Device and method for preparing phosphorus trifluoride

Abstract

The invention belongs to the technical field of preparation of phosphorus trichloride, and particularly relates to a preparation device and method of phosphorus trifluoride. The device comprises a reactor, a cold trap and a collector, the upper part of the reactor is provided with a phosphorus trichloride dropping device and a zinc fluoride feeding port, the upper end of the reactor is provided with a stirring paddle, the stirring paddle extends to the bottom of the reactor, the upper end of the reactor is communicated with the cold trap through a first pipeline, the pipeline is provided with a condensation pipe, and the condensation pipe is communicated with the cold trap through a second pipeline. The bottom of the cold trap is communicated with the reactor through a second pipeline; and the upper end of the cold trap is communicated with the collector through a third pipeline. The method comprises the following steps: dropwise adding phosphorus trichloride into anhydrous zinc fluoride powder in a nitrogen atmosphere, and stirring for reaction; and collecting a reaction product, and recovering phosphorus trichloride. By adding the stirring paddle into the reactor and adopting a two-stage condensation method, the conversion rate of the raw materials is increased, the production cost is reduced, and the operation process is simple.

Description

Technical Field

[0001] The present application belongs to the technical field of preparation of phosphorus trichloride, and specifically relates to a device and method for preparing phosphorus trifluoride. Background Art

[0002] Phosphorus trifluoride is an important inorganic compound, widely used in organic synthesis, chemical analysis and semiconductor industry. In organic synthesis, phosphorus trifluoride, as a fluorinating agent, can replace hydrogen atoms in organic compounds with fluorine atoms and introduce fluorine functional groups, which is very beneficial for the synthesis of drugs, pesticides and other organic compounds. In addition, phosphorus trifluoride can also be used for acylation reactions and as a catalyst in various organic reactions.

[0003] In the semiconductor industry, phosphorus trifluoride can be used in ion implantation and etching processes to improve the electronic properties of semiconductor materials. It can also be used for phosphating reactions and conductor surface treatment under anhydrous conditions. The synthesis of phosphorus trifluoride usually involves the reaction of phosphorus oxide and hydrofluoric acid, or it is prepared by the reaction of phosphorus chloride with sodium fluoride or potassium fluoride.

[0004] The preparation of phosphorus trifluoride by the reaction of zinc fluoride and phosphorus trichloride is a common preparation method of phosphorus trifluoride. Since phosphorus trichloride is easily volatilized, the utilization rate of phosphorus trichloride is not high, and there is a certain waste situation. At the same time, the zinc chloride byproduct produced by phosphorus trichloride and zinc fluoride will hinder phosphorus trichloride and zinc fluoride from contacting, reducing the utilization rate of raw materials. As disclosed in the Chinese patent of announcement number CN101955173A, a technology of preparing phosphorus trifluoride by the reaction of phosphorus trichloride and zinc fluoride is mainly made of a reactor integrated with a hydrogen fluoride storage bottle, connected with a dropping funnel and a conduit at the top, and the dropping funnel and the conduit are connected with a drier by connecting a pipeline, and the drier is connected with a zinc fluoride inlet pipe, and is assembled into one. Although the device process is reasonable and the preparation is simple, the zinc chloride byproduct produced by phosphorus trichloride and zinc fluoride will hinder phosphorus trichloride and zinc fluoride from contacting, reducing the utilization rate of raw materials. However, if a stirring device is added, the volatilization of phosphorus trichloride may be aggravated, further increasing the utilization rate of raw materials.

[0005] In summary, in the existing methods for preparing phosphorus trifluoride, the raw material utilization rate is low, the reaction by-products are relatively large, and the reaction products are seriously wasted. Therefore, it is urgent to propose a preparation device and method for phosphorus trifluoride to solve the current problems. Summary of the invention

[0006] In view of the low raw material utilization rate, the large number of reaction by-products and the serious waste of reaction products in the method for preparing phosphorus trifluoride in the prior art, the present application proposes a device and method for preparing phosphorus trifluoride.

[0007] The technical solution of this application:

[0008] On the one hand, the present application proposes a device for preparing phosphorus trifluoride, which is as follows:

[0009] The invention comprises a reactor, a cold trap and a collector. A phosphorus trichloride dropping device and a zinc fluoride feeding port are arranged on the upper part of the reactor. A stirring paddle is arranged on the upper end of the reactor, and the stirring paddle extends to the bottom of the reactor. The upper end of the reactor is connected with the cold trap through a first pipeline, and a condenser is arranged on the pipeline. The bottom of the cold trap is connected with the reactor through a second pipeline; and the upper end of the cold trap is connected with the collector through a third pipeline.

[0010] Preferably, a first nitrogen inlet is further provided at the upper portion of the reactor, and a water bath heating jacket is provided outside the reactor for heating the reactor.

[0011] Preferably, a first cooling jacket is provided outside the cold trap, the condensing medium in the first cooling jacket is dichloromethane, and a second nitrogen inlet is provided on the side of the cold trap; a second cooling jacket is provided outside the collector, the condensing medium of the second cooling jacket is liquid nitrogen, and a first nitrogen outlet is provided on the side of the collector.

[0012] Preferably, a valve is provided on the third pipeline; and the condensing medium of the condenser is dichloromethane.

[0013] Preferably, the reactor, condenser, cold trap and condenser are made of stainless steel.

[0014] Preferably, the stirring paddle is transmission connected to a motor.

[0015] In a second aspect, the present application provides a method for preparing phosphorus trifluoride.

[0016] The steps include:

[0017] Step S1. Under a nitrogen atmosphere, phosphorus trichloride was added dropwise to anhydrous zinc fluoride powder and stirred for reaction;

[0018] Step S2: Collect the reaction products and recover phosphorus trichloride.

[0019] Preferably, the temperature of the stirring reaction in step S1 is 30-60° C., the speed of the stirring reaction is 30-90 r / min; the dropping speed is 1-3 drops / second; and the ratio of the anhydrous zinc fluoride powder to phosphorus trichloride is (60-75) g:(55-65) mL.

[0020] Preferably, the temperature for collecting the reaction product in step S2 is -150 to -140°C, and the temperature for recovering phosphorus trichloride is -50 to -40°C.

[0021] Beneficial effects:

[0022] 1) The present application solves the contact problem in the reaction process of phosphorus trichloride and zinc fluoride by adding a stirring paddle in the reactor, thereby improving the utilization rate of raw materials. In the traditional reaction process, when phosphorus trichloride and zinc fluoride are mixed in the reactor, a layer of obstruction may be formed on the interface due to the formation of byproduct zinc chloride, which reduces the effective contact area between phosphorus trichloride and zinc fluoride, thereby reducing the reaction efficiency. This interface obstruction will cause the raw materials to fail to fully participate in the reaction, resulting in a waste of raw materials. The present application installs a stirring paddle in the reactor, and ensures that the reaction materials in the reactor are evenly mixed by mechanical stirring. The contact area between phosphorus trichloride and zinc fluoride is maximized, so that more fluoride ions can be exposed and effectively combined with phosphorus ions, which promotes the reaction. In addition, the stirring paddle can also promote the transfer of heat and mass, accelerate the reaction rate, shorten the reaction time, and further improve the production efficiency. At the same time, the design of the stirring paddle also takes into account the fluid dynamics characteristics in the reactor to ensure that the best stirring effect is maintained throughout the reaction process. The present application not only improves the utilization rate of raw materials, but also reduces production costs and improves the quality and output of products.

[0023] 2) The present application improves the utilization rate of phosphorus trichloride and reduces the volatilization loss of raw materials through a two-stage condensation system, thereby optimizing the production process. First, the present application adds a condenser above the reactor, which can initially capture and condense phosphorus trichloride that does not participate in the reaction. In this way, phosphorus trichloride is effectively recovered and refluxed back to the reactor to continue to participate in subsequent chemical reactions. The initial condensation not only reduces the loss of raw materials, but also improves the continuity and efficiency of the reaction. Secondly, the present application introduces a cold trap design as a secondary condensation system. The cold trap further condenses and collects the volatilized phosphorus trichloride, and recycles it to the reactor through the pipeline at the bottom of the cold trap. Not only does it improve the recovery rate of phosphorus trichloride, but it also realizes the recycling of raw materials, further reducing production costs. In addition, the condenser and cold trap in the present application use dichloromethane as a cooling medium. The boiling point of dichloromethane is about 39.8°C, which enables it to evaporate rapidly during the condensation process, effectively absorbing and taking away heat. The high thermal conductivity of dichloromethane further enhances the cooling effect and ensures the high efficiency of the condensation process. Combined with the stirring paddle in the reactor, the condensation system of the present application can work in conjunction with the stirring action to ensure that the raw materials are evenly distributed in the reactor and maximize the reaction efficiency. The stirring paddle promotes full contact between phosphorus trichloride and the reactants through mechanical stirring, thereby increasing the reaction rate and the conversion rate of the raw materials.

[0024] 3) In the traditional preparation method, the reaction of phosphorus trichloride and zinc fluoride is usually carried out in a glass reactor, but this method has certain safety hazards, and the glass reactor may not be stable enough under high temperature or high pressure conditions. The reaction device of the present application uses a stainless steel reactor to improve safety. Stainless steel has better corrosion resistance, high temperature resistance and high pressure resistance. Stainless steel reactors can withstand more severe chemical environments, reduce potential risks in the reaction process, and improve the stability and reliability of the reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Attached Figure 1 Schematic diagram of the reaction device of this application.

[0026] Figure numerals: 1, reactor; 2, cold trap; 3, collector; 4, stirring paddle; 5, phosphorus trichloride dropping device; 6, motor; 7, condenser; 8, first pipeline; 9, zinc fluoride feeding port; 10, third pipeline; 11, second pipeline; 12, second nitrogen inlet; 13, first nitrogen outlet; 14, second cooling jacket; 15, first cooling jacket; 16, first nitrogen inlet; 17, water bath heating jacket. DETAILED DESCRIPTION

[0027] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0028] Example 1

[0029] This embodiment provides a device and method for preparing phosphorus trifluoride.

[0030] Step 1, open the first nitrogen inlet 16 and the first nitrogen outlet 13, and inject nitrogen into the entire reaction device. After the first nitrogen outlet 13 detects nitrogen, it means that the entire reaction device is full of nitrogen. Close the first nitrogen outlet 13, and continue to fill the reaction device with nitrogen until the pressure of the nitrogen in the reaction device is 0.1 MPa, and maintain the pressure for 24 hours. Then, the entire reaction device is evacuated to -0.1 MPa, and the evacuation is repeated 30 times. Then, the condenser 7, the first cooling jacket 15 and the second cooling jacket 14 are opened, and the temperature of the condenser 7 and the first cooling jacket 15 is controlled to be -45 to -40°C, and the temperature of the collector 3 is -145 to -140°C, wherein the condensing medium of the condenser 7 and the first cooling jacket 15 is dichloromethane, and the cooling medium of the second cooling jacket is liquid nitrogen.

[0031] Step 2: Add 70 g of zinc fluoride powder into the reactor 1 through the zinc fluoride feeding port 9, turn on the water bath heating jacket 17, control the water bath temperature to 30° C., add 60 mL of phosphorus trichloride into the reactor 1 through the phosphorus trichloride dropping device 5, and add phosphorus trichloride at a rate of 2 drops / second. At the same time, turn on the stirring paddle 4. Driven by the motor 6, the stirring paddle 4 starts to rotate, and the speed is controlled to be 45 r / min. At this time, part of the phosphorus trichloride volatilized in the reactor 1 flows back into the reactor 1 through the condenser 7, and the remaining substances enter the cold trap 2 through the first pipe 8.

[0032] Step 3: After the phosphorus trichloride is added dropwise, 0.1 MPa nitrogen is injected into the cold trap 2 through the second nitrogen inlet 12, so that the phosphorus trichloride in the cold trap 2 flows back to the reactor 1 through the second pipe 11 to continue the reaction again, and the generated phosphorus trifluoride enters the collector 3 through the third pipe 10 for the next step of treatment.

[0033] Example 2

[0034] Step 1, open the first nitrogen inlet 16 and the first nitrogen outlet 13, and inject nitrogen into the entire reaction device. After the first nitrogen outlet 13 detects nitrogen, it means that the entire reaction device is full of nitrogen. Close the first nitrogen outlet 13, and continue to fill the reaction device with nitrogen until the pressure of the nitrogen in the reaction device is 0.1 MPa, and maintain the pressure for 24 hours. Then, the entire reaction device is evacuated to -0.1 MPa, and the evacuation is repeated 30 times. Then, the condenser 7, the first cooling jacket 15 and the second cooling jacket 14 are opened, and the temperature of the condenser 7 and the first cooling jacket 15 is controlled to be -50 to -40°C, and the temperature of the collector 3 is -150 to -140°C, wherein the condensing medium of the condenser 7 and the first cooling jacket 15 is dichloromethane, and the cooling medium of the second cooling jacket is liquid nitrogen.

[0035] Step 2: Add 60 g of zinc fluoride powder into the reactor 1 through the zinc fluoride feeding port 9, turn on the water bath heating jacket 17, control the water bath temperature to 30° C., add 55 ml of phosphorus trichloride into the reactor 1 through the phosphorus trichloride dropping device 5, and add phosphorus trichloride at a rate of 3 drops / second. At the same time, turn on the stirring paddle 4. Driven by the motor 6, the stirring paddle 4 starts to rotate, and the speed is controlled to be 30 r / min. At this time, part of the phosphorus trichloride volatilized in the reactor 1 flows back into the reactor 1 through the condenser 7, and the remaining substances enter the cold trap 2 through the first pipeline 8.

[0036] Step 3: After the phosphorus trichloride is added dropwise, 0.1 MPa nitrogen is injected into the cold trap 2 through the second nitrogen inlet 12, so that the phosphorus trichloride in the cold trap 2 flows back to the reactor 1 through the second pipe 11 to continue the reaction again, and the generated phosphorus trifluoride enters the collector 3 through the third pipe 10 for the next step of treatment.

[0037] Example 3

[0038] This embodiment provides a device and method for preparing phosphorus trifluoride.

[0039] Step 1, open the first nitrogen inlet 16 and the first nitrogen outlet 13, and inject nitrogen into the entire reaction device. After the first nitrogen outlet 13 detects nitrogen, it means that the entire reaction device is full of nitrogen. Close the first nitrogen outlet 13, and continue to fill the reaction device with nitrogen until the pressure of the nitrogen in the reaction device is 0.1 MPa, and maintain the pressure for 24 hours. Then, the entire reaction device is evacuated to -0.1 MPa, and the evacuation is repeated 30 times. Then, the condenser 7, the first cooling jacket 15 and the second cooling jacket 14 are opened, and the temperature of the condenser 7 and the first cooling jacket 15 is controlled to be -50 to -40°C, and the temperature of the collector 3 is -150 to -140°C, wherein the condensing medium of the condenser 7 and the first cooling jacket 15 is dichloromethane, and the cooling medium of the second cooling jacket is liquid nitrogen.

[0040] Step 2: Add 75 g of zinc fluoride powder into the reactor 1 through the zinc fluoride feeding port 9, turn on the water bath heating jacket 17, control the water bath temperature to 30° C., add 65 ml of phosphorus trichloride into the reactor 1 through the phosphorus trichloride dropping device 5, and add phosphorus trichloride at a rate of 1 drop / second. At the same time, turn on the stirring paddle 4. Driven by the motor 6, the stirring paddle 4 starts to rotate, and the speed is controlled to be 90 r / min. At this time, part of the phosphorus trichloride volatilized in the reactor 1 flows back into the reactor 1 through the condenser 7, and the remaining substances enter the cold trap 2 through the first pipe 8.

[0041] Step 3: After the phosphorus trichloride is added dropwise, 0.1 MPa nitrogen is injected into the cold trap 2 through the second nitrogen inlet 12, so that the phosphorus trichloride in the cold trap 2 flows back to the reactor 1 through the second pipe 11 to continue the reaction again, and the generated phosphorus trifluoride enters the collector 3 through the third pipe 10 for the next step of treatment.

[0042] Comparative Example 1

[0043] The difference between this comparative example and Example 1 is that the stirring paddle 4 is not provided in this comparative example.

[0044] Comparative Example 2

[0045] The difference between this comparative example and Example 1 is that the speed of the stirring paddle 4 in this comparative example is 120 r / min.

[0046] Comparative Example 3

[0047] The difference between this comparative example and Example 1 is that the speed of the stirring paddle 4 in this comparative example is 20 r / min.

[0048] Comparative Example 4

[0049] The difference between this comparative example and Example 1 is that this comparative example does not have a condenser 7 .

[0050] Results

[0051] The phosphorus trichloride conversion rate and zinc fluoride conversion rate of Examples 1 to 3 and Comparative Examples 1 to 4 were tested, and the results are shown in Table 1.

[0052] Table 1

[0053] sample Phosphorus trichloride conversion rate Zinc fluoride conversion rate Example 1 94.4％ 90.5％ Example 2 92.2％ 91.6％ Example 3 90.7％ 93.8％ Comparative Example 1 65.4％ 64.1％ Comparative Example 2 75.7％ 79.5％ Comparative Example 3 77.3％ 76.8％ Comparative Example 4 83.6％ 85.1％

[0054] Result analysis:

[0055] From the results in Table 1, it can be seen that the conversion rate of the raw materials is above 90% when phosphorus trifluoride is prepared by the device of the present application. On the one hand, this is because the present application installs a stirring paddle 4 in the reactor, and ensures that the reaction materials in the reactor are evenly mixed by mechanical stirring. The contact area between phosphorus trichloride and zinc fluoride is maximized, so that more fluoride ions can be exposed and effectively combined with phosphorus ions, which promotes the reaction. In addition, the stirring paddle 4 can also promote the transfer of heat and mass, accelerate the reaction rate, shorten the reaction time, and further improve the production efficiency. At the same time, the design of the stirring paddle 4 also takes into account the fluid dynamics characteristics in the reactor to ensure that the best stirring effect is maintained throughout the reaction process. The present application not only improves the utilization rate of raw materials, but also reduces production costs and improves the quality and output of products. On the other hand, the present application adds a condenser 7 above the reactor, which can initially capture and condense phosphorus trichloride that does not participate in the reaction. The phosphorus trichloride is effectively recovered and refluxed back to the reactor 1 to continue to participate in subsequent chemical reactions. Preliminary condensation not only reduces the loss of raw materials, but also improves the continuity and efficiency of the reaction. Secondly, the cold trap 2 of the present application, as a secondary condensation system, further condenses and collects the volatilized phosphorus trichloride, and recovers it to the reactor 1 through the pipeline at the bottom of the cold trap 2. Not only improve the recovery rate of phosphorus trichloride, but also achieve the recycling of raw materials, further reducing production costs. In addition, the condensing tube 7 and the cold trap 2 in the present application use dichloromethane as a cooling medium. The condensation system of the present application can work in coordination with the stirring device to ensure that the raw materials are evenly distributed in the reactor, maximizing the reaction efficiency. The stirring paddle 4 promotes the full contact of phosphorus trichloride with the reactant through mechanical stirring, and improves the reaction rate and the conversion rate of the raw material.

[0056] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A device for preparing phosphorus trifluoride, characterized in that: The invention comprises a reactor (1), a cold trap (2) and a collector (3). The upper part of the reactor (1) is provided with a phosphorus trichloride dropping device (5) and a zinc fluoride feeding port (9). The upper end of the reactor (1) is provided with a stirring paddle (4), and the stirring paddle (4) extends to the bottom of the reactor (1). The upper end of the reactor (1) is connected to the cold trap (2) through a first pipe (8), and a condenser (7) is provided on the pipe. The bottom of the cold trap (2) is connected to the reactor (1) through a second pipe (11); and the upper end of the cold trap (2) is connected to the collector (3) through a third pipe (10).

2. A phosphorus trifluoride preparation device according to claim 1, characterized in that: The upper portion of the reactor (1) is also provided with a first nitrogen inlet (16), and the outside of the reactor (1) is provided with a water bath heating jacket (17) for heating the reactor (1).

3. A phosphorus trifluoride preparation device according to claim 1, characterized in that: A first cooling jacket (15) is provided outside the cold trap (2), the condensing medium in the first cooling jacket (15) is dichloromethane, and a second nitrogen inlet (12) is also provided on the side of the cold trap (2); a second cooling jacket (14) is provided outside the collector (3), the condensing medium in the second cooling jacket (14) is liquid nitrogen, and a first nitrogen outlet (13) is also provided on the side of the collector (3).

4. The phosphorus trifluoride preparation device according to claim 1, characterized in that: The third pipeline (10) is provided with a valve; the condensing medium of the condenser (7) is dichloromethane.

5. The phosphorus trifluoride preparation device according to claim 1, characterized in that: The reactor (1), condenser (7), cold trap (2) and condenser are made of stainless steel.

6. The device for preparing phosphorus trifluoride according to claim 1, characterized in that: The stirring paddle (4) is drivingly connected to the motor (6).

7. A method for preparing phosphorus trifluoride, based on the device for preparing phosphorus trifluoride according to any one of claims 1 to 5, characterized in that: The steps include: Step S1. Under a nitrogen atmosphere, phosphorus trichloride was added dropwise to anhydrous zinc fluoride powder and stirred for reaction; Step S2: Collect the reaction products and recover phosphorus trichloride.

8. The method for preparing phosphorus trifluoride according to claim 7, characterized in that: The temperature of the stirring reaction in step S1 is 30-60° C., the speed of the stirring reaction is 30-90 r / min; the dropping speed is 1-3 drops / second; the ratio of the anhydrous zinc fluoride powder to phosphorus trichloride is (60-75) g:(55-65) mL.

9. The method for preparing phosphorus trifluoride according to claim 7, characterized in that: The temperature for collecting the reaction product in step S2 is -150 to -140°C, and the temperature for recovering phosphorus trichloride is -50 to -40°C.

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