Synthesis method of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol

Abstract

The invention discloses a synthetic method of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol. The synthetic method comprises the following steps: preparing the 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol from 2-nitroaniline through the processes of diazotization, coupling, reduction ring-closure reaction and after-treatment. According to the method, 2-nitroaniline and sodium nitrite are subjected to a diazotization reaction to generate diazonium salt, the diazotization reaction does not need to be carried out under a strong acid medium, 2-nitrodiazophenyl hydrochloride and 4-dodecyl p-cresol are subjected to a coupling reaction and then reduction ring closing is carried out, the reaction selectivity is high, byproducts are reduced, generation of impurities is reduced, and the method is suitable for industrial production. Not only is the product purity improved, but also the product yield is improved.

Description

Technical Field

[0001] The invention relates to a method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, belonging to the technical field of chemical industry. Background Art

[0002] 2-(2H-Benzotriazol-2-yl)-6-dodecyl-4-methylphenol, chemical formula C 25 H 35 N3O, CAS No. 23328-53-2, also known as UV absorber UV-571, is a type of benzotriazole UV absorber with good stability and low toxicity. It has high solubility in many solvents, monomers, and intermediates, is easily emulsified in water-based adhesives, and has high compatibility with a large number of base materials such as PC and PVC. It has low volatility even at high temperatures, so it can effectively protect the substrate from yellowing; it can also be used after being mixed with other additives such as phenolic antioxidants, synergists, hindered amine light stabilizers, etc.

[0003] At present, most manufacturers mainly produce 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol products by reducing azo compounds containing nitro groups. The reduction methods include one-step reduction method and two-step reduction method, such as zinc powder reduction method, hydrazine hydrate reduction method, sulfide reduction method, catalytic hydrogenation method, etc. Due to the different solvents and catalysts used in the reduction closed-loop process, the quality, yield and cost of the obtained products are different, causing different degrees of pollution to the environment. Summary of the invention

[0004] To address at least one of the problems existing in the above-mentioned prior art, the present invention provides a method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme: a method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, comprising the following steps: S1. Preparation of 2-nitrodiazonium phenyl hydrochloride: add 2-nitroaniline and hydrochloric acid into a diazotization reactor, cool and stir to 0-5°C, then dropwise add sodium nitrite aqueous solution, then keep warm for 30-40 minutes, then add 2-nitroaniline, continue to keep warm for 15-25 minutes, then filter, and the obtained filtrate is 2-nitrodiazonium phenyl hydrochloride solution; the mass fraction of hydrochloric acid is 25-30%, and the mass fraction of sodium nitrite aqueous solution is 30-40%; S2, preparation of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene: add 4-n-dodecyl-p-cresol and ethanol into a coupling reaction kettle, stir to dissolve, cool and stir to 0-5°C, adjust the pH to 8-8.5, maintain 0-5°C, add the 2-nitrodiazonium phenyl hydrochloride solution obtained in the above step S1, and react for 3-4h, remove the liquid by suction filtration, wash, and dry to obtain 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene; S3, preparation of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol: add the 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene obtained in step S2, an organic base, a sulfite, and a 60-75% ethanol aqueous solution into a reactor, stir to dissolve, heat to form reflux, then add a sulfonic acid resin modified with a reducing metal ion, keep reflux and react for 60-90 minutes, then cool to room temperature, filter to remove solids, add pure water, stir to mix, let stand, remove the water phase, and the oil phase is 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol.

[0006] Preferably, in step S1, the molar ratio of 2-nitroaniline, hydrochloric acid and sodium nitrite is 1:2~2.5:1.1~1.3.

[0007] Preferably, in step S1, the amount of 2-nitroaniline added is 95-100% of the molar difference between 2-nitroaniline and sodium nitrite.

[0008] Preferably, in step S2, the molar amount of 4-n-dodecyl-p-cresol added is equal to the molar amount of sodium nitrite in step S1.

[0009] Preferably, in step S2, the volume ratio of the molar amount of 4-n-dodecyl-p-cresol to the volume of ethanol is 1 mol: 1.5-2L.

[0010] Preferably, the pH in step S2 is adjusted by aqueous ammonia or aqueous sodium hydroxide solution.

[0011] Preferably, in step S3, the molar ratio of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene, the organic base and the sulfite is 1:0.8~1.2:3~8.

[0012] Preferably, the amount of the 60-75% ethanol aqueous solution added in step S3 is 3-5 times the mass of the sulfite.

[0013] Preferably, the amount of the sulfonic acid resin modified with reducing metal ions added in step S3 is 30-40% of the mass of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene.

[0014] Preferably, the organic base in step S3 is one of quinoline or pyridine.

[0015] Preferably, the sulfite in step S3 is one of sodium dithionite, sodium sulfite or sodium bisulfite.

[0016] Preferably, the sulfonic acid resin modified with reducing metal ions in step S3 is prepared by the following method: (1) First, immerse the sulfonic acid resin in pure water to fully swell, take it out, wash it, and then vacuum dry it, and then calcine it at 250-350° C. for 2-3 hours under an inert atmosphere. The calcined sulfonic acid resin is immersed in 10-15% hydrochloric acid to obtain a mixture; (2) dissolving a reducing metal salt in 10-15% hydrochloric acid to obtain a reducing metal salt solution; (3) adding the reducing metal salt solution of step (2) to the mixture of step (1), heating and stirring at 50-60° C. for 4-6 hours, filtering, washing, vacuum drying, and calcining at 250-350° C. for 1-2 hours under an inert atmosphere to obtain a sulfonic acid resin modified with reducing metal ions.

[0017] Preferably, in step (1), the mass ratio of the sulfonic acid resin to 10-15% hydrochloric acid is 1:2-3.

[0018] Preferably, in step (2), the mass of the 10-15% hydrochloric acid is 50% of the mass of the 10-15% hydrochloric acid in step (1), and the concentration of the reducing metal salt solution is 1-2 mol.

[0019] Preferably, the reducing metal salt is one or more of ferrous chloride and stannous chloride.

[0020] Preferably, the sulfonic acid resin is one of Amberlyst36, Amberlyst35, Amberlyst15 and the like.

[0021] Beneficial effects of the present invention: 1. The preparation method of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol of the present invention uses 2-nitroaniline, 2-nitroaniline and sodium nitrite to generate diazonium salt through diazotization reaction, and the diazotization reaction does not need to be carried out under a strong acid medium, thereby reducing the discharge of three wastes and having low cost; 2. In the preparation method of the present invention, 2-nitrodiazonium phenyl hydrochloride and 4-n-dodecyl-p-cresol are coupled and then reduced and cyclically closed, so the reaction selectivity is high and by-products are reduced; 3. In the reduction and cyclically closed reaction of the preparation method of the present invention, a sulfonic acid resin modified with reducing metal ions is used as a catalyst, so that the generation of impurities is reduced, and the catalyst can be removed by filtering, and then the impurities are removed by extraction with pure water and ethanol, so the treatment method is simple, the product purity is improved, and the product yield is also high; in addition, the catalyst, ethanol solvent, etc. used in the preparation method of the present invention are pollution-free to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the reaction equation for preparing 2-nitrodiazoniumphenyl hydrochloride of the present invention; Figure 2 The reaction equation for preparing 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene of the present invention; Figure 3 This is the reaction equation for preparing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol of the present invention. DETAILED DESCRIPTION

[0023] The following is a clear and complete description of the technical solutions in the implementation of the present invention. The described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. If the specific conditions are not specified in the embodiments, they are carried out according to the normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents, instruments, and components used, they are all conventional products that can be purchased commercially.

[0024] Preparatory Example 1 The preparation of sulfonic acid resin modified with reducing metal ions is carried out in the following specific steps: (1) First, sulfonic acid resin Amberlyst 35 is soaked in pure water to fully swell, taken out, washed, and vacuum dried, and then calcined at 300° C. for 2.5 h under an inert atmosphere, and 300 g of the calcined sulfonic acid resin Amberlyst 35 is soaked in 750 g of 12% hydrochloric acid to obtain a mixture; (2) dissolving the reducing metal salt ferrous chloride in 375 g of 12% hydrochloric acid to a concentration of 1.5 mol to obtain a reducing metal salt solution; (3) Add the reducing metal salt solution of step (2) to the mixture of step (1), heat and stir at 50-60°C for 5 hours, filter, wash, vacuum dry, and calcine at 300°C for 1.5 hours under an inert atmosphere to obtain a sulfonic acid resin modified with reducing metal ions.

[0025] Preparatory Example 2 The preparation of sulfonic acid resin modified with reducing metal ions is carried out in the following specific steps: (1) First, sulfonic acid resin Amberlyst 36 is soaked in pure water to fully swell, taken out, washed, and vacuum dried, and then calcined at 250° C. for 3 h in an inert atmosphere. 250 g of sulfonic acid resin Amberlyst 36 after calcination is soaked in 500 g of 10% hydrochloric acid to obtain a mixture; (2) dissolving the reducing metal salt stannous chloride in 250 g of 10% hydrochloric acid to a concentration of 2 mol to obtain a reducing metal salt solution; (3) Add the reducing metal salt solution of step (2) to the mixture of step (1), then heat and stir at 50-60° C. for 4 h, then filter, wash, vacuum dry, and then calcine at 250° C. for 2 h under an inert atmosphere to obtain a sulfonic acid resin modified with reducing metal ions.

[0026] Preparatory Example 3 The preparation of sulfonic acid resin modified with reducing metal ions is carried out in the following specific steps: (1) First, sulfonic acid resin Amberlyst 15 is soaked in pure water to fully swell, taken out, washed, and vacuum dried, and then calcined at 350° C. for 2 h under an inert atmosphere, and 200 g of the calcined sulfonic acid resin Amberlys 15 is soaked in 600 g of 12% hydrochloric acid to obtain a mixture; (2) dissolving the reducing metal salt ferrous chloride in 300 g of 15% hydrochloric acid to a concentration of 1 mol to obtain a reducing metal salt solution; (3) Add the reducing metal salt solution of step (2) to the mixture of step (1), then heat and stir at 50-60° C. for 6 h, then filter, wash, vacuum dry, and then calcine at 350° C. for 1 h under an inert atmosphere to obtain a sulfonic acid resin modified with reducing metal ions.

[0027] Example 1 A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, comprising the following steps: S1. Preparation of 2-nitrodiazonyl hydrochloride: 138 g of 2-nitroaniline and 292 g of 25% hydrochloric acid were added to a diazotization reactor. After cooling and stirring to 0-5°C, 253 g of 30% sodium nitrite aqueous solution was added dropwise. After the addition was completed, the mixture was kept warm for 30 min. 13.12 g of 2-nitroaniline was added and the mixture was kept warm for 15 min. The mixture was filtered and the filtrate was the 2-nitrodiazonyl hydrochloride solution. The reaction equation is as follows: Figure 1 As shown; S2, preparation of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene: 303.6 g of 4-n-dodecyl-p-cresol and 1.65 L of ethanol were added to a coupling reaction kettle, stirred to dissolve, cooled and stirred to 0-5°C, and then the pH was adjusted to 8 with an aqueous sodium hydroxide solution, maintained at 0-5°C, and the 2-nitrodiazonium phenyl hydrochloride solution obtained in the above step S1 was added, and reacted for 3 h, and the liquid was removed by suction filtration, washed, and dried to obtain 451.68 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene. The reaction equation is as follows: Figure 2 As shown; S3, preparation of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol: 451.68 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene obtained in step S2, 109.68 g of quinoline, 554.77 g of sodium dithionite, and 1665 g of 60% ethanol aqueous solution were added to a reactor, stirred to dissolve, heated to reflux, and then the reducing metal obtained in the preparation example 1 was added. 135.6 g of ion-modified sulfonic acid resin was kept under reflux and reacted for 60 min, then cooled to room temperature, filtered to remove solids, and then 2 L of pure water was added. After stirring and mixing, the mixture was allowed to stand, and the aqueous phase was removed. Then 1 L of pure water and 0.5 L of 75% ethanol water were added to the oil phase. After stirring and mixing, the mixture was allowed to stand, and the aqueous phase was removed. The oil phase was 404.93 g of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol. The reaction equation is as follows: Figure 3 As shown; The yield was calculated based on the total amount of 2-nitroaniline and the additional 2-nitroaniline, and the yield was 94.04% and the purity was 99.58%.

[0028] Example 2 A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, comprising the following steps: S1. Preparation of 2-nitrodiazonyl hydrochloride: 138 g of 2-nitroaniline and 286.79 g of 28% hydrochloric acid were added into a diazotization reactor. After cooling and stirring to 0-5°C, 236.57 g of 35% sodium nitrite aqueous solution was added dropwise. After the addition was completed, the mixture was kept warm for 35 min. 27 g of 2-nitroaniline was added and the mixture was kept warm for 20 min. The mixture was filtered and the filtrate was the 2-nitrodiazonyl hydrochloride solution. The reaction equation is as follows: Figure 1 As shown; S2, preparation of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene: 331.2 g of 4-n-dodecyl-p-cresol and 2.2 L of ethanol were added to a coupling reaction kettle, stirred to dissolve, cooled and stirred to 0-5°C, and the pH was adjusted to 8.2 with an aqueous sodium hydroxide solution, maintained at 0-5°C, and the 2-nitrodiazonium phenyl hydrochloride solution obtained in the above step S1 was added, and reacted for 3.5 h, and the liquid was removed by suction filtration, washed, and dried to obtain 496.23 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene. The reaction equation is as follows: Figure 2 As shown; S3, preparation of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol: 496.23 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene obtained in step S2, 150.62 g of quinoline, 711.1 g of sodium dithionite, and 2844 g of 65% ethanol aqueous solution were added to a reactor, stirred to dissolve, heated to reflux, and then the reducing metal ion obtained in the preparation example 1 was added. 173.7 g of sulfonic acid resin modified by the sulfonic acid resin was kept under reflux and reacted for 80 min, then cooled to room temperature, filtered to remove solids, and then 2 L of pure water was added. After stirring and mixing, the mixture was allowed to stand, and the water phase was removed. Then 1 L of pure water and 0.5 L of 75% ethanol water were added to the oil phase. After stirring and mixing, the mixture was allowed to stand, and the water phase was removed. The oil phase was 447.53 g of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol. The reaction equation is as follows: Figure 3 As shown; The yield was calculated based on the total amount of 2-nitroaniline and the additional 2-nitroaniline, and the yield was 95.24% and the purity was 99.73%.

[0029] Example 3 A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, comprising the following steps: S1. Preparation of 2-nitrodiazonyl hydrochloride: 138 g of 2-nitroaniline and 304.15 g of 30% hydrochloric acid were added into a diazotization reactor. After cooling and stirring to 0-5°C, 224.25 g of 35% sodium nitrite aqueous solution was added dropwise. After the addition was completed, the mixture was kept warm for 40 min. 41.3 g of 2-nitroaniline was added and the mixture was kept warm for 25 min. The mixture was filtered and the filtrate was the 2-nitrodiazonyl hydrochloride solution. The reaction equation is as follows: Figure 1 As shown; S2, preparation of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene: 358.8 g of 4-n-dodecyl-p-cresol and 2.6 L of ethanol were added to a coupling reaction kettle, stirred to dissolve, cooled and stirred to 0-5°C, and then the pH was adjusted to 8.5 with an aqueous sodium hydroxide solution, maintained at 0-5°C, and the 2-nitrodiazonium phenyl hydrochloride solution obtained in the above step S1 was added, and reacted for 4 hours, and the liquid was removed by suction filtration, washed, and dried to obtain 536.73 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene. The reaction equation is as follows: Figure 2 As shown; S3, preparation of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol: 536.73 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene obtained in step S2, 195.49 g of quinoline, 878.9 g of sodium dithionite, and 3960 g of 70% ethanol aqueous solution were added to a reactor, stirred to dissolve, heated to form reflux, and then 214.6 g of the sulfonic acid resin modified with reducing metal ions in Preparatory Example 1 was added, and reflux was maintained and reacted for 90 min, then cooled to room temperature, filtered to remove solids, and then 2 L of pure water was added. After stirring and mixing, the mixture was allowed to stand, and the water phase was removed. Then 1 L of pure water and 0.5 L of 75% ethanol water were added to the oil phase. After stirring and mixing, the mixture was allowed to stand, and the water phase was removed. The oil phase was 485 g of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol. The reaction equation is as follows: Figure 3 As shown; The yield was calculated based on the total amount of 2-nitroaniline and the additional 2-nitroaniline, and the yield was 94.98% and the purity was 99.65%.

[0030] Example 4 A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, comprising the following steps: S1. Preparation of 2-nitrodiazonyl hydrochloride: 138 g of 2-nitroaniline and 299.8 g of 28% hydrochloric acid were added to a diazotization reactor. After cooling and stirring to 0-5°C, 226.7 g of 35% sodium nitrite aqueous solution was added dropwise. After the addition was completed, the mixture was kept warm for 40 min. 20.44 g of 2-nitroaniline was added and the mixture was kept warm for 25 min. The mixture was filtered and the filtrate was the 2-nitrodiazonyl hydrochloride solution. The reaction equation is as follows: Figure 1 As shown; S2, preparation of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene: 317.4 g of 4-n-dodecyl-p-cresol and 1.9 L of ethanol were added to a coupling reaction kettle, stirred to dissolve, cooled and stirred to 0-5°C, and then the pH was adjusted to 8.3 with an aqueous sodium hydroxide solution, maintained at 0-5°C, and the 2-nitrodiazonium phenyl hydrochloride solution obtained in the above step S1 was added, and the reaction was continued for 4 hours, and the liquid was removed by suction, washed, and dried to obtain 475.6 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene. The reaction equation is as follows: Figure 2 As shown; S3, preparation of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol: 475.6 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene obtained in step S2, 88.4 g of pyridine, 493.5 g of sodium sulfite, and 3948 g of 65% ethanol aqueous solution were added to a reactor, stirred to dissolve, heated to form reflux, and then 166.5 g of the sulfonic acid resin modified with reducing metal ions in Preparatory Example 2 was added, and reflux was maintained and reacted for 80 min, then cooled to room temperature, filtered to remove solids, and then 2 L of pure water was added. After stirring and mixing, the mixture was allowed to stand, and the water phase was removed. Then 1 L of pure water and 0.5 L of 75% ethanol water were added to the oil phase. After stirring and mixing, the mixture was allowed to stand, and the water phase was removed. The oil phase was 428.95 g of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, and the reaction equation was as follows: Figure 3 As shown; The yield was calculated based on the total amount of 2-nitroaniline and the additional 2-nitroaniline, and the yield was 95.07% and the purity was 99.72%.

[0031] Example 5 A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, comprising the following steps: S1. Preparation of 2-nitrodiazonyl hydrochloride: 138 g of 2-nitroaniline and 273.75 g of 28% hydrochloric acid were added into a diazotization reactor. After cooling and stirring to 0-5°C, 246.43 g of 35% sodium nitrite aqueous solution was added dropwise. After the addition was completed, the mixture was kept warm for 40 min. 34 g of 2-nitroaniline was added and the mixture was kept warm for 25 min. The mixture was filtered and the filtrate was the 2-nitrodiazonyl hydrochloride solution. The reaction equation is as follows: Figure 1 As shown; S2, preparation of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene: 345 g of 4-n-dodecyl-p-cresol and 2.2 L of ethanol were added to a coupling reaction kettle, stirred to dissolve, cooled and stirred to 0-5°C, and the pH was adjusted to 8.3 with an aqueous sodium hydroxide solution, maintained at 0-5°C, and the 2-nitrodiazonium phenyl hydrochloride solution obtained in the above step S1 was added, and reacted for 4 hours, and the liquid was removed by suction filtration, washed, and dried to obtain 516.4 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene. The reaction equation is as follows: Figure 2 As shown; S3, preparation of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol: 516.4 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene obtained in step S2, 88.4 g of quinoline, 442.3 g of sodium bisulfite, and 3538 g of 65% ethanol aqueous solution were added to a reactor, stirred to dissolve, heated to form reflux, and then 180.74 g of the sulfonic acid resin modified with reducing metal ions in Preparatory Example 2 was added, and reflux was maintained and reacted for 80 min, then cooled to room temperature, filtered to remove solids, and then 2 L of pure water was added. After stirring and mixing, the mixture was allowed to stand, and the water phase was removed. Then 1 L of pure water and 0.5 L of 75% ethanol water were added to the oil phase. After stirring and mixing, the mixture was allowed to stand, and the water phase was removed. The oil phase was 465.2 g of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, and the reaction equation was as follows: Figure 3 As shown; The yield was calculated based on the total amount of 2-nitroaniline and the additional 2-nitroaniline, and the yield was 94.97% and the purity was 99.57%.

[0032] Example 6 A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, comprising the following steps: S1. Preparation of 2-nitrodiazonyl hydrochloride: 138 g of 2-nitroaniline and 273.75 g of 28% hydrochloric acid were added to a diazotization reactor. After cooling and stirring to 0-5°C, 246.43 g of 35% sodium nitrite aqueous solution was added dropwise. After the addition was completed, the mixture was kept warm for 40 min. 34.35 g of 2-nitroaniline was added and the mixture was kept warm for 25 min. The mixture was filtered and the filtrate was the 2-nitrodiazonyl hydrochloride solution. The reaction equation is as follows: Figure 1 As shown; S2, preparation of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene: 345 g of 4-n-dodecyl-p-cresol and 2 L of ethanol were added to a coupling reaction kettle, stirred to dissolve, cooled and stirred to 0-5°C, and then the pH was adjusted to 8.3 with an aqueous sodium hydroxide solution, maintained at 0-5°C, and the 2-nitrodiazonium phenyl hydrochloride solution obtained in the above step S1 was added, and the reaction was continued for 4 hours. The liquid was removed by suction filtration, washed, and dried to obtain 514.75 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene. The reaction equation is as follows: Figure 2 As shown; S3, preparation of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol: 514.75 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene obtained in step S2, 95.6 g of pyridine, 632.2 g of sodium dithionite, and 1897 g of 65% ethanol aqueous solution were added to a reactor, stirred to dissolve, heated to form reflux, and then 180.2 g of the sulfonic acid resin modified with reducing metal ions in Preparatory Example 3 was added, and reflux was maintained and reacted for 80 min, then cooled to room temperature, filtered to remove solids, and then 2 L of pure water was added. After stirring and mixing, the mixture was allowed to stand, and the water phase was removed. Then 1 L of pure water and 0.5 L of 75% ethanol water were added to the oil phase. After stirring and mixing, the mixture was allowed to stand, and the water phase was removed. The oil phase was 462.9 g of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, and the reaction equation was as follows: Figure 3 As shown; The yield was calculated based on the total amount of 2-nitroaniline and the additional 2-nitroaniline, and the yield was 94.31% and the purity was 99.65%.

[0033] Comparative Example 1 A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, comprising the following steps: S1. Preparation of 2-nitrodiazonium phenyl hydrochloride: Add 138 g of 2-nitroaniline and 292 g of 25% hydrochloric acid into a diazotization reactor, cool and stir to 0-5°C, then drop 253 g of 30% sodium nitrite aqueous solution, after the dropwise addition is completed, heat and react for 30 min, then add urea to terminate the reaction, and filter. The filtrate obtained is 2-nitrodiazonium phenyl hydrochloride solution. The reaction equation is as follows: Figure 1 As shown; S2, preparation of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene: add 276 g of 4-n-dodecyl-p-cresol and 1.5 L of ethanol into a coupling reaction kettle, stir and dissolve, cool and stir to 0-5°C, adjust the pH to 8 with an aqueous sodium hydroxide solution, maintain 0-5°C, add the 2-nitrodiazonium phenyl hydrochloride solution obtained in step S1, and react for 3 h, remove the liquid by suction filtration, wash, and dry to obtain 402.47 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene, the reaction equation is as follows: Figure 2 As shown; S3, preparation of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol: 402.47 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene obtained in step S2, 97.73 g of quinoline, 494.33 g of sodium dithionite, and 1483 g of 60% ethanol aqueous solution were added to a reactor, stirred to dissolve, heated to reflux, and then added with the reducing metal ion in the preparation example 1. 120.74 g of sulfonic acid resin modified by the sulfonic acid resin was kept under reflux and reacted for 60 min, then cooled to room temperature, filtered to remove solids, and then 2 L of pure water was added. After stirring and mixing, the mixture was allowed to stand and the water phase was removed. Then 1 L of pure water and 0.5 L of 75% ethanol water were added to the oil phase. After stirring and mixing, the mixture was allowed to stand and the water phase was removed. The oil phase was 358.58 g of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol. The reaction equation is as follows: Figure 3 As shown; The yield was calculated based on the total amount of 2-nitroaniline and the additional 2-nitroaniline, and the yield was 91.24% and the purity was 99.59%.

[0034] Comparative Example 2 A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, comprising the following steps: S1. Preparation of 2-nitrodiazonyl hydrochloride: 138 g of 2-nitroaniline and 292 g of 25% hydrochloric acid were added into a diazotization reactor. After cooling and stirring to 0-5°C, 241.5 g of 30% sodium nitrite aqueous solution was added dropwise. After the addition was completed, the mixture was kept warm for 30 min. 6.9 g of 2-nitroaniline was added and the mixture was kept warm for 15 min. The mixture was filtered and the filtrate was the 2-nitrodiazonyl hydrochloride solution. The reaction equation is as follows: Figure 1 As shown; S2, preparation of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene: 289.8 g of 4-n-dodecyl-p-cresol and 1.58 L of ethanol were added to a coupling reaction kettle, stirred to dissolve, cooled and stirred to 0-5°C, and then the pH was adjusted to 8 with an aqueous sodium hydroxide solution, maintained at 0-5°C, and the 2-nitrodiazonium phenyl hydrochloride solution obtained in the above step S1 was added, and the reaction was continued for 3 hours, and the liquid was removed by suction filtration, washed, and dried to obtain 419.0 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene. The reaction equation is as follows: Figure 2 As shown; S3, preparation of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol: 419.0 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene obtained in step S2, 101.8 g of quinoline, 514.65 g of sodium dithionite, and 1543.9 g of 60% ethanol aqueous solution were added to a reactor, stirred to dissolve, heated to reflux, and then the reducing metal obtained in the preparation example 1 was added. 125.7 g of ion-modified sulfonic acid resin was kept under reflux and reacted for 60 min, then cooled to room temperature, filtered to remove solids, and then 2 L of pure water was added. After stirring and mixing, the mixture was allowed to stand and the aqueous phase was removed. Then 1 L of pure water and 0.5 L of 75% ethanol water were added to the oil phase. After stirring and mixing, the mixture was allowed to stand and the aqueous phase was removed. The oil phase was 373.45 g of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol. The reaction equation is as follows: Figure 3 As shown; The yield was calculated based on the total amount of 2-nitroaniline and the additional 2-nitroaniline, and the yield was 90.5% and the purity was 99.6%.

[0035] Comparative Example 3 A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, comprising the following steps: S1. Preparation of 2-nitrodiazonyl hydrochloride: 138 g of 2-nitroaniline and 292 g of 25% hydrochloric acid were added to a diazotization reactor. After cooling and stirring to 0-5°C, 253 g of 30% sodium nitrite aqueous solution was added dropwise. After the addition was completed, the mixture was kept warm for 30 min. 13.12 g of 2-nitroaniline was added and the mixture was kept warm for 15 min. The mixture was filtered and the filtrate was the 2-nitrodiazonyl hydrochloride solution. The reaction equation is as follows: Figure 1 As shown; S2, preparation of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene: 303.6 g of 4-n-dodecyl-p-cresol and 1.65 L of ethanol were added to a coupling reaction kettle, stirred to dissolve, cooled and stirred to 0-5°C, and then the pH was adjusted to 7.5 with an aqueous sodium hydroxide solution, maintained at 0-5°C, and the 2-nitrodiazonium phenyl hydrochloride solution obtained in the above step S1 was added, and the reaction was continued for 3 hours, and the liquid was removed by suction, washed, and dried to obtain 424.6 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene. The reaction equation is as follows: Figure 2 As shown; S3, preparation of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol: 424.6 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene obtained in step S2, 103.1 g of quinoline, 521.6 g of sodium dithionite, and 1565 g of 60% ethanol aqueous solution were added to a reactor, stirred to dissolve, heated to form reflux, and then 135.6 g of the sulfonic acid resin modified with reducing metal ions in Preparatory Example 1 was added, and reflux was maintained and reacted for 60 min, then cooled to room temperature, filtered to remove solids, and then 2 L of pure water was added. After stirring and mixing, the mixture was allowed to stand, and the water phase was removed. Then 1 L of pure water and 0.5 L of 75% ethanol water were added to the oil phase. After stirring and mixing, the mixture was allowed to stand, and the water phase was removed. The oil phase was 380.1 g of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, and the reaction equation was as follows: Figure 3 As shown; The yield was calculated based on the total amount of 2-nitroaniline and the additional 2-nitroaniline, and the yield was 88.27% and the purity was 99.12%.

[0036] Comparative Example 4 A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, comprising the following steps: S1. Preparation of 2-nitrodiazonyl hydrochloride: 138 g of 2-nitroaniline and 292 g of 25% hydrochloric acid were added to a diazotization reactor. After cooling and stirring to 0-5°C, 253 g of 30% sodium nitrite aqueous solution was added dropwise. After the addition was completed, the mixture was kept warm for 30 min. 13.12 g of 2-nitroaniline was added and the mixture was kept warm for 15 min. The mixture was filtered and the filtrate was the 2-nitrodiazonyl hydrochloride solution. The reaction equation is as follows: Figure 1 As shown; S2, preparation of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene: 303.6 g of 4-n-dodecyl-p-cresol and 1.65 L of ethanol were added to a coupling reaction kettle, stirred to dissolve, cooled and stirred to 0-5°C, and then the pH was adjusted to 7.5 with an aqueous sodium hydroxide solution, maintained at 0-5°C, and the 2-nitrodiazonium phenyl hydrochloride solution obtained in the above step S1 was added, and reacted for 3 h, and the liquid was removed by suction filtration, washed, and dried to obtain 419.5 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene. The reaction equation is as follows: Figure 2 As shown; S3, preparation of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol: 419.5 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene obtained in step S2, 101.9 g of quinoline, 515.3 g of sodium dithionite, and 1546 g of 60% ethanol aqueous solution were added to a reactor, stirred to dissolve, heated to form reflux, and then 125.9 g of the sulfonic acid resin modified with reducing metal ions in Preparatory Example 1 was added, and reflux was maintained and reacted for 60 min, then cooled to room temperature, filtered to remove solids, and then 2 L of pure water was added. After stirring and mixing, the mixture was allowed to stand, and the water phase was removed. Then 1 L of pure water and 0.5 L of 75% ethanol water were added to the oil phase. After stirring and mixing, the mixture was allowed to stand, and the water phase was removed. The oil phase was 375.5 g of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, and the reaction equation was as follows: Figure 3 As shown; The yield was calculated based on the total amount of 2-nitroaniline and the additional 2-nitroaniline, and the yield was 87.20% and the purity was 99.03%.

[0037] Comparative Example 5 A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, comprising the following steps: S1. Preparation of 2-nitrodiazonyl hydrochloride: 138 g of 2-nitroaniline and 292 g of 25% hydrochloric acid were added to a diazotization reactor. After cooling and stirring to 0-5°C, 253 g of 30% sodium nitrite aqueous solution was added dropwise. After the addition was completed, the mixture was kept warm for 35 min. 13.2 g of 2-nitroaniline was added and the mixture was kept warm for 20 min. The mixture was filtered and the filtrate was the 2-nitrodiazonyl hydrochloride solution. The reaction equation is as follows: Figure 1 As shown; S2, preparation of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene: 303.6 g of 4-n-dodecyl-p-cresol and 1.65 L of ethanol were added to a coupling reaction kettle, stirred to dissolve, cooled and stirred to 0-5°C, and the pH was adjusted to 8.2 with an aqueous sodium hydroxide solution, maintained at 0-5°C, and the 2-nitrodiazonium phenyl hydrochloride solution obtained in the above step S1 was added, and reacted for 3.5 hours, and the liquid was removed by suction filtration, washed, and dried to obtain 450.5 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene. The reaction equation is as follows: Figure 2 As shown; S3, preparation of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol: 450.5 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene obtained in step S2, 50.88 g of sodium hydroxide, 553.4 g of sodium dithionite, and 1660 g of 65% ethanol aqueous solution were added to a reactor, stirred to dissolve, heated to form reflux, and then 67.6 g of ferrous chloride was added, and reflux was maintained and reacted for 80 min, then cooled to room temperature, filtered to remove solids, and then 2 L of pure water was added. After stirring and mixing, the mixture was allowed to stand, and the water phase was removed. Then 1 L of pure water and 0.5 L of 75% ethanol water were added to the oil phase. After stirring and mixing, the mixture was allowed to stand, and the water phase was removed. The oil phase was 372.02 g of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, and the reaction equation was as follows: Figure 3 As shown; The yield was calculated based on the total amount of 2-nitroaniline and the additional 2-nitroaniline, and the yield was 86.4% and the purity was 98.91%.

[0038] Comparative Example 6 A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, comprising the following steps: S1. Preparation of 2-nitrodiazonyl hydrochloride: 138 g of 2-nitroaniline and 292 g of 25% hydrochloric acid were added to a diazotization reactor. After cooling and stirring to 0-5°C, 253 g of 30% sodium nitrite aqueous solution was added dropwise. After the addition was completed, the mixture was kept warm for 30 min. 13.12 g of 2-nitroaniline was added and the mixture was kept warm for 15 min. The mixture was filtered and the filtrate was the 2-nitrodiazonyl hydrochloride solution. The reaction equation is as follows: Figure 1 As shown; S2, preparation of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene: 303.6 g of 4-n-dodecyl-p-cresol and 1.65 L of ethanol were added to a coupling reaction kettle, stirred to dissolve, cooled and stirred to 0-5°C, and then the pH was adjusted to 8 with an aqueous sodium hydroxide solution, maintained at 0-5°C, and the 2-nitrodiazonium phenyl hydrochloride solution obtained in the above step S1 was added, and reacted for 3 h, and the liquid was removed by suction filtration, washed, and dried to obtain 450.89 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene. The reaction equation is as follows: Figure 2 As shown; S3, preparation of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol: 450.89 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene obtained in step S2, 109.5 g of quinoline, 553.8 g of sodium dithionite, and 1662 g of 60% ethanol aqueous solution were added to a reactor, stirred to dissolve, heated to form reflux, and then 67.6 g of ferrous chloride was added, and reflux was maintained and reacted for 60 min, then cooled to room temperature, filtered to remove solids, and then 2 L of pure water was added. After stirring and mixing, the mixture was allowed to stand, and the water phase was removed. Then 1 L of pure water and 0.5 L of 75% ethanol water were added to the oil phase. After stirring and mixing, the mixture was allowed to stand, and the water phase was removed. The oil phase was 373.25 g of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, and the reaction equation was as follows: Figure 3 As shown; The yield was calculated based on the total amount of 2-nitroaniline and the additional 2-nitroaniline, and the yield was 86.68% and the purity was 98.93%.

[0039] Comparative Example 7 A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, comprising the following steps: S1. Preparation of 2-nitrodiazonyl hydrochloride: 138 g of 2-nitroaniline and 292 g of 25% hydrochloric acid were added to a diazotization reactor. After cooling and stirring to 0-5°C, 253 g of 30% sodium nitrite aqueous solution was added dropwise. After the addition was completed, the mixture was kept warm for 30 min. 13.12 g of 2-nitroaniline was added and the mixture was kept warm for 15 min. The mixture was filtered and the filtrate was the 2-nitrodiazonyl hydrochloride solution. The reaction equation is as follows: Figure 1 As shown; S2, preparation of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene: 303.6 g of 4-n-dodecyl-p-cresol and 1.65 L of ethanol were added to a coupling reaction kettle, stirred to dissolve, cooled and stirred to 0-5°C, and then the pH was adjusted to 8 with an aqueous sodium hydroxide solution, maintained at 0-5°C, and the 2-nitrodiazonium phenyl hydrochloride solution obtained in the above step S1 was added, and reacted for 3 h, and the liquid was removed by suction filtration, washed, and dried to obtain 452.24 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene. The reaction equation is as follows: Figure 2 As shown; S3, preparation of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol: 452.24 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene obtained in step S2, 102.95 g of quinoline, 555.46 g of sodium dithionite, and 1668 g of 60% ethanol aqueous solution were added to a reactor, stirred to dissolve, heated to reflux, and then the reducing metal obtained in the preparation example 1 was added. 135.7 g of ion-modified sulfonic acid resin was kept under reflux and reacted for 60 min, then cooled to room temperature, filtered to remove solids, and then 2 L of pure water was added. After stirring and mixing, the mixture was allowed to stand and the aqueous phase was removed. Then 1 L of pure water and 0.5 L of 75% ethanol water were added to the oil phase. After stirring and mixing, the mixture was allowed to stand and the aqueous phase was removed. The oil phase was 390.09 g of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol. The reaction equation is as follows: Figure 3 As shown; The yield was calculated based on the total amount of 2-nitroaniline and the additional 2-nitroaniline, and the yield was 90.59% and the purity was 99.63%.

[0040] Comparative Example 8 A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, comprising the following steps: S1. Preparation of 2-nitrodiazonyl hydrochloride: 138 g of 2-nitroaniline and 292 g of 25% hydrochloric acid were added to a diazotization reactor. After cooling and stirring to 0-5°C, 253 g of 30% sodium nitrite aqueous solution was added dropwise. After the addition was completed, the mixture was kept warm for 30 min. 13.12 g of 2-nitroaniline was added and the mixture was kept warm for 15 min. The mixture was filtered and the filtrate was the 2-nitrodiazonyl hydrochloride solution. The reaction equation is as follows: Figure 1 As shown; S2, preparation of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene: 303.6 g of 4-n-dodecyl-p-cresol and 1.65 L of ethanol were added to a coupling reaction kettle, stirred to dissolve, cooled and stirred to 0-5°C, and then the pH was adjusted to 8 with an aqueous sodium hydroxide solution, maintained at 0-5°C, and the 2-nitrodiazonium phenyl hydrochloride solution obtained in the above step S1 was added, and the reaction was continued for 3 hours, and the liquid was removed by suction filtration, washed, and dried to obtain 453.17 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene. The reaction equation is as follows: Figure 2 As shown; S3, preparation of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol: 453.17 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene obtained in step S2, 110.1 g of quinoline, 463.83 g of sodium dithionite, and 1392 g of 60% ethanol aqueous solution were added to a reactor, stirred to dissolve, heated to reflux, and then the reducing metal ion obtained in the preparation example 1 was added. 135.96 g of sulfonic acid resin modified by the sulfonic acid resin was kept under reflux and reacted for 60 min, then cooled to room temperature, filtered to remove solids, and then 2 L of pure water was added. After stirring and mixing, the mixture was allowed to stand and the water phase was removed. Then 1 L of pure water and 0.5 L of 75% ethanol water were added to the oil phase. After stirring and mixing, the mixture was allowed to stand and the water phase was removed. The oil phase was 385.3 g of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol. The reaction equation is as follows: Figure 3 As shown; The yield was calculated based on the total amount of 2-nitroaniline and the additional 2-nitroaniline, and the yield was 89.48% and the purity was 99.65%.

[0041] Comparative Example 9 A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, comprising the following steps: S1. Preparation of 2-nitrodiazonyl hydrochloride: 138 g of 2-nitroaniline and 292 g of 25% hydrochloric acid were added to a diazotization reactor. After cooling and stirring to 0-5°C, 253 g of 30% sodium nitrite aqueous solution was added dropwise. After the addition was completed, the mixture was kept warm for 30 min. 13.12 g of 2-nitroaniline was added and the mixture was kept warm for 15 min. The mixture was filtered and the filtrate was the 2-nitrodiazonyl hydrochloride solution. The reaction equation is as follows: Figure 1 As shown; S2, preparation of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene: 303.6 g of 4-n-dodecyl-p-cresol and 1.65 L of ethanol were added to a coupling reaction kettle, stirred to dissolve, cooled and stirred to 0-5°C, and then the pH was adjusted to 8 with an aqueous sodium hydroxide solution, maintained at 0-5°C, and the 2-nitrodiazonium phenyl hydrochloride solution obtained in the above step S1 was added, and reacted for 3 h, and the liquid was removed by suction filtration, washed, and dried to obtain 454.2 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene. The reaction equation is as follows: Figure 2 As shown; S3, preparation of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol: 454.2 g of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene obtained in step S2, 110.3 g of quinoline, 557.9 g of sodium dithionite, and 1674 g of 60% ethanol aqueous solution were added to a reactor, stirred to dissolve, heated to form reflux, and then 114 g of the sulfonic acid resin modified with reducing metal ions in the preparatory example 1 was added, and reflux was maintained and reacted for 60 min, then cooled to room temperature, filtered to remove solids, and then 2 L of pure water was added. After stirring and mixing, the mixture was allowed to stand, and the water phase was removed. Then, 1 L of pure water and 0.5 L of 75% ethanol water were added to the oil phase. After stirring and mixing, the mixture was allowed to stand, and the water phase was removed. The oil phase was 386.2 g of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, and the reaction equation was as follows: Figure 3 As shown; The yield was calculated based on the total amount of 2-nitroaniline and the additional 2-nitroaniline, and the yield was 89.71% and the purity was 99.46%.

[0042] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit and essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0043] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, It is characterized in that The following steps are involved: S1. Preparation of 2-nitrodiazonium phenyl hydrochloride: add 2-nitroaniline and hydrochloric acid into a diazotization reactor, cool and stir to 0-5°C, then dropwise add sodium nitrite aqueous solution, then keep warm for 30-40 minutes, then add 2-nitroaniline, continue to keep warm for 15-25 minutes, then filter, and the obtained filtrate is 2-nitrodiazonium phenyl hydrochloride solution; the mass fraction of hydrochloric acid is 25-30%, and the mass fraction of sodium nitrite aqueous solution is 30-40%; S2, preparation of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene: add 4-n-dodecyl-p-cresol and ethanol into a coupling reaction kettle, stir to dissolve, cool and stir to 0-5°C, adjust the pH to 8-8.5, maintain 0-5°C, add the 2-nitrodiazonium phenyl hydrochloride solution obtained in the above step S1, and react for 3-4h, remove the liquid by suction filtration, wash, and dry to obtain 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene; S3, preparation of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol: add the 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene obtained in step S2, an organic base, a sulfite, and a 60-75% ethanol aqueous solution into a reactor, stir to dissolve, heat to form reflux, then add a sulfonic acid resin modified with a reducing metal ion, keep reflux and react for 60-90 minutes, then cool to room temperature, filter to remove solids, add pure water, stir to mix, let stand, remove the water phase, and the oil phase is 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol.

2. A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol according to claim 1, It is characterized in that In step S1, the molar ratio of 2-nitroaniline, hydrochloric acid and sodium nitrite is 1:2-2.5:1.1-1.3; the amount of additional 2-nitroaniline is 95-100% of the molar difference between 2-nitroaniline and sodium nitrite.

3. A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol according to claim 1, It is characterized in that In step S2, the added molar amount of 4-n-dodecyl-p-cresol is equal to the molar amount of sodium nitrite in step S1; the volume ratio of the molar amount of 4-n-dodecyl-p-cresol to ethanol is 1 mol: 1.5-2L.

4. A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol according to claim 1, It is characterized in that In step S3, the molar ratio of the 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene, the organic base and the sulfite is 1:0.8~1.2:3~8.

5. A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol according to claim 1, It is characterized in that In step S3, the amount of the sulfonic acid resin modified with reducing metal ions added is 30-40% of the mass of 2-nitro-2-hydroxy-3-dodecyl-5-methylazobenzene.

6. A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol according to claim 1, It is characterized in that In step S3, the organic base is one of quinoline and pyridine.

7. A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol according to claim 1, It is characterized in that The sulfite is one of sodium dithionite, sodium sulfite or sodium bisulfite.

8. A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol according to claim 1, It is characterized in that In step S3, the sulfonic acid resin modified with reducing metal ions is prepared by the following method: (1) First, immerse the sulfonic acid resin in pure water to fully swell, take it out, wash it, and then vacuum dry it, and then calcine it at 250-350° C. for 2-3 hours under an inert atmosphere. The calcined sulfonic acid resin is immersed in 10-15% hydrochloric acid to obtain a mixture; (2) dissolving a reducing metal salt in 10-15% hydrochloric acid to obtain a reducing metal salt solution; (3) adding the reducing metal salt solution of step (2) to the mixture of step (1), heating and stirring at 50-60° C. for 4-6 hours, filtering, washing, vacuum drying, and calcining at 250-350° C. for 1-2 hours under an inert atmosphere to obtain a sulfonic acid resin modified with reducing metal ions.

9. A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol according to claim 8, It is characterized in that In step (1), the mass ratio of the sulfonic acid resin to 10-15% hydrochloric acid is 1:2-3; in step (2), the mass of the 10-15% hydrochloric acid is 50% of the mass of the 10-15% hydrochloric acid in step (1), and the concentration of the reducing metal salt solution is 1-2 mol.

10. A method for synthesizing 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol according to claim 8, It is characterized in that The sulfonic acid resin is one of Amberlyst 36, Amberlyst 35 or Amberlyst 15; the reducing metal salt is one or more of ferrous chloride and stannous chloride.

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