Preparation method of 6-bromo-5, 5, 6, 6-tetrafluorohexane-1-ol

Abstract

The invention relates to a preparation method of 6-bromo-5, 5, 6, 6-tetrafluorohexane-1-alcohol, and belongs to the technical field of organic synthesis. The preparation method comprises the following steps: S1, dissolving tetrafluorodibromoethane, 3-butene-1-ol, a photocatalyst, a reducing agent and a cosolvent in an organic solvent in a protective atmosphere, and reacting under the condition of an ultraviolet lamp to obtain a mixed solution; the photocatalyst is ferric salt; and S2, extracting the mixed solution, and carrying out reduced pressure distillation to obtain the 6-bromo-5, 5, 6, 6-tetrafluorohexane-1-ol. According to the preparation method, toxic or dangerous substances such as allyl alcohol and hydrogen do not need to be used, the 6-bromo-5, 5, 6, 6-tetrafluorohexane-1-ol is prepared through a one-step method by using ultraviolet light which is a safe and clean energy source, the operation process is simple and easy to repeat, and the requirement of large-scale production can be met.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a method for preparing 6-bromo-5,5,6,6-tetrafluorohexane-1-ol. Background Art

[0002] Photoresist refers to a thin film material that changes its solubility through irradiation or radiation of ultraviolet light, electron beam, ion beam, X-ray, etc. It is mainly composed of polymer resin, photoacid generator, related additives and solvents, and is widely used in fine graphic processing operations such as display panels, integrated circuits and semiconductor discrete devices. With the development of photoresist, from 365nm, 248nm, 193nm to 193 immersion, the hydrophobicity of photoresist has received more and more attention. Fluorine-containing substances are a class of extremely hydrophobic materials and are widely used in photoresist production. 6-Bromo-5,5,6,6-tetrafluorohexane-1-ol is a fluorine-containing compound with good hydrophobicity, which can be used to prepare suitable photoacid generators and form photoresist patterns with excellent sensitivity, resolution and mask performance.

[0003] However, due to the strong electronegativity of fluorine, fluorine-containing photoresist monomers often have the problem of poor stability. Therefore, there are few reports on the preparation method of 6-bromo-5,5,6,6-tetrafluorohexane-1-ol. Imaizumi Yuki et al. (JP 2022-51549A) used halogenated alkanes and terminal olefin linear alcohols as raw materials, and obtained the target product through addition, elimination and hydrogen hydrogenation reactions. However, since the reaction route uses highly toxic and difficult-to-obtain allyl alcohol and dangerous chemicals such as hydrogen, the use of this route is limited. Masashi Nagamori et al. (US20110112306A1) used 1-bromo-1,1,2,2-tetrafluoro-4-iodobutane as a raw material, and obtained the target product through operations such as diethyl malonate substitution, hydrolysis, decarboxylation, chlorination and final reduction. Compared with the former, this route abandons the method of using hazardous materials and obtains the product relatively gently. However, the acyl chloride product obtained by this method is extremely unstable, and it is difficult to control the subsequent reduction reaction well, which leads to poor reproducibility of the method and difficulty in large-scale production, which greatly affects the promotion of the method.

[0004] In view of the important potential of 6-bromo-5,5,6,6-tetrafluorohexane-1-ol in the field of photoresists and its inherent difficulty in synthesis, and considering avoiding the use of toxic, harmful and dangerous reagents and stably producing the product, the present invention is specially proposed. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for preparing 6-bromo-5,5,6,6-tetrafluorohexane-1-ol, using tetrafluorodibromoethane as a fluorine-containing substrate, using 3-butene-1-ol as an olefin substrate, using iron salt as a photocatalyst to perform a photoreaction to generate free radicals, thereby attacking the olefin substrate for an electrophilic addition reaction, and using a reducing agent for reduction elimination, and finally obtaining 6-bromo-5,5,6,6-tetrafluorohexane-1-ol. The method solves the problems of using expensive or dangerous materials, long routes, low yields, and difficult operations in traditional methods.

[0006] The object of the present invention is to provide a method for preparing 6-bromo-5,5,6,6-tetrafluorohexane-1-ol, comprising the following steps:

[0007] S1. Under a protective atmosphere, tetrafluorodibromoethane, 3-butene-1-ol, a photocatalyst, a reducing agent and a cosolvent are dissolved in an organic solvent, and reacted under ultraviolet light to obtain a mixed solution; the photocatalyst is an iron salt;

[0008] S2. Extracting and distilling the mixed solution described in S1 under reduced pressure to obtain the 6-bromo-5,5,6,6-tetrafluorohexane-1-ol.

[0009] In one embodiment of the present invention, in S1, the iron salt is selected from one or more of ferric triacetylacetonate, ferric nitrate, ferric chloride, ferric trifluoromethanesulfonate, ferrous 2-ethylhexanoate and ferrous acetate; the reducing agent is selected from vitamin C and / or hydrazine hydrate; the co-solvent is selected from one or more of pyridine, triethylamine and ammonia water; the organic solvent is selected from one or more of acetonitrile, ethanol and methanol.

[0010] In one embodiment of the present invention, in S1, the wavelength of the ultraviolet lamp is 350nm-400nm.

[0011] In one embodiment of the present invention, in S1, the molar ratio of tetrafluorodibromoethane to 3-butene-1-ol is (1-3):1.

[0012] In one embodiment of the present invention, in S1, the molar ratio of the 3-butene-1-ol, the photocatalyst, the reducing agent and the co-solvent is 1:(0.05-0.1):(1-3):(1-3).

[0013] In one embodiment of the present invention, in S1, the reaction temperature is 15°C-25°C, and the reaction time is 24h-28h.

[0014] In one embodiment of the present invention, in S1, the protective atmosphere is selected from a nitrogen atmosphere or an argon atmosphere.

[0015] In one embodiment of the present invention, in S2, the extraction specifically comprises the following steps: first quenching with a saturated sodium chloride aqueous solution, then extracting with ethyl acetate, and finally drying with anhydrous sodium sulfate.

[0016] In one embodiment of the present invention, the number of extractions with ethyl acetate is 2 to 5 times.

[0017] In one embodiment of the present invention, in S2, the pressure of the reduced pressure distillation does not exceed 0.5 mmHg, and the temperature is 40°C-50°C.

[0018] The technical solution of the present invention has the following advantages compared with the prior art:

[0019] (1) The preparation method of the present invention uses tetrafluorodibromoethane as a fluorine-containing substrate and 3-butene-1-ol as an olefin substrate, and uses iron salt as a photocatalyst to perform a photoreaction to generate free radicals, thereby attacking the olefin substrate to perform an electrophilic addition reaction, and simultaneously uses a reducing agent to perform reduction elimination, and finally obtains 6-bromo-5,5,6,6-tetrafluorohexane-1-ol. The two substances, iron salt and reducing agent, play an important role in the reaction; if there is no iron salt, the reaction will not proceed because no free radicals are generated, and if there is no reducing agent, the reaction can only generate 4,6-dibromo-5,5,6,6-tetrafluorohexane-1-ol as a byproduct, and the bromine atom cannot be further eliminated to obtain the product.

[0020] (2) The preparation method described in the present invention uses low-cost, less toxic, and widely available raw materials, and utilizes the current cutting-edge photocatalytic reaction technology under relatively mild conditions, abandoning the large amount of transition metals used in the prior art, and efficiently synthesizing the target product.

[0021] (3) The preparation method of the present invention does not require the use of toxic or dangerous substances such as allyl alcohol and hydrogen. By using ultraviolet light, a safe and clean energy source, 6-bromo-5,5,6,6-tetrafluorohexane-1-ol is prepared in one step. The operation process is simple and easy to repeat, and the demand for large-scale production can be met. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0023] Figure 1 The figure is the nuclear magnetic spectrum of 6-bromo-5,5,6,6-tetrafluorohexane-1-ol of the present invention. DETAILED DESCRIPTION

[0024] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. It should be understood that the specific embodiments are only used to explain the present invention, but the embodiments are not intended to limit the present invention.

[0025] In the present invention, unless otherwise explained, technical and scientific terms used in the present invention have the same meanings as commonly understood by those skilled in the art to which the present invention belongs.

[0026] In the present invention, unless otherwise stated, the term "and / or" used in the present invention includes any and all combinations of one or more of the associated listed items.

[0027] In the present invention, unless otherwise stated, the experimental methods used in the embodiments of the present invention are conventional methods unless otherwise stated, and the materials, reagents, etc. used are all commercially available unless otherwise stated.

[0028] Example 1

[0029] In this embodiment, 6-bromo-5,5,6,6-tetrafluorohexane-1-ol was prepared using iron (III) triacetylacetonate as a photocatalyst, specifically comprising the following steps:

[0030]

[0031] Under nitrogen protection, vitamin C (132.09 g, 750 mmol), triacetylacetonate iron (III) (8.83 g, 25 mmol) and pyridine (59.33 g, 750 mmol) were dispersed in 500 mL of acetonitrile and stirred at 20°C for 1 h. Subsequently, tetrafluorodibromoethane (194.87 g, 750 mmol) and 3-butene-1-ol (36.06 g, 500 mmol) were slowly added to the reaction system and stirred at 20°C for 1 h. Next, the system was irradiated with a 365 nm ultraviolet lamp and stirred at 20°C for 24 h. After the reaction was completed, 500 mL of saturated sodium chloride aqueous solution was added for quenching, and ethyl acetate (350 mL×2) was used for extraction 3 times, and finally dried with anhydrous sodium sulfate. The organic phase was concentrated and distilled under reduced pressure using an oil pump (0.5 mmHg, 48°C) to obtain 41.24 g 6-Bromo-5,5,6,6-tetrafluorohexane-1-ol product with a yield of 32.6%.

[0032] The NMR spectrum of 6-bromo-5,5,6,6-tetrafluorohexane-1-ol is as follows Figure 1 As shown, it was shown that 6-bromo-5,5,6,6-tetrafluorohexane-1-ol was successfully prepared.

[0033] Example 2

[0034] In this embodiment, 6-bromo-5,5,6,6-tetrafluorohexane-1-ol was prepared using iron (III) nitrate nonahydrate as a photocatalyst, specifically comprising the following steps:

[0035] Under nitrogen protection, vitamin C (132.09 g, 750 mmol), iron (III) nitrate nonahydrate (10.10 g, 25 mmol) and pyridine (59.33 g, 750 mmol) were dispersed in 500 mL of acetonitrile and stirred at 20°C for 1 h. Subsequently, tetrafluorodibromoethane (194.87 g, 750 mmol) and 3-butene-1-ol (36.06 g, 500 mmol) were slowly added to the reaction system and stirred at 20°C for 1 h. Next, the system was irradiated with a 365 nm ultraviolet lamp and stirred at 20°C for 24 h. After the reaction was completed, 500 mL of saturated sodium chloride aqueous solution was added for quenching, and ethyl acetate (350 mL×2) was used for extraction 3 times, and finally dried with anhydrous sodium sulfate. The organic phase was concentrated and distilled under reduced pressure using an oil pump (0.5 mmHg, 48°C) to obtain 52.50 g 6-Bromo-5,5,6,6-tetrafluorohexane-1-ol product with a yield of 41.5%.

[0036] Example 3

[0037] In this embodiment, 6-bromo-5,5,6,6-tetrafluorohexane-1-ol was prepared using iron (III) chloride as a photocatalyst, and the steps are as follows:

[0038] Under nitrogen protection, vitamin C (132.09 g, 750 mmol), iron (III) chloride (4.06 g, 25 mmol) and pyridine (59.33 g, 750 mmol) were dispersed in 500 mL of acetonitrile and stirred at 20°C for 1 h. Subsequently, tetrafluorodibromoethane (194.87 g, 750 mmol) and 3-butene-1-ol (36.06 g, 500 mmol) were slowly added to the reaction system and stirred at 20°C for 1 h. Next, the system was irradiated with a 365 nm ultraviolet lamp and stirred at 20°C for 24 h. After the reaction was completed, 500 mL of saturated sodium chloride aqueous solution was added for quenching, and ethyl acetate (350 mL×2) was used for extraction 3 times, and finally dried with anhydrous sodium sulfate. The organic phase was concentrated and distilled under reduced pressure using an oil pump (0.5 mmHg, 48°C) to obtain 36.82 g 6-Bromo-5,5,6,6-tetrafluorohexane-1-ol product with a yield of 29.1%.

[0039] Example 4

[0040] In this embodiment, 6-bromo-5,5,6,6-tetrafluorohexane-1-ol was prepared using iron (III) trifluoromethanesulfonate as a photocatalyst, and the steps are as follows:

[0041] Under nitrogen protection, vitamin C (132.09 g, 750 mmol), iron (III) trifluoromethanesulfonate (12.58 g, 25 mmol) and pyridine (59.33 g, 750 mmol) were dispersed in 500 mL of acetonitrile and stirred at 20°C for 1 h. Subsequently, tetrafluorodibromoethane (194.87 g, 750 mmol) and 3-butene-1-ol (36.06 g, 500 mmol) were slowly added to the reaction system and stirred at 20°C for 1 h. Next, the system was irradiated with a 365 nm ultraviolet lamp and stirred at 20°C for 24 h. After the reaction was completed, 500 mL of saturated sodium chloride aqueous solution was added for quenching, and ethyl acetate (350 mL×2) was used for extraction 3 times, and finally dried with anhydrous sodium sulfate. The organic phase was concentrated and distilled under reduced pressure using an oil pump (0.5 mmHg, 48°C) to obtain 49.21 g 6-Bromo-5,5,6,6-tetrafluorohexane-1-ol product with a yield of 38.9%.

[0042] Example 5

[0043] In this embodiment, 6-bromo-5,5,6,6-tetrafluorohexane-1-ol was prepared using 2-ethylhexanoate iron (III) as a photocatalyst, specifically comprising the following steps:

[0044] Under nitrogen protection, vitamin C (132.09 g, 750 mmol), 2-ethylhexanoic acid iron (III) (12.14 g, 25 mmol) and pyridine (59.33 g, 750 mmol) were dispersed in 500 mL of acetonitrile and stirred at 20°C for 1 h. Subsequently, tetrafluorodibromoethane (194.87 g, 750 mmol) and 3-butene-1-ol (36.06 g, 500 mmol) were slowly added to the reaction system and stirred at 20°C for 1 h. Next, the system was irradiated with a 365 nm ultraviolet lamp and stirred at 20°C for 24 h. After the reaction was completed, 500 mL of saturated sodium chloride aqueous solution was added for quenching, and ethyl acetate (350 mL×2) was used for extraction 3 times, and finally dried with anhydrous sodium sulfate. The organic phase was concentrated and distilled under reduced pressure using an oil pump (0.5 mmHg, 48°C) to obtain 44.41 g 6-Bromo-5,5,6,6-tetrafluorohexane-1-ol product with a yield of 35.1%.

[0045] Example 6

[0046] In this embodiment, 6-bromo-5,5,6,6-tetrafluorohexane-1-ol was prepared using iron (II) acetate as a photocatalyst, and the steps are as follows:

[0047] Under nitrogen protection, vitamin C (132.09 g, 750 mmol), iron (II) acetate (4.35 g, 25 mmol) and pyridine (59.33 g, 750 mmol) were dispersed in 500 mL of acetonitrile and stirred at 20°C for 1 h. Subsequently, tetrafluorodibromoethane (194.87 g, 750 mmol) and 3-butene-1-ol (36.06 g, 500 mmol) were slowly added to the reaction system and stirred at 20°C for 1 h. Next, the system was irradiated with a 365 nm ultraviolet lamp and stirred at 20°C for 24 h. After the reaction was completed, 500 mL of saturated sodium chloride aqueous solution was added for quenching, and ethyl acetate (350 mL×2) was used for extraction 3 times, and finally dried with anhydrous sodium sulfate. The organic phase was concentrated and distilled under reduced pressure using an oil pump (0.5 mmHg, 48°C) to obtain 28.59 g 6-Bromo-5,5,6,6-tetrafluorohexane-1-ol product with a yield of 22.6%.

[0048] Comparative Example 1

[0049] Under nitrogen protection, vitamin C (132.09 g, 750 mmol) and pyridine (59.33 g, 750 mmol) were dispersed in 500 mL of acetonitrile and stirred at 20°C for 1 h. Subsequently, tetrafluorodibromoethane (194.87 g, 750 mmol) and 3-butene-1-ol (36.06 g, 500 mmol) were slowly added to the reaction system and stirred at 20°C for 1 h. Next, the system was irradiated with a 365 nm ultraviolet lamp and stirred at 20°C for 24 h. After the reaction was completed, sampling was performed for GC detection, and no new substances were generated.

[0050] Comparative Example 2

[0051] Under nitrogen protection, triacetylacetonate iron (III) (8.83 g, 25 mmol) was dispersed in 500 mL of acetonitrile and stirred at 20°C for 1 h. Subsequently, tetrafluorodibromoethane (194.87 g, 750 mmol) and 3-butene-1-ol (36.06 g, 500 mmol) were slowly added to the reaction system and stirred at 20°C for 1 h. Next, the system was irradiated with a 365 nm ultraviolet lamp and stirred at 20°C for 24 h. After the reaction was completed, sampling was performed for GC detection, and new substances were generated but they were not the target compounds.

[0052] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from them are still within the protection scope of the invention.

Claims

1. A method for preparing 6-bromo-5,5,6,6-tetrafluorohexane-1-ol, characterized in that: The following steps are involved: S1. Under a protective atmosphere, tetrafluorodibromoethane, 3-butene-1-ol, a photocatalyst, a reducing agent and a cosolvent are dissolved in an organic solvent, and reacted under ultraviolet light to obtain a mixed solution; the photocatalyst is an iron salt; S2. Extracting and distilling the mixed solution described in S1 under reduced pressure to obtain the 6-bromo-5,5,6,6-tetrafluorohexane-1-ol.

2. The method for preparing 6-bromo-5,5,6,6-tetrafluorohexane-1-ol according to claim 1, characterized in that: In S1, the iron salt is selected from one or more of ferric triacetylacetonate, ferric nitrate, ferric chloride, ferric trifluoromethanesulfonate, ferrous 2-ethylhexanoate and ferrous acetate; the reducing agent is selected from vitamin C and / or hydrazine hydrate; the cosolvent is selected from one or more of pyridine, triethylamine and ammonia water; the organic solvent is selected from one or more of acetonitrile, ethanol and methanol.

3. The method for preparing 6-bromo-5,5,6,6-tetrafluorohexane-1-ol according to claim 1, characterized in that: In S1, the wavelength of the ultraviolet lamp is 350nm-400nm.

4. The method for preparing 6-bromo-5,5,6,6-tetrafluorohexane-1-ol according to claim 1, characterized in that: In S1, the molar ratio of tetrafluorodibromoethane to 3-butene-1-ol is (1-3):

1.

5. The method for preparing 6-bromo-5,5,6,6-tetrafluorohexane-1-ol according to claim 1, characterized in that: In S1, the molar ratio of the 3-butene-1-ol, the photocatalyst, the reducing agent and the co-solvent is 1:(0.05-0.1):(1-3):(1-3).

6. The method for preparing 6-bromo-5,5,6,6-tetrafluorohexane-1-ol according to claim 1, characterized in that: In S1, the reaction temperature is 15°C-25°C, and the reaction time is 24h-28h.

7. The method for preparing 6-bromo-5,5,6,6-tetrafluorohexane-1-ol according to claim 1, characterized in that: In S1, the protective atmosphere is selected from a nitrogen atmosphere or an argon atmosphere.

8. The method for preparing 6-bromo-5,5,6,6-tetrafluorohexane-1-ol according to claim 1, characterized in that: In S2, the extraction specifically includes the following steps: first quenching with a saturated sodium chloride aqueous solution, then extracting with ethyl acetate, and finally drying with anhydrous sodium sulfate.

9. The method for preparing 6-bromo-5,5,6,6-tetrafluorohexane-1-ol according to claim 8, characterized in that: The number of extractions with ethyl acetate ranged from 2 to 5 times.

10. The method for preparing 6-bromo-5,5,6,6-tetrafluorohexane-1-ol according to claim 1, characterized in that: In S2, the pressure of the reduced pressure distillation does not exceed 0.5 mmHg, and the temperature is 40°C-50°C.

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