A method for the synthesis of bromotriazines

Abstract

The application discloses a synthesis method of bromotriazine, and belongs to the technical field of organic synthesis. The method comprises the following steps: preparing an alumina-supported N,N-dimethylaminopyridine catalyst, filling the catalyst into a fixed bed reactor, introducing a mixed slurry of tribromophenol and a metal oxide and a cyanuric chloride slurry, and performing reaction by increasing temperature to obtain a crude product solution; and performing post-treatment to obtain a bromotriazine product. The application synthesizes an alumina-supported N,N-dimethylaminopyridine catalyst. The N,N-dimethylaminopyridine makes the reaction speed faster and the yield higher. The nanometer alumina support realizes the dealkalization synthesis of bromotriazine and accelerates the reaction efficiency. The continuous process realizes non-aqueous medium and low-temperature short-time reaction, and further avoids the occurrence of hydrolysis. The alumina-supported N,N-dimethylaminopyridine catalyst has high activity and high stability, simplifies the synthesis method, and is suitable for industrial large-scale production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of organic synthesis, and particularly relates to a synthesis method of brominated triazine. BACKGROUND

[0002] Brominated triazine is a new type of environmentally friendly flame retardant as a bromine / nitrogen synergistic flame retardant, has superior flame retardant effect, and has a small dosage. Brominated triazine is often used in plastic products such as ABS, PBT and PC due to good thermal stability, and has high whiteness and good light resistance, and is a good upgrade and replacement product of decabromide.

[0003] At present, the mainstream production method of brominated triazine is to dissolve tribromophenol in an organic solvent, then react with a sodium hydroxide solution, add triethylamine for catalysis, then add cyanuric chloride, separate layers and wash after reaction for a period of time, and then crystallize and dry to obtain the product. The common problems are that cyanuric chloride is hydrolyzed, the utilization rate of raw materials is low, and the yield is low.

[0004] For example, patent CN 117903073A uses metal oxides instead of sodium hydroxide to reduce the hydrolysis of cyanuric chloride, but the reaction rate is reduced. Patent CN 113214175A uses batch addition of cyanuric chloride and dropwise addition of liquid alkali to reduce the hydrolysis of cyanuric chloride, which is complicated and difficult to control. Patent CN 115785011A reduces the hydrolysis of cyanuric chloride by controlling the pH of the reaction system through an online pH meter, which is complex and difficult to control the pH precision of the sodium hydroxide solution. In summary, we need a suitable method to fundamentally reduce the hydrolysis of cyanuric chloride to reduce byproducts while not affecting the reaction efficiency, and to improve the utilization rate of raw materials and the yield. SUMMARY

[0005] The purpose of the embodiment of the present application is to provide a synthesis method of brominated triazine to solve the technical problems in the prior art that a large amount of alkali is needed in the synthesis system of brominated triazine, cyanuric chloride is easily hydrolyzed, there are many byproducts, and the yield is low.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is to provide a synthesis method of brominated triazine, which specifically comprises the following steps:

[0007] (1) preparing a catalyst: adding nano-aluminum oxide into hydrochloric acid and stirring, then performing an amination reaction with 3-aminopropyltriethoxysilane to prepare aminated aluminum oxide; performing a carboxylation reaction with N,N-dimethylaminopyridine and succinic anhydride in a solvent to generate carboxylated N,N-dimethylaminopyridine; and mixing and reacting aminated aluminum oxide, carboxylated N,N-dimethylaminopyridine, N,N-dimethylformamide and a condensing agent to prepare an aluminum oxide loaded N,N-dimethylaminopyridine catalyst;

[0008] (II) dissolving 2,4,6-tribromophenol in chlorobenzene solution, adding magnesium oxide powder to obtain a slurry of tribromophenol; dispersing cyanuric chloride in chlorobenzene solution to obtain a slurry of cyanuric chloride;

[0009] (III) filling the fixed bed reactor with alumina-supported N,N-dimethylaminopyridine catalyst, passing the slurry of tribromophenol and the slurry of cyanuric chloride, and heating to react to obtain a crude solution; washing, atmospheric distillation, crystallization, centrifugation, and drying of the crude solution to obtain the bromotriazine product; the reaction equation is as follows:

[0010] .

[0011] In one embodiment,

[0012] Step (I) the crystal form of the nano-alumina is γ-Al2O3, and the particle size of the nano-alumina is 50-80 nm.

[0013] In one embodiment,

[0014] Step (I) the concentration of hydrochloric acid is 6 M, the stirring temperature is 60 °C, and the stirring time is 2 h.

[0015] In one embodiment,

[0016] Step (I) the mass ratio of nano-alumina and 3-aminopropyltriethoxysilane is 1:0.2-0.4, the solvent for the amination reaction is anhydrous ethanol, the reaction time is 4 h, and the reaction temperature is 80 °C.

[0017] In one embodiment,

[0018] Step (I) the mass ratio of N,N-dimethylaminopyridine and succinic anhydride is 1:1.2-1.5, the solvent for the carboxylation reaction is triethylamine, the reaction time is 12 h, and the reaction temperature is 80 °C.

[0019] In one embodiment,

[0020] Step (I) the condensing agent is a mixture of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide, and the mixing mass ratio is 1:1.

[0021] In one embodiment,

[0022] Step (II) the mass ratio of 2,4,6-tribromophenol to chlorobenzene solution is 1:1.3-1.4, the molar ratio of 2,4,6-tribromophenol to magnesium oxide is 1:0.6-0.7, and the mass ratio of cyanuric chloride to chlorobenzene solution is 1:1.8-2.

[0023] In one embodiment,

[0024] The mass ratio of the cyanuric chloride slurry to the tribromophenol solution in step (three) is 1:4.9-5.3.

[0025] In one embodiment,

[0026] The temperature of the heating in step (three) is 55-60 ℃.

[0027] In one embodiment,

[0028] The flow rate of the tribromophenol solution and the cyanuric chloride slurry in step (three) is 20 ml / min.

[0029] The application provides an alumina-supported N,N-dimethylaminopyridine catalyst. The N,N-dimethylaminopyridine can catalyze a highly hindered and low-activity hydroxyl compound under mild conditions, the reaction speed is fast, and the yield is higher. The nanometer alumina support and the addition of magnesium oxide can replace a strong base to realize the dealkalization synthesis of bromotriazine and reduce the corrosion of the equipment in the synthesis. The use of the strong base is avoided, the hydrolysis of cyanuric chloride is reduced, the side reaction is extremely small, the quality of the product is improved, and the thermal stability is improved. On the other hand, the nanometer alumina has a large specific surface area and a strong loading capacity, and the reaction efficiency is accelerated. The continuous process realizes the non-aqueous medium and low-temperature short-time reaction, and further avoids the hydrolysis. The alumina-supported N,N-dimethylaminopyridine catalyst has high activity and high stability, simplifies the synthesis method, and is suitable for industrial large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative labor.

[0031] Figure 1 The liquid phase diagram of the product obtained in Example 1;

[0032] Figure 2 The thermogravimetric measurement diagram of the product obtained in Example 1;

[0033] Figure 3 The electron microscope diagram of the alumina-supported N,N-dimethylaminopyridine catalyst in Example 1. DETAILED DESCRIPTION

[0034] In order to make the technical problems, technical solutions and beneficial effects of the application more clearly understood, the application will be further described in detail. It should be understood that the specific embodiments described herein are only used to explain the application and not to limit the application.

[0035] Example 1

[0036] A method for synthesizing a brominated triazine, specifically comprising the following steps:

[0037] (I) Preparation of catalyst: 1 kg of nano-alumina with a particle size of 60 nm and a crystal form of γ crystal form was added to an appropriate amount of hydrochloric acid (6 M) and stirred at 60 °C for 2 h; then anhydrous ethanol, 0.3 kg of 3-aminopropyl triethoxysilane were added, and an amination reaction was carried out at 80 °C for 4 h; after the reaction was completed, the 3-aminopropyl triethoxysilane adsorbed on the surface was removed by washing with ethanol for multiple times and vacuum drying at 110 °C; thus, aminated alumina was prepared; 1 kg of N,N-dimethylaminopyridine and 1.3 kg of succinic anhydride were added to triethylamine, and a carboxylation reaction was carried out at 80 °C for 12 h; the triethylamine was removed by atmospheric distillation, and the remaining solid was washed with ethyl acetate to remove unreacted succinic anhydride; then, recrystallization was carried out using a mixed solvent of isopropyl alcohol / ethyl acetate (volume ratio of 1:3) to obtain white crystalline carboxylated N,N-dimethylaminopyridine; 500 g of aminated alumina, 500 g of carboxylated N,N-dimethylaminopyridine, 1.1 kg of N,N-dimethylformamide, 275 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 275 g of N-hydroxysuccinimide were mixed, and a reaction was carried out for 20 h; thus, an alumina-supported N,N-dimethylaminopyridine catalyst was prepared;

[0038] (II) 5 kg of 2,4,6-tribromophenol and 0.365 kg of magnesium oxide were dispersed in 6.5 kg of chlorobenzene to obtain 11.86 kg of a tribromophenol slurry; 5 kg of cyanuric chloride was dispersed in 9 kg of chlorobenzene to obtain 14 kg of a cyanuric chloride slurry;

[0039] (III) 1 kg of the alumina-supported N,N-dimethylaminopyridine catalyst was filled into a fixed bed reactor; first, 2 kg of the tribromophenol slurry was passed into the fixed bed reactor filled with the catalyst, and the reaction liquid was collected into a second fixed bed reactor; then, 10 kg of the cyanuric chloride slurry was passed into the second fixed bed reactor at a flow rate of 20 ml / min, and the temperature was raised to 60 °C for reaction; after the continuous feeding reaction was carried out for 2 h, the crude product solution was collected; the crude product solution was washed with dilute hydrochloric acid with a mass percentage of 3% to remove residual magnesium oxide powder in the solution, and atmospheric distillation, crystallization, centrifugation, and drying were carried out to obtain the brominated triazine product 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine, as shown in Figure 1 , with a yield of 98.7%, a purity of 99.52%, and a 1% TGA thermal weight loss of 354 °C, as shown in Figure 2 .

[0040] Example 2

[0041] The difference between this embodiment and Example 1 is that in step (one), the mass ratio of nano-alumina and 3-aminopropyl triethoxysilane is 1:0.2, and the rest of the operations are the same, to obtain the brominated triazine product, the yield is 97.3%, the purity is 99.21%, and the 1% TGA thermal weight loss is 357°C.

[0042] Example 3

[0043] The difference between this embodiment and Example 1 is that in step (one), the mass ratio of nano-alumina and 3-aminopropyl triethoxysilane is 1:0.4, and the rest of the operations are the same, to obtain the brominated triazine product, the yield is 98.5%, the purity is 99.48%, and the 1% TGA thermal weight loss is 355°C.

[0044] Example 4

[0045] The difference between this embodiment and Example 1 is that in step (one), the mass ratio of N,N-dimethylaminopyridine and succinic anhydride is 1:1.2, and the rest of the operations are the same, to obtain the brominated triazine product, the yield is 98.6%, the purity is 99.4%, and the 1% TGA thermal weight loss is 355°C.

[0046] Example 5

[0047] The difference between this embodiment and Example 1 is that in step (one), the mass ratio of N,N-dimethylaminopyridine and succinic anhydride is 1:1.5, and the rest of the operations are the same, to obtain the brominated triazine product, the yield is 97.8%, the purity is 99.37%, and the 1% TGA thermal weight loss is 354°C.

[0048] Example 6

[0049] The difference between this embodiment and Example 1 is that in step (two), the molar ratio of 2,4,6-tribromophenol to magnesium oxide is 1:0.7, and the rest of the operations are the same, to obtain the brominated triazine product, the yield is 97.8%, the purity is 99.40%, and the 1% TGA thermal weight loss is 359°C.

[0050] Example 7

[0051] The difference between this embodiment and Example 1 is that in step (two), the mass ratio of 2,4,6-tribromophenol to chlorobenzene solution is 1:1.4, the molar ratio of 2,4,6-tribromophenol to magnesium oxide is 1:0.7, and the mass ratio of cyanuric chloride to chlorobenzene solution is 1:2, and the rest of the operations are the same, to obtain the brominated triazine product, the yield is 97.8%, the purity is 99.40%, and the 1% TGA thermal weight loss is 359°C.

[0052] Example 8

[0053] The difference between this embodiment and embodiment 1 is that in step (three), the mass ratio of cyanuric chloride slurry to tribromophenol solution is 1:4.9, and the rest of the operations are the same, to obtain a brominated triazine product with a yield of 98.9% and a purity of 99.52%, and the 1% TGA thermal weight loss is 357℃.

[0054] Embodiment 9

[0055] The difference between this embodiment and embodiment 1 is that in step (three), the mass ratio of cyanuric chloride slurry to tribromophenol solution is 1:5.3, and the rest of the operations are the same, to obtain a brominated triazine product with a yield of 98.9% and a purity of 99.39%, and the 1% TGA thermal weight loss is 353℃.

[0056] The application provides a synthesis method of brominated triazine, comprising the following steps: preparing an alumina-supported N,N-dimethylaminopyridine catalyst, filling the alumina-supported N,N-dimethylaminopyridine catalyst into a fixed bed reactor, introducing tribromophenol solution and cyanuric chloride slurry, and heating to react to obtain a crude product solution; and post-treating the crude product solution to obtain a brominated triazine product; the application synthesizes an alumina-supported N,N-dimethylaminopyridine catalyst, N,N-dimethylaminopyridine can catalyze highly hindered and low-activity hydroxyl compounds under mild conditions, the reaction speed is fast, and the yield is higher; the use of nano-alumina loading, on the one hand, alumina and magnesium oxide can replace strong alkali to realize the dealkalization synthesis of brominated triazine and reduce the corrosion of the equipment in the synthesis; without using strong alkali, the hydrolysis of cyanuric chloride is reduced, the side reaction is extremely small, the quality of the product is improved, and the thermal stability is improved; on the other hand, nano-alumina has a large specific surface area and strong loading capacity, and the reaction efficiency is accelerated; the continuous process realizes non-aqueous medium and low-temperature short-time reaction, and further avoids the occurrence of hydrolysis; the alumina-supported N,N-dimethylaminopyridine catalyst has high activity and high stability, the synthesis method is simplified, and the application is suitable for industrial large-scale production.

[0057] In addition, the terms "first", "second", "third", etc., are used only for descriptive purposes and should not be construed as indicating or implying relative importance or an indicated number of technical features. Therefore, the features defined as "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0058] The above only describes the preferred embodiments of the present application and should not be used to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for the synthesis of bromotriazines, characterized in that, Specifically comprising the following steps: (I) preparing a catalyst: adding nano-alumina into hydrochloric acid for stirring, and then performing an amination reaction with 3-aminopropyl triethoxysilane to prepare aminated alumina; performing a carboxylation reaction with N,N-dimethylaminopyridine and succinic anhydride in a solvent to prepare carboxylated N,N-dimethylaminopyridine; and performing a mixed reaction of the aminated alumina, the carboxylated N,N-dimethylaminopyridine, N,N-dimethylformamide and a condensing agent to prepare an alumina-supported N,N-dimethylaminopyridine catalyst; (II) dissolving 2,4,6-tribromophenol in a chlorobenzene solution, adding magnesium oxide powder to obtain a tribromophenol slurry; dispersing cyanuric chloride in a chlorobenzene solution to obtain a cyanuric chloride slurry; (III) filling the alumina-supported N,N-dimethylaminopyridine catalyst into a fixed bed reactor, introducing the tribromophenol solution and the cyanuric chloride slurry, and performing a reaction by heating to obtain a crude product solution; washing, normal-pressure distilling, crystallizing, centrifuging and drying the crude product solution to obtain a bromotriazine product; In step (I), the mass ratio of the nano-alumina and the 3-aminopropyl triethoxysilane is 1:0.2-0.4, the mass ratio of the N,N-dimethylaminopyridine and the succinic anhydride is 1:1.2-1.5, and the condensing agent is a mixture of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide, and the mixing mass ratio is 1:

1.

2. The method of claim 1, wherein the brominated triazine is synthesized by the reaction of a triazine with bromine in the presence of a solvent. In step (I), the crystal form of the nano-alumina is γ-Al2O3, and the particle size of the nano-alumina is 50-80 nm.

3. The method for synthesizing a bromotriazine according to claim 1, characterized in that, In step (I), the concentration of the hydrochloric acid is 6 M, the stirring temperature is 60°C, and the stirring time is 2 h.

4. The method for synthesizing a bromotriazine according to claim 1, characterized in that, In step (I), the solvent for the amination reaction is anhydrous ethanol, the reaction time is 4 h, and the reaction temperature is 80°C.

5. The method for synthesizing a bromotriazine according to claim 1, characterized in that, In step (I), the solvent for the carboxylation reaction is triethylamine, the reaction time is 12 h, and the reaction temperature is 80°C.

6. The method for synthesizing a bromotriazine according to claim 1, characterized in that, In step (II), the mass ratio of the 2,4,6-tribromophenol and the chlorobenzene solution is 1:1.3-1.4, the molar ratio of the 2,4,6-tribromophenol to the magnesium oxide is 1:0.6-0.7, and the mass ratio of the cyanuric chloride to the chlorobenzene solution is 1:1.8-2.

7. The method of claim 1, wherein the brominated triazine is synthesized by the reaction of 2,4,6-trichloro-1,3,5-triazine with a bromide source in the presence of a base. In step (III), the mass ratio of the cyanuric chloride slurry to the tribromophenol solution is 1:4.9-5.

3.

8. The method of claim 1, wherein the brominated triazine is synthesized by the reaction of 2,4,6-trichloro-1,3,5-triazine with a bromide source in the presence of a base. In step (III), the heating temperature is 55-60°C.

9. The method of claim 1, wherein the brominated triazine is synthesized by the reaction of 2,4,6-trichloro-1,3,5-triazine with a bromide source in the presence of a base. In step (III), the flow rate of the tribromophenol solution and the cyanuric chloride slurry is 20 ml / min.

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