A method for synthesizing 9,10-dibromoanthracene

Abstract

The application provides a synthesis method of 9,10-dibromoanthracene, by introducing HBr generated by a solvent water adsorption reaction, using an industrial sodium hypochlorite solution to react the HBr into bromine, ensuring high concentration of bromine, introducing a solvent dichloroethane to uniformly disperse raw materials, keeping the concentration of bromine stable in the reaction, greatly promoting the reaction speed, greatly shortening the reaction time, and converting the sodium hypochlorite into a sodium chloride aqueous solution after the reaction is completed. The purity of the prepared 9,10-dibromoanthracene is more than 99%, and the by-products generated in the reaction are environment-friendly and non-polluting.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis technology, and in particular to a method for synthesizing 9,10-dibromoanthracene. Background Technology

[0002] OLED materials (organic light-emitting materials) possess advantages such as self-illumination, wide viewing angle, infinitely high contrast, low power consumption, and extremely fast response speed. OLED materials are widely used in mobile phones, computers, and televisions. OLED displays are very thin and light, do not use backlighting, and can be manufactured into flexible screens. Therefore, OLED materials are considered one of the most promising products of the 21st century.

[0003] 9,10-Dibromoanthracene is widely used as an important raw material or intermediate in the fine chemical industry, including pharmaceuticals, pesticides, dyes, and fragrances. Therefore, its preparation methods have always been a focus of attention for chemists.

[0004]

[0005] Existing literature reports that most bromine or NBS is used as the bromine source for the synthesis of brominated polycyclic aromatic hydrocarbons. However, the inherent drawback of using bromine is that half of the bromine in the reaction is converted into the corrosive bromine product HBr, and the theoretical utilization rate of bromine is only 50%, resulting in serious resource waste. Although NBS is a relatively safe brominating reagent, its preparation process is complex and costly, and it is usually accompanied by the use of special chemical auxiliaries, so it cannot be widely used in actual production processes. In addition to elemental bromine and NBS, brominating reagents include HBr / NH4NO3, ZnBr2 / NaBiO3, NC-CBr2-NO2, dimethyl sulfide bromide (BDMS), etc.

[0006] Although existing technologies disclose various methods for preparing 9,10-dibromoanthracene, these methods generally have one or more drawbacks, such as harsh reaction conditions, low yield, long reaction time, cumbersome reaction operation and post-processing, and serious pollution.

[0007] Therefore, it is necessary to design a synthetic method for 9,10-dibromoanthracene that is suitable for industrial production, economically viable, and environmentally friendly to meet market demands. Summary of the Invention

[0008] This invention provides a method for synthesizing 9,10-dibromoanthracene, which aims to solve the problems of low purification efficiency, poor product quality, resource waste, and environmental pollution caused by reaction reagents in the preparation of 9,10-dibromoanthracene by existing technologies.

[0009] To achieve the above objectives, embodiments of the present invention provide a method for synthesizing 9,10-dibromoanthracene, comprising the following steps:

[0010] S1. Take a container and add a mixed solution of water and dichloroethane. Add anthracene while stirring and cool.

[0011] S2. Simultaneously add bromine and sodium hypochlorite solution. After the addition is complete, stop the reaction if the change in the reaction of the raw materials is less than 1% within 1 hour by monitoring the liquid phase.

[0012] S3. After standing and cooling, filter, wash and dry to obtain crude 9,10-dibromoanthracene;

[0013] S4. Add the crude 9,10-dibromoanthracene to an organic solvent, heat and stir, cool and filter, and centrifuge to obtain 9,10-dibromoanthracene;

[0014] The total volume of the mixed solution of water and dichloroethane, expressed as anthracene, is 1.0–2.0 mL / mmol.

[0015] The molar ratio of anthracene to bromine is 1:(1.00~1.25);

[0016] The molar ratio of anthracene to sodium hypochlorite (aq) is 1:(1.00-1.50).

[0017] Furthermore, the organic solvent is at least one selected from toluene, ethyl acetate, acetic acid, xylene, and n-butanol. Preferably, it is at least one selected from toluene, xylene, and n-butanol.

[0018] Furthermore, the total volume of the mixed solution of water and dichloroethane is 1.1 to 1.5 mL / mmol based on the amount of anthracene.

[0019] Furthermore, the mass ratio of water to dichloroethane in the mixed solvent of water and dichloroethane is 1:1.0 to 8.0; preferably 1:2.1 to 4.8.

[0020] Furthermore, the sodium hypochlorite (aq) has a mass fraction of 10.0–13.0%; preferably 12.0–12.5%.

[0021] Furthermore, in step S1, the temperature is lowered to 10–30°C; preferably 15–22°C.

[0022] Furthermore, in step S4, the temperature is heated to 80–100°C; preferably 90–95°C.

[0023] Furthermore, the molar ratio of anthracene to bromine is 1:(1.14 to 1.21).

[0024] Furthermore, the molar ratio of anthracene to sodium hypochlorite (aq) is 1:(1.15-1.30).

[0025] Furthermore, the 9,10-dibromoanthracene is a yellow-green needle-like crystal with a purity of over 99%.

[0026] The reaction principle of this invention:

[0027] Anthracene undergoes an electrophilic substitution reaction with bromine, and the generated HBr is simultaneously and rapidly oxidized to bromine by sodium hypochlorite. The bromine concentration remains stable during the reaction, which greatly promotes the reaction rate and shortens the reaction time. Furthermore, after the sodium hypochlorite has reacted, it is converted into an aqueous solution of sodium chloride. The byproducts generated by the reaction are environmentally friendly and pollution-free.

[0028] The above-described solution of the present invention has the following beneficial effects:

[0029] 1) The method for synthesizing 9,10-dibromoanthracene of the present invention is economical, meets market demand, is environmentally friendly, and is suitable for industrial production.

[0030] 2) The raw materials of this invention are readily available, the operation is simple, the yield is high, and production at the hundred-kilogram level has been achieved. The high purity and quality of the product obtained are over 99%. Attached Figure Description

[0031] Figure 1 This is the liquid phase spectrum of 9,10-dibromoanthracene prepared in Example 1 of this invention;

[0032] Figure 2 This is the HNMR spectrum of 9,10-dibromoanthracene prepared in Example 1 of this invention. Detailed Implementation

[0033] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0034] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0035] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0036] This invention addresses the existing problems by providing a method for synthesizing 9,10-dibromoanthracene, the synthetic route of which is shown below:

[0037] Example 1

[0038] A process for synthesizing 9,10-dibromoanthracene, comprising the following steps:

[0039] 25.3 g of water and 62.7 g of 1,2-dichloroethane were added to a 500 mL three-necked reaction flask. Under mechanical stirring at room temperature, 10 g of anthracene was added, and the temperature was lowered to 20 °C. Simultaneously, 10.6 g of bromine and 43.5 g of 12% sodium hypochlorite solution were slowly added dropwise to the reaction system. After the addition was complete, the reaction was stopped when the change in the reactants was less than 1% within 1 hour, as monitored by liquid chromatography. The mixture was filtered, and the filter cake was washed with dichloroethane. The crude product was dried, and then added to 80 mL of toluene. The temperature was raised to 95 °C and stirred for 0.5 h. After cooling to room temperature, the mixture was filtered to obtain 17.1 g of purified product with a purity of 99.85% and a yield of 89.68%. Liquid chromatography was performed as follows: Figure 1 As described above, HNMR, as Figure 2 As shown.

[0040] Example 2

[0041] A process for synthesizing 9,10-dibromoanthracene, comprising the following steps:

[0042] 2.53 kg of water and 6.27 kg of 1,2-dichloroethane were added to a 20 L reactor and stirred at room temperature. 1.00 kg of anthracene was then added, and the mixture was cooled to 20 °C. Simultaneously, 1.06 kg of bromine and 4.35 kg of a 12% sodium hypochlorite solution were slowly added dropwise to the reaction system. The reaction was stopped after the change in the reactant concentration was less than 1% within 1 hour, as monitored by liquid chromatography. The mixture was directly filtered, and the filter cake was washed twice with dichloroethane. After drying the crude product, 8 L of toluene was added, and the mixture was heated to 95 °C and stirred for 0.5 hours. The mixture was then cooled to room temperature and filtered to obtain 1.65 kg of purified product with a purity of 99.35% and a yield of 86.91%.

[0043] Example 3

[0044] A process for synthesizing 9,10-dibromoanthracene, comprising the following steps:

[0045] 253.29 kg of water and 627.03 kg of 1,2-dichloroethane were added to a 2000 L reactor and stirred at room temperature. 100.05 kg of anthracene was then added, and the mixture was cooled to 17 °C. Simultaneously, 105.82 kg of bromine and 435.05 kg of a 12% sodium hypochlorite solution were slowly added dropwise to the reaction system. The reaction was stopped when the change in the reactants was less than 1% within 1 hour, as monitored by liquid chromatography. The product was directly filtered, and the filter cake was washed twice with dichloroethane. After centrifugation and drying of the crude product, 800 L of toluene was added to a 1000 L reactor, followed by the dried crude product. The mixture was heated to 95 °C and stirred for 0.5 hours. After cooling to room temperature, the product was filtered and centrifuged to obtain 168.21 kg of purified product with a purity of 99.75% and a yield of 88.75%.

[0046] Comparative Example 1

[0047] In Example 1, the mixed solvents dichloroethane and water were replaced with pure dichloroethane, while all other steps remained the same, as follows:

[0048] 62.7 g of 1,2-dichloroethane was added to a 500 mL three-necked reaction flask. Under mechanical stirring at room temperature, 10 g of anthracene was added, and the temperature was lowered to 20 °C. Simultaneously, 10.6 g of bromine and 43.5 g of 12% sodium hypochlorite solution were slowly added dropwise to the reaction system. After the addition was complete, the reaction was stopped when the change in the reactant concentration was less than 1% within 1 hour, as monitored by liquid chromatography. The aqueous phase was separated by standing, and the sample was washed twice with hot water. Separation was then performed by silica gel column chromatography to obtain 10.13 g of crude product with a purity of 99.26% and a yield of 53.34%.

[0049] Comparative Example 2

[0050] In Example 1, the mixed solvents dichloroethane and water were replaced with pure water, while all other steps remained the same, as follows:

[0051] 25.3 g of water was added to a 500 mL three-necked reaction flask. Under mechanical stirring at room temperature, 10 g of anthracene was added, and the temperature was lowered to 20 °C. Simultaneously, 10.6 g of bromine and 43.5 g of 12% sodium hypochlorite solution were slowly added dropwise to the reaction system. The reaction was stopped when the change in the reactant concentration was less than 1% within 1 hour, as monitored by liquid chromatography. The aqueous phase was separated by standing, and the sample was washed twice with hot water. Separation was then performed by silica gel column chromatography to obtain 11.43 g of crude product with a purity of 99.36% and a yield of 60.54%.

[0052] Comparative Example 3

[0053] The sodium hypochlorite solution in Example 1 is removed, and all other steps are the same, as follows:

[0054] 25.3 g of water and 62.7 g of 1,2-dichloroethane were added to a 500 mL three-necked reaction flask. Under mechanical stirring at room temperature, 10 g of anthracene was added. The mixture was cooled to 20 °C, and 10.6 g of bromine was slowly added dropwise. The reaction was stopped when the change in the reactant concentration was less than 1% within 1 hour, as monitored by liquid chromatography. The aqueous phase was separated by standing, and the mixture was washed twice with hot water. Separation was then performed by silica gel column chromatography to obtain 0.65 g of crude product with a purity of 99.58% and a yield of 3.45%.

[0055] Comparative Example 4

[0056] The bromine equivalent in Example 1 was reduced from 1.18 eq to 1.05 eq, while all other steps remained the same, as follows:

[0057] 25.3 g of water and 62.7 g of 1,2-dichloroethane were added to a 500 mL three-necked reaction flask. Under mechanical stirring at room temperature, 10 g of anthracene was added, and the temperature was lowered to 20 °C. Simultaneously, 9.41 g of bromine and 43.5 g of 12% sodium hypochlorite solution were slowly added dropwise to the reaction system. After the addition was complete, the reaction was stopped when the change in the reactant concentration was less than 1% within 1 hour, as monitored by liquid chromatography. The aqueous phase was separated by standing, and the mixture was washed twice with hot water. Separation was then performed by silica gel column chromatography to obtain 14.26 g of crude product with a purity of 99.46% and a yield of 75.21%.

[0058] Comparative Example 5

[0059] The equivalent amount of sodium hypochlorite solution in Example 1 was reduced from 1.25 eq to 1.05 eq, while all other steps remained the same, as follows:

[0060] 25.3 g of water and 62.7 g of 1,2-dichloroethane were added to a 500 mL three-necked reaction flask. Under mechanical stirring at room temperature, 10 g of anthracene was added, and the mixture was cooled to 20 °C. Simultaneously, 10.6 g of bromine and 36.54 g of 12% sodium hypochlorite solution were slowly added dropwise to the reaction system. After the addition was complete, the reaction was stopped when the change in the reactant concentration was less than 1% within 1 hour, as monitored by liquid chromatography. The aqueous phase was separated by standing, and the mixture was washed twice with hot water. Separation was then performed by silica gel column chromatography to obtain 15.25 g of crude product with a purity of 99.33% and a yield of 80.35%.

[0061] Comparative Example 6

[0062] The sodium hypochlorite solution content in Example 1 was changed from 12% to 10%, while all other steps remained the same, as follows:

[0063] 25.3 g of water and 62.7 g of 1,2-dichloroethane were added to a 500 mL three-necked reaction flask. Under mechanical stirring at room temperature, 10 g of anthracene was added, and the mixture was cooled to 20 °C. Simultaneously, 10.6 g of bromine and 52.21 g of 10% sodium hypochlorite solution were slowly added dropwise to the reaction system. After the addition was complete, the reaction was stopped when the change in the reactant concentration was less than 1% within 1 hour, as monitored by liquid chromatography. The aqueous phase was separated by standing, and the mixture was washed twice with hot water. Separation was then performed by silica gel column chromatography to obtain 14.7 g of crude product with a purity of 99.16% and a yield of 77.33%.

[0064] Table 1. Reaction conditions and yields of Example 1 and each comparative example.

[0065] Synthesis scheme Reaction conditions Yield % Example 1 1.18 eq bromine, 1.25 eq 12% sodium hypochlorite solution, 11.3 eq dichloroethane, 25 eq water 89.68％ Comparative Example 1 1.18 eq bromine, 1.25 eq 12% sodium hypochlorite solution, 11.3 eq dichloroethane 53.34％ Comparative Example 2 1.18 eq bromine, 1.25 eq 12% sodium hypochlorite solution, 25 eq water 60.54％ Comparative Example 3 1.18 eq bromine, 11.3 eq dichloroethane, 25 eq water 3.45％ Comparative Example 4 1.05 eq bromine, 1.25 eq 12% sodium hypochlorite solution, 11.3 eq dichloroethane, 25 eq water 75.21％ Comparative Example 5 1.18 eq bromine, 1.05 eq 12% sodium hypochlorite solution, 11.3 eq dichloroethane, 25 eq water 80.35％ Comparative Example 6 1.18 eq bromine, 1.25 eq 10% sodium hypochlorite solution, 11.3 eq dichloroethane, 25 eq water 77.33％

[0066] As shown in Table 1, compared to Example 1, Comparative Example 1, without adding water to absorb hydrogen bromide, had a yield reduction of 36.34%; Comparative Example 2, without adding dichloroethane solvent to uniformly disperse the material, had a yield reduction of 21.14%; Comparative Example 3, without adding sodium hypochlorite solution, had a yield of only 3.45%, with the main product being the single-side product 9-bromoanthracene; Comparative Example 4, compared to Example 1, reduced the amount of bromine, resulting in a yield reduction of 14.47%; Comparative Example 5, compared to Example 1, reduced the amount of sodium hypochlorite solution by 12%, resulting in a yield reduction of 9.68%; and Comparative Example 6, compared to Example 1, reduced the mass fraction of sodium hypochlorite solution, resulting in a yield reduction of 12.35%.

[0067] In summary, by setting different reaction conditions, including no solvent or any component corresponding to the reaction and oxidant, and changing the proportion of materials, the product yield obtained is optimal according to the synthesis scheme of the preferred method in this paper. At the same time, this paper also carried out industrial production according to this scheme, and obtained high yield, low production cost, simple operation and extremely high product quality.

[0068] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for the synthesis of 9,10-dibromoanthracene, characterized in that, The method comprises the following steps: S1. A container is taken to add a mixed solution of water and dichloroethane, and anthracene is added under stirring, and the temperature is lowered; S2. Bromine and sodium hypochlorite solution are simultaneously added dropwise, and after the dropwise addition is completed, the reaction is stopped after the raw material reaction change is less than 1% within 1h is monitored by liquid phase; S3. After standing and cooling, filtration, washing and drying, the crude 9,10-dibromoanthracene is obtained; S4. The crude 9,10-dibromoanthracene is added to an organic solvent, heated and stirred, cooled, filtered, and centrifuged to obtain 9,10-dibromoanthracene; The total volume of the mixed solution of water and dichloroethane is 1.1-1.5 mL / mmol based on the amount of anthracene; the mass ratio of water to dichloroethane in the mixed solvent of water and dichloroethane is 1:1.0-8.0; The molar ratio of anthracene to bromine is 1:(1.14-1.21); The molar ratio of anthracene to sodium hypochlorite (aq) is 1:(1.15-1.30); The organic solvent is toluene; The mass fraction of sodium hypochlorite (aq) is 10.0-13.0%; The 9,10-dibromoanthracene is yellow-green needle-shaped crystal with a purity of more than 99%.

2. The method of synthesis of claim 1, wherein, In step S1, the temperature is lowered to 10-30℃.

3. The method of synthesis of claim 1, wherein, In step S4, the temperature is heated to 80-100℃.

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