A process for the preparation of phosphorus trifluoride

Abstract

The application belongs to the field of organic phosphorus chemistry and phosphorus chemical industry, and particularly relates to a preparation method of phosphorus trifluoride, comprising the following steps: under the protection of inert gas, reacting phosphorus trichloride with an ionic liquid to obtain phosphorus trifluoride. The application uses the ionic liquid as a fluorine source, avoids using dangerous raw materials such as hydrogen fluoride and metal fluoride, and the ionic liquid can not only be used as a fluorine source, but also as a reaction solvent, so that the reaction activity of phosphorus trichloride and the ionic liquid is greatly improved. The application has mild reaction conditions, low reaction temperature, short reaction time, and the reaction system does not produce other byproduct gases, the post-processing operation is simple, and the reaction yield and purity are high.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of organic phosphorus chemistry and phosphorus chemical industry, and particularly relates to a preparation method of phosphorus trifluoride. BACKGROUND

[0002] Phosphorus trifluoride (PF3) is an important inorganic compound, which is a colorless and odorless gas at room temperature and pressure, and a colorless transparent liquid at liquid state. The melting point thereof is -151.3℃, the boiling point thereof is -101.2℃, the density thereof is 3.907 g / L, the molecular weight thereof is 87.97, and the phosphorus trifluoride is soluble in ethanol. The phosphorus trifluoride is widely used in the fields of electronic industry, battery manufacturing, polymer materials and organic synthesis. In the aspect of semiconductor manufacturing, the phosphorus trifluoride can be used as a dopant for doping semiconductor materials such as silicon, so as to change the electronic properties of the semiconductor materials and significantly improve the performance of the semiconductor. In the field of polymer materials, the phosphorus trifluoride as a reactant can be used to synthesize fluorinated organic dithiophosphate and terephthalate, which are high polymer materials with good corrosion resistance. In the field of organic synthesis, the phosphorus trifluoride as a reaction reagent plays an important role in the generation of fluorinated hydrocarbon compounds, the fluorination reaction of aromatic compounds and the reaction of amines and acid anhydrides.

[0003] At present, the methods for synthesizing phosphorus trifluoride in the prior art mainly include:

[0004] 1) Elemental reaction method. That is, phosphorus compounds and fluorine element are directly reacted to generate phosphorus trifluoride, and the reaction process is as follows: However, the amount of fluorine element used in the above method needs to be accurately controlled. If the fluorine element is insufficient, the reaction may not be complete. If the fluorine element is excessive, side reactions may occur to generate PF5 or other unnecessary products, thereby affecting the selectivity and yield of the reaction. In addition, although the reaction principle of this method is relatively simple, it directly uses the chemical reaction between elements. However, due to the strong oxidizing property of fluorine gas and the very active chemical property, the reaction conditions are relatively high, and professional equipment resistant to corrosion and accurate operation process are required to ensure the safety, efficiency and selectivity of the reaction.

[0005] 2) Double decomposition reaction method. Phosphorus trihalide is reacted with a fluorinated reagent (such as hydrogen fluoride, sodium fluoride, ammonium fluoride, etc.) to generate phosphorus trifluoride and corresponding hydrogen halide gas (hydrogen chloride, hydrogen bromide, hydrogen fluoride).

[0006] CN117228643A discloses a preparation method of electronic grade phosphorus trifluoride. Under the protection of inert atmosphere, phosphorus trichloride is first added to a reactor, heated, and the temperature is controlled at 40-60°C. The temperature is maintained for 20-50 min. Then, anhydrous hydrogen fluoride is slowly introduced from the bottom of the reactor to make it fully contact with the reaction to generate phosphorus trifluoride, which is directly condensed and collected. Finally, electronic grade phosphorus trifluoride is prepared by rectification and purification. However, this scheme has the disadvantages of severe equipment corrosion (HF is highly corrosive), low reaction conversion rate, etc.

[0007] CN101955173A discloses a technology for preparing phosphorus trifluoride by reacting phosphorus trichloride and zinc fluoride. Phosphorus trichloride and zinc fluoride are reacted in a reactor at 140-150°C. This method has low reaction activity, long reaction time, requires the use of hydrogen fluoride, has high requirements for reaction equipment, and is not suitable for large-scale production.

[0008] CN117163925A discloses a preparation method of phosphorus trifluoride. Phosphorus triiodide organic solution and fluorinated metal salt are used, the reaction temperature is high (270-400°C), a large amount of organic solvent is used, a large amount of three wastes is generated, and the production cost is high.

[0009] CN118723947A discloses a preparation method of phosphorus trifluoride. Fluoride salt and phosphorus trichloride are mixed and reacted under inert atmosphere to obtain phosphorus trifluoride. However, this method has a complicated post-treatment process, and the yield and purity are low.

[0010] In view of the problems of high reaction temperature, long reaction time, environmental pollution, low yield and purity, etc. in the prior art, there is an urgent need to develop a new method for preparing phosphorus trifluoride. SUMMARY

[0011] The purpose of the present application is to provide a preparation method of phosphorus trifluoride to solve the problems of high reaction temperature, long reaction time, environmental pollution, low yield and purity, etc. in the prior art. To solve the above technical problems, the present application provides the following technical solutions:

[0012] A preparation method of phosphorus trifluoride, comprising the following steps:

[0013] Under the protection of inert gas, phosphorus trichloride is reacted with ionic liquid to obtain phosphorus trifluoride;

[0014] The structural formula of the ionic liquid is:

[0015] 、 or .

[0016] In some embodiments, the inert gas is selected from one or more of nitrogen, helium, neon, and argon.

[0017] In some embodiments, the reaction temperature is 30-50℃, and the reaction time is 0.5-5h.

[0018] In some embodiments, the molar ratio of phosphorus trichloride to ionic liquid is 1:(3-10).

[0019] In some embodiments, the reaction method continuously generates phosphorus trifluoride gas during the reaction, which is condensed and collected to obtain liquid phosphorus trifluoride product.

[0020] In some embodiments, the condensation and collection temperature is -140 to -120℃.

[0021] In some embodiments, the method comprises the following steps:

[0022] Under the protection of nitrogen, phosphorus trichloride is added to the reactor, followed by slow addition of ionic liquid After completion of the addition, the mixture is warmed to 40℃ and stirred for 1h, during which phosphorus trifluoride gas is continuously generated, which is condensed and collected at -120℃ to obtain liquid phosphorus trifluoride product.

[0023] In some embodiments, under the protection of nitrogen, phosphorus trichloride is added to the reactor, followed by slow addition of ionic liquid After completion of the addition, the mixture is warmed to 40℃ and stirred for 1h, during which phosphorus trifluoride gas is continuously generated, which is condensed and collected at -120℃ to obtain liquid phosphorus trifluoride product.

[0024] In some embodiments, under the protection of nitrogen, phosphorus trichloride is added to the reactor, followed by slow addition of ionic liquid After completion of the addition, the mixture is warmed to 40℃ and stirred for 1h, during which phosphorus trifluoride gas is continuously generated, which is condensed and collected at -120℃ to obtain liquid phosphorus trifluoride product.

[0025] The present application has the following beneficial effects:

[0026] 1) The present application uses ionic liquid as a fluorine source, avoiding the use of dangerous materials such as hydrogen fluoride and metal fluoride. The ionic liquid not only serves as a fluorine source, but also as a reaction solvent, greatly improving the reactivity of phosphorus trichloride and ionic liquid.

[0027] 2) The reaction conditions of the present application are mild, with low reaction temperature and short reaction time. The reaction system does not produce other byproduct gases, the post-treatment operation is simple, and the reaction yield of phosphorus trifluoride is as high as 96%, with a purity of 99.7%.

[0028] 3) The present application can maintain a high yield and purity even with kilogram-level raw material feeding, making it suitable for large-scale industrial production. DETAILED DESCRIPTION

[0029] The embodiments of the present application are described in detail below, which are exemplary and intended to explain the present application, and cannot be understood as a limitation of the present application.

[0030] The endpoints of the ranges of the present application and any values described are not limited to the precise range or value, and are understood to include values approximately or reasonably similar to those recited. For ranges of values, the endpoints of each range are included, as well as individual points within the range, and the ranges of values are understood to include the values approximately or reasonably similar to those recited. The source of the materials used in the present application is not limited, and the materials used in the present application are commercially available unless otherwise specified.

[0031] Example 1

[0032] Phosphorus trichloride (2.74 kg, 20.0 mol) was added into the reactor under nitrogen protection, then the ionic liquid (12.88 kg, 80.0 mol) was slowly added, after the addition was completed, the mixture was warmed to 40°C and stirred for 1 h, during the reaction, phosphorus trifluoride gas was continuously generated, the phosphorus trifluoride gas was collected by condensation at -120°C, to obtain the liquid product of phosphorus trifluoride, the product yield was 95.6%, and the HPLC purity was 99.7%.

[0033] Example 2

[0034] Phosphorus trichloride (2.74 kg, 20.0 mol) was added into the reactor under nitrogen protection, then the ionic liquid (12.64 kg, 80.0 mol) was slowly added, after the addition was completed, the mixture was warmed to 40°C and stirred for 1 h, during the reaction, phosphorus trifluoride gas was continuously generated, the phosphorus trifluoride gas was collected by condensation at -120°C, to obtain the liquid product of phosphorus trifluoride, the product yield was 84.7%, and the HPLC purity was 99.5%.

[0035] Example 3

[0036] Phosphorus trichloride (2.74 kg, 20.0 mol) was added into the reactor under nitrogen protection, then the ionic liquid (1.24 kg, 80.0 mol) was slowly added, after the addition was completed, the mixture was warmed to 40°C and stirred for 1 h, during the reaction, phosphorus trifluoride gas was continuously generated, the phosphorus trifluoride gas was collected by condensation at -120°C, to obtain the liquid product of phosphorus trifluoride, the product yield was 86.3%, and the HPLC purity was 99.4%.

[0037] Example 4

[0038] Under nitrogen protection, phosphorus trichloride (2.74 kg, 20.0 mol) was added to the reactor, followed by the slow addition of an ionic liquid. (16.1 kg, 100.0 mol) After addition, the mixture was heated to 40℃ and stirred for 1 h. During the reaction, phosphorus trifluoride gas was continuously generated. The phosphorus trifluoride gas was collected by condensation at -120℃ to obtain phosphorus trifluoride liquid product with a product yield of 96.2% and HLPC purity of 99.7%.

[0039] Example 5

[0040] Under nitrogen protection, phosphorus trichloride (2.74 kg, 20.0 mol) was added to the reactor, followed by the slow addition of an ionic liquid. (12.64 kg, 80.0 mol) After addition, the mixture was heated to 50℃ and stirred for 30 min. Phosphorus trifluoride gas was continuously generated during the reaction. The phosphorus trifluoride gas was collected by condensation at -120℃ to obtain phosphorus trifluoride liquid product with a product yield of 83.2% and HLPC purity of 99.4%.

[0041] Comparative Example 1

[0042] Based on Example 1 Replace with sodium fluoride, and follow the same procedures and conditions as in Example 1:

[0043] Under nitrogen protection, phosphorus trichloride (2.74 kg, 20.0 mol) was added to the reactor, followed by the slow addition of sodium fluoride (3.36 kg, 80.0 mol). After the addition was complete, the mixture was heated to 40 °C and reacted for 1 h. Phosphorus trifluoride gas was continuously generated during the reaction. The phosphorus trifluoride gas was collected by condensation at -120 °C to obtain a liquid phosphorus trifluoride product with a yield of 61.7% and an HLPC purity of 91.3%.

[0044] Comparative Example 2

[0045] Based on Example 1 Replace with ammonium fluoride, and follow the same procedures and conditions as in Example 1:

[0046] Under nitrogen protection, phosphorus trichloride (2.74 kg, 20.0 mol) was added to the reactor, followed by the slow addition of ammonium fluoride (2.96 kg, 80.0 mol). After the addition was complete, the mixture was heated to 40 °C and stirred for 1 h. Phosphorus trifluoride gas was continuously generated during the reaction. The phosphorus trifluoride gas was collected by condensation at -120 °C to obtain a liquid phosphorus trifluoride product with a yield of 69.5% and an HLPC purity of 84.8%.

[0047] Comparative Example 3

[0048] On the basis of Example 1, replace the tetrabutylammonium fluoride with sodium fluoride, and the other operations and conditions are the same as in Example 1:

[0049] Under nitrogen protection, phosphorus trichloride (2.74 kg, 20.0 mol) was added into a reactor, then tetrabutylammonium fluoride (20.88 kg, 80.0 mol) was slowly added. After the addition was completed, the mixture was warmed to 40°C and stirred for 1 h. During the reaction, phosphorus trifluoride gas was continuously generated, which was condensed and collected at -120°C to obtain liquid phosphorus trifluoride product. The product yield was 73.8% and the HPLC purity was 94.5%.

[0050] The above examples are merely illustrative for the sake of clarity and are in no way limiting on the embodiments. Those skilled in the art can further make variations and / or changes in the form of other different forms on the basis of the above description. It is not necessary or possible to exhaust all the embodiments. The obvious variations and changes derived therefrom are still within the protection scope of the present application.​

Claims

1. A method for preparing phosphorus trifluoride, characterized in that, Includes the following steps: Phosphorus trichloride is reacted with an ionic liquid under an inert gas atmosphere to produce phosphorus trifluoride. The structural formula of the ionic liquid is: , or .

2. The preparation method according to claim 1, characterized in that, The inert gas is selected from one or more of nitrogen, helium, neon and argon.

3. The preparation method according to claim 1, characterized in that, The reaction temperature is 30~50℃ and the reaction time is 0.5~5h.

4. The preparation method according to claim 1, characterized in that, The molar ratio of phosphorus trichloride to ionic liquid is 1:(3~10).

5. The preparation method according to claim 1, characterized in that, This method continuously generates phosphorus trifluoride gas during the reaction process, which is then condensed and collected to obtain a liquid phosphorus trifluoride product.

6. The preparation method according to claim 5, characterized in that, The temperature for condensation collection is -140 to -120℃.

7. The preparation method according to claim 1, characterized in that, Includes the following steps: Phosphorus trichloride was added to the reactor under nitrogen protection, followed by the slow addition of an ionic liquid. After the addition is complete, the mixture is heated to 40°C and stirred for 1 hour. During the reaction, phosphorus trifluoride gas will be continuously generated. The phosphorus trifluoride liquid product is obtained by condensing and collecting at -120°C.

8. The preparation method according to claim 1, characterized in that, Includes the following steps: Phosphorus trichloride was added to the reactor under nitrogen protection, followed by the slow addition of an ionic liquid. After the addition is complete, the mixture is heated to 40°C and stirred for 1 hour. During the reaction, phosphorus trifluoride gas will be continuously generated. The phosphorus trifluoride liquid product is obtained by condensing and collecting at -120°C.

9. The preparation method according to claim 1, characterized in that, Includes the following steps: Phosphorus trichloride was added to the reactor under nitrogen protection, followed by the slow addition of an ionic liquid. After the addition is complete, the mixture is heated to 40°C and stirred for 1 hour. During the reaction, phosphorus trifluoride gas will be continuously generated. The phosphorus trifluoride liquid product is obtained by condensing and collecting at -120°C.

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