in the research on the catalytic role of sulfides in the azo compound reduction cyclization reaction, and based on this, constructs a highly efficient, environmentally friendly, and economical production process route for benzotriazole-based ultraviolet absorbers. Compared with traditional technologies, this preparation method overcomes the drawbacks of complex processes, high pollution, and high costs, while exhibiting significant advantages such as high raw material conversion rate and excellent product quality.

[0006] The specific technical solution is as follows: The first objective of this invention is to provide a method for preparing a sulfide-supported dispersion reducing agent, comprising the following steps: suspending a sulfur-containing compound raw material in a solvent under stirring, then adding a dispersion carrier, heating and stirring under an air atmosphere, filtering and drying after the reaction is completed, and obtaining a sulfide-supported dispersion reducing agent.

[0007] Furthermore, the sulfur-containing compound raw material is sodium sulfide, sodium dithionite, sodium thiosulfate, or sodium metabisulfite, and the dispersion carrier is silica gel, molecular sieve, diatomaceous earth, or alumina.

[0008] Furthermore, the mass ratio of the sulfur-containing compound raw material to the dispersion carrier is (1-10):1.

[0009] Furthermore, the mass ratio of the sulfur-containing compound raw material to the dispersion carrier is (1.5-7.5):1.

[0010] Furthermore, the mass ratio of the sulfur-containing compound raw material to the solvent is (0.1-1):1.

[0011] Furthermore, the mass ratio of sulfur-containing compound raw material to solvent is (0.1-0.75):1.

[0012] Furthermore, the silica gel has a mesh size of 300-500, the molecular sieve is a 5A molecular sieve, the alumina is neutral alumina or basic alumina, and the solvent is selected from one or more of methanol, ethanol, and water.

[0013] Furthermore, when the solvent is selected from ethanol and water, the amount of ethanol used is 10-60 parts by weight, and the amount of water used is 10-40 parts by weight.

[0014] Furthermore, the mass ratio of ethanol to water is (0.25-6):1.

[0015] Furthermore, the mass ratio of ethanol to water is (1.3-3):1.

[0016] Furthermore, the heating and stirring time is 1.5-3 hours, and the temperature is 40-60℃.

[0017] Furthermore, the drying time is 20-26 hours, and the temperature is 50-70℃.

[0018] The second objective of this invention is to provide a sulfide-supported dispersion reducing agent, which is prepared by the method described above for preparing a sulfide-supported dispersion reducing agent.

[0019] The third objective of this invention is to provide a method for preparing a benzotriazole-based ultraviolet absorber, using the sulfide-supported dispersion reducing agent as described above as the reducing agent.

[0020] Furthermore, the preparation method of the benzotriazole ultraviolet absorber includes the following steps: (1) Reduction of sulfide-supported dispersion reducing agent: Dissolve the azo compound shown in Formula I in a mixed solution of ethanol and water, then add the sulfide-supported dispersion reducing agent and caustic soda flakes, and carry out a heating reduction reaction; (2) Crystallization: Adjust the pH of the solution obtained in step (1) to acidic, cool it to below room temperature and filter it, wash it with methanol and water, and then dry it in a vacuum oven to obtain the benzotriazole ultraviolet absorber product, namely the compound shown in formula II;

[0021] In Formula I and Formula II, R1 is one of H, Cl, C1-C4 alkyl, and C1-C4 alkoxy. R2 is H, Cl-C 12 One of alkyl groups and C1-C8 alkylphenyl groups; R3 is H, Cl, or Cl-C. 12 Alkyl, C1-C 12 One of alkoxy, phenyl, C1-C8 alkylphenyl, and C1-C4 alkoxyphenyl.

[0022] Furthermore, in Formula I and Formula II, when R1 is H or Cl, R2 and R3 are independently selected from one of H, methyl, tert-butyl, pentyl, tert-pentyl, tert-octyl, tert-octyl, and cumyl, respectively.

[0023] Further, in step (1), by weight, the amount of the azo compound shown in Formula I is 6.5-12 parts, the amount of ethanol is 20-50 parts, the amount of water is 20-100 parts, the amount of caustic soda is 10-20 parts, and the amount of sulfide-supported dispersion reducing agent is 7-35 parts.

[0024] Furthermore, in step (1), the temperature of the heating reduction reaction is 75-85℃ and the time is 2-5h.

[0025] Furthermore, in step (2), the pH is adjusted to a range of 1-2, and the product is vacuum dried at 70-90℃ for 10-12 hours.

[0026] The fourth objective of this invention is to provide a benzotriazole-based ultraviolet absorber, which is prepared by the method described above for preparing benzotriazole-based ultraviolet absorbers.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows: In the reaction of reducing azo compounds to benzotriazole UV absorbers, this invention employs a sulfide-supported dispersion reducing agent. This reducing agent uses 300-500 mesh silica gel, 5A molecular sieve, diatomaceous earth, neutral alumina, or basic alumina as the dispersion carrier, and sodium sulfide, sodium dithionite, sodium thiosulfate, or sodium metabisulfite as the active component. While serving as the dispersion carrier, the 300-500 mesh silica gel, 5A molecular sieve, diatomaceous earth, neutral alumina, or basic alumina allow for the slow release of sodium sulfide, sodium dithionite, sodium thiosulfate, or sodium metabisulfite to participate in the reaction, avoiding excessively high local concentrations that could lead to violent exothermic reactions and effectively suppressing excessive reduction side reactions. This achieves the goal of highly selective synthesis of benzotriazole UV absorbers. In this reaction, sodium sulfide, sodium dithionite, sodium thiosulfate, or sodium metabisulfite generate strong reducing free radicals (SO2) in an alkaline solution. ·- The azo group (-NO) preferentially acts on the most reactive nitro group, gradually reducing it to a nitroso group (-NO), then to a hydroxylamine group (-NHOH), and finally to an amino group (-NH2). This then triggers a tandem ring closure: the newly formed amino group (-NH2) rapidly attacks the neighboring azo group (-N=N-), undergoing intramolecular nucleophilic addition. This step achieves two goals simultaneously: through ring closure, it constructs the benzotriazole skeleton; and it reduces and breaks the original azo bond, allowing the product to detach from the parent compound.

[0028] The sulfide-supported dispersion reducing agent of this invention enables the completion of complex reduction and ring-closing reactions in a clever one-step process, while also considering economic cost, operational safety, and environmental friendliness. In particular, it avoids heavy metal pollution problems, representing a significant breakthrough in the synthesis of benzotriazole UV absorbers. This process effectively reduces the generation of byproducts and achieves efficient and highly selective synthesis of benzotriazole UV absorbers. Attached Figure Description

[0029] Figure 1 For the UV-P in this application 1 H-NMR spectrum; Figure 2 For the UV-P in this application 13 C-NMR spectrum; Figure 3 The HPLC chromatogram of UV-P in this application; Figure 4 For UV-329 in this application 1 H-NMR spectrum; Figure 5 For UV-329 in this application 13 C-NMR spectrum; Figure 6 This is the HPLC chromatogram of UV-329 in this application; Figure 7 For UV-234 in this application 1 H-NMR spectrum; Figure 8 For UV-234 in this application 13 C-NMR spectrum; Figure 9 This is the HPLC chromatogram of UV-234 in this application. Detailed Implementation

[0030] The principles and features of the present invention are described below with reference to examples. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0031] This invention uses the preparation of UV-P, UV-329, UV-234, UV-320, UV-326, UV-327, UV-328, and UV-171 / 571 as examples to illustrate the invention. The reaction routes of the azo compounds (azo intermediates) shown in Formula I are as follows:

[0032] In the specific implementation, the 300-400 mesh silica gel and 500 mesh silica gel used were purchased from Yantai Xinnuo New Material Technology Co., Ltd., the neutral alumina was purchased from Sinopharm Reagent (Shanghai) 2002361, and the alkaline alumina was purchased from Sinopharm Reagent (Shanghai) 2001861.

[0033] Example 1: A method for preparing an ultraviolet absorber UV-P Using silica gel as the dispersion carrier and sodium sulfide as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 1.1 This embodiment provides a method for preparing an ultraviolet absorber UV-P, including the following steps: (1) Preparation of sulfide-supported dispersion reducing agent using silica gel as dispersion carrier 15g of sodium sulfide was dissolved in a mixed solvent of 30g anhydrous ethanol and 20g deionized water under stirring. The mixture was stirred at 1000rpm for 10min. Then, 2g of 300-400 mesh silica gel was added, and the mixture was heated and stirred at 50℃ in air for 2h. After the reaction was completed, the mixture was filtered, and the filter cake was vacuum dried in a vacuum oven at 70℃ for 24h to obtain the sulfide supported dispersion reducing agent. (2) Reduction of sulfide-supported dispersion reducing agent: In a 250 mL three-necked flask, 6.5 g of UV-P azo intermediate was dissolved in a mixed solvent of 50 g ethanol and 40 g deionized water. Then, 8 g of the sulfide-supported dispersion reducing agent prepared in step (1) and 16 g of caustic soda were added. The mixture was heated to 80 °C and stirred (stirring speed about 600 rpm) for 4 h. After the reaction was completed, the excess reducing agent was removed by filtration to obtain the filtrate. The filtrate was slowly cooled to 0 °C, and 36 wt% concentrated hydrochloric acid was added dropwise to adjust the pH to 1. The filtrate was filtered to obtain the filter cake. The composition of the filter cake product was analyzed by high performance liquid chromatography. The solvent was evaporated under reduced pressure, washed with deionized water and methanol, and then vacuum dried in an 80 °C vacuum drying oven for 10 h to obtain the target product UV-P.

[0034] Example 1.2 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that 6g of 300-400 mesh silica gel is added in step (1).

[0035] Example 1.3 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that 10g of 300-400 mesh silica gel is added in step (1).

[0036] Example 1.4 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that 2g of 500-mesh silica gel is added in step (1) (replacing 2g of 300-400-mesh silica gel).

[0037] Example 1.5 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that 6g of 500-mesh silica gel is added in step (1) (replacing 2g of 300-400-mesh silica gel).

[0038] Example 1.6 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that 10g of 500-mesh silica gel is added in step (1) (replacing 2g of 300-400-mesh silica gel).

[0039] Example 1.7 This embodiment provides a method for preparing an ultraviolet absorber UV-P, including the following steps: (1) Preparation of sulfide-supported dispersion reducing agent using silica gel as dispersion carrier 15g of sodium sulfide was dissolved in a mixed solvent of 60g of anhydrous ethanol and 20g of deionized water under stirring. The mixture was stirred at 1000rpm for 10min. Then, 2g of 300-400 mesh silica gel was added, and the mixture was heated and stirred at 40℃ in air for 3h. After the reaction was completed, the mixture was filtered, and the filter cake was vacuum dried in a vacuum oven at 50℃ for 26h to obtain the sulfide supported dispersion reducing agent. (2) Reduction of sulfide-supported dispersion reducing agent: In a 250 mL three-necked flask, 6.5 g of UV-P azo intermediate was dissolved in a mixed solvent of 20 g ethanol and 100 g deionized water. Then, 8 g of the sulfide-supported dispersion reducing agent prepared in step (1) and 20 g of caustic soda were added. The mixture was heated to 75 °C and stirred (stirring speed about 600 rpm) for 5 h. After the reaction was completed, the excess reducing agent was removed by filtration to obtain the filtrate. The filtrate was slowly cooled to 0 °C, and 36 wt% concentrated hydrochloric acid was added dropwise to adjust the pH to 1. The filtrate was filtered to obtain the filter cake. The composition of the filter cake product was analyzed by high performance liquid chromatography. The solvent was evaporated under reduced pressure, washed with deionized water and methanol, and then vacuum dried in a vacuum drying oven at 70 °C for 12 h to obtain the target product UV-P.

[0040] Example 1.8 This embodiment provides a method for preparing an ultraviolet absorber UV-P, including the following steps: (1) Preparation of sulfide-supported dispersion reducing agent using silica gel as dispersion carrier 30g of sodium sulfide was dissolved in a mixed solvent of 40g of anhydrous ethanol and 30g of deionized water under stirring. The mixture was stirred at 1000rpm for 10min. Then, 4g of 300-400 mesh silica gel was added, and the mixture was heated and stirred at 60℃ in air for 1.5h. After the reaction was completed, the mixture was filtered, and the filter cake was vacuum dried in a vacuum oven at 70℃ for 20h to obtain a sulfide-supported dispersion reducing agent. (2) Reduction of sulfide-supported dispersion reducing agent: 6.5g of UV-P azo intermediate was dissolved in a mixed solvent of 50g ethanol and 20g deionized water, followed by the addition of 8g of sulfide-supported dispersion reducing agent prepared in step (1) and 10g of caustic soda flakes. The mixture was heated to 85°C and stirred (stirring speed about 600rpm) for 2h. After the reaction was completed, excess reducing agent was removed by filtration to obtain filtrate. The filtrate was slowly cooled to 0°C, and 36wt% concentrated hydrochloric acid was added dropwise to adjust the pH to 1. The filtrate was filtered to obtain filter cake, and the composition of the filter cake product was analyzed by high performance liquid chromatography. The solvent was evaporated under reduced pressure, washed with deionized water and methanol, and then vacuum dried in a vacuum drying oven at 90°C for 11h to obtain the target product UV-P.

[0041] Example 2: A method for preparing an ultraviolet absorber UV-P Using diatomaceous earth as a dispersion carrier and sodium sulfide as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared: Example 2.1 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that 2g of diatomaceous earth is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0042] Example 2.2 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that 6g of diatomaceous earth is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0043] Example 2.3 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that 10g of diatomaceous earth is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0044] Example 3: A method for preparing an ultraviolet absorber UV-P Using 5A molecular sieve as the dispersion carrier and sodium sulfide as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared: Example 3.1 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that 2g of 5A molecular sieve (replacing 2g of 300-400 mesh silica gel) is added in step (1).

[0045] Example 3.2 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that 6g of 5A molecular sieve is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0046] Example 3.3 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that 10g of 5A molecular sieve is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0047] Example 4: A method for preparing an ultraviolet absorber UV-P Using alumina as the dispersion carrier and sodium sulfide as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 4.1 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that 2g of neutral alumina is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0048] Example 4.2 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that 6g of neutral alumina is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0049] Example 4.3 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that 10g of neutral alumina is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0050] Example 4.4 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that 2g of alkaline alumina is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0051] Example 4.5 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that 6g of alkaline alumina is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0052] Example 4.6 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that 10g of alkaline alumina is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0053] Example 5: A method for preparing an ultraviolet absorber UV-P Using silica gel as a dispersion carrier and sodium dithionite as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 5.1 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0054] Example 5.2 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.2, the difference from Example 1.2 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0055] Example 5.3 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.3, the difference from Example 1.3 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0056] Example 5.4 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.4, the difference from Example 1.4 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0057] Example 5.5 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.5, the difference from Example 1.5 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0058] Example 5.6 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.6, the difference from Example 1.6 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0059] Example 6: A method for preparing an ultraviolet absorber UV-P Using diatomaceous earth as a dispersion carrier and sodium dithionite as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 6.1 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 2.1, the difference from Example 2.1 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0060] Example 6.2 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 2.2, the difference from Example 2.2 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0061] Example 6.3 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 2.3, the difference from Example 2.3 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0062] Example 7: A method for preparing an ultraviolet absorber UV-P Using 5A molecular sieve as the dispersion carrier and sodium dithionite as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared: Example 7.1 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 3.1, the difference from Example 3.1 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0063] Example 7.2 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 3.2, the difference from Example 3.2 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0064] Example 7.3 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 3.3, the difference from Example 3.3 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0065] Example 8: A method for preparing an ultraviolet absorber UV-P Using alumina as the dispersion carrier and sodium dithionite as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 8.1 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 4.1, the difference from Example 4.1 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0066] Example 8.2 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 4.2, the difference from Example 4.2 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0067] Example 8.3 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 4.3, the difference from Example 4.3 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0068] Example 8.4 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 4.4, the difference from Example 4.4 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0069] Example 8.5 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 4.5, the difference from Example 4.5 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0070] Example 8.6 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 4.6, the difference from Example 4.2 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0071] Example 9: A method for preparing an ultraviolet absorber UV-P Using silica gel as a dispersion carrier and sodium metabisulfite as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared: Example 9.1 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0072] Example 9.2 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.2, the difference from Example 1.2 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0073] Example 9.3 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.3, the difference from Example 1.3 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0074] Example 9.4 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.4, the difference from Example 1.4 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0075] Example 9.5 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.5, the difference from Example 1.5 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0076] Example 9.6 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.6, the difference from Example 1.6 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0077] Example 10: A method for preparing an ultraviolet absorber UV-P Using diatomaceous earth as a dispersion carrier and sodium metabisulfite as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared: Example 10.1 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 2.1, the difference from Example 2.1 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0078] Example 10.2 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 2.2, the difference from Example 2.2 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0079] Example 10.3 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 2.3, the difference from Example 2.3 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0080] Example 11: A method for preparing an ultraviolet absorber UV-P Using 5A molecular sieve as the dispersion carrier and sodium metabisulfite as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared: Example 11.1 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 3.1, the difference from Example 3.1 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0081] Example 11.2 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 3.2, the difference from Example 3.2 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0082] Example 11.3 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 3.3, the difference from Example 3.3 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0083] Example 12: A method for preparing an ultraviolet absorber UV-P Using alumina as the dispersion carrier and sodium metabisulfite as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared: Example 12.1 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 4.1, the difference from Example 4.1 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0084] Example 12.2 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 4.2, the difference from Example 4.2 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0085] Example 12.3 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 4.3, the difference from Example 4.3 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0086] Example 12.4 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 4.4, the difference from Example 4.4 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0087] Example 12.5 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 4.5, the difference from Example 4.5 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0088] Example 12.6 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 4.6, the difference from Example 4.6 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0089] Example 13: A method for preparing an ultraviolet absorber UV-P Using silica gel as a dispersion carrier and sodium thiosulfate as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 13.1 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0090] Example 13.2 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.2, the difference from Example 1.2 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0091] Example 13.3 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.3, the difference from Example 1.3 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0092] Example 13.4 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.4, the difference from Example 1.4 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0093] Example 13.5 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.5, the difference from Example 1.5 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0094] Example 13.6 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 1.6, the difference from Example 1.6 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0095] Example 14: A method for preparing an ultraviolet absorber UV-P Using diatomaceous earth as a dispersion carrier and sodium thiosulfate as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 14.1 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 2.1, the difference from Example 2.1 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0096] Example 14.2 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 2.2, the difference from Example 2.2 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0097] Example 14.3 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 2.3, the difference from Example 2.3 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0098] Example 15: A method for preparing an ultraviolet absorber UV-P Using 5A molecular sieve as the dispersion carrier and sodium thiosulfate as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 15.1 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 3.1, the difference from Example 3.1 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0099] Example 15.2 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 3.2, the difference from Example 3.2 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0100] Example 15.3 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 3.3, the difference from Example 3.3 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0101] Example 16: A method for preparing an ultraviolet absorber UV-P Using alumina as the dispersion carrier and sodium thiosulfate as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 16.1 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 4.1, the difference from Example 4.1 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0102] Example 16.2 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 4.2, the difference from Example 4.2 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0103] Example 16.3 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 4.3, the difference from Example 4.3 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0104] Example 16.4 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 4.4, the difference from Example 4.4 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0105] Example 16.5 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 4.5, the difference from Example 4.5 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0106] Example 16.6 This embodiment provides a method for preparing ultraviolet absorber UV-P. Referring to Example 4.6, the difference from Example 4.6 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0107] Example 17: A method for preparing an ultraviolet absorber UV-329 Using silica gel as a dispersion carrier and sodium sulfide as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 17.1 This embodiment provides a method for preparing ultraviolet absorber UV-329, including the following steps: (1) Preparation of sulfide-supported dispersion reducing agent using silica gel as dispersion carrier 15g of sodium sulfide was dissolved in a mixed solvent of 30g of anhydrous ethanol and 20g of deionized water under stirring. The mixture was stirred at 600rpm for 10min. Then, 2g of 300-400 mesh silica gel was added, and the mixture was heated and stirred at 50℃ in air for 2h. After the reaction was completed, the mixture was filtered, and the filter cake was vacuum dried in a vacuum oven at 70℃ for 24h to obtain the sulfide supported dispersion reducing agent. (2) Reduction of sulfide-supported dispersion reducing agent: In a 250mL three-necked flask, 9g of UV... The 329 azo intermediate was dissolved in a mixed solvent of 50g ethanol and 40g deionized water. Then, 8g of the sulfide-supported dispersion reducing agent prepared in step (1) and 16g of caustic soda were added. The mixture was heated to 80°C and stirred (stirring speed about 600rpm) for 4h. After the reaction was completed, the excess reducing agent was removed by filtration to obtain the filtrate. The filtrate was slowly cooled to 0°C, and 36wt% concentrated hydrochloric acid was added dropwise to adjust the pH to 1. The filtrate was filtered to obtain the filter cake, and the composition of the filter cake product was analyzed by high performance liquid chromatography. The solvent was evaporated under reduced pressure, washed with deionized water and methanol, and then vacuum dried in a vacuum drying oven at 80°C for 10h to obtain the target product UV-329.

[0108] Example 17.2 This embodiment provides a method for preparing ultraviolet absorber UV-329, referring to Example 17.1. The difference between Example 17.1 and Example 17.1 is that 6g of 300-400 mesh silica gel is added in step (1).

[0109] Example 17.3 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that 10g of 300-400 mesh silica gel is added in step (1).

[0110] Example 17.4 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that 2g of 500-mesh silica gel is added in step (1) (replacing 2g of 300-400-mesh silica gel).

[0111] Example 17.5 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that 6g of 500-mesh silica gel is added in step (1) (replacing 2g of 300-400-mesh silica gel).

[0112] Example 17.6 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that 10g of 500-mesh silica gel is added in step (1) (replacing 2g of 300-400-mesh silica gel).

[0113] Example 17.7 This embodiment provides a method for preparing ultraviolet absorber UV-329, including the following steps: (1) Preparation of sulfide-supported dispersion reducing agent using silica gel as dispersion carrier 15g of sodium sulfide was dissolved in a mixed solvent of 50g anhydrous ethanol and 30g deionized water under stirring. The mixture was stirred at 600rpm for 10min. Then, 2g of 300-400 mesh silica gel was added, and the mixture was heated and stirred at 40℃ in air for 3h. After the reaction was completed, the mixture was filtered, and the filter cake was vacuum dried in a vacuum oven at 50℃ for 26h to obtain the sulfide supported dispersion reducing agent. (2) Reduction of sulfide-supported dispersion reducing agent: In a 250mL three-necked flask, 9g of UV... The 329 azo intermediate was dissolved in a mixed solvent of 20g ethanol and 100g deionized water. Then, 35g of the sulfide-supported dispersion reducing agent prepared in step (1) and 10g of caustic soda were added. The mixture was heated to 75°C and stirred (stirring speed about 600rpm) for 5h. After the reaction was completed, the excess reducing agent was removed by filtration to obtain the filtrate. The filtrate was slowly cooled to 0°C, and 36wt% concentrated hydrochloric acid was added dropwise to adjust the pH to 1. The filtrate was filtered to obtain the filter cake, and the composition of the filter cake product was analyzed by high performance liquid chromatography. The solvent was evaporated under reduced pressure, washed with deionized water and methanol, and then vacuum dried in a vacuum drying oven at 70°C for 12h to obtain the target product UV-329.

[0114] Example 17.8 This embodiment provides a method for preparing ultraviolet absorber UV-329, including the following steps: (1) Preparation of sulfide-supported dispersion reducing agent using silica gel as dispersion carrier 15g of sodium sulfide was dissolved in a mixed solvent of 60g anhydrous ethanol and 20g deionized water under stirring. The mixture was stirred at 600rpm for 10min. Then, 2g of 300-400 mesh silica gel was added, and the mixture was placed in an oil bath and heated to 60℃ for 1.5h. After the reaction was completed, the mixture was filtered, and the filter cake was vacuum dried at 60℃ for 20h to obtain the sulfide supported dispersion reducing agent. (2) Reduction of sulfide-supported dispersion reducing agent: In a 250mL three-necked flask, 9g of UV... The 329 azo intermediate was dissolved in a mixed solvent of 20g ethanol and 100g deionized water. Then, 7g of the sulfide-supported dispersion reducing agent prepared in step (1) and 20g of caustic soda were added. The mixture was heated to 85°C and stirred (stirring speed about 600rpm) for 2h. After the reaction was completed, the excess reducing agent was removed by filtration to obtain the filtrate. The filtrate was slowly cooled to 0°C, and 36wt% concentrated hydrochloric acid was added dropwise to adjust the pH to 1. The filtrate was filtered to obtain the filter cake, and the composition of the filter cake product was analyzed by high performance liquid chromatography. The solvent was evaporated under reduced pressure, washed with deionized water and methanol, and then vacuum dried in a vacuum drying oven at 90°C for 10h to obtain the target product UV-329.

[0115] Example 18: A method for preparing an ultraviolet absorber UV-329 Using diatomaceous earth as a dispersion carrier and sodium sulfide as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared: Example 18.1 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that 2g of diatomaceous earth is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0116] Example 18.2 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that 6g of diatomaceous earth is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0117] Example 18.3 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that 10g of diatomaceous earth is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0118] Example 19: A method for preparing an ultraviolet absorber UV-329 Using 5A molecular sieve as the dispersion carrier and sodium sulfide as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared: Example 19.1 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that 2g of 5A molecular sieve (replacing 2g of 300-400 mesh silica gel) is added in step (1).

[0119] Example 19.2 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that 6g of 5A molecular sieve is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0120] Example 19.3 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that 10g of 5A molecular sieve (replacing 2g of 300-400 mesh silica gel) is added in step (1).

[0121] Example 20: A method for preparing an ultraviolet absorber UV-329 Using alumina as the dispersion carrier and sodium sulfide as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 20.1 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that 2g of neutral alumina is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0122] Example 20.2 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that 6g of neutral alumina is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0123] Example 20.3 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that 10g of neutral alumina is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0124] Example 20.4 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that 2g of alkaline alumina is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0125] Example 20.5 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that 6g of alkaline alumina is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0126] Example 20.6 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that 10g of alkaline alumina is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0127] Example 21: A method for preparing an ultraviolet absorber UV-329 Using silica gel as a dispersion carrier and sodium dithionite as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 21.1 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0128] Example 21.2 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.2, the difference from Example 17.2 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0129] Example 21.3 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.3, the difference from Example 17.3 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0130] Example 21.4 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.4, the difference from Example 17.4 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0131] Example 21.5 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.5, the difference from Example 17.5 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0132] Example 21.6 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.6, the difference from Example 17.6 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0133] Example 22: A method for preparing an ultraviolet absorber UV-329 Using diatomaceous earth as a dispersion carrier and sodium dithionite as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 22.1 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 18.1, the difference from Example 18.1 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0134] Example 22.2 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 18.2, the difference from Example 18.2 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0135] Example 22.3 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 18.3, the difference from Example 18.3 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0136] Example 23: A method for preparing ultraviolet absorber UV-329 Using 5A molecular sieve as the dispersion carrier and sodium dithionite as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared: Example 23.1 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 19.1, the difference from Example 19.1 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0137] Example 23.2 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 19.2, the difference from Example 19.2 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0138] Example 23.3 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 19.3, the difference from Example 19.3 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0139] Example 24: A method for preparing an ultraviolet absorber UV-329 Using alumina as the dispersion carrier and sodium dithionite as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 24.1 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 20.1, the difference from Example 20.1 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0140] Example 24.2 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 20.2, the difference from Example 20.2 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0141] Example 24.3 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 20.3, the difference from Example 20.3 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0142] Example 24.4 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 20.4, the difference from Example 20.4 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0143] Example 24.5 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 20.5, the difference from Example 20.5 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0144] Example 24.6 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 20.6, the difference from Example 20.2 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0145] Example 25: A method for preparing UV-329, an ultraviolet absorber. Using silica gel as a dispersion carrier and sodium metabisulfite as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared: Example 25.1 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0146] Example 25.2 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.2, the difference from Example 17.2 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0147] Example 25.3 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.3, the difference from Example 17.3 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0148] Example 25.4 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.4, the difference from Example 17.4 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0149] Example 25.5 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.5, the difference from Example 17.5 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0150] Example 25.6 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.6, the difference from Example 17.6 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0151] Example 26: A method for preparing an ultraviolet absorber UV-329 Using diatomaceous earth as a dispersion carrier and sodium metabisulfite as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared: Example 26.1 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 18.1, the difference from Example 18.1 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0152] Example 26.2 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 18.2, the difference from Example 18.2 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0153] Example 26.3 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 18.3, the difference from Example 18.3 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0154] Example 27: A method for preparing an ultraviolet absorber UV-329 Using 5A molecular sieve as the dispersion carrier and sodium metabisulfite as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared: Example 27.1 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 19.1, the difference from Example 19.1 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0155] Example 27.2 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 19.2, the difference from Example 19.2 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0156] Example 27.3 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 19.3, the difference from Example 19.3 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0157] Example 28: A method for preparing an ultraviolet absorber UV-329 Using alumina as the dispersion carrier and sodium metabisulfite as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 28.1 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 20.1, the difference from Example 20.1 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0158] Example 28.2 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 20.2, the difference from Example 20.2 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0159] Example 28.3 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 20.3, the difference from Example 20.3 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0160] Example 28.4 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 20.4, the difference from Example 20.4 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0161] Example 28.5 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 20.5, the difference from Example 20.5 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0162] Example 28.6 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 20.6, the difference from Example 20.6 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0163] Example 29: A method for preparing an ultraviolet absorber UV-329 Using silica gel as a dispersion carrier and sodium thiosulfate as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 29.1 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0164] Example 29.2 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.2, the difference from Example 17.2 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0165] Example 29.3 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.3, the difference from Example 17.3 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0166] Example 29.4 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.4, the difference from Example 17.4 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0167] Example 29.5 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.5, the difference from Example 17.5 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0168] Example 29.6 This embodiment provides a method for preparing ultraviolet absorber UV-329, referring to Example 17.6. The difference between Example 17.6 and Example 17.6 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0169] Example 30: A method for preparing an ultraviolet absorber UV-329 Using diatomaceous earth as a dispersion carrier and sodium thiosulfate as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 30.1 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 18.1, the difference from Example 18.1 is that 15g of sodium thiosulfate is added in step (1) (replacing 15g of sodium sulfide), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0170] Example 30.2 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 18.2, the difference from Example 18.2 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0171] Example 30.3 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 18.3, the difference from Example 18.3 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0172] Example 31: A method for preparing an ultraviolet absorber UV-329 Using 5A molecular sieve as the dispersion carrier and sodium thiosulfate as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 31.1 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 19.1, the difference from Example 19.1 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0173] Example 31.2 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 19.2, the difference from Example 19.2 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0174] Example 31.3 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 19.3, the difference from Example 19.3 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0175] Example 32: A method for preparing ultraviolet absorber UV-329 Using alumina as the dispersion carrier and sodium thiosulfate as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 32.1 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 20.1, the difference from Example 20.1 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0176] Example 32.2 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 20.2, the difference from Example 20.2 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0177] Example 32.3 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 20.3, the difference from Example 20.3 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0178] Example 32.4 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 20.4, the difference from Example 20.4 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0179] Example 32.5 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 20.5, the difference from Example 20.5 is that 15g of sodium thiosulfate is added in step (1) (replacing 15g of sodium sulfide), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0180] Example 32.6 This embodiment provides a method for preparing ultraviolet absorber UV-329. Referring to Example 20.6, the difference from Example 20.6 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0181] Example 33: A method for preparing an ultraviolet absorber UV-234 Using silica gel as a dispersion carrier and sodium sulfide as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 33.1 This embodiment provides a method for preparing ultraviolet absorber UV-234, including the following steps: (1) Preparation of sulfide-supported dispersion reducing agent using silica gel as dispersion carrier 15g of sodium sulfide was dissolved in a mixed solvent of 30g anhydrous ethanol and 20g deionized water under stirring. The mixture was stirred at 800rpm for 10min. Then, 2g of 300-400 mesh silica gel was added, and the mixture was heated and stirred at 50℃ in air for 2h. After the reaction was completed, the mixture was filtered, and the filter cake was vacuum dried in a vacuum oven at 70℃ for 24h to obtain the sulfide supported dispersion reducing agent. (2) Reduction of sulfide-supported dispersion reducing agent: In a 250mL three-necked flask, 12g of UV... The 234 azo intermediate was dissolved in a mixed solvent of 50g ethanol and 40g deionized water. Then, 8g of the sulfide-supported dispersion reducing agent prepared in step (1) and 16g of caustic soda were added. The mixture was heated to 80°C and stirred (stirring speed about 600rpm) for 4h. After the reaction was completed, the excess reducing agent was removed by filtration to obtain the filtrate. The filtrate was slowly cooled to 0°C, and 36wt% concentrated hydrochloric acid was added dropwise to adjust the pH to 1. The filtrate was filtered to obtain the filter cake, and the composition of the filter cake product was analyzed by high performance liquid chromatography. The solvent was evaporated under reduced pressure, washed with deionized water and methanol, and then vacuum dried in an 80°C vacuum drying oven for 10h to obtain the target product UV-234.

[0182] Example 33.2 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that 6g of 300-400 mesh silica gel is added in step (1).

[0183] Example 33.3 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that 10g of 300-400 mesh silica gel is added in step (1).

[0184] Example 33.4 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that 2g of 500-mesh silica gel is added in step (1) (replacing 2g of 300-400-mesh silica gel).

[0185] Example 33.5 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that 6g of 500-mesh silica gel is added in step (1) (replacing 2g of 300-400-mesh silica gel).

[0186] Example 33.6 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that 10g of 500-mesh silica gel is added in step (1) (replacing 2g of 300-400-mesh silica gel).

[0187] Example 33.7 This embodiment provides a method for preparing ultraviolet absorber UV-234, including the following steps: (1) Preparation of sulfide-supported dispersion reducing agent using silica gel as dispersion carrier 15g of sodium sulfide was dissolved in a mixed solvent of 30g anhydrous ethanol and 20g deionized water under stirring. The mixture was stirred at 800rpm for 10min. Then, 2g of 300-400 mesh silica gel was added, and the mixture was heated and stirred at 40℃ in air for 3h. After the reaction was completed, the mixture was filtered, and the filter cake was vacuum dried in a vacuum oven at 50℃ for 26h to obtain the sulfide supported dispersion reducing agent. (2) Reduction of sulfide-supported dispersion reducing agent: In a 250mL three-necked flask, 12g of UV... The 234 azo intermediate was dissolved in a mixed solvent of 50g ethanol and 20g deionized water. Then, 8g of the sulfide-supported dispersion reducing agent prepared in step (1) and 20g of caustic soda were added. The mixture was heated to 75°C and stirred (stirring speed about 600rpm) for 5h. After the reaction was completed, the excess reducing agent was removed by filtration to obtain the filtrate. The filtrate was slowly cooled to 0°C, and 36wt% concentrated hydrochloric acid was added dropwise to adjust the pH to 1. The filtrate was filtered to obtain the filter cake. The composition of the filter cake product was analyzed by high performance liquid chromatography. The solvent was evaporated under reduced pressure, washed with deionized water and methanol, and then vacuum dried in a vacuum drying oven at 70°C for 12h to obtain the target product UV-234.

[0188] Example 33.8 This embodiment provides a method for preparing ultraviolet absorber UV-234, including the following steps: (1) Preparation of sulfide-supported dispersion reducing agent using silica gel as dispersion carrier 15g of sodium sulfide was dissolved in a mixed solvent of 30g anhydrous ethanol and 20g deionized water under stirring. The mixture was stirred at 800rpm for 10min. Then, 2g of 300-400 mesh silica gel was added, and the mixture was heated and stirred at 60℃ in air for 1.5h. After the reaction was completed, the mixture was filtered, and the filter cake was vacuum dried in a vacuum drying oven at 60℃ for 20h to obtain the sulfide supported dispersion reducing agent. (2) Reduction of sulfide-supported dispersion reducing agent: In a 250mL three-necked flask, 12g of UV... The 234 azo intermediate was dissolved in a mixed solvent of 20g ethanol and 100g deionized water. Then, 8g of the sulfide-supported dispersion reducing agent prepared in step (1) and 10g of caustic soda were added. The mixture was heated to 85°C and stirred (stirring speed about 600rpm) for 2h. After the reaction was completed, the excess reducing agent was removed by filtration to obtain the filtrate. The filtrate was slowly cooled to 0°C, and 36wt% concentrated hydrochloric acid was added dropwise to adjust the pH to 1. The filtrate was filtered to obtain the filter cake. The composition of the filter cake product was analyzed by high performance liquid chromatography. The solvent was evaporated under reduced pressure, washed with deionized water and methanol, and then vacuum dried in a vacuum drying oven at 90°C for 11h to obtain the target product UV-234.

[0189] Example 34: A method for preparing an ultraviolet absorber UV-234 Using diatomaceous earth as a dispersion carrier and sodium sulfide as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared: Example 34.1 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that 2g of diatomaceous earth is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0190] Example 34.2 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that 6g of diatomaceous earth is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0191] Example 34.3 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that 10g of diatomaceous earth is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0192] Example 35: A method for preparing an ultraviolet absorber UV-234 Using 5A molecular sieve as the dispersion carrier and sodium sulfide as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared: Example 35.1 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that 2g of 5A molecular sieve (replacing 2g of 300-400 mesh silica gel) is added in step (1).

[0193] Example 35.2 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that 6g of 5A molecular sieve is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0194] Example 35.3 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that 10g of 5A molecular sieve (replacing 2g of 300-400 mesh silica gel) is added in step (1).

[0195] Example 36: A method for preparing UV-234, an ultraviolet absorber. Using alumina as the dispersion carrier and sodium sulfide as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 36.1 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that 2g of neutral alumina is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0196] Example 36.2 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that 6g of neutral alumina is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0197] Example 36.3 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that 10g of neutral alumina is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0198] Example 36.4 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that 2g of alkaline alumina is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0199] Example 36.5 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that 6g of alkaline alumina is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0200] Example 36.6 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that 10g of alkaline alumina is added in step (1) (replacing 2g of 300-400 mesh silica gel).

[0201] Example 37: A method for preparing UV-234, an ultraviolet absorber. Using silica gel as a dispersion carrier and sodium dithionite as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared: Example 37.1 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0202] Example 37.2 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.2, the difference from Example 33.2 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0203] Example 37.3 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.3, the difference from Example 33.3 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0204] Example 37.4 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.4, the difference from Example 33.4 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0205] Example 37.5 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.5, the difference from Example 33.5 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0206] Example 37.6 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.6, the difference from Example 33.6 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0207] Example 38: A method for preparing UV-234, an ultraviolet absorber. Using diatomaceous earth as a dispersion carrier and sodium dithionite as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 38.1 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 34.1, the difference from Example 34.1 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0208] Example 38.2 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 34.2, the difference from Example 34.2 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0209] Example 38.3 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 34.3, the difference from Example 34.3 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0210] Example 39: A method for preparing UV-234, an ultraviolet absorber. Using 5A molecular sieve as the dispersion carrier and sodium dithionite as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared: Example 39.1 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 35.1, the difference from Example 35.1 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0211] Example 39.2 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 35.2, the difference from Example 35.2 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0212] Example 39.3 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 35.3, the difference from Example 35.3 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0213] Example 40: A method for preparing UV-234, an ultraviolet absorber. Using alumina as the dispersion carrier and sodium dithionite as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 40.1 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 36.1, the difference from Example 36.1 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0214] Example 40.2 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 36.2, the difference from Example 36.2 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0215] Example 40.3 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 36.3, the difference from Example 36.3 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0216] Example 40.4 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 36.4, the difference from Example 36.4 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0217] Example 40.5 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 36.5, the difference from Example 36.5 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0218] Example 40.6 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 36.6, the difference from Example 36.2 is that 15g of sodium dithionite (replacing 15g of sodium sulfide) is added in step (1), and 18g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0219] Example 41: A method for preparing UV-234, an ultraviolet absorber. Using silica gel as a dispersion carrier and sodium metabisulfite as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared: Example 41.1 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0220] Example 41.2 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.2, the difference from Example 33.2 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0221] Example 41.3 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.3, the difference from Example 33.3 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0222] Example 41.4 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.4, the difference from Example 33.4 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0223] Example 41.5 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.5, the difference from Example 33.5 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0224] Example 41.6 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.6, the difference from Example 33.6 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0225] Example 42: A method for preparing UV-234, an ultraviolet absorber. Using diatomaceous earth as a dispersion carrier and sodium metabisulfite as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared: Example 42.1 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 34.1, the difference from Example 34.1 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0226] Example 42.2 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 34.2, the difference from Example 34.2 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0227] Example 42.3 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 34.3, the difference from Example 34.3 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0228] Example 43: A method for preparing UV-234, an ultraviolet absorber. Using 5A molecular sieve as the dispersion carrier and sodium metabisulfite as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared: Example 43.1 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 35.1, the difference from Example 35.1 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0229] Example 43.2 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 35.2, the difference from Example 35.2 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0230] Example 43.3 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 35.3, the difference from Example 35.3 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0231] Example 44: A method for preparing an ultraviolet absorber UV-234 Using alumina as the dispersion carrier and sodium metabisulfite as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 44.1 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 36.1, the difference from Example 36.1 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0232] Example 44.2 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 36.2, the difference from Example 36.2 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0233] Example 44.3 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 36.3, the difference from Example 36.3 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0234] Example 44.4 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 36.4, the difference from Example 36.4 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0235] Example 44.5 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 36.5, the difference from Example 36.5 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0236] Example 44.6 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 36.6, the difference from Example 36.6 is that 15g of sodium metabisulfite (replacing 15g of sodium sulfide) is added in step (1), and 20g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0237] Example 45: A method for preparing an ultraviolet absorber UV-234 Using silica gel as a dispersion carrier and sodium thiosulfate as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 45.1 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0238] Example 45.2 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.2, the difference from Example 33.2 is that 15g of sodium thiosulfate is added in step (1) (replacing 15g of sodium sulfide), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0239] Example 45.3 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.3, the difference from Example 33.3 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0240] Example 45.4 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.4, the difference from Example 33.4 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0241] Example 45.5 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.5, the difference from Example 33.5 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0242] Example 45.6 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.6, the difference from Example 33.6 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0243] Example 46: A method for preparing UV-234, an ultraviolet absorber. Using diatomaceous earth as a dispersion carrier and sodium thiosulfate as a sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 46.1 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 34.1, the difference from Example 34.1 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0244] Example 46.2 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 34.2, the difference from Example 34.2 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0245] Example 46.3 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 34.3, the difference from Example 34.3 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0246] Example 47: A method for preparing UV-234, an ultraviolet absorber. Using 5A molecular sieve as the dispersion carrier and sodium thiosulfate as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 47.1 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 35.1, the difference from Example 35.1 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0247] Example 47.2 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 35.2, the difference from Example 35.2 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0248] Example 47.3 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 35.3, the difference from Example 35.3 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0249] Example 48: A method for preparing UV-234, an ultraviolet absorber. Using alumina as the dispersion carrier and sodium thiosulfate as the sulfur-containing compound raw material, a sulfide-supported dispersion reducing agent was prepared. Example 48.1 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 36.1, the difference from Example 36.1 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0250] Example 48.2 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 36.2, the difference from Example 36.2 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0251] Example 48.3 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 36.3, the difference from Example 36.3 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0252] Example 48.4 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 36.4, the difference from Example 36.4 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0253] Example 48.5 This embodiment provides a method for preparing ultraviolet absorber UV-234. Referring to Example 36.5, the difference from Example 36.5 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0254] Example 48.6 This embodiment provides a method for preparing ultraviolet absorber UV-234, referring to Example 36.6. The difference between Example 36.6 and Example 36.6 is that 15g of sodium thiosulfate (replacing 15g of sodium sulfide) is added in step (1), and 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is added in step (2).

[0255] Example 49: A method for preparing an ultraviolet absorber UV-320 This embodiment provides a method for preparing ultraviolet absorber UV-320, including the following steps: (1) Preparation of sulfide-supported dispersion reducing agent using neutral alumina as dispersion carrier 15g of sodium dithionite was dissolved in a mixed solvent of 30g anhydrous ethanol and 20g deionized water under stirring. The mixture was stirred at 1000rpm for 10min, then 10g of neutral alumina was added. The mixture was heated and stirred at 50℃ in air for 2h. After the reaction was completed, the mixture was filtered, and the filter cake was vacuum dried in a vacuum oven at 70℃ for 24h to obtain a sulfide-supported dispersion reducing agent. (2) Reduction of sulfide-supported dispersion reducing agent: In a 250 mL three-necked flask, 8 g of UV-320 azo intermediate was dissolved in a mixed solvent of 50 g ethanol and 40 g deionized water. Then, 20 g of the sulfide-supported dispersion reducing agent prepared in step (1) and 16 g of caustic soda were added. The mixture was heated to 80 °C and stirred (stirring speed about 600 rpm) for 4 h. After the reaction was completed, the excess reducing agent was removed by filtration to obtain the filtrate. The filtrate was slowly cooled to 0 °C, and 36 wt% concentrated hydrochloric acid was added dropwise to adjust the pH to 1. The filtrate was filtered to obtain the filter cake. The composition of the filter cake product was analyzed by high performance liquid chromatography. The solvent was evaporated under reduced pressure, washed with deionized water and methanol, and then vacuum dried in an 80 °C vacuum drying oven for 10 h to obtain the target product UV-320.

[0256] Example 50: A method for preparing an ultraviolet absorber UV-326 This embodiment provides a method for preparing ultraviolet absorber UV-326, including the following steps: (1) Preparation of sulfide-supported dispersion reducing agent using neutral alumina as dispersion carrier 15g of sodium dithionite was dissolved in a mixed solvent of 30g anhydrous ethanol and 40g deionized water under stirring. The mixture was stirred at 1000rpm for 10min, then 10g of neutral alumina was added. The mixture was heated and stirred at 50℃ in air for 2h. After the reaction was completed, the mixture was filtered, and the filter cake was vacuum dried in a vacuum oven at 70℃ for 24h to obtain a sulfide-supported dispersion reducing agent. (2) Reduction of sulfide-supported dispersion reducing agent: In a 250 mL three-necked flask, 10 g of UV-326 azo intermediate was dissolved in a mixed solvent of 50 g ethanol and 40 g deionized water. Then, 19 g of the sulfide-supported dispersion reducing agent prepared in step (1) and 16 g of caustic soda were added. The mixture was heated to 80 °C and stirred (stirring speed about 600 rpm) for 4 h. After the reaction was completed, the excess reducing agent was removed by filtration to obtain the filtrate. The filtrate was slowly cooled to 0 °C, and 36 wt% concentrated hydrochloric acid was added dropwise to adjust the pH to 1. The filtrate was filtered to obtain the filter cake. The composition of the filter cake product was analyzed by high performance liquid chromatography. The solvent was evaporated under reduced pressure, washed with deionized water and methanol, and then vacuum dried in an 80 °C vacuum oven for 10 h to obtain the target product UV-326.

[0257] Example 51: A method for preparing UV-327, an ultraviolet absorber. This embodiment provides a method for preparing ultraviolet absorber UV-327, including the following steps: (1) Preparation of sulfide-supported dispersion reducing agent using neutral alumina as dispersion carrier 15g of sodium dithionite was dissolved in a mixed solvent of 20g anhydrous ethanol and 40g deionized water under stirring. The mixture was stirred at 1000rpm for 10min, then 10g of neutral alumina was added. The mixture was heated and stirred at 50℃ in air for 2h. After the reaction was completed, the mixture was filtered, and the filter cake was vacuum dried in a vacuum drying oven at 70℃ for 24h to obtain a sulfide-supported dispersion reducing agent. (2) Reduction of sulfide-supported dispersion reducing agent: In a 250 mL three-necked flask, 11 g of UV-327 azo intermediate was dissolved in a mixed solvent of 50 g ethanol and 40 g deionized water. Then, 25 g of the sulfide-supported dispersion reducing agent prepared in step (1) and 16 g of caustic soda were added. The mixture was heated to 80 °C and stirred (stirring speed about 600 rpm) for 4 h. After the reaction was completed, the excess reducing agent was removed by filtration to obtain the filtrate. The filtrate was slowly cooled to 0 °C, and 36 wt% concentrated hydrochloric acid was added dropwise to adjust the pH to 1. The filtrate was filtered to obtain the filter cake. The composition of the filter cake product was analyzed by high performance liquid chromatography. The solvent was evaporated under reduced pressure, washed with deionized water and methanol, and then vacuum dried in an 80 °C vacuum drying oven for 10 h to obtain the target product UV-327.

[0258] Example 52: A method for preparing an ultraviolet absorber UV-328 This embodiment provides a method for preparing ultraviolet absorber UV-328, including the following steps: (1) Preparation of sulfide-supported dispersion reducing agent using neutral alumina as dispersion carrier 15g of sodium dithionite was dissolved in a mixed solvent of 10g anhydrous ethanol and 10g deionized water under stirring. The mixture was stirred at 1000rpm for 10min, then 10g of neutral alumina was added. The mixture was heated and stirred at 50℃ in air for 2h. After the reaction was completed, the mixture was filtered, and the filter cake was vacuum dried in a vacuum oven at 70℃ for 24h to obtain a sulfide-supported dispersion reducing agent. (2) Reduction of sulfide-supported dispersion reducing agent: In a 250 mL three-necked flask, 10 g of UV-328 azo intermediate was dissolved in a mixed solvent of 50 g ethanol and 40 g deionized water. Then, 16 g of the sulfide-supported dispersion reducing agent prepared in step (1) and 16 g of caustic soda flakes were added. The mixture was heated to 80 °C and stirred (stirring speed about 600 rpm) for 4 h. After the reaction was completed, the excess reducing agent was removed by filtration to obtain the filtrate. The filtrate was slowly cooled to 0 °C, and 36 wt% concentrated hydrochloric acid was added dropwise to adjust the pH to 1. The filtrate was filtered to obtain the filter cake. The composition of the filter cake product was analyzed by high performance liquid chromatography. The solvent was evaporated under reduced pressure, washed with deionized water and methanol, and then vacuum dried in an 80 °C vacuum oven for 10 h to obtain the target product UV-328.

[0259] Example 53: A method for preparing an ultraviolet absorber UV-171 / 571 This embodiment provides a method for preparing ultraviolet absorber UV-171 / 571, including the following steps: (1) Preparation of sulfide-supported dispersion reducing agent using neutral alumina as dispersion carrier 15g of sodium dithionite was dissolved in a mixed solvent of 20g anhydrous ethanol and 20g deionized water under stirring. The mixture was stirred at 1000rpm for 10min, then 10g of neutral alumina was added. The mixture was heated and stirred at 50℃ in air for 2h. After the reaction was completed, the mixture was filtered, and the filter cake was vacuum dried in a vacuum oven at 70℃ for 24h to obtain a sulfide-supported dispersion reducing agent. (2) Reduction of sulfide-supported dispersion reducing agent: In a 250 mL three-necked flask, 12 g of UV-171 / 571 azo intermediate was dissolved in a mixed solvent of 50 g ethanol and 40 g deionized water. Then, 20 g of the sulfide-supported dispersion reducing agent prepared in step (1) and 16 g of caustic soda were added. The mixture was heated to 80 °C and stirred (stirring speed about 600 rpm) for 4 h. After the reaction was completed, the excess reducing agent was removed by filtration to obtain the filtrate. The filtrate was slowly cooled to 0 °C, and 36 wt% concentrated hydrochloric acid was added dropwise to adjust the pH to 1. The filtrate was filtered to obtain the filter cake. The composition of the filter cake product was analyzed by high performance liquid chromatography. The solvent was evaporated under reduced pressure, washed with deionized water and methanol, and then vacuum dried in an 80 °C vacuum oven for 10 h to obtain the target product UV-171 / 571.

[0260] Comparative Example 1: A method for preparing an ultraviolet absorber UV-P (zinc powder reduction). This comparative example provides a method for preparing an ultraviolet absorber UV-P, comprising the following steps: In a 250 mL three-necked flask, 18 g of 300-mesh zinc powder, 6.5 g of UV-P azo intermediate, 18 g of caustic soda flakes, and 40 g of anhydrous ethanol were added. The mixture was heated to 80 °C and stirred (at a stirring speed of approximately 500 rpm) for 4 h. After the reaction was completed, excess zinc powder was removed by filtration. The mixture was washed three times with 5 wt% sodium hydroxide solution. The filtrates were combined and slowly cooled to 0 °C. 36 wt% concentrated hydrochloric acid was added dropwise to adjust the pH to 1. The mixture was then filtered to obtain a filter cake. The composition of the filter cake product was analyzed by high performance liquid chromatography. The solvent was evaporated under reduced pressure, and the product was washed with deionized water and methanol. The product was then vacuum dried in a vacuum drying oven at 60 °C for 12 h to obtain the target product UV-P.

[0261] Comparative Example 2: A method for preparing an ultraviolet absorber UV-P (sodium sulfide reduction). This comparative example provides a method for preparing an ultraviolet absorber UV-P. Referring to Example 1.1, the difference from Example 1.1 is that step (1) is omitted, and 8g of the sulfide-supported dispersion reducing agent prepared in step (1) is replaced with 8g of sodium sulfide in step (2).

[0262] Comparative Example 3: A method for preparing an ultraviolet absorber UV-P (reduction with sodium dithionite). This comparative example provides a method for preparing an ultraviolet absorber UV-P. Referring to Example 5.1, the difference from Example 5.1 is that step (1) is omitted, and the 18g of the sulfide-supported dispersion reducing agent prepared in step (1) in step (2) is replaced with 18g of sodium dithionite.

[0263] Comparative Example 4: A method for preparing an ultraviolet absorber UV-P (reduction with sodium metabisulfite) This comparative example provides a method for preparing an ultraviolet absorber UV-P. Referring to Example 9.1, the difference from Example 9.1 is that step (1) is omitted, and the 20g of the sulfide-supported dispersion reducing agent prepared in step (1) in step (2) is replaced with 20g of sodium metabisulfite.

[0264] Comparative Example 5: A method for preparing an ultraviolet absorber UV-P (reduction with sodium metabisulfite) This comparative example provides a method for preparing an ultraviolet absorber UV-P. Referring to Example 13.1, the difference from Example 13.1 is that step (1) is omitted, and the 15.5g of the sulfide-supported dispersion reducing agent prepared in step (1) is replaced with 15.5g of sodium thiosulfate in step (2).

[0265] Comparative Example 6: A method for preparing UV-329, an ultraviolet absorber (zinc powder reduction). This comparative example provides a method for preparing the ultraviolet absorber UV-329, including the following steps: In a 250 mL three-necked flask, 18 g of 300-mesh zinc powder, 9 g of UV-329 azo intermediate, 18 g of caustic soda flakes, and 40 g of anhydrous ethanol were added. The mixture was heated to 80 °C and stirred (at a stirring speed of approximately 500 rpm) for 4 h. After the reaction was completed, excess zinc powder was removed by filtration. The mixture was washed three times with 5 wt% sodium hydroxide solution. The filtrates were combined and slowly cooled to 0 °C. 36 wt% concentrated hydrochloric acid was added dropwise to adjust the pH to 1. The mixture was then filtered to obtain a filter cake. The composition of the filter cake product was analyzed by high performance liquid chromatography. The solvent was evaporated under reduced pressure, and the product was washed with deionized water and methanol. The product was then vacuum dried in a vacuum drying oven at 60 °C for 12 h to obtain the target product UV-329.

[0266] Comparative Example 7: A method for preparing UV-329, an ultraviolet absorber (sodium sulfide reduction). This comparative example provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that step (1) is omitted, and 8g of the sulfide-supported dispersion reducing agent prepared in step (1) is replaced with 8g of sodium sulfide in step (2).

[0267] Comparative Example 8: A method for preparing UV-329, an ultraviolet absorber (reduction with sodium dithionite). This comparative example provides a method for preparing ultraviolet absorber UV-329. Referring to Example 17.1, the difference from Example 17.1 is that step (1) is omitted, and the 18g of sulfide-supported dispersion reducing agent prepared in step (1) in step (2) is replaced with 18g of sodium dithionite.

[0268] Comparative Example 9: A method for preparing UV-329, an ultraviolet absorber (reduction with sodium metabisulfite). This comparative example provides a method for preparing ultraviolet absorber UV-329. Referring to Example 25.1, the difference from Example 25.1 is that step (1) is omitted, and the 20g of sulfide-supported dispersion reducing agent prepared in step (1) in step (2) is replaced with 20g of sodium metabisulfite.

[0269] Comparative Example 10: A method for preparing UV-329, an ultraviolet absorber (reduction with sodium thiosulfate). This comparative example provides a method for preparing ultraviolet absorber UV-329, referring to Example 29.1. The difference from Example 29.1 is that step (1) is omitted, and the 15.5g of sulfide-supported dispersion reducing agent prepared in step (1) is replaced with 15.5g of sodium thiosulfate in step (2).

[0270] Comparative Example 11: A method for preparing UV-234, an ultraviolet absorber (zinc powder reduction). This comparative example provides a method for preparing the ultraviolet absorber UV-234, including the following steps: In a 250 mL three-necked flask, 18 g of 300-mesh zinc powder, 12 g of UV-234 azo intermediate, 18 g of caustic soda flakes, and 40 g of anhydrous ethanol were added. The mixture was heated to 80 °C and stirred (at a stirring rate of approximately 500 rpm) for 4 h. After the reaction was completed, excess zinc powder was removed by filtration. The mixture was washed three times with 5 wt% sodium hydroxide solution. The filtrates were combined and slowly cooled to 0 °C. The pH was adjusted to 1 by adding 36 wt% concentrated hydrochloric acid. The mixture was then filtered to obtain a filter cake. The composition of the filter cake product was analyzed by high performance liquid chromatography. The solvent was evaporated under reduced pressure, and the product was washed with deionized water and methanol. The product was then vacuum dried in a vacuum drying oven at 60 °C for 12 h to obtain the target product UV-234.

[0271] Comparative Example 12: A method for preparing UV-234, an ultraviolet absorber (sodium sulfide reduction). This comparative example provides a method for preparing ultraviolet absorber UV-234. Referring to Example 33.1, the difference from Example 33.1 is that step (1) is omitted, and 8g of the sulfide-supported dispersion reducing agent prepared in step (1) is replaced with 8g of sodium sulfide in step (2).

[0272] Comparative Example 13: A method for preparing UV-234, an ultraviolet absorber (reduction with sodium dithionite). This comparative example provides a method for preparing ultraviolet absorber UV-234. Referring to Example 37.1, the difference from Example 37.1 is that step (1) is omitted, and the 18g of sulfide-supported dispersion reducing agent prepared in step (1) in step (2) is replaced with 18g of sodium dithionite.

[0273] Comparative Example 14: A method for preparing UV-234, an ultraviolet absorber (reduction with sodium metabisulfite). This comparative example provides a method for preparing ultraviolet absorber UV-234. Referring to Example 41.1, the difference from Example 41.1 is that step (1) is omitted, and the 20g of sulfide-supported dispersion reducing agent prepared in step (1) in step (2) is replaced with 20g of sodium metabisulfite.

[0274] Comparative Example 15: A method for preparing UV-234, an ultraviolet absorber (reduction with sodium thiosulfate). This comparative example provides a method for preparing ultraviolet absorber UV-234, referring to Example 45.1. The difference from Example 45.1 is that step (1) is omitted, and the 15.5g of sulfide-supported dispersion reducing agent prepared in step (1) is replaced with 15.5g of sodium thiosulfate in step (2).

[0275] test: UV-P 1 H-NMR spectrum as follows Figure 1 As shown, 13 C-NMR spectra as follows Figure 2 As shown, the HPLC chromatogram is as follows: Figure 3 As shown in Table 1, the analysis results are as follows.

[0276] The specific data for the proton spectrum are as follows: 1 H NMR (400 MHz, CDCl3) δ 11.09 (s, 1H), 8.18 (s, 1H), 7.95 – 7.85 (m,2H), 7.51 – 7.36 (m, 2H), 7.17 – 7.03 (m, 2H), 2.38 (s, 3H). The specific carbon spectrum data are as follows: 13 C NMR (101 MHz, CDCl3) δ 147.62, 142.86, 131.33, 129.68, 127.69,124.89, 121.17, 118.83, 117.71, 20.63. Table 1. Analysis results of UV-P

[0277] UV-329 1 H-NMR spectrum as follows Figure 4 As shown, 13 C-NMR spectra as follows Figure 5 As shown, the HPLC chromatogram is as follows: Figure 6 As shown in Table 2, the analysis results are as follows.

[0278] The specific data for the proton spectrum are as follows: 1H NMR (400 MHz, CDCl3) δ 11.18 (s, 1H), 8.41 (d, J = 2.4 Hz, 1H), 7.95 (dd, J = 6.5, 3.1 Hz, 2H), 7.47 (dd, J = 6.6, 3.1 Hz, 2H), 7.38 (dd, J =8.7, 2.4 Hz, 1H), 7.14 (d, J = 8.7 Hz, 1H), 1.81 (s, 2H), 1.46 (s, 6H), 0.78(s, 9H). The specific carbon spectrum data are as follows: 13 C NMR (101 MHz, CDCl3) δ 147.45, 142.89, 142.40, 128.70, 127.63,124.68, 118.62, 118.36, 117.75, 56.91, 38.35, 32.50, 31.96, 31.75. Table 2 Analysis Results of UV-329

[0279] UV-234 1 H-NMR spectrum as follows Figure 7 As shown, 13 C-NMR spectra as follows Figure 8 As shown, the HPLC chromatogram is as follows: Figure 9 As shown in Table 3, the analysis results are as follows.

[0280] The specific data for the proton spectrum are as follows: 1 H NMR (400 MHz, CDCl3) δ 11.57 (s, 1H), 8.48 (d, J = 2.3 Hz, 1H), 7.90– 7.85 (m, 2H), 7.52 (d, J = 2.4 Hz, 1H), 7.49 – 7.41 (m, 6H), 7.38 (d, J = 4.3Hz, 4H), 7.34 – 7.24 (m, 2H), 1.95 (s, 6H), 1.85 (s, 6H). The specific carbon spectrum data are as follows: 13C NMR (101 MHz, CDCl3) δ 150.67, 150.57, 146.40, 142.59, 141.30,138.32, 128.22, 127.98, 127.49, 126.80, 125.88, 125.57, 125.29, 117.79,117.51, 77.48, 76.84, 42.93, 42.78, 31.08, 29.69. Table 3. Analysis Results of UV-234

[0281] The specific data for the proton spectrum of UV-320 are as follows: 1 H NMR (300 MHz, CDCl3) δ 1.39 (s, 9H), 1.51 (s, 9H), 7.40 (d, 1H, J =2.0 Hz), 7.39-7.45 (m, 2H), 7.86-7.92 (m, 2H), 8.30 (d, 1H, J = 2 Hz), 11,76(s, 1H). The specific data for the proton spectrum of UV-326 are as follows: 1 HNMR (300 MHz, CDCl3) 8: 11.61 (s, 1H), 8.31 (s,1H), 8.04-8.08 (m,2H), 7.58-7.60 (m, 2H), 7.29 (s, 1H), 2.36 (s,3H), 1.39-1.41 (m, 9H). The specific data for the proton spectrum of UV-327 are as follows: 1 H NMR (300 MHz, CDCl3) δ 1.39 (s, 9H), 1.50 (s, 9H), 7.45 (d, 1H, J =2.0 Hz), 7.47 (d, 1H, J = 1.0 Hz), 7.85-7.95 (m, 2H), 8.36 (d, 1H, J = 2.0Hz), 11.52 (s, 1H). The specific data for the proton spectrum of UV-328 are as follows: 1H NMR (300 MHz, CDCl3) δ 0.66 (t, 3H, J = 7.5 Hz), 0.70 (t, 3H, J =7.5 Hz), 1.36 (s, 6H), 1.45 (s, 6H), 1.68 (q, 2H, J = 7.5 Hz), 2.00 (q, 2H, J= 7.5 Hz), 7.28 (d, 1H, J = 2.0 Hz), 7.45 (m, 2H), 7.95 (m, 2H), 8.23 ​​(d, 1H,J = 2.0 Hz), 11.74 (s, 1H). The raw material conversion rate, product selectivity, and product yield of each embodiment and comparative example were tested and calculated.

[0282] The performance of reducing agents prepared by using silica gel as a dispersion carrier for sulfide dispersions is shown in Table 4.

[0283] Table 4 Performance of reducing agents for sulfide dispersions prepared using silica gel as a dispersion carrier

[0284] Note: The proportions in the table are the weight ratios of sulfur-containing compound raw materials to dispersion carriers, and the same applies below.

[0285] The performance of reducing agents for sulfide dispersions prepared using diatomaceous earth as a dispersion carrier is shown in Table 5.

[0286] Table 5 Performance of reducing agents for sulfide dispersions prepared using diatomaceous earth as a dispersion carrier

[0287] The performance of reducing agents for sulfide dispersions prepared using 5A molecular sieve as a dispersion carrier is shown in Table 6.

[0288] Table 6. Performance of reducing agents for sulfide dispersions prepared using 5A molecular sieve as a dispersion carrier.

[0289] The performance of reducing agents for sulfide dispersions prepared using alumina as a dispersion carrier is shown in Table 7.

[0290] Table 7 Performance of reducing agents for sulfide dispersions prepared using alumina as a dispersion carrier

[0291] The reducing agent performance effects of other embodiments are shown in Table 8.

[0292] Table 8. Performance of reducing agents in other embodiments

[0293] The reducing agent performance of Comparative Examples 1-15 is shown in Table 9.

[0294] Table 9. Performance of reducing agents in Comparative Examples 1-15

[0295] By comparing the performance of the reducing agents in Tables 4-9, it can be seen that, compared with the traditional zinc powder reduction method, the sulfide-supported dispersion reducing agent used in this invention can significantly improve the reaction performance. Specifically, the raw material conversion rate is increased by an average of about 11%, the product selectivity is increased by an average of about 10%, and thus the product yield is increased by an average of about 22%. The above results fully demonstrate the superiority of the technical solution of this invention, especially in improving reaction efficiency and target product yield.

[0296] Compared to single sulfide reducing agent systems without a dispersing carrier, this invention employs a sulfide-supported dispersion reducing agent. Although the improvement in feed conversion is relatively limited, it still significantly improves product selectivity, increasing it by an average of about 10%, thereby increasing product yield. This phenomenon is attributed to the crucial role of the dispersing carrier in this invention: it enables the slow release of sulfides, allowing them to participate in the reduction reaction in a controlled manner, thus effectively avoiding the violent exothermic phenomenon caused by excessively high local concentrations and significantly suppressing side reactions such as over-reduction. It is through the precise control of the reaction microenvironment that this invention successfully achieves the highly selective synthesis of benzotriazole ultraviolet absorbers.

[0297] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a sulfide-supported dispersion reducing agent, characterized in that, Includes the following steps: Sulfur-containing compound raw materials are suspended in a solvent under stirring, and then a dispersion carrier is added. The mixture is heated and stirred in an air atmosphere for 1.5-3 hours at a temperature of 40-60°C. After the reaction is completed, the mixture is filtered and dried to obtain a sulfide-supported dispersion reducing agent. The sulfur-containing compound raw material is sodium sulfide, sodium dithionite, sodium thiosulfate, or sodium metabisulfite, and the dispersion carrier is silica gel, molecular sieve, diatomaceous earth, or alumina. The mass ratio of the sulfur-containing compound raw material to the dispersion carrier is 1:1-10:

1.

2. The method for preparing the sulfide-supported dispersion reducing agent according to claim 1, characterized in that, The silica gel has a mesh size of 300-500, the molecular sieve is a 5A molecular sieve, and the solvent is selected from one or more of methanol, ethanol, and water.

3. The method for preparing the sulfide-supported dispersion reducing agent according to claim 1, characterized in that, The drying time is 20-26 hours, and the temperature is 50-70℃.

4. A sulfide-supported dispersion reducing agent, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 3.

5. A method for preparing a benzotriazole-based ultraviolet absorber, characterized in that, The sulfide-supported dispersion reducing agent as described in claim 4 is used as the reducing agent.

6. The method for preparing the benzotriazole ultraviolet absorber according to claim 5, characterized in that, Includes the following steps: (1) Reduction of sulfide-supported dispersion reducing agent: Dissolve the azo compound shown in Formula I in a mixed solution of ethanol and water, add the sulfide-supported dispersion reducing agent and caustic soda flakes, carry out the reduction reaction by heating, filter after the reaction is completed, and obtain the filtrate; (2) Crystallization: Cool the filtrate obtained in step (1) to below room temperature, adjust the pH to acidic, wash with methanol and water, and then vacuum dry to obtain the benzotriazole ultraviolet absorber product, namely the compound shown in formula II; In Formula I and Formula II, R1 is one of H, Cl, C1-C4 alkyl, and C1-C4 alkoxy. R2 is H, Cl-C 12 One of alkyl groups and C1-C8 alkylphenyl groups; R3 is H, Cl, or Cl-C. 12 Alkyl, C1-C 12 One of alkoxy, phenyl, C1-C8 alkylphenyl, and C1-C4 alkoxyphenyl.

7. The method for preparing the benzotriazole ultraviolet absorber according to claim 6, characterized in that, In step (1), by weight, the amount of the azo compound shown in Formula I is 6.5-12 parts, the amount of ethanol is 20-50 parts, the amount of water is 20-100 parts, the amount of caustic soda is 10-20 parts, and the amount of sulfide supported dispersion reducing agent is 7-35 parts.

8. The method for preparing the benzotriazole ultraviolet absorber according to claim 6, characterized in that, In step (1), the temperature of the heating reduction reaction is 75-85℃ and the time is 2-5h.

9. The method for preparing the benzotriazole ultraviolet absorber according to claim 6, characterized in that, In step (2), the pH is adjusted to a range of 1-2, and the product is vacuum dried at 70-90℃ for 10-12 hours.

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