WO2021022731A1 - Method for preparing intermediate of ultraviolet light absorber uv-1600 - Google Patents

Abstract

Provided is a method for preparing an intermediate of an ultraviolet light absorber UV-1600, in particular, a method for preparing 2,4-bis(4-biphenylyl)-6-(2,4-dyhydroxy)phenyl-1,3,5-triazine as an intermediate of the ultraviolet light absorber UV-1600. The method involves subjecting cyanuric chloride and biphenyl, as raw materials, to a Friedel-Crafts alkylation reaction, with aluminum trichloride as a catalyst and HCl gas as a cocatalyst, in order to obtain 2,4-bis(4-biphenylyl)-6-chloro-1,3,5-triazine, and then subjecting the latter to a Friedel-Crafts reaction with resorcinol to obtain the target product. In the method for preparing the intermediate of the ultraviolet light absorber UV-1600 of the present invention, with HCl gas as the cocatalyst, the catalytic activity of a catalytic system is greatly increased, and the yield of the product can be substantially improved. Same provides a new process route for the industrial production of UV-1600.

Description

A kind of preparation method of ultraviolet absorber UV-1600 intermediate Technical field

The invention belongs to the field of functional additives for polymer materials, and in particular relates to an ultraviolet absorber UV-1600 intermediate 2,4-bis(4-biphenyl)-6-(2,4-dihydroxy)phenyl- Preparation method of 1,3,5-triazine.

Background technique

Compared with the most widely used benzotriazole and benzophenone UV absorbers, triazine UV absorbers are a relatively new type of product. This type of product has high efficiency (small addition amount and effective Good), low color (making it more widely used), high processing temperature, better compatibility (good dispersibility, and the molecule itself is easy to be chemically modified) and excellent broad-spectrum (in UVA and UVB UV It has the advantages of higher molar absorption coefficient in the light range. These advantages make triazine UV absorbers become the development direction of UV absorbers. Its basic structure is as follows:

Among them, R ₁ , R ₂ , R ₃ , and R _{4 are} mostly alkyl groups or H, such as UV-1164, UV-1577, and R _{5 are} mostly alkyl groups or hydroxy ethers, such as UV-400, UV-405.

UV-1600 (Tinuvin1600, CAS number: 204583-39-1), with the following structure, is the latest special triazine-based high-efficiency ultraviolet absorber developed and commercialized by BASF in Germany. It has extremely low volatility and high Ultraviolet absorption efficiency, good compatibility with various polymer substrates, does not affect transparency, does not affect coloring, and the required amount of addition is lower than traditional ultraviolet absorbers. Therefore, UV-1600 is hailed as "a new benchmark for the entire industry in terms of durability and long-term weather resistance", and its performance surpasses most UV absorbers currently on the market.

To date, there are still few reports on the synthesis process of UV-1600. The main difficulty lies in its intermediate 2,4-bis(4-biphenyl)-6-(2,4-dihydroxy)phenyl- Preparation of 1,3,5-triazine, traditional triazine ultraviolet absorbers, such as UV-1164, UV-400, UV-405 (the three have the same intermediate) and UV-460, their intermediates All adopt Friedel-Crafts alkylation method, which is highly feasible in industrial production, but among the intermediates of UV-1600, the substituents on the 2, 4 positions of the triazine ring are biphenyl, and the reaction of biphenyl with cyanuric chloride The activity is much worse than meta-xylene, and there is no selectivity. It is difficult to control the number of biphenyl substituents on the triazine ring by controlling the molar ratio of biphenyl to cyanuric chloride. Therefore, the Friedel-Crafts alkylation method is adopted. Has been greatly restricted. Currently, the preparation of UV-1600 intermediates mainly includes the following methods:

(1) Grignard reagent method, the reaction route is as follows:

At present, the most widely reported in the literature is the Grignard reagent method, but this process requires high water content in THF, is difficult to handle, and has a very low flash point (-17°C), which is relatively dangerous during production. Therefore, before this process In two steps, the preparation of Grignard reagent and the reaction between Grignard reagent and cyanuric chloride are basically difficult to industrially produce. In addition, Grignard reagent is very active and difficult to store. It can react with water and carbon dioxide, and the reaction is very fast. Therefore, the effective content of the material may be reduced during the feeding process, making accurate measurement difficult. Specific documents can be found in: Jingxi Huaagong, 28(3), 284-288; 2011, WO 2011067282, etc.

(2) Palladium catalytic method, the route is as follows:

The palladium catalysis method has good selectivity and mild synthesis conditions, but the biggest drawback is that the palladium catalyst is much more expensive than conventional catalysts (the palladium catalyst used in the first reaction is more expensive), although the amount required for each reaction Not much (3mol%), but its molecular weight is relatively large, resulting in a lot of actual feeding quality and high cost. For similar reactions, please refer to patent KR 2016132724.

(3) The route of the cyclization method is as follows:

There are many steps in this method. The triazine ring is obtained by the reaction of two intermediates to form a ring, and the intermediates need a separate process route to synthesize, and some raw materials, such as 4-methyl salicylamide, are more expensive. Combining all the steps, this route is not only long but also expensive, and the industrial production is not feasible. This method can refer to patent US6255438.

At present, the process route of UV-1600 intermediate 2,4-bis(4-biphenyl)-6-(2,4-dihydroxy)phenyl-1,3,5-triazine is highly dangerous , High cost and other issues, it is necessary to find an industrialization route with low risk factor, low operation difficulty and low cost.

Summary of the invention

In view of this, the present invention aims to propose a UV-1600 intermediate 2,4-bis(4-biphenyl)-6-(2,4-dihydroxy)phenyl-1,3,5 -The preparation method of triazine, including the step of making cyanuric chloride and biphenyl in the presence of a catalyst aluminum trichloride and a co-catalyst hydrogen chloride gas to carry out Friedel-Crafts alkylation reaction to produce a compound of formula I;

The inventor found through a lot of experiments that in the preparation process of the compound of formula I, without adding HCl gas, the reaction is almost difficult to proceed. Using aluminum trichloride as a catalyst and HCl gas as a co-catalyst can greatly improve the catalytic activity of the catalytic system. Significantly improve the reaction rate and reaction depth.

The amount of HCl gas is not particularly limited in the present invention, it is kept in excess, and HCl gas is continuously introduced during the reaction. In a specific embodiment, under normal temperature and pressure, the flow rate of HCl gas can be controlled to be 20-60 cm ³ /min (preferably 30-40 cm ³ /min).

In order to achieve the above objective, the technical solution of the present invention is achieved as follows:

A method for preparing ultraviolet absorber UV-1600 intermediate 2,4-bis(4-biphenyl)-6-(2,4-dihydroxy)phenyl-1,3,5-triazine, and its characteristics The method includes the steps of making cyanuric chloride and biphenyl in the presence of a catalyst aluminum trichloride and a co-catalyst hydrogen chloride gas to perform Friedel-Crafts alkylation reaction to produce a compound of formula I;

As a preferred embodiment of the present invention, the preparation of the compound of formula I is carried out in a solvent selected from one or more of chlorobenzene, o-dichlorobenzene, and nitrobenzene.

As a preferred embodiment of the present invention, in the preparation process of the compound of formula I, biphenyl is first dissolved in a solvent, and then it is added dropwise to the solution in which cyanuric chloride is dissolved.

As a more preferred embodiment of the present invention, in the preparation process of the compound of formula I, the mass ratio of biphenyl to solvent is 1: (2-5).

As a preferred embodiment of the present invention, the preparation of the compound of formula I is carried out at a temperature of 0-30°C.

As a more preferred embodiment of the present invention, in the preparation process of the compound of formula I, the molar ratio of cyanuric chloride, biphenyl and aluminum trichloride is 1: (2-2.5): (1.5-3).

As a preferred embodiment of the present invention, in the preparation process of the compound of formula I, cyanuric chloride and aluminum trichloride are dissolved in a solvent and cooled to 0-3°C under the protection of an inert gas; hydrogen chloride gas is introduced into the system and The solution containing biphenyl is added dropwise, and the temperature of the system is maintained at 0-3°C during the dropping process; after the dropwise addition, the temperature is raised to 15-30°C to continue the reaction, and it is obtained. The solvent here refers to one or more of the above-mentioned chlorobenzene, o-dichlorobenzene, and nitrobenzene. The inert gas is preferably nitrogen.

Preferably, in the preparation process of the above formula I compound, the solution containing biphenyl refers to a solution formed by dissolving biphenyl in a solvent.

Preferably, the dropping time of the biphenyl-containing solution is 1-4 hours.

Preferably, during the preparation process of the above formula I compound, after passing hydrogen chloride gas into the system and dripping the solution containing biphenyl, the reaction is carried out at 0-3°C for a period of time and then the temperature is raised to 15-30°C to continue the reaction. Wherein, the "period of time" can be 0.5-1.5h, preferably 1h. More preferably, the reaction is carried out at 30°C after raising the temperature.

Preferably, the preparation process of the above-mentioned compound of formula I further includes a process of post-processing the reaction liquid after the temperature-raising reaction. In this post-treatment, the reaction liquid is phase-separated, and then the organic phase is crystallized to obtain the compound of formula I.

Specifically, the method for phase separation of the reaction liquid is: pour the reaction liquid into dilute acid, separate the water phase, and perform crystallization treatment on the organic phase.

As a more preferred embodiment of the present invention, the crystallization solvent in the preparation reaction post-treatment process of the compound of formula I is at least one of methanol, ethanol, propanol, and isopropanol.

As a preferred embodiment of the present invention, the preparation method further includes the step of reacting the compound of formula I with resorcinol under the action of the catalyst aluminum trichloride to produce the compound of formula II after the preparation of the compound of formula I is completed;

More specifically, the preparation of the compound of formula II includes the following steps:

1) Dissolve the formula I compound and aluminum trichloride in the solvent, stir and raise the temperature for a period of time;

2) The solvent is recovered, filtered and dried with suction, and the solid is refined with a crystallization solvent to obtain the compound of formula II.

Preferably, in step 1), add formula I compound and aluminum trichloride into another reaction vessel, then add formula amount of solvent, stir and heat to 85-100°C; preferably, stir here Warm up to 90-95°C.

Preferably, the reaction in step 1) is carried out in a solvent, which is the same as the solvent used when preparing the compound of formula I.

Preferably, in step 1), the reaction time is 2-4 hours, preferably 3 hours.

Preferably, in step 2), the method for recovering the solvent is: pour the reaction liquid into dilute acid, raise the temperature, steam distillation, and recover the solvent.

As a preferred embodiment of the present invention, in the preparation process of the compound of formula II, the molar ratio of the compound of formula I, resorcinol and aluminum trichloride is 1:(1-1.1):(1-1.2).

As a preferred embodiment of the present invention, in the post-treatment process of the preparation reaction of the compound of formula II, that is, in step 2), one or more of toluene, xylene, and chlorobenzene is used as the crystallization solvent of the compound of formula II.

On the basis of conforming to common knowledge in the field, the above-mentioned preferred conditions can be combined with each other to obtain preferred embodiments of the present invention.

The raw materials and reagents involved in the present invention are commercially available.

Compared with the prior art, the preparation method of the present invention has the following advantages:

(1) Intermediate 2,4-bis(4-biphenyl)-6-chloro-1,3,5-triazine is synthesized by Friedel-Crafts alkylation method, which avoids the danger of Grignard reagent method In addition to higher operating difficulty, the cost of the catalyst is much lower than that of the palladium catalyst, and the process route is short, the practicability is high, and it is suitable for industrial production.

(2) The purification process of intermediate 2,4-bis(4-biphenyl)-6-chloro-1,3,5-triazine is simple and easy.

(3) The post-treatment and purification process of the target product 2,4-bis(4-biphenyl)-6-(2,4-dihydroxy)phenyl-1,3,5-triazine is simple and efficient.

detailed description

Except for definitions, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which the present invention belongs. The test reagents used in the following examples are conventional biochemical reagents unless otherwise specified; the experimental methods are conventional methods unless otherwise specified.

The present invention will be described in detail below in conjunction with embodiments.

Comparative example

A method for preparing ultraviolet absorber UV-1600 intermediate 2,4-bis(4-biphenyl)-6-(2,4-dihydroxy)phenyl-1,3,5-triazine, as follows :

Step 1: Weigh 27.6g (0.15mol) cyanuric chloride and 40.0g (0.30mol) aluminum trichloride, and add them to a 1000ml four-necked flask in turn, then add 250ml of chlorobenzene, protected by nitrogen, and then put the four-necked flask Place in an ice-water bath and cool to 0-3°C; then start to add biphenyl chlorobenzene solution (biphenyl 46.26g, 0.3mol, dissolved in 150ml chlorobenzene) dropwise, dripping time is 1h, dripping temperature has been 0-3℃, after dripping, react at this temperature for 1h, then remove the ice-water bath, heat up to 30℃, and react at T=30℃ for 3h; stop the reaction, then pour the reaction solution into 100ml at 30℃3 Separate the aqueous phase from 5% dilute hydrochloric acid. The organic phase is directly crystallized by alcohol precipitation in 300 ml of methanol, and a white solid is precipitated. Suction filtration obtains 5.5-6 g of a white solid. The yield is about 10% and the HPLC purity is 94-95%.

Step 2: Weigh 15g (35.7mmol) 2,4-bis(4-biphenyl)-6-chloro-1,3,5-triazine, 5.3g (39.3mmol) aluminum trichloride and 3.93g ( 35.7mmol) resorcinol was added to a 250ml four-necked flask, and then 75ml of chlorobenzene was added, stirred, heated to 90-95°C, reacted for 3 hours and then stopped; the system was poured into 100ml of 3% dilute hydrochloric acid and heated , Steam distillation, recovery of chlorobenzene, suction filtration, drying, and purification of the solid with toluene to obtain the target product of yellow solid 13.8g, yield 78%, HPLC purity 98%, MS (MOLDI TOF) m/z (C ₃₃ H ₂₃ N ₃ O ₂ )[M] ⁺ =493.57, measured value 495.29.

Example 1

A method for preparing ultraviolet absorber UV-1600 intermediate 2,4-bis(4-biphenyl)-6-(2,4-dihydroxy)phenyl-1,3,5-triazine, as follows :

Step 1: Weigh 27.6g (0.15mol) cyanuric chloride and 40.0g (0.30mol) aluminum trichloride, and add them to a 1000ml four-necked flask in turn, then add 250ml of chlorobenzene, protected by nitrogen, and then put the four-necked flask Place in an ice water bath and cool to 0-3°C; then start to pass HCl gas into the system and start to add biphenyl chlorobenzene solution (biphenyl 46.26g, 0.3mol, dissolved in 150ml chlorobenzene) dropwise The time is 1h, and the temperature of the dripping is always 0-3℃. After the dripping is completed, react at this temperature for 1h, then remove the ice-water bath and heat up to 30℃. The color of the reaction system gradually deepens and finally becomes reddish black. After reacting at T=30°C for 3 hours, stop passing HCl gas; stop the reaction, then pour the reaction solution into 100ml 3wt% dilute hydrochloric acid at 30°C, separate the water phase, and directly crystallize the organic phase in 300ml methanol. A white solid was separated out and filtered with suction to obtain 35.5-36g of a white solid with a yield of 58-60%, HPLC purity of 94-95%, containing 3.5-4.0wt% 2,4,6-tris(4-biphenyl)- 1,3,5-Triazine.

Step 2: Weigh 15g (35.7mmol) 2,4-bis(4-biphenyl)-6-chloro-1,3,5-triazine, 5.3g (39.3mmol) aluminum trichloride and 3.93g ( 35.7mmol) resorcinol was added to a 250ml four-necked flask, and then 75ml of chlorobenzene was added, stirred, heated to 90-95°C, reacted for 3h, and then the reaction was stopped; pour the system into 100ml of 3wt% dilute hydrochloric acid and increase the temperature , Steam distillation, recovery of chlorobenzene, suction filtration, drying, and purification of the solid with toluene to obtain the target yellow solid 14.5g, yield 82%, HPLC purity 98%, MS (MOLDI TOF) m/z (C ₃₃ H ₂₃ N ₃ O ₂ )[M] ⁺ =493.57, measured value 495.29.

Example 2

A method for preparing ultraviolet absorber UV-1600 intermediate 2,4-bis(4-biphenyl)-6-(2,4-dihydroxy)phenyl-1,3,5-triazine, as follows :

Step 1: Weigh 27.6g (0.15mol) cyanuric chloride and 40.0g (0.30mol) aluminum trichloride, and add them to a 1000ml four-necked flask in turn, then add 250ml of chlorobenzene, protected by nitrogen, and then put the four-necked flask Place in an ice-water bath and cool to 0-3°C; then start to pass HCl gas into the system and start to add biphenyl chlorobenzene solution (diphenyl 57.82g, 0.375mol, dissolved in 180ml chlorobenzene) dropwise The addition time is 1h, and the dripping temperature is always 0-3℃. After dripping, react at this temperature for 1h, then remove the ice-water bath and heat up to 15℃. During the reaction process, the color of the system gradually deepens and finally becomes red and black. , T=15℃ react for 3h, then stop passing HCl gas; stop the reaction, then pour the reaction solution into 100ml 3wt% dilute hydrochloric acid at 15℃, separate the water phase, the organic phase will directly crystallize in 300ml methanol , A white solid separated out, filtered with suction to obtain 33g of a white solid, yield 55%, HPLC purity 95.4%, containing 3.4wt% 2,4,6-tris(4-biphenyl)-1,3,5-tri Azine.

Step 2: Weigh 15g (35.7mmol) 2,4-bis(4-biphenyl)-6-chloro-1,3,5-triazine, 5.3g (39.3mmol) aluminum trichloride and 3.93g ( 35.7mmol) resorcinol, add to a 250ml four-necked flask, then add 75ml of chlorobenzene, stir, warm up to 90-95℃, and stop the reaction after reacting for 3 hours; pour the system into 100ml 3wt% dilute hydrochloric acid and increase the temperature , Steam distillation, recovery of chlorobenzene, suction filtration, drying, and purification of the solid with toluene to obtain the target product as a yellow solid 14.5g, the yield is 82%, and the HPLC purity is 98%.

Example 3

A method for preparing ultraviolet absorber UV-1600 intermediate 2,4-bis(4-biphenyl)-6-(2,4-dihydroxy)phenyl-1,3,5-triazine, as follows :

Step 1: Weigh 27.6g (0.15mol) cyanuric chloride and 40.0g (0.30mol) aluminum trichloride, and add them to a 1000ml four-necked flask in turn, then add 250ml o-dichlorobenzene, nitrogen protection, and then add four The mouth flask was placed in an ice water bath and cooled to 0-3°C; then HCl gas was introduced into the system and the biphenyl o-dichlorobenzene solution (biphenyl 50.88g, 0.33mol, dissolved in 150ml o-dichlorobenzene) was added dropwise. Chlorobenzene), the dripping time is 1h, and the dripping temperature is always 0-3℃. After the dripping is completed, react at this temperature for 1h, then remove the ice water bath and heat up to 30℃. The color of the reaction system gradually deepens. It becomes red and black, reacting at T=30°C for 3h, then stop passing HCl gas; stop the reaction, then pour the reaction solution into 100ml 3wt% dilute hydrochloric acid at 30°C, separate the water phase, and the organic phase directly in 300ml Alcohol crystallized from ethanol to precipitate a white solid, which was filtered with suction to obtain 34 g of a white solid with a yield of 53.9% and an HPLC purity of 94.4%, containing 5 wt% of 2,4,6-tris(4-biphenyl)-1,3 ,5-Triazine.

Step 2: Weigh 15g (35.7mmol) 2,4-bis(4-biphenyl)-6-chloro-1,3,5-triazine, 5.3g (39.3mmol) aluminum trichloride and 3.93g ( 35.7mmol) resorcinol, add to a 250ml four-necked flask, then add 75ml o-dichlorobenzene, stir, heat up to 90-95℃, react for 3h, stop the reaction; pour the system into 100ml 3wt% dilute hydrochloric acid , Heating, steam distillation, recovery of o-dichlorobenzene, suction filtration, drying, the solid is refined with xylene to obtain the target product of yellow solid 13g, yield 73.8%, HPLC purity 98%.

Example 4

A method for preparing ultraviolet absorber UV-1600 intermediate 2,4-bis(4-biphenyl)-6-(2,4-dihydroxy)phenyl-1,3,5-triazine, as follows :

Step 1: Weigh 27.6g (0.15mol) cyanuric chloride and 40.0g (0.30mol) aluminum trichloride, and add them to a 1000ml four-necked flask in turn, then add 250ml of nitrobenzene, protect with nitrogen, and then add four-necked The bottle was placed in an ice water bath and cooled to 0-3°C; then HCl gas was introduced into the system and the nitrobenzene solution of biphenyl was added dropwise (biphenyl 46.26g, 0.3mol, dissolved in 150ml nitrobenzene) The dripping time is 1h, and the dripping temperature is always 0-3℃. After the dripping is completed, react at this temperature for 1h, then remove the ice water bath and heat up to 30℃. The color of the reaction system gradually deepens and finally becomes Red and black, react at T=30℃ for 3h, then stop passing HCl gas; stop the reaction, then pour the reaction solution into 100ml 3wt% dilute hydrochloric acid at 30℃, separate the water phase, and the organic phase directly in 300ml ethanol. After crystallization, a white solid was precipitated. Suction filtration yielded 35 g of a white solid. The yield was 54%. The HPLC purity was 94.8%, containing 4.5wt% of 2,4,6-tris(4-biphenyl)-1,3,5. -Triazine.

Step 2: Weigh 15g (35.7mmol) 2,4-bis(4-biphenyl)-6-chloro-1,3,5-triazine, 5.3g (39.3mmol) aluminum trichloride and 3.93g ( 35.7mmol) resorcinol was added to a 250ml four-necked flask, and then 75ml nitrobenzene was added, stirred, heated to 90-95°C, reacted for 3h, and then the reaction was stopped; pour the system into 100ml of 3wt% dilute hydrochloric acid and raise the temperature , Steam distillation, recovery of nitrobenzene, suction filtration, drying, and refining the solid with xylene to obtain 14 g of the target yellow solid with a yield of 79.5% and a purity of 98% by HPLC.

Example 5

A method for preparing ultraviolet absorber UV-1600 intermediate 2,4-bis(4-biphenyl)-6-(2,4-dihydroxy)phenyl-1,3,5-triazine, as follows :

Step 1: Weigh 27.6g (0.15mol) cyanuric chloride and 40.0g (0.30mol) aluminum trichloride, and add them to a 1000ml four-necked flask in turn, then add 250ml of chlorobenzene, protected by nitrogen, and then put the four-necked flask Place in an ice water bath and cool to 0-3°C; then start to pass HCl gas into the system and start to add biphenyl chlorobenzene solution (biphenyl 46.26g, 0.3mol, dissolved in 150ml chlorobenzene) dropwise The time is 1h, and the temperature of the dripping is always 0-3℃. After the dripping is completed, react at this temperature for 1h, then remove the ice-water bath and heat up to 30℃. The color of the reaction system gradually deepens and finally becomes reddish black. After reacting for 3 hours at T=30℃, stop passing HCl gas; stop the reaction, then pour the reaction solution into 100ml 3wt% dilute hydrochloric acid at 30℃, separate the water phase, and directly alcohol out the organic phase in 300ml isopropanol Crystallized and precipitated a white solid, which was filtered with suction to obtain 36 g of a white solid with a yield of 57.1% and a purity of 95.5% by HPLC, containing 4wt% of 2,4,6-tris(4-biphenyl)-1,3,5-tri Azine.

Step 2: Weigh 15g (35.7mmol) 2,4-bis(4-biphenyl)-6-chloro-1,3,5-triazine, 5.3g (39.3mmol) aluminum trichloride and 3.93g ( 35.7mmol) resorcinol, add to a 250ml four-necked flask, then add 75ml of chlorobenzene, stir, warm up to 90-95℃, and stop the reaction after reacting for 3 hours; pour the system into 100ml 3wt% dilute hydrochloric acid and increase the temperature , Steam distillation, recovery of chlorobenzene, suction filtration, drying, and purification of the solid with xylene to obtain the target product as a yellow solid 14.5g with a yield of 82% and a purity of 98% by HPLC.

It should be noted that in the above embodiments, "the color of the system gradually deepens during the reaction process, and finally becomes red-black", which means that the aluminum trichloride and the raw material form a complex, and the red-black is the color of the complex. It should also be noted that in the above embodiments, the flow rate of HCl gas under reaction conditions in step 1 is converted to a flow rate of 20-60 cm ³ /min under normal temperature and pressure.

The above descriptions are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the present invention. Within the scope of protection.

Claims (10)

1. A method for preparing ultraviolet absorber UV-1600 intermediate 2,4-bis(4-biphenyl)-6-(2,4-dihydroxy)phenyl-1,3,5-triazine, and its characteristics The method includes the steps of making cyanuric chloride and biphenyl in the presence of a catalyst aluminum trichloride and a co-catalyst hydrogen chloride gas to perform Friedel-Crafts alkylation reaction to produce a compound of formula I;

   
2. The preparation method according to claim 1, characterized in that: the preparation of the compound of formula I is carried out in a solvent, and the solvent is selected from one or more of chlorobenzene, o-dichlorobenzene, and nitrobenzene;

   Preferably, the biphenyl is first dissolved in the solvent, and then added dropwise into the solution with cyanuric chloride;

   Further preferably, the mass ratio of biphenyl to solvent is 1: (2-5).
3. The preparation method according to claim 1 or 2, characterized in that the preparation of the compound of formula I is carried out at a temperature of 0-30°C.
4. The preparation method according to claim 3, characterized in that: cyanuric chloride and aluminum trichloride are dissolved in a solvent, and cooled to 0-3°C under the protection of an inert gas; hydrogen chloride gas is introduced into the system and the containing For the solution of biphenyl, maintain the system temperature at 0-3°C during the dripping process; after the dripping, the temperature is raised to 15-30°C to continue the reaction, and it is obtained.
5. The preparation method according to any one of claims 1 to 4, wherein the molar ratio of cyanuric chloride, biphenyl and aluminum trichloride is 1: (2-2.5): (1.5-3).
6. The preparation method according to any one of claims 1 to 5, wherein at least one of methanol, ethanol, propanol, and isopropanol is used as the crystallization solvent of the compound of formula I in the post-reaction process.
7. The preparation method according to any one of claims 1 to 6, characterized in that it further comprises the step of reacting the compound of formula I with resorcinol under the action of the catalyst aluminum trichloride to produce the compound of formula II;

   
8. The preparation method according to claim 7, wherein the molar ratio of the compound of formula I, resorcinol, and aluminum trichloride is 1:(1-1.1):(1-1.2).
9. The preparation method according to claim 7 or 8, characterized in that the synthesis temperature of the compound of formula II is 85-100°C, preferably 90-95°C.
10. The preparation method according to any one of claims 7-9, wherein one or more of toluene, xylene, and chlorobenzene are used as the crystallization solvent of the compound of formula II during the post-reaction treatment.