Preparation method of 2, 4-bis (4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1, 3, 5-triazine

Abstract

The invention discloses a preparation method of 2, 4-bis (4-alkoxy-2-hydroxyl)-phenyl-6-(4-alkoxyphenyl)-1, 3, 5-triazine, and relates to the technical field of chemical synthesis, the preparation method comprises the following steps: S10, Grignard coupling reaction to obtain a first intermediate of formula (I); s20, carrying out Friedel-Crafts alkylation reaction to obtain a second intermediate as shown in a formula (II); s30, carrying out an etherification reaction, so as to obtain 2, 4-bis (4-alkoxy-2-hydroxyl)-phenyl-6-(4-alkoxyphenyl)-1, 3, 5-triazine of a formula (III) shown in the description; wherein the solvent in the step S10, the solvent in the step S20 and the solvent in the step S30 are the same, and the solvent comprises a urea reagent; r1 comprises hydrogen or a C1-C18 alkyl group; and R2 is a C1-C18 alkyl group. The product obtained by the preparation method provided by the invention has the advantages of fewer solvent residues, fewer impurities and higher product quality.

Description

Technical Field

[0001] The invention relates to the technical field of chemical synthesis, and in particular to a method for preparing 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine. Background Art

[0002] Generally, ultraviolet absorbers such as 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine, which have the characteristics of safe and efficient absorption of ultraviolet radiation, are widely used in cosmetics, hair care products, fabric treatment and detergents to protect the human body from excessive ultraviolet radiation.

[0003] The industrial preparation method of 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine generally uses p-halogenated benzene alkyl ether, cyanuric chloride, resorcinol and halogenated hydrocarbon as raw materials, toluene, tetrahydrofuran, chlorobenzene, ethanol, N,N-dimethylformamide (DMF) and acetone as solvents, and is prepared by Grignard reaction, coupling reaction, Friedel-Crafts reaction and alkylation reaction in sequence. The post-processing purification process is to obtain a product with qualified purity and appearance through acid washing, water washing, distillation, crystallization and other means.

[0004] However, the chemical synthesis process in the prior art requires the addition of a large amount of solvents, there are many types of solvents, the solvent loss is large, and the production cost is high. After the synthesis is completed, a large amount of solvent residue will be left, which brings pressure to the subsequent treatment of the three wastes. Summary of the invention

[0005] The main purpose of the present invention is to provide a method for preparing 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine, aiming to solve the problems of using many types of solvents and large solvent loss in the prior art.

[0006] To achieve the above object, the present invention provides a method for preparing 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine, comprising the following steps:

[0007] S10, mixing a halogenated phenyl alkyl ether, magnesium, an initiator, cyanuric chloride and a solvent, and performing a Grignard coupling reaction to obtain a first intermediate of formula (I);

[0008]

[0009] S20, mixing the first intermediate of formula (I), Lewis acid, resorcinol and a solvent, and performing a Friedel-Crafts alkylation reaction to obtain a second intermediate of formula (II);

[0010]

[0011] S30, mixing the second intermediate of formula (II), a catalyst, a halogenated hydrocarbon and a solvent, and performing an etherification reaction to obtain 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine of formula (III);

[0012]

[0013] Wherein, the solvent in steps S10, S20 and S30 is the same, and the solvent is a urea reagent;

[0014] R 1 Including hydrogen or C1-C 18 alkyl;

[0015] R 2 C1-C 18 alkyl.

[0016] In one embodiment, the solvent comprises N,N-dimethylpropyleneurea.

[0017] In one embodiment, step S10 includes:

[0018] S101, mixing magnesium, a solvent and an initiator to obtain a first mixed solution, adding a halogenated phenyl alkyl ether to the first mixed solution by dropwise addition, and performing a Grignard reaction to obtain a Grignard reagent;

[0019] S102, mixing cyanuric chloride and a solvent to obtain a second mixed solution, adding the Grignard reagent to the second mixed solution by dropwise addition, performing a coupling reaction, and quenching to obtain a first intermediate of formula (I).

[0020] In one embodiment, in step S10:

[0021] The molar ratio of the halophenyl alkyl ether, the magnesium, the cyanuric chloride and the solvent is 1:(1-2):(1-1.8):(5-9); and / or,

[0022] The halophenyl alkyl ether includes chlorophenyl alkyl ether, bromophenyl alkyl ether or iodophenyl alkyl ether; and / or,

[0023] The initiator includes iodine.

[0024] In one embodiment, in step S101, the dripping time is 30 to 60 minutes; and / or,

[0025] In step S101, the dropping temperature is 75-80° C.; and / or,

[0026] In step S101, the Grignard reaction time is 1.5 to 2.5 hours; and / or,

[0027] In step S101, the temperature of the Grignard reaction is 75-80°C;

[0028] In step S102, the temperature of the dropping is 0-5°C; and / or,

[0029] In step S102, the dripping time is 30 to 60 minutes; and / or,

[0030] In step S102, the coupling reaction time is 1.5 to 2.5 hours; and / or,

[0031] In step S102, the coupling reaction temperature is 30-40°C.

[0032] In one embodiment, in step S20, the molar ratio of the first intermediate of formula (I), the Lewis acid, the resorcinol and the solvent is 1: (2-2.5): (2-2.5): (3.5-10); and / or,

[0033] In step S20, the Lewis acid includes one or more of aluminum chloride, ferric chloride, zinc chloride and boron trifluoride; and / or,

[0034] In step S30, the molar ratio of the second intermediate of formula (II), the catalyst, the halogenated hydrocarbon and the solvent is 1: (1-2.5): (2-3): (10-45); and / or,

[0035] In step S30, the halogenated hydrocarbon includes a bromohydrocarbon, a chlorinated hydrocarbon or an iodinated hydrocarbon; and / or,

[0036] In step S30, the catalyst includes at least one of sodium carbonate, magnesium chloride, potassium bicarbonate, potassium carbonate, sodium bicarbonate and ammonium bicarbonate.

[0037] In one embodiment, the first intermediate is solid, and step S20 comprises:

[0038] S201, mixing the first intermediate and a solvent to obtain a third mixed solution;

[0039] S202, mixing Lewis acid, resorcinol and a solvent to obtain a fourth mixed solution;

[0040] S203, adding the third mixed solution into the fourth mixed solution by dropwise addition, performing Friedel-Crafts alkylation reaction, and quenching to obtain a second intermediate of formula (II).

[0041] In one embodiment, in step S203:

[0042] The dripping time is 30 to 60 minutes; and / or,

[0043] The Friedel-Crafts alkylation reaction time is 4 to 6 hours; and / or,

[0044] The temperature of the Friedel-Crafts alkylation reaction is 50-70°C;

[0045] The quenching temperature is ≤30°C; and / or,

[0046] The quenching time is 1.5 to 2.5 hours; and / or,

[0047] The quenching reagent includes water or an aqueous acid solution, and the mass ratio of the quenching reagent to the first intermediate of formula (I) is (8-15):1.

[0048] In one embodiment, step S30 includes:

[0049] S301, mixing the second intermediate of formula (II), a catalyst and a solvent, and performing a dehydration treatment to obtain a fifth mixed solution;

[0050] S302, mixing the fifth mixed solution with a halogenated hydrocarbon, performing an etherification reaction, filtering, taking the filtrate for crystallization, and obtaining 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine of formula (III).

[0051] In one embodiment, in step S302:

[0052] The temperature of the etherification reaction is 80-100° C.; and / or,

[0053] The etherification reaction time is 8 to 10 hours.

[0054] In the technical scheme of the present invention, urea reagents are used as the only solvent in the Grignard coupling reaction, Friedel-Crafts alkylation reaction and etherification reaction, which reduces the types of solvents in the existing synthesis process, avoids the solvent recovery step in the original step S10, thereby reducing the loss of the first intermediate of formula (I), and also avoids the side reaction between the original solvent tetrahydrofuran in step S10 and the Lewis acid in step S20. At the same time, compared with the original solvent chlorobenzene in step S20, the urea reagent has a better solubility in the first intermediate of formula (I), which can make step S20 The reaction system in the step S30 is in a clear state, which reduces the adhesion of the reaction materials on the reaction container, speeds up the reaction rate and makes the reaction more stable, and also improves the conversion rate and purity of the second intermediate of formula (II), and also reduces the amount of solvent used; the original reagent N, N-dimethylformamide of step S30 is replaced by a urea reagent, which reduces the temperature of the etherification reaction, shortens the time of the etherification reaction, and improves the conversion rate of 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine of formula (III). Therefore, the three-step reaction system of the preparation method of the present invention is a single urea solvent, which has good stability, high safety, less solvent usage, low unit consumption, easy recovery, low recovery energy consumption, and less solvent residue and impurities in the final product, and higher product quality.

[0055] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with the embodiments. DETAILED DESCRIPTION

[0056] To make the purpose, technical scheme and advantages of the embodiment of the present invention clearer, the technical scheme in the embodiment of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiment, it is carried out according to the normal conditions or the conditions recommended by the manufacturer. If the reagents or instruments used do not specify the manufacturer, they are all conventional products that can be purchased commercially. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes, taking "A and / or B" as an example, including scheme A, or scheme B, or schemes that A and B meet at the same time. In addition, the technical schemes between the various embodiments can be combined with each other, but must be based on the ability of ordinary technicians in the field to achieve. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that the combination of such technical solutions does not exist, and is not within the scope of protection required by the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present invention.

[0057] Generally, ultraviolet absorbers such as 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine, which have the characteristics of safe and efficient absorption of ultraviolet radiation, are widely used in cosmetics, hair care products, fabric treatment and detergents to protect the human body from excessive ultraviolet radiation.

[0058] Among them, 2,4-bis((4-(2-ethyl-hexyloxy)-2-hydroxy)-phenyl-6-(4-methoxyphenyl)-1,3,5-triazine, also known as bis-ethylhexyloxyphenol methoxyphenyl triazine, referred to as BEMT, absorbs in both UVA and UVB bands and can fully cover the UVA band. It has strong light absorption ability, excellent light stability, and good dispersibility in water. It can be used in combination with other sunscreen products. It is a new generation of high-end sunscreen products with good market prospects. Its chemical structure is as follows:

[0059]

[0060] The industrial preparation method of 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine generally uses p-halogenated benzene alkyl ether, cyanuric chloride, resorcinol and halogenated hydrocarbon as raw materials, toluene, tetrahydrofuran, chlorobenzene, ethanol, N,N-dimethylformamide (DMF) and acetone as solvents, and is prepared by Grignard reaction, coupling reaction, Friedel-Crafts reaction and alkylation reaction in sequence. The post-processing purification process is to obtain a product with qualified purity and appearance through acid washing, water washing, distillation, crystallization and other means.

[0061] It can be seen that the chemical synthesis process in the prior art requires the addition of a large amount of solvent, there are many types of solvents, the solvent loss is large, and the production cost is high. After the synthesis is completed, a large amount of solvent residue will be left, which brings pressure to the subsequent treatment of the three wastes.

[0062] In view of this, the present invention provides a method for preparing 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine, comprising the following steps:

[0063] S10, mixing a halogenated phenyl alkyl ether, magnesium, an initiator, cyanuric chloride and a solvent, and performing a Grignard coupling reaction to obtain a first intermediate of formula (I);

[0064]

[0065] S20, mixing the first intermediate of formula (I), Lewis acid, resorcinol and a solvent, and performing a Friedel-Crafts alkylation reaction to obtain a second intermediate of formula (II);

[0066]

[0067] S30, mixing the second intermediate of formula (II), a catalyst, a halogenated hydrocarbon and a solvent, and performing an etherification reaction to obtain 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine of formula (III);

[0068]

[0069] Wherein, the solvent in steps S10, S20 and S30 is the same, and the solvent is a urea reagent;

[0070] R 1 Including hydrogen or C1-C 18 alkyl;

[0071] R 2 C1-C 18 alkyl.

[0072] In the technical scheme of the present invention, a urea reagent is used as the only solvent in the Grignard coupling reaction, the Friedel-Crafts alkylation reaction and the etherification reaction, thereby reducing the types of solvents in the existing synthesis process, avoiding the solvent recovery step in the original step S10, thereby reducing the loss of the first intermediate of formula (I), and also avoiding the side reaction between the original solvent tetrahydrofuran in step S10 and the Lewis acid in step S20. At the same time, compared with the original solvent chlorobenzene in step S20, the urea reagent has a better solubility in the first intermediate of formula (I), which can make step S20 The reaction system in the step S30 is in a clear state, which reduces the adhesion of the reaction materials on the reaction container, speeds up the reaction rate and makes the reaction more stable, and also improves the conversion rate and purity of the second intermediate of formula (II), and also reduces the amount of solvent used; the original reagent N, N-dimethylformamide of step S30 is replaced by a urea reagent, which reduces the temperature of the etherification reaction, shortens the time of the etherification reaction, and improves the conversion rate of 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine of formula (III). Therefore, the three-step reaction system of the preparation method of the present invention is a single urea solvent, which has good stability, high safety, less solvent usage, low unit consumption, easy recovery, low recovery energy consumption, and less solvent residue and impurities in the final product, and higher product quality.

[0073] Specifically, the present invention makes the following improvements: (1) In step S10, the original solvent is toluene and tetrahydrofuran. In the process of industrial production and acid washing, the recovery rate of tetrahydrofuran is low, resulting in high unit consumption. In the present invention, the toluene and tetrahydrofuran used in step S10 are replaced with urea reagents, which not only reduces the number of solvents but also improves the quality of the first intermediate (including purity and yield); (2) In step S20, the original solvent is chlorobenzene. In the reaction process, it is a heterogeneous reaction system. In the present invention, after chlorobenzene is replaced with urea reagents, the reaction system is in a clear state, and the reaction materials will not adhere to the reaction container and affect the reaction rate, thereby accelerating the reaction. The reaction rate is increased and the reaction is more stable, and the quality of the second intermediate (including purity and yield) is improved; (3) In step S20, the original solvent is N,N-dimethylformamide, the reaction conditions are a high temperature of 130-150°C, and the reaction time is 20 hours. After the N,N-dimethylformamide is replaced with a urea reagent, the reaction temperature is lowered, the reaction time is shortened, and the product quality (including purity and yield) is improved; (4) The entire reaction system is a single urea reagent, with less solvent residue, reduced impurity generation, improved product quality, less solvent usage, low unit consumption, and easy recovery, and lower recovery energy consumption.

[0074] Among them, R 1 and R 2 Can be branched or unbranched C1-C 18 Alkyl, such as methyl, ethyl, n-propyl, 1-methylethyl, n-butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, n-hexyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethyl Butyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethyl-1-methylpropyl, 1-ethyl-2-methylpropyl, n-heptyl, 2-ethylhexyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl. 1 It is preferably a C1-C5 alkyl group, more preferably a C1-C2 alkyl group, and most preferably a methyl group. 2 Preferably it is a C3-C10 alkyl group, more preferably a C6-C 10 Alkyl, most preferably ethylhexyl.

[0075] In some embodiments of the present invention, the solvent includes N, N-dimethylpropylene urea. The above solvent can not only make the Grignard coupling reaction, Friedel-Crafts alkylation reaction and etherification reaction proceed smoothly, but also has a good solvent effect, which can reduce the amount of solvent used in the Grignard coupling reaction and Friedel-Crafts alkylation reaction, shorten the time of the etherification reaction, reduce the temperature of the etherification reaction, and reduce energy consumption and reagent costs.

[0076] In some embodiments of the present invention, step S10 includes:

[0077] S101, mixing magnesium, a solvent and an initiator to obtain a first mixed solution, adding a halogenated phenyl alkyl ether to the first mixed solution by dropwise addition, and performing a Grignard reaction to obtain a Grignard reagent;

[0078] S102, mixing cyanuric chloride and a solvent to obtain a second mixed solution, adding the Grignard reagent to the second mixed solution by dropwise addition, performing a coupling reaction, and quenching to obtain a first intermediate of formula (I).

[0079] In the technical scheme of the present invention, in step S101, solid magnesium (such as magnesium chips) and an initiator are first dispersed in a solvent to obtain a first mixed solution, which can increase the contact area between the solid raw material and the solvent and accelerate the reaction rate of magnesium and halogenated hydrocarbons; in step S102, solid cyanuric chloride is first dispersed in a solvent to obtain a second mixed solution, which can increase the solubility of solid cyanuric chloride, avoid its precipitation and cause incomplete reaction, and enhance the interaction between it and the Grignard reagent. After the coupling reaction, an aqueous solution of hydrochloric acid can be added to the reaction solution for quenching, filtering, and the filtrate is used in the reaction of step S20; the filtrate can also be further cooled and crystallized, and the filter cake is obtained by suction filtration, and the filter cake is used in the reaction of step S20, which has the advantage that the filtrate obtained by suction filtration can take away some impurities and improve the purity of the first intermediate of formula (I).

[0080] In some embodiments of the present invention, in step S10: the molar ratio of the halophenyl alkyl ether, the magnesium, the cyanuric chloride and the solvent is 1: (1-2): (1-1.8): (5-9). The molar ratio of the halophenyl alkyl ether, the magnesium, the cyanuric chloride and the solvent can be 1: 2: 1.8: 9, 1: 1.5: 1.5: 7 or 1: 1: 1: 5. The molar ratio within the appropriate range can ensure that the efficiency of the Grignard coupling reaction is high and the yield of the first intermediate of formula (I) is high.

[0081] In some embodiments of the present invention, in step S10: the halophenyl alkyl ether includes chlorophenyl alkyl ether, bromophenyl alkyl ether or iodophenyl alkyl ether. The above halophenyl alkyl ether can be selected to obtain the Grignard reagent more quickly. The halophenyl alkyl ether is preferably bromophenyl alkyl ether, and the bromophenyl alkyl ether is preferably p-bromoanisole.

[0082] In some embodiments of the present invention, in step S10: the initiator includes iodine. Iodine can be in the form of iodine particles, and its amount is preferably 10% of the mass of the reaction solution in step S101. Iodine can form a magnesium iodide film that is easy to break with the surface of magnesium, thereby exposing a new magnesium surface for halogenated hydrocarbons to attack and promote the formation of Grignard reagents. Therefore, using iodine as an initiator can accelerate the reaction between magnesium and halogenated hydrocarbons.

[0083] It should be noted that the Grignard reagent prepared in step S101 can also be used as an initiator for the next Grignard reaction.

[0084] In some embodiments of the present invention, in step S101, the dripping time is 30 to 60 minutes; and / or, in step S101, the dripping temperature is 75 to 80° C. The dripping time can be 30 minutes, 45 minutes or 60 minutes, and the dripping temperature can be 75° C., 77° C. or 80° C. The dripping time and temperature within the above range can ensure the smooth progress of the Grignard reaction.

[0085] In some embodiments of the present invention, in step S101, the time of the Grignard reaction is 1.5 to 2.5 hours; and / or, in step S101, the temperature of the Grignard reaction is 75 to 80° C. The time of the Grignard reaction can be 1.5 hours, 2 hours or 2.5 hours, and the temperature of the Grignard reaction can be 75° C., 77° C. or 80° C. The temperature and time of the Grignard reaction within the above range can ensure the smooth progress of the Grignard reaction.

[0086] In some embodiments of the present invention, in step S102, the temperature of the dripping is 0-5°C; and / or, in step S102, the time of the dripping is 30-60 min. The temperature of the dripping can be 0°C, 3°C or 5°C, and the time of the dripping can be 30 min, 45 min or 60 min. The temperature and time of the dripping within the above range can ensure the smooth progress of the coupling reaction, the reaction of the raw materials is relatively complete, and the yield of the first intermediate of formula (I) is improved.

[0087] In some embodiments of the present invention, in step S102, the coupling reaction time is 1.5 to 2.5 hours; and / or, in step S102, the coupling reaction temperature is 30 to 40° C. The coupling reaction time can be 1.5 hours, 2 hours or 2.5 hours, and the coupling reaction temperature can be 30° C., 35° C. or 40° C. The coupling reaction time and temperature within the above range can ensure the smooth progress of the coupling reaction.

[0088] In some embodiments of the present invention, in step S20, the molar ratio of the first intermediate of formula (I), the Lewis acid, the resorcinol and the solvent is 1: (2-2.5): (2-2.5): (3.5-10). The molar ratio of the first intermediate of formula (I), the Lewis acid, the resorcinol and the solvent can be 1: 2.5: 2.5: 10, 1: 2.3: 2.3: 7 or 1: 2: 2: 3.5. The molar ratio within the above range can ensure that the efficiency of the Friedel-Crafts alkylation reaction is high and the yield of the second intermediate of formula (II) is high.

[0089] In some embodiments of the present invention, in step S20, the Lewis acid includes one or more of aluminum chloride, ferric chloride, zinc chloride and boron trifluoride. Selecting the above Lewis acid can ensure that the Friedel-Crafts alkylation reaction is carried out under relatively mild conditions, which helps to reduce the occurrence of side reactions and improve the yield and purity of the second intermediate of formula (II).

[0090] In some embodiments of the present invention, in step S30, the molar ratio of the second intermediate of formula (II), the catalyst, the halogenated hydrocarbon and the solvent is 1: (1-2.5): (2-3): (10-45). The molar ratio of the second intermediate of formula (II), the catalyst, the halogenated hydrocarbon and the solvent can be 1: 2.5: 3: 45, 1: 2: 2.5: 25 or 1: 1: 2: 10. The molar ratio within the above range can ensure that the etherification reaction efficiency is high and the yield of 2,4-bis (4-alkoxy-2-hydroxy) -phenyl-6- (4-alkoxyphenyl) -1,3,5-triazine of formula (III) is high.

[0091] In some embodiments of the present invention, in step S30, the halogenated hydrocarbon includes a bromohydrocarbon, a chlorohydrocarbon or an iodohydrocarbon. The above halogenated hydrocarbons can be selected to increase the yield of the target product. 2 The halogenated hydrocarbon is preferably a chlorinated hydrocarbon, and the chlorinated hydrocarbon is preferably chloroisooctane.

[0092] In some embodiments of the present invention, in step S30, the catalyst includes at least one of sodium carbonate, magnesium chloride, potassium bicarbonate, potassium carbonate, sodium bicarbonate and ammonium bicarbonate. That is, the catalyst can be any one of sodium carbonate, magnesium chloride, potassium bicarbonate, potassium carbonate, sodium bicarbonate and ammonium bicarbonate, or two or more of sodium carbonate, magnesium chloride, potassium bicarbonate, potassium carbonate, sodium bicarbonate and ammonium bicarbonate, all within the protection scope of the present invention. The above catalysts can provide the necessary alkaline conditions, promote the formation of ether bonds, and improve the selectivity and yield of the etherification reaction.

[0093] In some embodiments of the present invention, the first intermediate is solid, and step S20 comprises:

[0094] S201, mixing the first intermediate and a solvent to obtain a third mixed solution;

[0095] S202, mixing Lewis acid, resorcinol and a solvent to obtain a fourth mixed solution;

[0096] S203, adding the third mixed solution into the fourth mixed solution by dropwise addition, performing Friedel-Crafts alkylation reaction, and quenching to obtain a second intermediate of formula (II).

[0097] In the technical solution of the present invention, the purpose of premixing in steps S201 and S202 is to make the raw materials evenly distributed in the solvent, ensure that they are fully contacted in the Friedel-Crafts alkylation reaction, and improve the reaction efficiency. The dripping method can control the mixing rate of the third mixed solution and the fourth mixed solution, thereby better controlling the reaction rate, avoiding the generation of by-products caused by excessive instantaneous reaction, and improving the purity of the second intermediate of formula (II).

[0098] In some embodiments of the present invention, in step S203: the dripping time is 30 to 60 minutes. The dripping time can be 30 minutes, 45 minutes or 60 minutes. The dripping time within the above range can ensure the smooth progress of the Friedel-Crafts alkylation reaction and reduce the generation of by-products.

[0099] In some embodiments of the present invention, in step S203: the time of the Friedel-Crafts alkylation reaction is 4 to 6 hours; and / or the temperature of the Friedel-Crafts alkylation reaction is 50 to 70° C. The time of the Friedel-Crafts alkylation reaction can be 4 hours, 5 hours or 6 hours, and the temperature of the Friedel-Crafts alkylation reaction can be 50° C., 60° C. or 70° C. The time and temperature of the Friedel-Crafts alkylation reaction within the above range can ensure the smooth progress of the Friedel-Crafts alkylation reaction and reduce the generation of by-products.

[0100] In some embodiments of the present invention, in step S203: the quenching temperature is ≤30°C; and / or, the quenching time is 1.5-2.5h; and / or, the quenching reagent includes water or an acid aqueous solution, and the mass ratio of the quenching reagent to the first intermediate of formula (I) is (8-15):1. The quenching temperature can be 30°C, 20°C, 10°C or lower. The quenching temperature within the above range can ensure that the system temperature is low and reduce the occurrence of side reactions. The quenching time can be 1.5h, 2h or 2.5h. The quenching time within the above range can ensure that the reaction is completely terminated. The mass ratio of the quenching reagent to the first intermediate of formula (I) can be 8:1, 11:1 or 15:1, and the acid in the acid aqueous solution can be hydrochloric acid or sulfuric acid, and its mass concentration is preferably 2% to 5%. Selecting the quenching reagent and the mass ratio of the quenching reagent to the first intermediate of formula (I) can ensure that the quenching is more thorough and the reagent cost is lower.

[0101] It should be noted that after quenching in step S203, the reaction solution can be filtered and the urea reagent in the filtrate can be extracted with an organic reagent. The obtained urea reagent can be recycled and used as the solvent in steps S10, S20 and S30.

[0102] In some embodiments of the present invention, step S30 includes:

[0103] S301, mixing the second intermediate of formula (II), a catalyst and a solvent, and performing a dehydration treatment to obtain a fifth mixed solution;

[0104] S302, mixing the fifth mixed solution with a halogenated hydrocarbon, performing an etherification reaction, filtering, taking the filtrate for crystallization, and obtaining 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine of formula (III).

[0105] In the technical solution of the present invention, in step S301, water in the reaction system is removed by dehydration treatment, which is beneficial to improving the efficiency and yield of the etherification reaction. The dehydration treatment includes high-temperature reduced-pressure distillation.

[0106] In some embodiments of the present invention, in step S302: the temperature of the etherification reaction is 80-100°C; and / or the time of the etherification reaction is 8-10 hours. The temperature of the etherification reaction can be 80°C, 90°C or 100°C, and the time of the etherification reaction can be 8 hours, 9 hours or 10 hours. The time and temperature of the etherification reaction within the above range can improve the yield and purity of 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine of formula (III).

[0107] The filtration temperature in step S302 is consistent with the temperature of the etherification reaction, the crystallization temperature is 0-5°C, and the crystallization time is 6-8h. Further, the crystallized product is rinsed and recrystallized with 0-5°C acetone, and the obtained finished product has a higher purity.

[0108] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only used to explain the present invention, and are not used to limit the present invention.

[0109] Example 1

[0110] A method for preparing 2,4-bis((4-(2-ethyl-hexyloxy)-2-hydroxy)-phenyl-6-(4-methoxyphenyl)-1,3,5-triazine comprises the following steps:

[0111] S10. Mix magnesium chips and N,N-dimethylpropyleneurea in a bottle, control the temperature at 80°C, add iodine particles to obtain a first mixed solution, slowly drop a small amount of p-bromoanisole into the reaction bottle to initiate the reaction, and continue to drop p-bromoanisole after confirming the initiation. Control the dropping time to 30 min and keep the temperature at 77°C. After the dropping is completed, keep the temperature at 77°C for 2 h to obtain the Grignard reagent.

[0112] Disperse cyanuric chloride in N, N-dimethylpropylene urea to obtain a second mixed solution. At 0°C, drip the Grignard reagent prepared in step S101 into the second mixed solution, and after the dripping, heat it to 30°C and keep it for 2 hours. After the reaction is complete, add a 5% hydrochloric acid aqueous solution to quench, filter the quenched solution while hot, cool it down and crystallize it, and filter it to obtain a filter cake, which is the first intermediate. The purity of the first intermediate is 97.1%, and the yield is 95.2%.

[0113] Wherein, the molar ratio of p-bromoanisole, magnesium chips, cyanuric chloride and N,N-dimethylpropyleneurea is 1:1.5:1.5:7.

[0114] S20, heat the first intermediate prepared in step S102 and N, N-dimethylpropylene urea to 50°C to dissolve, and obtain a third mixed solution; heat aluminum chloride, resorcinol and N, N-dimethylpropylene urea to 65°C to dissolve, and obtain a fourth mixed solution; drip the third mixed solution into the fourth mixed solution, the dripping time is 30min, and the temperature is kept for 4h. After the reaction is completed, slowly drip the reaction solution into a 5°C, 5% mass concentration hydrochloric acid aqueous solution for quenching, control the temperature not to exceed 30°C, stir for 2h, filter by suction, extract the collected mother liquor with ethyl acetate to recover N, N-dimethylpropylene urea, rinse the filter cake twice with hot water twice the mass of the filter cake to dissolve the aluminum salt therein, and then wash the filter cake with 80°C tap water to neutrality, and finally reduce the pressure and dry to obtain the second intermediate. The purity of the second intermediate is 96.8%, and the yield is 92.2%.

[0115] Among them, the molar ratio of the first intermediate, aluminum chloride, resorcinol and the total N,N-dimethylpropylene urea in step S20 is 1:2.5:2.5:10; the mass ratio of the hydrochloric acid aqueous solution and the first intermediate is 8:1.

[0116] S30, add the second intermediate prepared in step S20, N, N-dimethyl propylene urea and sodium carbonate to a four-mouth reaction bottle, distill under high temperature and reduced pressure to remove water, and obtain a fifth mixed solution; add chloroisooctane to the fifth mixed solution, heat to 80°C and react for 8h. After the reaction is complete, filter the sodium carbonate at 80°C, cool the filtrate to 0°C in a flask for crystallization for 6h, filter by suction, rinse the filter cake with 0°C acetone, and recrystallize it at 0°C with acetone 4 times the mass of the filter cake, and place the recrystallized crystals in a vacuum oven at 40°C to dry and dry to obtain a light yellow solid powder, which is the finished product 2,4-bis((4-(2-ethyl-hexyloxy)-2-hydroxy)-phenyl-6-(4-methoxyphenyl)-1,3,5-triazine. The purity of the finished product is 97.6%, and the yield is 90.2%.

[0117] The molar ratio of the second intermediate, sodium carbonate, isooctane chloride and N,N-dimethylpropylene urea is 1:2.5:3:45.

[0118] Example 2

[0119] Compared with Example 1, Example 2 is different in that:

[0120] In step S10: the halogenated benzene alkyl ether is p-chloroanisole, and the molar ratio of p-chloroanisole, magnesium chips, cyanuric chloride and N,N-dimethylpropylene urea is 1:2:1.8:9; the Grignard reaction dropping time is 45 minutes, the Grignard reaction dropping temperature is 77°C, the Grignard reaction time is 2.5 hours, and the Grignard reaction temperature is 80°C; the coupling reaction dropping temperature is 3°C, the coupling reaction dropping time is 45 minutes, the coupling reaction time is 2 hours, and the coupling reaction temperature is 35°C;

[0121] In step S20: the Lewis acid is ferric chloride, the molar ratio of the first intermediate, ferric chloride, resorcinol and the total N,N-dimethylpropylene urea in step S20 is 1:2.3:2.3:7; the quenching reagent is water, and the mass ratio of water to the first intermediate is 10:1;

[0122] In step S30, the catalyst is magnesium chloride, the halogenated hydrocarbon is isooctane bromide, the molar ratio of the second intermediate, magnesium chloride, isooctane bromide and N,N-dimethylpropylene urea is 1:2:2.5:25; the etherification reaction temperature is 90°C, and the etherification reaction time is 9h.

[0123] The purity of the first intermediate obtained in Example 2 was 97.3%, and the yield was 95.2%; the purity of the second intermediate was 96.7%, and the yield was 92.1%; the purity of the finished product was 97.5%, and the yield was 90.1%.

[0124] Example 3

[0125] Compared with Example 1, Example 3 is different in that:

[0126] In step S10: the halogenated benzene alkyl ether is p-iodoanisole, and the molar ratio of p-chloroanisole, magnesium chips, cyanuric chloride and N,N-dimethylpropylene urea is 1:1:1:5; the Grignard reaction dropping time is 60 min, the Grignard reaction dropping temperature is 75° C., the Grignard reaction time is 1.5 h, and the Grignard reaction temperature is 75° C.; the coupling reaction dropping temperature is 5° C., the coupling reaction dropping time is 60 min, the coupling reaction time is 2.5 h, and the coupling reaction temperature is 40° C.;

[0127] In step S20: the molar ratio of the first intermediate, aluminum chloride, resorcinol and the total N,N-dimethylpropylene urea in step S20 is 1:2:2:3.5; the quenching reagent is an aqueous solution of sulfuric acid, and the mass ratio of the aqueous solution of sulfuric acid to the first intermediate is 15:1;

[0128] In step S30: the catalyst is potassium bicarbonate, the halogenated hydrocarbon is iodo-isooctane, the molar ratio of the second intermediate, potassium bicarbonate, iodo-isooctane and N,N-dimethylpropylene urea is 1:1:2:16; the etherification reaction temperature is 100°C, and the etherification reaction time is 10 hours.

[0129] The purity of the first intermediate obtained in Example 3 was 97.2%, and the yield was 95.4%; the purity of the second intermediate was 97.0%, and the yield was 92.3%; the purity of the finished product was 98.0%, and the yield was 90.3%.

[0130] Example 4

[0131] Compared with Example 1, Example 4 is different in that:

[0132] In step S10: the molar ratio of p-bromoanisole, magnesium chips, cyanuric chloride and N,N-dimethylpropyleneurea is 1:1:1.1:7.29;

[0133] In step S20: the molar ratio of the first intermediate, aluminum chloride, resorcinol and the total N,N-dimethylpropylene urea in step S20 is 1:2.1:2.1:5.99;

[0134] In step S30: the molar ratio of the second intermediate, sodium carbonate, isooctane chloride and N,N-dimethylpropylene urea is 1:1.5:2.1:12.58.

[0135] The purity of the first intermediate obtained in Example 4 was 97.5%, and the yield was 95.5%; the purity of the second intermediate was 97.5%, and the yield was 92.5%; the purity of the finished product was 98.5%, and the yield was 90.6%.

[0136] Example 5

[0137] Compared with Example 1, Example 5 is different in that:

[0138] In step S30: the catalyst is potassium carbonate.

[0139] The purity of the first intermediate obtained in Example 5 was 96.2%, and the yield was 94.4%; the purity of the second intermediate was 96.4%, and the yield was 92.3%; the purity of the finished product was 97.3%, and the yield was 90.2%.

[0140] Example 6

[0141] Compared with Example 1, Example 5 is different in that:

[0142] In step S30: the catalyst is sodium bicarbonate.

[0143] The purity of the first intermediate obtained in Example 6 was 96.4%, and the yield was 94.5%; the purity of the second intermediate was 96.3%, and the yield was 92.4%; the purity of the finished product was 97.4%, and the yield was 90.3%.

[0144] Example 7

[0145] Compared with Example 1, Example 5 is different in that:

[0146] In step S30: the catalyst is ammonium bicarbonate.

[0147] The purity of the first intermediate obtained in Example 7 was 96.1%, and the yield was 94.3%; the purity of the second intermediate was 96.2%, and the yield was 92.2%; the purity of the finished product was 97.2%, and the yield was 90.1%.

[0148] Comparative Example 1

[0149] Compared with Example 1, Comparative Example 1 is different in that:

[0150] In step S10, the solvent is tetrahydrofuran and toluene, and the specific operation steps are: 37.4g of p-bromoanisole, 37.4g of tetrahydrofuran and 8.6g of toluene are mixed and then put into a dropping funnel, and then added dropwise in batches (first add 5% of the above raw materials and a small amount of iodine particles for initiation, and then add dropwise after the initiation is completed) to a reaction bottle containing 7.3g of magnesium chips and 15 of tetrahydrofuran. After the addition is completed, the reaction is kept at 67°C for 180min to obtain a Grignard reagent.

[0151] The Grignard reagent was added dropwise at 5-10°C to a reaction bottle containing 55.32g of cyanuric chloride and 166g of toluene. After the addition was completed, the temperature was raised to 30°C and the reaction was kept at this temperature for 240 minutes.

[0152] After the reaction is completed, 40 g of pre-prepared hydrochloric acid with a concentration of 1 mol / L is added to the reaction bottle, the layers are separated, and the water layer is discarded to obtain an organic layer. The organic layer is then washed with 50 g of water, and the water washing step is repeated twice. The organic layer is then evaporated until it becomes viscous, cooled to 5°C for crystallization, filtered, rinsed with 20 g of fresh cold toluene, filtered, and dried to obtain the first intermediate;

[0153] Among them, the molar ratio of p-bromoanisole, magnesium chips, cyanuric chloride, tetrahydrofuran, toluene and water is 1:2:1.8:15:15:62.33.

[0154] The purity of the first intermediate prepared in Comparative Example 1 was 96.4%, and the yield was 85.4%; the purity of the second intermediate was 95.7%, and the yield was 82.3%; the purity of the finished product was 97.3%, and the yield was 80.3%.

[0155] Comparative Example 2

[0156] Compared with Example 1, Comparative Example 2 is different in that:

[0157] In step S20, the solvent is chlorobenzene, wherein the molar ratio of the first intermediate, aluminum chloride, resorcinol and chlorobenzene is 1:2.5:2.5:10.

[0158] The purity of the first intermediate obtained in Comparative Example 2 was 96.5%, and the yield was 85.3%; the purity of the second intermediate was 96.7%, and the yield was 82.3%; the purity of the finished product was 97.4%, and the yield was 80.3%.

[0159] Comparative Example 3

[0160] Compared with Example 1, Comparative Example 3 is different in that:

[0161] In step S30, the solvent is N,N-dimethylformamide, wherein the molar ratio of the second intermediate, sodium carbonate, chloroisooctane and N,N-dimethylformamide is 1:2.5:3:45, the etherification reaction time is 20 hours, and the etherification reaction temperature is 120°C.

[0162] The purity of the first intermediate obtained in Comparative Example 3 was 96.4%, and the yield was 85.3%; the purity of the second intermediate was 95.8%, and the yield was 82.2%; the purity of the finished product was 97.2%, and the yield was 80.3%.

[0163] Comparative Example 4

[0164] Compared with Example 1, Comparative Example 4 is different in that:

[0165] In step S10, the solvent is tetrahydrofuran and toluene, and the specific operation steps are the same as those in comparative example 1, wherein the molar ratio of p-bromoanisole, magnesium chips, cyanuric chloride, tetrahydrofuran, toluene and water is 1:2:1.8:15:15:62.33;

[0166] In step S20, the solvent is chlorobenzene, wherein the molar ratio of the first intermediate, aluminum chloride, resorcinol and chlorobenzene is 1:2.5:2.5:10.

[0167] The purity of the first intermediate obtained in Comparative Example 4 was 96.2%, and the yield was 82.5%; the purity of the second intermediate was 95.6%, and the yield was 80.4%; the purity of the finished product was 97.2%, and the yield was 80.2%.

[0168] Comparative Example 5

[0169] Compared with Example 1, Comparative Example 5 is different in that:

[0170] In step S10, the solvent is tetrahydrofuran and toluene, and the specific operation steps are the same as those in comparative example 1, wherein the molar ratio of p-bromoanisole, magnesium chips, cyanuric chloride, tetrahydrofuran, toluene and water is 1:2:1.8:15:15:62.33;

[0171] In step S30, the solvent is N,N-dimethylformamide, wherein the molar ratio of the second intermediate, sodium carbonate, chloroisooctane and N,N-dimethylformamide is 1:2.5:3:45, the etherification reaction time is 20 hours, and the etherification reaction temperature is 120°C.

[0172] The purity of the first intermediate obtained in Comparative Example 5 was 96.3%, and the yield was 84.3%; the purity of the second intermediate was 95.5%, and the yield was 80.5%; the purity of the finished product was 97.5%, and the yield was 81.2%.

[0173] Comparative Example 6

[0174] Compared with Example 1, Comparative Example 6 is different in that:

[0175] In step S20, the solvent is chlorobenzene, wherein the molar ratio of the first intermediate, aluminum chloride, resorcinol and chlorobenzene is 1:2.5:2.5:10;

[0176] In step S30, the solvent is N,N-dimethylformamide, wherein the molar ratio of the second intermediate, sodium carbonate, chloroisooctane and N,N-dimethylformamide is 1:2.5:3:45, the etherification reaction time is 20 hours, and the etherification reaction temperature is 120°C.

[0177] The purity of the first intermediate obtained in Comparative Example 6 was 96.3%, and the yield was 83.5%; the purity of the second intermediate was 96.8%, and the yield was 80.7%; the purity of the finished product was 97.5%, and the yield was 81.3%.

[0178] Comparative Example 7

[0179] Compared with Example 1, Comparative Example 7 is different in that:

[0180] In step S10, the solvent is tetrahydrofuran and toluene, and the specific operation steps are the same as those in comparative example 1, wherein the molar ratio of p-bromoanisole, magnesium chips, cyanuric chloride, tetrahydrofuran, toluene and water is 1:2:1.8:15:15:62.33;

[0181] In step S20, the solvent is chlorobenzene, wherein the molar ratio of the first intermediate, aluminum chloride, resorcinol and chlorobenzene is 1:2.5:2.5:10;

[0182] In step S30, the solvent is N,N-dimethylformamide, wherein the molar ratio of the second intermediate, sodium carbonate, chloroisooctane and N,N-dimethylformamide is 1:2.5:3:45, the etherification reaction time is 20 hours, and the etherification reaction temperature is 120°C.

[0183] The purity of the first intermediate obtained in Comparative Example 7 was 96.3%, and the yield was 83.4%; the purity of the second intermediate was 96.7%, and the yield was 80.6%; the purity of the finished product was 97.3%, and the yield was 81.1%.

[0184] The purity of the first intermediate, the second intermediate and the finished product is detected by high performance liquid chromatography, and the yield calculation formula is: (actual amount of target product produced / theoretical amount of target product produced)×100%.

[0185] The above are only preferred embodiments of the present invention, and do not limit the patent scope of the present invention. For those skilled in the art, the present invention may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the patent protection scope of the present invention.

Claims

1. A method for preparing 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine, characterized in that: The following steps are involved: S10, mixing a halogenated phenyl alkyl ether, magnesium, an initiator, cyanuric chloride and a solvent, and performing a Grignard coupling reaction to obtain a first intermediate of formula (I); S20, mixing the first intermediate of formula (I), Lewis acid, resorcinol and a solvent, and performing a Friedel-Crafts alkylation reaction to obtain a second intermediate of formula (II); S30, mixing the second intermediate of formula (II), a catalyst, a halogenated hydrocarbon and a solvent, and performing an etherification reaction to obtain 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine of formula (III); Wherein, the solvent in steps S10, S20 and S30 is the same, and the solvent is a urea reagent; R 1 Including hydrogen or C1-C 18 alkyl; R 2 C1-C 18 alkyl.

2. The method for preparing 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine according to claim 1, characterized in that: The solvent includes N,N-dimethylpropylene urea.

3. The method for preparing 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine according to claim 1, characterized in that: Step S10 includes: S101, mixing magnesium, a solvent and an initiator to obtain a first mixed solution, adding a halogenated phenyl alkyl ether to the first mixed solution by dropwise addition, and performing a Grignard reaction to obtain a Grignard reagent; S102, mixing cyanuric chloride and a solvent to obtain a second mixed solution, adding the Grignard reagent to the second mixed solution by dropwise addition, performing a coupling reaction, and quenching to obtain a first intermediate of formula (I).

4. The method for preparing 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine according to claim 3, characterized in that: In step S10: The molar ratio of the halophenyl alkyl ether, the magnesium, the cyanuric chloride and the solvent is 1:(1-2):(1-1.8):(5-9); and / or, The halophenyl alkyl ether includes chlorophenyl alkyl ether, bromophenyl alkyl ether or iodophenyl alkyl ether; and / or, The initiator includes iodine.

5. The method for preparing 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine according to claim 3, characterized in that: In step S101, the dripping time is 30 to 60 minutes; and / or, In step S101, the dropping temperature is 75-80° C.; and / or, In step S101, the Grignard reaction time is 1.5 to 2.5 hours; and / or, In step S101, the temperature of the Grignard reaction is 75-80°C; In step S102, the temperature of the dropping is 0-5°C; and / or, In step S102, the dripping time is 30 to 60 minutes; and / or, In step S102, the coupling reaction time is 1.5 to 2.5 hours; and / or, In step S102, the coupling reaction temperature is 30-40°C.

6. The method for preparing 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine according to claim 1, characterized in that: In step S20, the molar ratio of the first intermediate, the Lewis acid, the resorcinol and the solvent is 1:(2-2.5):(2-2.5):(3.5-10); and / or, In step S20, the Lewis acid includes one or more of aluminum chloride, ferric chloride, zinc chloride and boron trifluoride; and / or, In step S30, the molar ratio of the second intermediate of formula (II), the catalyst, the halogenated hydrocarbon and the solvent is 1: (1-2.5): (2-3): (10-45); and / or, In step S30, the halogenated hydrocarbon includes a bromohydrocarbon, a chlorinated hydrocarbon or an iodinated hydrocarbon; and / or, In step S30, the catalyst includes at least one of sodium carbonate, magnesium chloride, potassium bicarbonate, potassium carbonate, sodium bicarbonate and ammonium bicarbonate.

7. The method for preparing 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine according to claim 1, characterized in that: The first intermediate is solid, and step S20 comprises: S201, mixing the first intermediate of formula (I) and a solvent to obtain a third mixed solution; S202, mixing Lewis acid, resorcinol and a solvent to obtain a fourth mixed solution; S203, adding the third mixed solution into the fourth mixed solution by dropwise addition, performing Friedel-Crafts alkylation reaction, and quenching to obtain a second intermediate of formula (II).

8. The method for preparing 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine according to claim 7, characterized in that: In step S203: The dripping time is 30 to 60 minutes; and / or, The Friedel-Crafts alkylation reaction time is 4 to 6 hours; and / or, The temperature of the Friedel-Crafts alkylation reaction is 50-70°C; The quenching temperature is ≤30°C; and / or, The quenching time is 1.5 to 2.5 hours; and / or, The quenching reagent includes water or an acid aqueous solution, and the mass ratio of the quenching reagent to the first intermediate of formula (I) is (8-15):

1.

9. The method for preparing 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine according to claim 1, characterized in that: Step S30 includes: S301, mixing the second intermediate of formula (II), a catalyst and a solvent, and performing a dehydration treatment to obtain a fifth mixed solution; S302, mixing the fifth mixed solution with a halogenated hydrocarbon, performing an etherification reaction, filtering, taking the filtrate for crystallization, and obtaining 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine of formula (III).

10. The method for preparing 2,4-bis(4-alkoxy-2-hydroxy)-phenyl-6-(4-alkoxyphenyl)-1,3,5-triazine according to claim 9, characterized in that: In step S302: The temperature of the etherification reaction is 80-100° C.; and / or, The etherification reaction time is 8 to 10 hours.

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