Synthesis method of ultraviolet absorbent UV400

Abstract

The invention discloses a synthesis method of an ultraviolet absorbent UV400, and particularly relates to a synthesis method of a compound (II), which comprises the following steps: in a solvent, in the presence of inorganic alkali and organic alkali, performing etherification reaction on a compound (I) and epoxy chloropropane to generate the compound (II). The synthesis method provided by the invention has the advantages of low intermediate ring opening rate, higher yield than the prior art, simpler operation, and good application prospect and value. # imgabs0 #

Description

Technical Field

[0001] The invention relates to a method for synthesizing ultraviolet absorber UV400. Background Art

[0002] Adding UV absorbers is an important method currently used to prevent polymer materials from aging. The main UV absorbers on the market can be divided into benzophenones, benzotriazoles, salicylates and triazines. Among them, triazine UV absorbers have the characteristics of wide absorption range from 280 nm to 380 nm, high absorption efficiency, lighter color, less yellowing, and better compatibility, so they are very popular. On this basis, the latest UV-400 on the market has better thermal stability and environmental durability in addition to the above advantages, which in turn attracts more attention.

[0003] At present, there is little information on the synthesis of UV400. According to the current information, its synthesis route is mainly as follows: Step 1, synthesizing 4-[4,6-di(2´,4´-dimethylphenyl)-1,3,5-s-triazine-2-yl]phenyl-1,3-diol. The method for synthesizing the compound is basically the same. There are two main methods for synthesizing UV400 from the intermediate. One is that the higher alcohol undergoes an etherification reaction with 3-alkoxy-2-hydroxy-bromopropane to synthesize a chain ether, which is then reacted with the intermediate to synthesize UV400. The other is that the intermediate undergoes an etherification reaction with epichlorohydrin, and then undergoes a ring-opening addition reaction with the higher alcohol to synthesize UV400. Since the chain ether synthesized by the first method is difficult to separate, the second method is mainly used for synthesis. However, the second method currently has the problem of low yield after the intermediate reacts with epichlorohydrin and many impurities in the product. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the problem that in the process of synthesizing UV400 in the prior art, the intermediate is easily ring-opened after being connected to epichlorohydrin, and the overall yield is low, and a synthesis method of ultraviolet absorber UV400 is provided. In the synthesis method of the present invention, the intermediate ring-opening rate is low, the yield is higher than the prior art, the operation is simpler, and it has good application prospects and value.

[0005] The present invention provides a method for synthesizing a compound (II), comprising the following steps: in a solvent, in the presence of an inorganic base and an organic base, subjecting a compound (I) to an etherification reaction with epichlorohydrin to generate a compound (II);

[0006] ;

[0007] The inorganic base and the organic base are a combination of sodium hydroxide and triethylamine, a combination of potassium hydroxide and triethylamine, a combination of potassium carbonate and triethylamine, or a combination of potassium hydroxide and pyridine;

[0008] The solvent is an aromatic hydrocarbon solvent.

[0009] In a certain embodiment, when the solvent is an aromatic hydrocarbon solvent, the aromatic hydrocarbon solvent is chlorobenzene.

[0010] In some embodiments, the molar ratio of the compound (I) to the solvent is (0.1-2) mol / L; preferably (0.1-0.5) mol / L; for example 0.25 mol / L.

[0011] In some embodiments, the molar ratio of the inorganic base to the compound (I) is 1:(0.4-2); preferably 1:(0.5-1); preferably 1:0.89.

[0012] In some embodiments, the molar ratio of the organic base to the compound (I) is 1:(0.6-4); preferably 1:(1-2); for example 1:1.78.

[0013] In some embodiments, the molar ratio of the compound (I) to the epichlorohydrin is 1:(0.8-2), preferably 1:(1-1.4); for example 1:1.2.

[0014] The reaction time of the etherification reaction can be the conventional reaction time of this type of reaction in the art.

[0015] The reaction temperature of the etherification reaction can be a conventional reaction temperature for this type of reaction in the art.

[0016] In some embodiments, the reaction temperature of the etherification reaction is 60°C-120°C, preferably 80°C-110°C, such as 85°C.

[0017] In some embodiments, the synthesis method of the compound (II) is: under nitrogen protection, the compound (I), the inorganic base, the organic base and the solvent are mixed, epichlorohydrin dissolved in the solvent is added at 85°C, and the reaction is carried out while maintaining the temperature at 85°C.

[0018] In some embodiments, the materials for the etherification reaction are the compound (I), the inorganic base and the organic base, the epichlorohydrin and the solvent.

[0019] In some embodiments, after the etherification reaction is completed, the following post-treatment step is further included: concentrating the reaction solution, adding saturated ammonium chloride aqueous solution, filtering with suction, washing with a nitrile solvent, and filtering with suction to obtain compound (II).

[0020] Preferably, the nitrile solvent is acetonitrile.

[0021] The present invention also provides a synthesis method of UV400, which comprises the following steps:

[0022] S1: Compound (II) was synthesized by the above-described synthesis method;

[0023] S2: Under the action of a catalyst, dodecanol, tridecanol and the compound (II) undergo a ring-opening addition reaction to generate UV400;

[0024] .

[0025] Preferably, the catalyst is a quaternary phosphonium salt catalyst, such as ethyltriphenylphosphonium bromide.

[0026] In some embodiments, the molar ratio of the catalyst to the compound (II) is 1:(0.4-1.5), more preferably 1:(0.7-1.1); for example 1:0.8, 1:0.9 or 1:1.

[0027] In some embodiments, the molar ratio of the compound (II) to the dodecanol is 1:(0.6-1.2), more preferably 1:(0.6-1); for example 1:0.7, 1:0.8 or 1:0.9.

[0028] In some embodiments, the molar ratio of the compound (II) to the tridecanol is 1:(0.3-0.6), more preferably 1:0.35, 1:0.4 or 1:0.45.

[0029] In some embodiments, in the synthesis method of UV400, in S2, the compound (II) can be used in the form of the reaction solution obtained in S1.

[0030] Preferably, the reaction solution obtained in S1 is adjusted to a pH of 6-7 using an acidic solution; the acidic solution is preferably acetic acid.

[0031] The reaction time of the ring-opening addition reaction can be the conventional reaction time of this type of reaction in the art.

[0032] In some embodiments, the reaction time of the ring-opening addition reaction is 10 to 40 hours, for example, 20 to 26 hours.

[0033] The reaction temperature of the ring-opening addition reaction can be a conventional reaction temperature for this type of reaction in the art.

[0034] In some embodiments, the reaction temperature of the ring-opening addition reaction is 60-100°C, for example 85°C.

[0035] In some embodiments, the synthesis method of UV400 is a one-pot reaction.

[0036] In some embodiments, the synthesis method of UV400 is: under nitrogen protection, the compound (I), the inorganic base and the organic base and the solvent are mixed, epichlorohydrin dissolved in the solvent is added at 85°C, and the etherification reaction is carried out at 85°C to obtain compound (II);

[0037] A mixed solution of the compound (II), the catalyst, the dodecanol and the tridecanol is subjected to a ring-opening addition reaction.

[0038] In some embodiments, the synthesis method of UV400 is preferably: under nitrogen protection, the compound (I), the inorganic base and the organic base and the solvent are mixed, epichlorohydrin dissolved in the solvent is added at 85°C, and the etherification reaction is carried out at 85°C; after the reaction, the acidic solution is added to the reaction solution to adjust the pH to 6-7, and the catalyst, the mixed solution of the dodecanol and the tridecanol are added to carry out a ring-opening addition reaction at 85°C.

[0039] After the ring-opening addition reaction is completed, post-treatment can be performed through the following steps; which includes a recrystallization step.

[0040] Preferably, the solvent used in the recrystallization is an alcohol solvent, and the alcohol solvent is ethanol or isopropanol.

[0041] Preferably, before the recrystallization, the reaction solution is mixed with a saturated aqueous ammonium chloride solution, or the reaction solution is mixed with a saturated aqueous ammonium chloride solution and a water-insoluble organic solvent, and the organic phase is retained and concentrated. The water-insoluble organic solvent may be an ester solvent and / or a halogenated alkane solvent, the ester solvent is, for example, ethyl acetate, and the halogenated alkane solvent is dichloromethane and / or chloroform.

[0042] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0043] The reagents and raw materials used in the present invention are commercially available.

[0044] The positive progressive effect of the present invention is that the present invention adds an inorganic base and an organic base in the synthesis method of UV400, resulting in a low intermediate ring-opening rate, so that this method has a high yield and high purity, and the synthesis method of the present invention is also suitable for a one-pot reaction, which can reduce the operation steps, thereby reducing the errors caused by the operation, reducing the loss of raw materials and solvents, and is conducive to industrial production, and has good application prospects and value. DETAILED DESCRIPTION

[0045] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0046]

[0047] Example 1

[0048] Compound I (10 g, 0.025 mol), sodium hydroxide (1.12 g, 0.028 mol), triethylamine (1.39 g, 0.014 mol) were added to a 500 ml three-necked flask equipped with a stirrer. Chlorobenzene (90 ml) was added. The mixture was heated to 85 °C under nitrogen protection. Epichlorohydrin (2.78 g, 0.03 mol) and 10 ml of chlorobenzene were added dropwise. After the addition was completed, the reaction was maintained at 85 °C. The liquid phase was monitored until the conversion of the raw materials was basically completed. Acetic acid was added until the pH reached 6-7. Ethyltriphenylphosphonium bromide (8.67 g, 0.022 mol) was added according to the liquid phase yield of Compound II of 70%. Dodecanol (2.61 g, 0.014mol), tridecanol (1.40g, 0.007mol), the mixed liquid, dropwise addition, maintain 85℃ and continue the reaction for 20~26h, liquid phase detection shows that the raw material reaction is complete, add saturated ammonium chloride aqueous solution to quench, add ethyl acetate to extract, concentrate to obtain an oily product, recrystallize from ethanol, filter, concentrate the filtrate to obtain a light yellow oily substance UV400, weigh 9.14g, yield 56.72%, purity 85%. H NMR (CDCl 3 , 400MHz) δ: 13.44(1H, s, Ar-OH), 8.49~8.52(1H, d, Ar-H), 8.20 (2H, s,Ar-H), 7.16~7.18(4H, d, Ar-H), 6.60~6.62(1H, dd, Ar-H), 6.55~6.60(1H,d, Ar-H), 4.10~4.11 (1H, m, -CH-), 4.08~4.10(2H, m, -CH- 2 -), 3.61~3.65(1H, m, -CH-), 3.52~3.54(4H, m, -CH 2 -), 3.37~3.40(4H, d, -CH 2 -), 3.22~3.26(1H, d, -CH-), 2.76(6H,s,-CH 3 ), 2.46(6H ,s,-CH 3), 1.15~1.27(13H,m), 0.78~0.94(13H,m).

[0049] Example 2

[0050] Compound I (10 g, 0.025 mol), sodium hydroxide (1.12 g, 0.028 mol), triethylamine (1.39 g, 0.014 mol) were added to a 500 ml three-necked flask equipped with a stirrer. Chlorobenzene (90 ml) was added. The mixture was heated to 85 °C under nitrogen protection. Epichlorohydrin (2.78 g, 0.03 mol) and 10 ml of chlorobenzene were added dropwise. After the addition was completed, the reaction was maintained at 85 °C. The liquid phase was monitored until the conversion of the raw materials was basically completed. Acetic acid was added until the pH reached 6-7. Ethyltriphenylphosphonium bromide (7.50 g, 0.02 mol) was added according to the liquid phase yield of Compound II of 70%. Dodecanol (2.93 g, 0.03 mol) was added dropwise. After the addition was complete, the mixture was kept at 85°C for 20-26 hours. The reaction was complete after liquid phase detection. Saturated aqueous ammonium chloride solution was added to quench the mixture. Ethyl acetate was added for extraction and the mixture was concentrated to obtain an oily product. The product was recrystallized from ethanol and filtered. The filtrate was concentrated to obtain a light yellow oily product UV400, which was 8.91 g, with a yield of 55.29% and a purity of 84.65%.

[0051] Example 3

[0052] Compound I (10 g, 0.025 mol), sodium hydroxide (1.12 g, 0.028 mol), triethylamine (1.39 g, 0.014 mol) were added to a 500 ml three-necked flask equipped with a stirrer. 90 ml of chlorobenzene was added. The mixture was protected by nitrogen and heated to 85 °C. A mixed liquid of epichlorohydrin (2.78 g, 0.03 mol) and 10 ml of chlorobenzene was added dropwise. After the addition was completed, the reaction was maintained at 85 °C. The liquid phase was monitored until the raw material was basically converted and the rotary evaporation was completed. Saturated ammonium chloride aqueous solution was added to quench the mixture, and the mixture was filtered with suction. Acetonitrile was added for washing and filtering. The reaction was repeated 3 times to obtain 7.42 g of the product Compound II with a yield of 65.43% and a purity of 91.50%.

[0053] Compound II (5 g, 0.01 mol) and ethyltriphenylphosphonium bromide (3.69 g, 0.01 mol) were added, and a mixed liquid of dodecanol (1.49 g, 0.008 mol) and tridecanol (0.8 g, 0.004 mol) was added dropwise. The temperature was maintained at 50 °C until the addition was completed, and the temperature was raised to 85 °C for reaction for 20-26 h. The reaction of the raw materials was completed after liquid phase detection. Saturated aqueous ammonium chloride was added to quench, and ethyl acetate was added for extraction and concentrated to obtain an oily product. The product was recrystallized from ethanol, filtered, and the filtrate was concentrated to obtain a light yellow oily substance UV400, which was weighed to obtain 5.04 g, with a yield of 78.15%, a purity of 85%, and a comprehensive yield of 51.13%.

[0054] Example 4

[0055] Compound I (10 g, 0.025 mol), potassium carbonate (3.88 g, 0.028 mol), triethylamine (1.39 g, 0.014 mol) were added to a 500 ml three-necked flask equipped with a stirrer. Chlorobenzene (90 ml) was added. The mixture was heated to 85 °C under nitrogen protection. Epichlorohydrin (2.78 g, 0.03 mol) and 10 ml chlorobenzene were added dropwise. After the addition was completed, the reaction was maintained at 85 °C. The liquid phase was monitored until the conversion of the raw materials was basically completed. Acetic acid was added until the pH reached 6-7. According to the liquid phase yield of compound II of 68%, ethyltriphenylphosphonium bromide (7.80 g, 0.021 mol) was added dropwise. Dodecanol (2.61 g, 0.014 mol) and tridecanol (1.40 g, The reaction was continued at 85 °C for 20-26 h. The reaction of the raw materials was completed after liquid phase detection. Saturated aqueous ammonium chloride solution was added to quench the reaction. Ethyl acetate was added for extraction and the mixture was concentrated to obtain an oily product. The product was recrystallized from ethanol and filtered. The filtrate was concentrated to obtain a light yellow oily product UV400, which was weighed to obtain 8.54 g, with a yield of 52.98% and a purity of 85%.

[0056] Example 5

[0057] Compound I (10 g, 0.025 mol), potassium hydroxide (1.568 g, 0.028 mol), pyridine (1.11 g, 0.014 mol) were added to a 500 ml three-necked flask equipped with a stirrer. Chlorobenzene (90 ml) was added. The mixture was protected by nitrogen and heated to 85 °C. Epichlorohydrin (2.78 g, 0.03 mol) and 10 ml of chlorobenzene were added dropwise. After the addition was completed, the reaction was maintained at 85 °C. The liquid phase was monitored until the conversion of the raw materials was basically completed. Acetic acid was added until the pH reached 6-7. Ethyltriphenylphosphonium bromide (6.92 g, 0.02 mol) was added according to the liquid phase yield of compound II of 68%. Dodecanol (2.23 g, 0.03 mol) was added dropwise. The reaction was continued at 85°C for 20-26 hours. The reaction was completed after the raw material reaction was detected by liquid phase. Saturated aqueous ammonium chloride solution was added to quench the reaction. Ethyl acetate was added for extraction and the reaction was concentrated to obtain an oily product. The product was recrystallized from ethanol and filtered. The filtrate was concentrated to obtain a light yellow oily product UV400, which was weighed to obtain 8.69 g, with a yield of 53.93% and a purity of 85%.

[0058] Comparative Example 1

[0059] Compound I (10 g, 0.025 mol), sodium hydroxide (1.32 g, 0.033 mol), and 90 ml of chlorobenzene were added to a 500 ml three-necked flask equipped with a stirrer. The mixture was protected by nitrogen and heated to 85 °C. A mixed liquid of epichlorohydrin (2.78 g, 0.03 mol) and 10 ml of chlorobenzene was added dropwise. After the addition was completed, the reaction was maintained at 85 °C. The liquid phase was monitored until the conversion of the raw materials was basically completed. Acetic acid was added until the pH reached 6-7. According to the liquid phase yield of compound II of 60%, ethyl triphenylphosphonium bromide (7.50 g, 0.02 mol) was added dropwise. Dodecanol (2.42 g, 0.013 mol) and tridecanol (1.30 g, The reaction was continued at 85 °C for 20-26 h. The reaction of the raw materials was completed after liquid phase detection. Saturated aqueous ammonium chloride solution was added to quench the reaction. Ethyl acetate was added for extraction and the mixture was concentrated to obtain an oily product. The product was recrystallized from ethanol and filtered. The filtrate was concentrated to obtain a light yellow oily product UV400, which was weighed to obtain 7.58 g, with a yield of 47.04% and a purity of 85%.

[0060] Comparative Example 2

[0061] Compound I (10 g, 0.025 mol), sodium hydroxide (1.12 g, 0.028 mol), sodium carbonate (1.48 g, 0.014 mol) were added to a 500 ml three-necked flask equipped with a stirrer. 90 ml of chlorobenzene was added. The mixture was protected by nitrogen and heated to 85 °C. Epichlorohydrin (2.78 g, 0.03 mol) and 10 ml of chlorobenzene were added dropwise. After the addition was completed, the reaction was maintained at 85 °C. The liquid phase was monitored until the conversion of the raw materials was basically completed. Acetic acid was added until the pH reached 6-7. According to the liquid phase yield of compound II of 61%, ethyltriphenylphosphonium bromide (6.92 g, 0.02 mol) was added dropwise. Dodecanol (2.23 g, 0.03 mol) was added dropwise. The reaction was continued at 85 °C for 20-26 h. The reaction of the raw materials was completed after liquid phase detection. Saturated aqueous ammonium chloride solution was added to quench the reaction. Ethyl acetate was added for extraction and the reaction was concentrated to obtain an oily product. The product was recrystallized from ethanol and filtered. The filtrate was concentrated to obtain a light yellow oily product UV400, which was weighed to obtain 7.67 g, with a yield of 47.60% and a purity of 85%.

[0062] Comparative Example 3

[0063] Compound I (2 g, 0.005 mol), sodium hydroxide (0.22 g, 0.006 mol), triethylamine (0.28 g, 0.003 mol) were added to a 500 ml three-necked flask equipped with a stirrer. 18 ml of tetrahydrofuran was added. The temperature was raised to 45 °C under nitrogen protection. A mixed liquid of epichlorohydrin (0.56 g, 0.006 mol) and 10 ml of tetrahydrofuran was added dropwise. After the addition was completed, the reaction was maintained at 66 °C. The liquid phase was monitored for 3 to 24 h. The liquid phase yield of compound II was 5%. There was basically no significant change when the reaction time was extended. The liquid phase monitoring showed that the number of ring-opening products increased, so the reaction was terminated.

[0064] Comparative Example 4

[0065] Compound I (2 g, 0.005 mol), sodium hydroxide (0.22 g, 0.006 mol), triethylamine (0.28 g, 0.003 mol) were added to a 500 ml three-necked flask equipped with a stirrer. 18 ml of 2-methyltetrahydrofuran was added. The mixture was protected by nitrogen and heated to 45 °C. A mixed liquid of epichlorohydrin (0.56 g, 0.006 mol) and 10 ml of 2-methyltetrahydrofuran was added dropwise. After the addition was completed, the reaction was maintained at 80 °C. The liquid phase was monitored for 3 to 24 hours. The liquid phase yield of compound II was 5%. There was basically no significant change when the reaction time was extended. The liquid phase monitoring showed that the number of ring-opening products increased, so the reaction was terminated.

[0066] Comparative Example 5

[0067] In a 500ml three-necked flask equipped with a stirrer, compound I (2g, 0.005mol), sodium hydroxide (0.22g, 0.006mol), triethylamine (0.28g, 0.003mol) and 18ml of anhydrous ethanol were added. Under nitrogen protection, the temperature was raised to 45°C, and a mixed liquid of epichlorohydrin (0.56g, 0.006mol) and 10ml of anhydrous ethanol was added dropwise. After the addition was completed, the reaction was maintained at 85°C, and the liquid phase was monitored. The reaction was performed for 3-24h. The liquid phase yield of compound II was less than 1%, and basically no reaction occurred and a ring-opening product was generated, so the reaction was terminated.

[0068] Comparative Example 6

[0069] Compound I (2 g, 0.005 mol), sodium hydroxide (0.22 g, 0.006 mol), triethylamine (0.28 g, 0.003 mol) were added to a 500 ml three-necked flask equipped with a stirrer. 18 ml of methanol was added. The mixture was protected by nitrogen and heated to 45 °C. A mixed liquid of epichlorohydrin (0.56 g, 0.006 mol) and 10 ml of methanol was added dropwise. After the addition was completed, the reaction was maintained at 65 °C. The liquid phase was monitored for 3 to 24 h. The liquid phase yield of compound II was less than 5%, and the ring-opening product increased, so the reaction was terminated.

[0070] Comparative Example 7

[0071] Compound I (10 g, 0.025 mol), sodium hydroxide (1.12 g, 0.028 mol), triethylamine (1.39 g, 0.014 mol) were added to a 500 ml three-necked flask equipped with a stirrer. 130 ml of acetonitrile was added. The mixture was heated to 85 °C under nitrogen protection. A mixed liquid of epichlorohydrin (2.78 g, 0.03 mol) and 10 ml of acetonitrile was added dropwise. After the addition was completed, the reaction was maintained at 85 °C. The liquid phase was monitored until the conversion of the raw materials was basically completed. Acetic acid was added until the pH reached 6-7. Ethyltriphenylphosphonium bromide (5.10 g, 0.014 mol) was added according to the liquid phase yield of Compound II of 50%. Dodecanol (1.55 g, 0.03 mol) was added dropwise. After the addition was complete, the mixture was kept at 85°C for 20-26 hours. The reaction was complete after liquid phase detection. Saturated aqueous ammonium chloride solution was added to quench the mixture. Ethyl acetate was added for extraction and the mixture was concentrated to obtain an oily product. The product was recrystallized from ethanol and filtered. The filtrate was concentrated to obtain a light yellow oily substance UV400, which was 6.32 g in weight, with a yield of 39.22% and a purity of 85%.

[0072] Liquid phase test method used in the embodiments and comparative examples:

[0073] Agilent 1260 HPLC, C18 column, test wavelength 290nm, column temperature 40℃, run for 30min, then run for 5min (during this period, the system gradually and automatically adjusted the water:acetonitrile ratio from 10:90 to 30:70). The first 15min was gradient elution (during this period, the system gradually and automatically adjusted the water:acetonitrile ratio from 30:70 to 10:90), and 15min to 30min was isocratic elution (the water:acetonitrile ratio was kept at 10:90 during this period).

[0074] .

Claims

1. A method for synthesizing compound (II), comprising the following steps: In a solvent, in the presence of an inorganic base and an organic base, compound (I) undergoes an etherification reaction with epichlorohydrin to produce compound (II); ； The inorganic base and the organic base are a combination of sodium hydroxide and triethylamine, a combination of potassium hydroxide and triethylamine, a combination of potassium carbonate and triethylamine, or a combination of potassium hydroxide and pyridine; The solvent is an aromatic hydrocarbon solvent.

2. The method for synthesizing compound (II) according to claim 1, characterized in that: It meets one or more of the following conditions: (1) When the solvent is an aromatic hydrocarbon solvent, the aromatic hydrocarbon solvent is chlorobenzene; (2) The molar ratio of the compound (I) to the solvent is (0.1-2) mol / L; (3) The molar ratio of the inorganic base to the compound (I) is 1:(0.4-2); (4) The molar ratio of the organic base to the compound (I) is 1:(0.6-4); (5) The molar ratio of the compound (I) to the epichlorohydrin is 1:(0.8-2); (6) The reaction temperature of the etherification reaction is 60°C-120°C; (7) After the etherification reaction is completed, the following post-treatment step is further included: concentrating the reaction solution, adding a saturated aqueous ammonium chloride solution, filtering with suction, washing with a nitrile solvent, and filtering with suction to obtain compound (II).

3. The method for synthesizing compound (II) according to claim 2, characterized in that: It meets one or more of the following conditions: (1) The molar ratio of the compound (I) to the solvent is (0.1-0.5) mol / L; (2) The molar ratio of the inorganic base to the compound (I) is 1:(0.5-1); (3) The molar ratio of the organic base to the compound (I) is 1:(1-2); (4) The molar ratio of the compound (I) to the epichlorohydrin is 1:(1-1.4); (5) The reaction temperature of the etherification reaction is 80°C-110°C; (6) The nitrile solvent is acetonitrile.

4. The method for synthesizing compound (II) according to claim 3, characterized in that: It meets one or more of the following conditions: (1) The molar ratio of the compound (I) to the solvent is 0.25 mol / L; (2) The molar ratio of the inorganic base to the compound (I) is 1:0.89; (3) The molar ratio of the organic base to the compound (I) is 1:1.78; (4) The molar ratio of the compound (I) to the epichlorohydrin is 1:1.2; (5) The reaction temperature of the etherification reaction is 85°C; (6) The materials for the etherification reaction are the compound (I), the inorganic base and the organic base, the epichlorohydrin and the solvent.

5. The method for synthesizing compound (II) according to claim 1, characterized in that: Under nitrogen protection, the compound (I), the inorganic base, the organic base and the solvent are mixed, epichlorohydrin dissolved in the solvent is added at 85°C, and the reaction is carried out while maintaining the temperature at 85°C.

6. A method for synthesizing UV400, characterized in that: It includes the following steps: S1: Compound (II) is synthesized by the method for synthesizing compound (II) according to any one of claims 1 to 5; S2: Under the action of a catalyst, dodecanol, tridecanol and the compound (II) undergo a ring-opening addition reaction to generate UV400; 。 7. The synthesis method of UV400 as claimed in claim 6, characterized in that, It meets one or more of the following conditions: (1) The catalyst is a quaternary phosphonium salt catalyst; (2) The molar ratio of the catalyst to the compound (II) is 1:(0.4-1.5); (3) The molar ratio of the compound (II) to the dodecanol is 1:(0.6-1.2); (4) The molar ratio of the compound (II) to the tridecanol is 1:(0.3-0.6); (5) In S2, the compound (II) is used in the form of the reaction solution obtained in S1; (6) The reaction temperature of the ring-opening addition reaction is 60-100°C; (7) After the ring-opening addition reaction is completed, post-treatment is performed by the following steps; which includes a recrystallization step; (8) The synthesis method of UV400 is a one-pot reaction.

8. The method for synthesizing UV400 as claimed in claim 7, characterized in that: It meets one or more of the following conditions: (1) When the catalyst is a quaternary phosphonium salt catalyst, the quaternary phosphonium salt catalyst is ethyltriphenylphosphonium bromide; (2) The molar ratio of the catalyst to the compound (II) is 1:(0.7-1.1); (3) The molar ratio of the compound (II) to the dodecanol is 1:(0.6-1); (4) The molar ratio of the compound (II) to the tridecanol is 1:0.35, 1:0.4 or 1:0.45; (5) The reaction solution obtained in S1 is adjusted to pH 6-7 using an acidic solution; (6) The reaction temperature of the ring-opening addition reaction is 85°C; (7) The solvent used in the recrystallization is an alcohol solvent; (8) Before the recrystallization, the reaction solution is mixed with a saturated aqueous ammonium chloride solution, or the reaction solution is mixed with a saturated aqueous ammonium chloride solution and a water-insoluble organic solvent, and the organic phase is retained and concentrated.

9. The method for synthesizing UV400 as claimed in claim 8, characterized in that: It meets one or more of the following conditions: (1) The molar ratio of the catalyst to the compound (II) is 1:0.8, 1:0.9 or 1:1; (2) The molar ratio of the compound (II) to the dodecanol is 1:0.7, 1:0.8 or 1:0.9; (3) When the reaction solution obtained in S1 is adjusted to a pH of 6 to 7 using an acidic solution, the acidic solution is acetic acid; (4) When the solvent used for the recrystallization is an alcohol solvent, the alcohol solvent is ethanol or isopropanol; (5) The water-insoluble organic solvent is an ester solvent and / or a halogenated alkane solvent; the ester solvent is preferably ethyl acetate; the halogenated alkane solvent is preferably dichloromethane and / or chloroform.

10. The method for synthesizing UV400 according to claim 6, characterized in that: Under nitrogen protection, the compound (I), the inorganic base, the organic base and the solvent are mixed, epichlorohydrin dissolved in the solvent is added at 85° C., and the etherification reaction is carried out at 85° C. to obtain compound (II); subjecting the compound (II), the catalyst, the dodecanol and the tridecanol to a mixed solution for a ring-opening addition reaction; Preferably, the synthesis method of UV400 is: under nitrogen protection, the compound (I), the inorganic base and the organic base and the solvent are mixed, epichlorohydrin dissolved in the solvent is added at 85°C, and the etherification reaction is carried out at 85°C; after the reaction, the acidic solution is added to the reaction solution to adjust the pH to 6-7, and the catalyst, the mixed solution of the dodecanol and the tridecanol are added to carry out a ring-opening addition reaction at 85°C.

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