A method for preparing electronic grade phosphorus trifluoride

Abstract

The application discloses a preparation method of electronic-grade phosphorus trifluoride. Under the protection of inert atmosphere, first, phosphorus trichloride is added into a reactor, and the phosphorus trichloride is heated, with the temperature being controlled at 40-60 DEG C, and the temperature being kept for 20-50 minutes; then, anhydrous hydrogen fluoride is slowly introduced from the bottom of the reactor, and the anhydrous hydrogen fluoride is fully contacted with the phosphorus trichloride to generate phosphorus trifluoride, which is directly condensed and collected; finally, the electronic-grade phosphorus trifluoride is prepared through rectification and purification. The molar ratio of the phosphorus trichloride to the anhydrous hydrogen fluoride is 4:1-1.2. The preparation method of the application adopts a direct synthesis method, which is beneficial to the purification of the product; all raw materials are conventional market products, so that the synthesis cost and the toxicity of the reaction are reduced, and the method has better operability, higher yield and is easy to be scaled up; and additionally, the product is subjected to a rectification step, so that the purity and granularity of the product can meet the product requirements of the electronic industry.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material preparation, in particular to a preparation method of electronic-grade phosphorus trifluoride. BACKGROUND

[0002] Phosphorus trifluoride is an inorganic compound with chemical formula PF3, melting point of -151.3℃, boiling point of -101.2℃. Phosphorus trifluoride is a colorless and odorless gas at normal temperature and pressure, and is a colorless transparent liquid in liquid state. It is relatively stable in air, and reacts with hydrogen to generate PH3 when heated, and can react with water to generate phosphorous acid and hydrogen fluoride. It can also be decomposed in alkali, and is soluble in ethanol. Except at high temperature, it does not corrode glass.

[0003] Phosphorus trifluoride can be used as a fluorinating agent, and can be ionically transferred, and is applied in the fields of electronic industry, battery manufacturing, polymer materials and catalysts. In the aspect of semiconductor manufacturing, it is reported in the literature that phosphorus trifluoride can be converted into plasma gas under the action of microwaves for doping, which can significantly improve the performance of semiconductors. In the field of polymer materials, it is reported in the literature that phosphorus trifluoride can be used as a reactant to synthesize fluorinated organic dithiophosphate and terephthalate, which are high molecular materials with good corrosion resistance.

[0004] At present, the synthesis methods of phosphorus trifluoride include: (1) phosphorus powder is added to hydrogen fluoride to generate phosphorus fluoride (PF5), and then the phosphorus fluoride and hydrogen gas are reacted under the action of a catalyst to generate phosphorus trifluoride; (2) the patent CN201010508844.9 reports that phosphorus trichloride and zinc fluoride are reacted to produce phosphorus trifluoride. The hot and anhydrous zinc fluoride powder dried at 140-150℃ is placed in a reactor, and the phosphorus trichloride is dropped into the reactor from a dropping funnel and a guide pipe. This reaction is a strong exothermic reaction with a long induction period. The phosphorus trichloride is added at a speed of 1 drop per second within the first 12 minutes. Then the adding speed of the phosphorus trichloride is adjusted, and the reactor 2 is immersed in a cold water bath to control the speed of generating phosphorus trifluoride. It takes about 1.5-2 hours to drop the phosphorus trichloride. In the last stage of the reaction, the reaction can be changed to a hot water bath to make the reaction complete. The reaction tube is connected to hydrogen fluoride to react with the phosphorus trichloride in the reactor. The reaction is carried out at 50-60℃. The mixture collected in the reactor is distilled to obtain phosphorus trifluoride. However, the purity of the electronic-grade phosphorus trifluoride obtained by the above two methods is relatively low. Method (1) is not mature enough to produce electronic-grade phosphorus trifluoride. Method (2) is complex in process operation and is not easy to scale up.

[0005] Therefore, it is necessary to invent a new preparation method of electronic-grade phosphorus trifluoride to realize the scale-up production of phosphorus trifluoride products with a purity of 99.99%. SUMMARY

[0006] The purpose of the present application is to provide a preparation method of electronic-grade phosphorus trifluoride, filling the gap in the current technology.

[0007] The purpose of the present application is achieved by the following technical solutions:

[0008] A preparation method of electronic-grade phosphorus trifluoride, comprising the following steps:

[0009] (1) Under the protection of an inert atmosphere, first add phosphorus trichloride to the reactor, heat it, control the temperature at 40-60°C, and maintain the temperature for 20-50 minutes;

[0010] (2) Then slowly introduce anhydrous hydrogen fluoride from the bottom of the reactor, make it fully contact with the reaction, generate phosphorus trifluoride, and directly condense and collect;

[0011] (3) Finally, perform rectification and purification to obtain electronic-grade phosphorus trifluoride.

[0012] Preferably, the inert gas is nitrogen gas. Of course, other conventional inert gases such as argon, helium, carbon dioxide gas, etc. can also be used.

[0013] Preferably, the heating temperature in step (1) is controlled at 45-55°C.

[0014] Further preferably, the heating temperature in step (1) is 50°C.

[0015] Preferably, the temperature maintenance time in step (1) is 25-40 minutes.

[0016] Further preferably, the temperature maintenance time in step (1) is 30 minutes.

[0017] Preferably, the molar ratio of the amount of phosphorus trichloride to anhydrous hydrogen fluoride is 4:1-1.2.

[0018] Further preferably, the molar ratio of the amount of phosphorus trichloride to anhydrous hydrogen fluoride is 4:1.

[0019] Due to the use of the above technical solutions, the present application has the following advantages and beneficial effects compared with the prior art:

[0020] 1. The present application is a direct synthesis method, which is beneficial to product purification.

[0021] 2. The raw materials used are conventional commercially available products, which reduces the synthesis cost and the toxicity of the reaction, has better operability, has a higher yield, and is easy to scale up.

[0022] 3. The present application additionally performs a rectification step, which finally makes the purity and particle size of the product better meet the product requirements of the electronic industry. Detailed Implementation

[0023] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific implementation schemes are now described in detail.

[0024] The present invention will be further described below with reference to embodiments, but the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0025] Example 1

[0026] (1) Under an inert atmosphere, first add 137.3 g (1 mol) of phosphorus trichloride to a 1 L reaction flask, heat it, and keep the temperature at 50 °C for 30 minutes.

[0027] (2) Then, 5g (0.25mol) of anhydrous hydrogen fluoride was slowly introduced from the bottom of the reactor to allow it to fully contact and react, producing 1.6g of phosphorus trifluoride with a yield of 95%, which was directly condensed and collected.

[0028] (3) Finally, the phosphorus trifluoride was purified by distillation to obtain electronic grade phosphorus trifluoride with a purity of 99.99%.

[0029] Example 2

[0030] (1) Under an inert atmosphere, first add 137.3 g (1 mol) of phosphorus trichloride to a 1 L reaction flask, heat it, and keep the temperature at 40 °C for 30 minutes.

[0031] (2) Then, 5g (0.25mol) of anhydrous hydrogen fluoride was slowly introduced from the bottom of the reactor to allow it to fully contact and react, producing 1.52g of phosphorus trifluoride with a yield of 90.52%, which was directly condensed and collected.

[0032] (3) Finally, the phosphorus trifluoride was purified by distillation to obtain electronic grade phosphorus trifluoride with a purity of 99.99%.

[0033] Comparative Example 1

[0034] (1) Under an inert atmosphere, first add 137.3 g (1 mol) of phosphorus trichloride to a 1 L reaction flask, heat it, and keep the temperature at 50 °C for 30 minutes.

[0035] (2) Then slowly pass 5g (0.25mol) of anhydrous hydrogen fluoride from the bottom of the reactor, make it fully contact the reaction, generate 1.6g of phosphorus trifluoride, the yield is 95%, directly condensed collection; the phosphorus trifluoride prepared, the purity is 90.89%.

[0036] Comparative Example 2

[0037] (1) Under the protection of inert atmosphere, first, 137.3g (1mol) of phosphorus trichloride is added to a 1L reaction bottle, heated, the temperature is controlled at 50℃, and the temperature is kept for 30 minutes;

[0038] (2) Then slowly pass 5g (0.25mol) of anhydrous hydrogen fluoride from the bottom of the reactor, make it fully contact the reaction, generate 1.6g of phosphorus trifluoride, the yield is 95%, directly condensed collection;

[0039] (3) Finally, a single distillation is carried out, and the phosphorus trifluoride prepared, the purity is 95.69%.

[0040]

[0041] In summary, compared with the prior art, the electronic grade phosphorus trifluoride preparation method provided by the present application adopts a direct synthesis method, which is beneficial to the purification of the product; the raw materials are all conventional commercially available products, which reduces the synthesis cost and the toxicity of the reaction, and has better operability, higher yield, and is easy to scale up; the present application additionally passes through a rectification step, finally the purity and granularity of the product can better meet the product requirements of the electronic industry.

[0042] The above-described embodiments only express two embodiments of the present application, which are described in more detail and in detail, but should not be understood as limiting the scope of the patent. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. A process for the preparation of electronic grade phosphorus trifluoride, characterized in that, It comprises the following steps: (1) under the protection of inert atmosphere, first add phosphorus trichloride into the reactor, heat it, control the temperature at 40-60℃, keep the temperature for 20-50 minutes; (2) then slowly pass anhydrous hydrogen fluoride from the bottom of the reactor, make it contact with the reaction sufficiently, generate phosphorus trifluoride, collect it directly by condensation; (3) finally, carry out rectification and purification, prepare electronic grade phosphorus trifluoride; The molar ratio of the amount of phosphorus trichloride to that of anhydrous hydrogen fluoride is 4:

1.

2. The process for the preparation of electronic grade phosphorus trifluoride according to claim 1, characterized in that, The inert atmosphere is nitrogen atmosphere.

3. The process for the preparation of electronic grade phosphorus trifluoride as claimed in claim 1, wherein, The heating temperature in step (1) is controlled at 50℃.

4. The process for the preparation of electronic grade phosphorus trifluoride as claimed in claim 1, wherein, The temperature keeping time in step (1) is 30 minutes.

Images