Preparation method of 2, 4-bis ([1, 1 '-biphenyl]-4-yl)-6-chloro-1, 3, 5-triazine

Abstract

The invention discloses a method for preparing 2, 4-di ([1, 1 '-biphenyl]-4-yl)-6-chloro-1, 3, 5-triazine, which comprises the following steps: (1) carrying out substitution reaction on cyanuric chloride and an alkali metal substituted tert-butyl alcohol compound to prepare 2, 4-dichloro-6-tert-butoxy-1, 3, 5-triazine; (2) carrying out Friedel-Crafts reaction on the 2, 4-dichloro-6-tert-butoxy-1, 3, 5-triazine prepared in the step (1) and biphenyl, so as to prepare 2, 4-bis ([1, 1 '-biphenyl]-4-yl)-6-tert-butoxy-1, 3, 5-triazine; and (3) carrying out a chlorination reaction on the 2, 4-bis ([1, 1 '-biphenyl]-4-yl)-6-tert-butoxy-1, 3, 5-triazine prepared in the step (2) under the action of a chlorination reagent to prepare the 2, 4-bis ([1, 1'-biphenyl]-4-yl)-6-chloro-1, 3, 5-triazine.The preparation method provided by the invention has the advantages of mild reaction conditions, simple separation process, high reaction selectivity and high product yield, and can realize industrial large-scale production.

Description

Technical Field

[0001] The present invention relates to the field of functional additives for polymer materials, and particularly to a preparation method of a light stabilizer synthesis intermediate 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine. Background Art

[0002] With the rapid development of polymer materials, the research and development of their additives have gradually become the focus of attention. Among them, triazine ultraviolet absorbers are regarded as new light stabilizers with great development prospects due to their high efficiency, high temperature resistance, light color, and good compatibility.

[0003] UV-1600 (2-[4,6-bis([1,1'-biphenyl]-4-yl)-1,3,5-triazin-2-yl]-5-[(2-ethylhexyl)oxy]phenol), as a triazine ultraviolet absorber, has extremely excellent comprehensive application performance. The synthesis of UV-1600 using 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine as an intermediate is the main synthesis method at present. Therefore, developing a new and efficient synthesis process of 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine and solving the problems in the current process are of great significance for the product upgrade and sustainable development of light stabilizers.

[0004] For the synthesis of this intermediate, the currently reported synthesis technologies mainly include the following several:

[0005] 1. CN110372620A reports a method for preparing 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine by directly performing a Friedel-Crafts alkylation reaction between cyanuric chloride and biphenyl. The reaction route is as follows:

[0006]

[0007] This method has concise steps, but the reaction selectivity is poor, and it is difficult to remove the impurities of the polyalkylated products generated, making it difficult to obtain a qualified final product, and requiring cumbersome post-treatment and separation and purification operations.

[0008] 2. CN102782033A and WO2011067282A1 disclose a method for preparing 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine using 4-bromobiphenyl as a raw material, first performing a Grignard reaction to prepare a biphenyl Grignard reagent, and then reacting it with cyanuric chloride. The reaction route is as follows:

[0009]

[0010] The 4-bromobiphenyl and anhydrous tetrahydrofuran used in this method are costly; moreover, since a Grignard reagent needs to be prepared, the reaction conditions are relatively harsh, appropriate initiation of the reaction is required, the reaction conditions are relatively complex to control, and the requirement for the water content of the solvent is relatively high, which is not conducive to industrial scale-up production.

[0011] 3. WO2020144094A1 discloses a method in which one chlorine group in cyanuric chloride is first converted into an amino group that is inert in the Friedel-Crafts reaction, then reacted with biphenyl, and then the amino group is converted into 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine through hydrolysis and chlorination. The reaction route is as follows:

[0012]

[0013] This route effectively improves the reaction selectivity, but three unit steps of ammonolysis, hydrolysis, and chlorination are introduced, and the synthesis process is relatively cumbersome and the production cost is relatively high.

[0014] 4. CN112028846A further improves WO2020144094A1. First, cyanuric chloride reacts with an amide to form a salt, then undergoes a Friedel-Crafts reaction with biphenyl to obtain 2,4-bis([1,1'-biphenyl]-4-yl)-6-hydroxy-1,3,5-triazine, and then the hydroxyl group is chlorinated to prepare 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine. The reaction route is as follows:

[0015]

[0016] This method requires a low-temperature reaction to form a salt, and the actual reaction selectivity is not high. The salt intermediate has poor thermal stability and is prone to generating other by-products.

[0017] 5. CN113234032A and CN113087678A respectively disclose a method for obtaining 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine by first condensing and cyclizing 4-cyanobiphenyl and urea in the presence of a strong base sodium hydride or sodium amide, and then chlorinating. The reaction route is as follows:

[0018]

[0019] This method has a relatively short reaction route and less wastewater volume, but 4-cyanobiphenyl is expensive, and the reaction involves the use of a large amount of strong bases sodium hydride and sodium amide, which are sensitive to water and require anhydrous operation, posing certain risks and making it difficult to achieve industrial production.

[0020] 6. CN113149918A discloses a method for synthesizing 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine. This method consists of three-step reactions: (1) Using cyanuric chloride and organic carboxylic acid as raw materials, reacting in the presence of a basic catalyst to obtain 4,6-dichloro-2-hydroxy-1,3,5-triazine; (2) Performing a Friedel-Crafts reaction on 4,6-dichloro-2-hydroxy-1,3,5-triazine and biphenyl under the catalysis of a Lewis acid to obtain 2,4-bis([1,1'-biphenyl]-4-yl)-6-hydroxy-1,3,5-triazine; (3) Performing a chlorination reaction on 2,4-bis([1,1'-biphenyl]-4-yl)-6-hydroxy-1,3,5-triazine in the presence of a chlorinating reagent and a catalyst to obtain 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine. The reaction route is shown as follows:

[0021]

[0022] The selectivity of the first-step reaction of this method is poor, and it is easy to generate by-products with two hydroxyl groups; the separation process is relatively complex, requiring filtration and drying operations, and also requires recovering the solvent tetrahydrofuran from water, with high energy consumption.

[0023] As can be seen from the above, the currently reported methods for synthesizing 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine have one or more of the following problems: poor reaction selectivity, requiring a cumbersome separation and purification process to improve the purity of the target intermediate; requiring more reaction units, with low efficiency; relatively high cost of raw materials, expensive catalysts and reagents, etc.; harsh reaction process conditions. These problems lead to high production costs and difficulty in realizing industrial scale-up production.

[0024] Therefore, there is an urgent need to develop a method for synthesizing 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine with mild reaction conditions, simple separation process, high reaction selectivity, high product yield, and easy to realize industrial scale-up production. Summary of the Invention

[0025] In view of the problems existing in the prior art, the present invention discloses a method for preparing the intermediate 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine of the light stabilizer UV-1600. This synthesis method uses cyanuric chloride and an alkali metal-substituted tert-butanol compound as raw materials, and successively undergoes a substitution reaction, a Friedel-Crafts reaction with biphenyl, and a chlorination reaction to obtain 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine. This preparation method has mild reaction conditions, a simple separation process, high reaction selectivity, and a high product yield, and can achieve industrial scale-up production.

[0026] Specifically, the present invention provides a method for preparing 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine, and the method comprises the following steps:

[0027] (1) Subjecting cyanuric chloride and an alkali metal-substituted tert-butanol compound to a substitution reaction to obtain 2,4-dichloro-6-tert-butoxy-1,3,5-triazine;

[0028] (2) Subjecting the 2,4-dichloro-6-tert-butoxy-1,3,5-triazine obtained in step (1) and biphenyl to a Friedel-Crafts reaction to obtain 2,4-bis([1,1'-biphenyl]-4-yl)-6-tert-butoxy-1,3,5-triazine;

[0029] (3) Subjecting the 2,4-bis([1,1'-biphenyl]-4-yl)-6-tert-butoxy-1,3,5-triazine obtained in step (2) to a chlorination reaction under the action of a chlorinating reagent to obtain 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine.

[0030] In one or more embodiments, in step (1), the substitution reaction is carried out in a solvent; preferably, the solvent is selected from one or more of orthodichlorobenzene, metadichlorobenzene, paradichlorobenzene, and dichlorocyclohexane, and preferably orthodichlorobenzene; preferably, the mass ratio of cyanuric chloride to the solvent is 1:(5-10).

[0031] In one or more embodiments, the alkali metal-substituted tert-butanol compound is selected from one or more of sodium tert-butoxide, lithium tert-butoxide, and potassium tert-butoxide, and preferably sodium tert-butoxide.

[0032] In one or more embodiments, in step (1), the reaction temperature is 10-40 °C.

[0033] In one or more embodiments, in step (1), the molar ratio of cyanuric chloride to the alkali metal-substituted tert-butanol compound is 1:(1-1.5).

[0034] In one or more embodiments, in step (1), the alkali metal-substituted tert-butanol compound is added to the reaction system of step (1) in a one-time or batch manner; preferably, the alkali metal-substituted tert-butanol compound is added to the reaction system of step (1) in a batch manner.

[0035] In one or more embodiments, in step (2), the molar ratio of biphenyl to 2,4-dichloro-6-tert-butoxy-1,3,5-triazine prepared in step (1) is (2-2.5):1.

[0036] In one or more embodiments, in step (2), the Friedel-Crafts reaction is carried out under the action of a Lewis acid catalyst; preferably, the Lewis acid catalyst is selected from one or more of anhydrous aluminum trichloride, zinc chloride, ferrous chloride, copper chloride, boron trifluoride, niobium pentachloride, and cerium trifluoromethanesulfonate; preferably, the molar ratio of the Lewis acid catalyst to 2,4-dichloro-6-tert-butoxy-1,3,5-triazine prepared in step (1) is (2-3):1.

[0037] In one or more embodiments, in step (2), the Friedel-Crafts reaction is carried out in a solvent; preferably, the solvent is selected from one or more of ortho-dichlorobenzene, meta-dichlorobenzene, para-dichlorobenzene, and dichlorocyclohexane, preferably ortho-dichlorobenzene; preferably, the mass ratio of biphenyl to the solvent is 1:(3-15).

[0038] In one or more embodiments, in step (2), the reaction temperature is 80-120 °C.

[0039] In one or more embodiments, in step (2), first mix 2,4-dichloro-6-tert-butoxy-1,3,5-triazine prepared in step (1) and the Lewis acid catalyst evenly, raise the temperature, then add biphenyl dissolved in the solvent, and then carry out the Friedel-Crafts reaction.

[0040] In one or more embodiments, during the mixing process, the temperature of the mixture of 2,4-dichloro-6-tert-butoxy-1,3,5-triazine prepared in step (1) and the Lewis acid catalyst when adding biphenyl dissolved in the solvent is 40-60 °C.

[0041] In one or more embodiments, in step (3), the chlorinating reagent is selected from one or more of thionyl chloride, phosphorus trichloride, and phosphorus oxychloride, preferably thionyl chloride.

[0042] In one or more embodiments, in step (3), the molar ratio of 2,4-bis([1,1'-biphenyl]-4-yl)-6-tert-butoxy-1,3,5-triazine prepared in step (2) to the chlorinating reagent is 1:(1.5-3).

[0043] In one or more embodiments, in step (3), the chlorination reaction is carried out under the action of a catalyst; preferably, the catalyst is selected from one or both of N,N-dimethylformamide and N,N-dimethylacetamide; preferably, the molar ratio of 2,4-bis([1,1'-biphenyl]-4-yl)-6-tert-butoxy-1,3,5-triazine prepared in step (2) to the catalyst is 1:(0.3-1).

[0044] In one or more embodiments, in step (3), the chlorination reaction is carried out in a solvent; preferably, the solvent is selected from one or more of ortho-dichlorobenzene, meta-dichlorobenzene, para-dichlorobenzene and dichlorocyclohexane, preferably ortho-dichlorobenzene; preferably, the mass ratio of 2,4-bis([1,1'-biphenyl]-4-yl)-6-tert-butoxy-1,3,5-triazine prepared in step (2) to the solvent is 1:(5-10).

[0045] In one or more embodiments, in step (3), the reaction temperature is 75-85 °C.

[0046] In one or more embodiments, the same solvent is used in steps (1), (2) and (3). Description of the Drawings

[0047] Figure 1 High performance liquid chromatography (HPLC) of 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine prepared in Example 1.

[0048] Figure 2 Proton nuclear magnetic resonance spectrum (HNMR) of 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine prepared in Example 1. Detailed Description of the Invention

[0049] To enable those skilled in the art to understand the features and effects of the present invention, the following provides a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein shall have the ordinary meaning understood by those skilled in the art with respect to the present invention. In case of conflict, the definition in this specification shall prevail.

[0050] The theories or mechanisms described and disclosed herein, whether correct or incorrect, shall not in any way limit the scope of the present invention, that is, the present invention may be implemented without being limited by any specific theory or mechanism.

[0051] In this text, terms such as "comprising", "including", "containing" and similar terms encompass the meanings of "consisting essentially of" and "consisting of". For example, when this text discloses that "A comprises B and C", "A consists essentially of B and C" and "A consists of B and C" should be considered to have been disclosed in this text.

[0052] In this text, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents and concentrations, are only for the sake of brevity and convenience. Accordingly, the description of a numerical range or percentage range should be regarded as having covered and specifically disclosed all possible sub-ranges and individual numerical values (including integers and fractions) within the range.

[0053] In this text, unless otherwise specified, percentages refer to mass percentages and ratios refer to mass ratios.

[0054] In this text, when describing embodiments or examples, it should be understood that it is not intended to limit the present invention to these embodiments or examples. On the contrary, all alternatives, improvements and equivalents of the methods and materials described in the present invention can be covered within the scope defined by the claims.

[0055] In this text, for the sake of concise description, all possible combinations of all technical features in each embodiment or example are not described. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered to be within the scope described in this specification.

[0056] The present invention provides a method for preparing 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine, and the method comprises the following steps:

[0057] (1) Subjecting cyanuric chloride and an alkali metal-substituted tert-butanol compound to a substitution reaction to obtain 2,4-dichloro-6-tert-butoxy-1,3,5-triazine;

[0058] (2) Subjecting the 2,4-dichloro-6-tert-butoxy-1,3,5-triazine obtained in step (1) and biphenyl to a Friedel-Crafts reaction to obtain 2,4-bis([1,1'-biphenyl]-4-yl)-6-tert-butoxy-1,3,5-triazine;

[0059] (3) Subjecting the 2,4-bis([1,1'-biphenyl]-4-yl)-6-tert-butoxy-1,3,5-triazine obtained in step (2) to a chlorination reaction under the action of a chlorinating reagent to obtain 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine.

[0060] In the present invention, step (1) is a substitution reaction with high selectivity, and it is difficult to generate disubstituted products, which is beneficial to improving the yield of the substitution reaction and further improving the yield of the total reaction.

[0061] In step (1), the substitution reaction can be carried out in a solvent.

[0062] In step (1), the solvent can be one or more selected from o-dichlorobenzene (o-DCB), m-dichlorobenzene, p-dichlorobenzene, and dichlorocyclohexane, and preferably o-dichlorobenzene.

[0063] In step (1), the mass ratio of cyanuric chloride to the solvent can be 1:(5 - 10), such as 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, 1:8.5, 1:9, 1:9.5, 1:10.

[0064] In step (1), the alkali metal-substituted tert-butanol compound can be one or more selected from sodium tert-butoxide, lithium tert-butoxide, and potassium tert-butoxide, and preferably sodium tert-butoxide. In some embodiments, using sodium tert-butoxide as a reactant can improve the reaction yield.

[0065] In step (1), the reaction temperature can be 10 - 40 °C, such as 15 °C, 20 °C, 25 °C, 30 °C, 35 °C. The substitution reaction is carried out at the above reaction temperature, the reaction is mild, the conditions are not harsh, which is conducive to large-scale industrial production.

[0066] In step (1), the molar ratio of cyanuric chloride to the alkali metal-substituted tert-butanol compound can be 1:(1 - 1.5), such as 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5.

[0067] In step (1), the alkali metal-substituted tert-butanol compound is added to the reaction system of step (1) in one-time or in batches. Preferably, the alkali metal-substituted tert-butanol compound is added to the reaction system of step (1) in batches. In some embodiments, adding the alkali metal-substituted tert-butanol compound to the reaction system of step (1) in batches can improve the reaction yield.

[0068] In the present invention, after the reaction of step (1) is completed, water is added and stirred, then left to stand for phase separation. The lower organic phase is separated out, and after drying to remove water, a solution of 2,4-dichloro-6-tert-butoxy-1,3,5-triazine containing the solvent is obtained. This separation and purification process only requires liquid-liquid phase separation. After simple dehydration of the organic phase, the Friedel-Crafts reaction can be directly carried out, and the separation step is simple.

[0069] In step (2), the molar ratio of biphenyl to 2,4-dichloro-6-tert-butoxy-1,3,5-triazine prepared in step (1) can be (2-2.5):1, such as 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1.

[0070] In step (2), the Friedel-Crafts reaction can be carried out under the action of a Lewis acid catalyst.

[0071] In step (2), the Lewis acid catalyst can be one or more selected from anhydrous aluminum trichloride, zinc chloride, ferrous chloride, copper chloride, boron trifluoride, niobium pentachloride, and cerium trifluoromethanesulfonate.

[0072] In step (2), the molar ratio of the Lewis acid catalyst to 2,4-dichloro-6-tert-butoxy-1,3,5-triazine prepared in step (1) can be (2-3):1, such as 2:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1, 3:1.

[0073] In step (2), the Friedel-Crafts reaction can be carried out in a solvent.

[0074] In step (2), the solvent can be one or more selected from o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, and dichlorocyclohexane, preferably o-dichlorobenzene.

[0075] In step (2), the mass ratio of biphenyl to the solvent can be 1:(3-15), such as 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14.

[0076] In step (2), the reaction temperature can be 80-120 °C, such as 80 °C, 85 °C, 90 °C, 95 °C, 100 °C, 105 °C, 110 °C, 115 °C, 120 °C.

[0077] In step (2), first mix 2,4-dichloro-6-tert-butoxy-1,3,5-triazine prepared in step (1) and the Lewis acid catalyst evenly, heat up and then add biphenyl dissolved in the solvent, and then carry out the Friedel-Crafts reaction.

[0078] In step (2), during the mixing process, the temperature of the mixture of 2,4-dichloro-6-tert-butoxy-1,3,5-triazine prepared in step (1) and the Lewis acid catalyst when adding biphenyl dissolved in the solvent can be 40-60 °C, such as 40 °C, 45 °C, 50 °C, 55 °C, 60 °C.

[0079] In the present invention, after the reaction in step (2) is completed, the reaction mixture is cooled and quenched with water. The precipitated solid is collected by filtration, and the filter cake is washed by slurrying. After filtration and drying, 2,4-bis([1,1'-biphenyl]-4-yl)-6-tert-butoxy-1,3,5-triazine is obtained.

[0080] In step (3), the reaction progress can be monitored by liquid chromatography.

[0081] In step (3), the chlorinating reagent can be one or more selected from thionyl chloride, phosphorus trichloride, and phosphorus oxychloride, preferably thionyl chloride. In some embodiments, using thionyl chloride as the chlorinating reagent can achieve higher yields and product purities.

[0082] In step (3), the molar ratio of 2,4-bis([1,1'-biphenyl]-4-yl)-6-tert-butoxy-1,3,5-triazine prepared in step (2) to the chlorinating reagent can be 1:(1.5 - 3), such as 1:1.5, 1:1.8, 1:2, 1:2.1, 1:2.4, 1:2.7.

[0083] In step (3), the chlorination reaction can be carried out under the action of a catalyst.

[0084] In step (3), the catalyst can be one or two selected from N,N-dimethylformamide (DMF) and N,N-dimethylacetamide.

[0085] In step (3), the molar ratio of 2,4-bis([1,1'-biphenyl]-4-yl)-6-tert-butoxy-1,3,5-triazine prepared in step (2) to the catalyst can be 1:(0.3 - 1). For example, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1.

[0086] In step (3), the chlorination reaction can be carried out in a solvent.

[0087] In step (3), the solvent can be one or more selected from o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, and dichlorocyclohexane, preferably o-dichlorobenzene.

[0088] In step (3), the mass ratio of 2,4-bis([1,1'-biphenyl]-4-yl)-6-tert-butoxy-1,3,5-triazine prepared in step (2) to the solvent can be 1:(5 - 10), such as 1:5, 1:6, 1:7, 1:8, 1:9, 1:10.

[0089] In step (3), the reaction temperature can be 75 - 85 °C, such as 75 °C, 77 °C, 79 °C, 81 °C, 83 °C, 85 °C.

[0090] In some embodiments, the same solvent can be used in steps (1), (2) and (3). This is beneficial to avoid introducing new impurities and reduce the separation and purification operation steps.

[0091] In the present invention, after the reaction in step (3) is completed, the chlorinating reagent is removed by concentration under reduced pressure. n-Heptane is added to the remaining part and cooled to room temperature, followed by filtration, washing, and drying under vacuum to obtain 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine.

[0092] Compared with the prior art, the present invention has the following beneficial effects: the raw materials are cheap and easily available, the reaction conditions are mild, the separation process is simple, the reaction selectivity is relatively high and the yield is relatively high, the obtained product has a relatively high purity, which is convenient for reaction control and meets the requirements of industrial scale-up production, and the waste is relatively less, and resource recycling can be achieved.

[0093] The present invention will be described below by way of specific embodiments. It should be understood that these embodiments are merely illustrative and are not intended to limit the scope of the present invention. The methods, reagents and materials used in the embodiments are conventional methods, reagents and materials in the art unless otherwise specified. The starting compounds in the embodiments can be obtained through commercial channels.

[0094] Example 1

[0095] A preparation method of a key intermediate of a s-triazine type ultraviolet absorber UV-1600, the method comprising the following steps:

[0096] (1) Synthesis of 2,4-dichloro-6-tert-butoxy-1,3,5-triazine (Intermediate 1):

[0097] 10.0 g (54.2 mmol) of cyanuric chloride and 50 mL of o-dichlorobenzene (o-DCB) were added to a three-necked flask, stirred and dispersed evenly. 5.4 g (56.2 mmol) of sodium tert-butoxide was added in batches at 25 °C. After the addition was completed, the reaction was continued for 20 min. After the reaction was completed, 20 g of deionized water was added, stirred and allowed to stand for phase separation. The lower organic phase was separated, dried to remove water, and an o-dichlorobenzene solution containing 2,4-dichloro-6-tert-butoxy-1,3,5-triazine was obtained. The selectivity was 99.5%, the yield was 97.6%, and the purity measured by HPLC was 99.3%.

[0098] 1 H NMR (400 MHz, DMSO-d 6 ) δ (ppm): 1.68 (s, 9H).

[0099]

[0100] (2) Synthesis of 2,4-bis([1,1'-biphenyl]-4-yl)-6-tert-butoxy-1,3,5-triazine (Intermediate 2):

[0101] Add the o-dichlorobenzene solution containing 2,4-dichloro-6-tert-butoxy-1,3,5-triazine (0.05 mol) prepared in step (1) and 17.6 g (0.13 mol) of anhydrous aluminum trichloride to a three-necked flask, stir and disperse evenly, and heat up to 50 °C. Dissolve 17.5 g (0.11 mol) of biphenyl in 40 mL of o-dichlorobenzene, and add it to the above reaction solution at one time. After adding, heat up to 100 °C and stir for 2 h. After all the raw materials are converted, cool the reaction mixture to 80 °C and pour it into 105 g of distilled water for quenching. Filter and collect the precipitated yellow solid, wash the filter cake with n-heptane by pulping, filter to obtain the yellow solid product, dry it at room temperature, and obtain 23.03 g of the product with a yield of 95.1% and a purity of 98.8% measured by HPLC.

[0102]

[0103] 1 H NMR (400 MHz, DMSO-d 6 ) δ (ppm): 7.82 (d, J = 8.3 Hz, 4H), 7.64 (d, J = 8.4 Hz, 4H), 7.41 (d, J = 7.6 Hz, 4Η), 7.33 (t, J = 7.5Ηz, 4Η), 7.26 (t, J = 7.3 Hz, 2Η), 1.53 (s, 9H).

[0104] (3) Synthesis of 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine (Intermediate 3):

[0105] Add 20.0 g (0.043 mol) of 2,4-bis([1,1'-biphenyl]-4-yl)-6-tert-butoxy-1,3,5-triazine prepared in step (2), 100 mL of o-dichlorobenzene, 2.0 mL (0.026 mol) of DMF, and 10.4 g (0.087 mol) of thionyl chloride to a reaction flask, reflux at 80 °C for 2 h, monitor the reaction process by liquid chromatography, and after all the raw materials are converted, evaporate the excess thionyl chloride under reduced pressure. Then, add 250 mL of n-heptane to the residue and cool the reaction mixture to room temperature. Filter the precipitated solid, wash the filter cake with cold methanol and dry it in vacuo to obtain 16.67 g of 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine with a yield of 90.8% and a purity of 99.2% measured by HPLC.

[0106]

[0107] 1 1H NMR (400 MHz, DMSO-d 6 ) δ (ppm): 8.64 (d, J = 8.5 Hz, 4H), 7.96 (d, J = 8.5 Hz, 4H), 7.81 (d, J = 7.2 Hz, 4H), 7.54 (t, J = 7.5 Hz, 4H), 7.50–7.42 (m, 2H).

[0108] Figure 1 and Figure 2 are the high-performance liquid chromatography and proton nuclear magnetic resonance spectra of the product 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine, respectively.

[0109] Example 2

[0110] In step (1), the amount of sodium tert-butoxide was changed so that the molar ratio of cyanuric chloride to sodium tert-butoxide in the feed was 1:1, and other conditions were the same as those in step (1) of Example 1. The yield of intermediate 1 was 95.8% and the purity was 98.2%.

[0111] Example 3

[0112] In step (1), the amount of sodium tert-butoxide was changed so that the molar ratio of cyanuric chloride to sodium tert-butoxide in the feed was 1:1.1, and other conditions were the same as those in step (1) of Example 1. The yield of intermediate 1 was 96.3% and the purity was 98.7%.

[0113] Example 4

[0114] In step (1), sodium tert-butoxide was added in one portion, and other conditions were the same as those in step (1) of Example 1. The yield of intermediate 1 was 94.2% and the purity was 97.7%.

[0115] Example 5

[0116] In step (1), an equimolar amount of lithium tert-butoxide was used instead of sodium tert-butoxide for feeding, the reaction time was extended to 2 h, and other conditions were the same as those in step (1) of Example 1. The yield of intermediate 1 was 97.9% and the purity was 99.5%.

[0117] Example 6

[0118] In step (1), an equimolar amount of potassium tert-butoxide was used instead of sodium tert-butoxide for feeding, and other conditions were the same as those in step (1) of Example 1. The yield of intermediate 1 was 88.6% and the purity was 90.1%.

[0119] Example 7

[0120] Step (1) was the same as step (1) of Example 1.

[0121] In step (2), change the dosage of biphenyl so that the molar ratio of intermediate 1, anhydrous aluminum trichloride, and biphenyl in the feed is 1:2.6:2.0. Other conditions are the same as those in step (2) of Example 1, and the yield of intermediate 2 is 91.4%.

[0122] Example 8

[0123] Step (1) is the same as step (1) of Example 1.

[0124] In step (2), change the dosage of anhydrous aluminum trichloride so that the molar ratio of intermediate 1, anhydrous aluminum trichloride, and biphenyl in the feed is 1:2.2:2.2. Other conditions are the same as those in step (2) of Example 1, and the yield of intermediate 2 is 90.3%.

[0125] Example 9

[0126] Step (1) is the same as step (1) of Example 1.

[0127] In step (2), change the dosage of anhydrous aluminum trichloride so that the molar ratio of intermediate 1, anhydrous aluminum trichloride, and biphenyl in the feed is 1:3.0:2.2. Other conditions are the same as those in step (2) of Example 1, and the yield of intermediate 2 is 95.5%.

[0128] Example 10

[0129] Steps (1) and (2) are the same as steps (1) and (2) of Example 1.

[0130] In step (3), change the dosage of DMF so that the molar ratio of intermediate 2, thionyl chloride, and DMF in the feed is 1:2:0.3. Other conditions are the same as those in step (3) of Example 1, and the yield of intermediate 3 is 91.4% and the purity is 95.8%.

[0131] Example 11

[0132] Steps (1) and (2) are the same as steps (1) and (2) of Example 1.

[0133] In step (3), change the dosage of DMF so that the molar ratio of intermediate 2, thionyl chloride, and DMF in the feed is 1:2:1.0. Other conditions are the same as those in step (3) of Example 1, and the yield of intermediate 3 is 86.2% and the purity is 99.1%.

[0134] Example 12

[0135] Steps (1) and (2) are the same as steps (1) and (2) of Example 1.

[0136] In step (3), the amount of thionyl chloride was changed so that the molar ratio of intermediate 2, thionyl chloride, and DMF in the feed was 1:1.5:0.6, and other conditions were the same as those in step (3) of Example 1. The yield of intermediate 3 was 81.3% and the purity was 94.9%.

[0137] Example 13

[0138] Steps (1) and (2) were the same as steps (1) and (2) of Example 1.

[0139] In step (3), phosphorus trichloride in an equimolar amount was used instead of thionyl chloride for feeding, and other conditions were the same as those in step (3) of Example 1. The yield of intermediate 3 was 89.1% and the purity was 98.7%.

Claims

1. A method for preparing 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine, characterized in that, The method includes the following steps: (1) Subject cyanuric chloride and an alkali metal-substituted tert-butanol compound to a substitution reaction to obtain 2,4-dichloro-6-tert-butoxy-1,3,5-triazine; (2) Subject the 2,4-dichloro-6-tert-butoxy-1,3,5-triazine obtained in step (1) and biphenyl to a Friedel-Crafts reaction to obtain 2,4-bis([1,1'-biphenyl]-4-yl)-6-tert-butoxy-1,3,5-triazine; (3) Subject the 2,4-bis([1,1'-biphenyl]-4-yl)-6-tert-butoxy-1,3,5-triazine obtained in step (2) to a chlorination reaction under the action of a chlorinating reagent to obtain 2,4-bis([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine.

2. The method according to claim 1, wherein In step (1), the substitution reaction is carried out in a solvent; preferably, the solvent is selected from one or more of ortho-dichlorobenzene, meta-dichlorobenzene, para-dichlorobenzene, and dichlorocyclohexane; preferably, the mass ratio of cyanuric chloride to the solvent is 1:(5-10).

3. The method according to claim 1, wherein The method has one or more of the following characteristics: In step (1), the alkali metal-substituted tert-butanol compound is selected from one or more of sodium tert-butoxide, lithium tert-butoxide, and potassium tert-butoxide, preferably sodium tert-butoxide; In step (1), the reaction temperature is 10-40 °C; In step (1), the molar ratio of cyanuric chloride to the alkali metal-substituted tert-butanol compound is 1:(1-1.5).

4. The method according to claim 1, wherein In step (1), the alkali metal-substituted tert-butanol compound is added to the reaction system of step (1) in a one-time or batchwise manner; preferably, the alkali metal-substituted tert-butanol compound is added to the reaction system of step (1) in a batchwise manner.

5. The method according to claim 1, wherein The method has one or more of the following characteristics: In step (2), the molar ratio of biphenyl to the 2,4-dichloro-6-tert-butoxy-1,3,5-triazine obtained in step (1) is (2-2.5):1; In step (2), the Friedel-Crafts reaction is carried out under the action of a Lewis acid catalyst; preferably, the Lewis acid catalyst is selected from one or more of anhydrous aluminum trichloride, zinc chloride, ferrous chloride, copper chloride, boron trifluoride, niobium pentachloride, and cerium trifluoromethanesulfonate; preferably, the molar ratio of the Lewis acid catalyst to the 2,4-dichloro-6-tert-butoxy-1,3,5-triazine obtained in step (1) is (2-3):1; In step (2), the Friedel-Crafts reaction is carried out in a solvent; preferably, the solvent is selected from one or more of ortho-dichlorobenzene, meta-dichlorobenzene, para-dichlorobenzene, and dichlorocyclohexane; preferably, the mass ratio of biphenyl to the solvent is 1:(3-15).

6. The method according to claim 1, wherein In step (2), the reaction temperature is 80-120 °C.

7. The method according to claim 1, wherein In step (2), first mix the 2,4-dichloro-6-tert-butoxy-1,3,5-triazine obtained in step (1) and the Lewis acid catalyst evenly, heat up and then add biphenyl dissolved in the solvent, and then carry out the Friedel-Crafts reaction.

8. The method according to claim 7, wherein During the mixing process, when adding biphenyl dissolved in the solvent, the temperature of the mixture of 2,4-dichloro-6-tert-butoxy-1,3,5-triazine and the Lewis acid catalyst prepared in step (1) is 40 to 60 °C.

9. The method according to claim 1, characterized in that, The method has one or more of the following characteristics: In step (3), the chlorinating reagent is selected from one or more of thionyl chloride, phosphorus trichloride, and phosphorus oxychloride, preferably thionyl chloride; In step (3), the molar ratio of 2,4-bis([1,1'-biphenyl]-4-yl)-6-tert-butoxy-1,3,5-triazine prepared in step (2) to the chlorinating reagent is 1:(1.5 - 3); In step (3), the chlorination reaction is carried out under the action of a catalyst; preferably, the catalyst is selected from one or two of N,N-dimethylformamide and N,N-dimethylacetamide; preferably, the molar ratio of 2,4-bis([1,1'-biphenyl]-4-yl)-6-tert-butoxy-1,3,5-triazine prepared in step (2) to the catalyst is 1:(0.3 - 1); In step (3), the chlorination reaction is carried out in a solvent; preferably, the solvent is selected from one or more of o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, and dichlorocyclohexane; preferably, the mass ratio of 2,4-bis([1,1'-biphenyl]-4-yl)-6-tert-butoxy-1,3,5-triazine prepared in step (2) to the solvent is 1:(5 - 10); In step (3), the reaction temperature is 75 to 85 °C.

10. The method according to claim 1, wherein The same solvent is used in step (1), step (2), and step (3).

Images