Synthesis method of chlorine trifluoride

Abstract

The invention relates to a synthesis method of chlorine trifluoride, which comprises the following steps: S1, connecting a cold trap with a gas outlet of a metal pipeline of a reactor, adding a metal chloride into the reactor, with the addition amount of the metal chloride being two thirds of that of the reactor, and maintaining the pressure; s2, cooling to-100 DEG C to-60 DEG C by a cold trap; s3, the metal pipeline of the reactor is heated to 850-1000 DEG C; s4, starting to introduce fluorine gas, and stopping introducing the fluorine gas when the pressure reaches 3.5 MPa; s5, after reacting for 1-2 hours, opening an outlet valve of the reactor, and collecting through a cold trap; s6, after collection is completed, the temperature of the cold trap is increased to-20 DEG C to 0 DEG C, an emptying opening is opened, and the emptying opening is closed after 5-20 min. The raw materials are simple, and the conversion rate can be effectively improved.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis, and more particularly to a method for synthesizing chlorine trifluoride using metal chlorides and fluorine gas as raw materials. Background Technology

[0002] Chlorine trifluoride (ClF3) is an inorganic compound primarily used as a fluorinating agent, combustion agent, oxidizer in propellants, and cutting oil for high-temperature metals. Due to its unique chemical structure, chlorine trifluoride (ClF3) exhibits chemical reactivity similar to fluorine but is much milder and more environmentally friendly than fluorocarbons. With a GWP of zero, it is considered an ideal cleaning gas for LPCVD (Limited-Limited Circuit Drilling). Japanese companies such as Kanto Chemical, Chuo Asahi Glass, and Iwatani Corporation had already begun large-scale production of high-purity ClF3 products as early as 2010. However, due to its highly reactive chemical properties, its safety remains somewhat controversial.

[0003] In microelectronics manufacturing, etching is a critical process used to precisely remove material from silicon wafers to form circuit patterns. Chlorine trifluoride (ClF3) is highly reactive and hazardous, but it has significant industrial applications. Nuclear fuel processing: ClF3 is primarily used to produce uranium hexafluoride (UF6), a key component of nuclear reactor fuel. In nuclear fuel processing, chlorine trifluoride is used to convert metallic uranium into uranium hexafluoride. Semiconductor manufacturing: In the semiconductor industry, ClF3 is used to clean the reaction chambers of chemical vapor deposition (CVD) reactors, effectively removing semiconductor materials adhering to the chamber walls. Because it decomposes at high temperatures and reacts with semiconductor materials, cleaning can be performed without disassembling the reaction chamber. Due to its strong oxidizing properties, ClF3 is also used as an oxidant in rocket propellants.

[0004] Although chlorine trifluoride has broad application prospects, its synthesis methods still have some limitations. Chinese Patent CN114715850A discloses a high-yield method for synthesizing chlorine trifluoride. This method uses chlorine and fluorine gases as raw materials to produce chlorine trifluoride gas, utilizing the excellent catalytic effect of anhydrous NiF2 in the temperature range of 150–400°C. Through effective temperature control during the reaction and rational and efficient utilization of the heat generated, it not only suppresses the formation of ClF as a byproduct of the disproportionation reaction but also avoids the formation of fluorinated halogen compounds such as ClF5 and ClF7 due to high-temperature deep fluorination. Ultimately, chlorine trifluoride can be obtained in a high yield of 95%. The raw materials used in this invention for synthesizing chlorine trifluoride are simple and readily available, the operation process is convenient, the purity and conversion rate of the raw materials are high, and the final product, chlorine trifluoride, has a high yield, which is beneficial for industrial production.

[0005] Chinese patent CN113562700A discloses a method for preparing chlorine trifluoride, relating to the field of chemical synthesis technology. The method includes the following steps: a fluorine-containing mixed gas generated by electrolysis undergoes primary condensation, secondary condensation, alkali metal adsorption, and filtration to obtain purified fluorine gas; the purified fluorine gas and high-purity chlorine gas are added to a reactor containing a catalyst to react and obtain crude chlorine trifluoride; the crude chlorine trifluoride is then liquefied, vaporized, adsorbed, and distilled to obtain high-purity chlorine trifluoride. This invention provides a method for preparing high-purity chlorine trifluoride.

[0006] The above synthesis method requires the use of chlorine gas, which reacts with fluorine gas at high temperature. The reaction raw materials are relatively dangerous, and the yield and purity of the product are difficult to control. Summary of the Invention

[0007] The purpose of this invention is to provide a method for synthesizing chlorine trifluoride, so as to solve the technical problems of harsh reaction conditions and low product yield in the prior art.

[0008] To achieve the objectives of this invention, the specific technical solution provided by this invention is as follows:

[0009] A method for synthesizing chlorine trifluoride involves placing a metal chloride into a reactor via a metal pipe, heating the reactor, introducing fluorine gas under high temperature conditions, and then collecting the chlorine trifluoride through a cold trap to obtain a purity greater than 90%.

[0010] Preferably, the steps include:

[0011] S1. Connect the cold trap to the gas outlet of the reactor's metal pipe, add the metal chloride into the reactor, and maintain the pressure.

[0012] S2. Reduce the temperature of the cold trap;

[0013] S3. Heat the metal pipes of the reactor to increase their temperature;

[0014] S4. Introduce fluorine gas into the metal pipe of the reactor, and stop the gas flow after the pressure is reached;

[0015] S5. After the reaction has proceeded for a period of time, begin collecting the product;

[0016] S6. After collection is complete, heat the cold trap to a certain temperature, open the vent, and close the vent after a period of time.

[0017] Preferably, the metal pipe is made of 316 stainless steel, Hastelloy, titanium alloy, Monel or manganese-cadmium alloy.

[0018] Preferably, the metal chloride is sodium chloride, ferrous chloride, copper chloride, barium chloride, lithium chloride, magnesium chloride, calcium chloride, or potassium chloride, and the amount added is two-thirds of the reactor volume.

[0019] Preferably, the cold trap temperature in step S2 is -100 to -60°C.

[0020] Preferably, the heating temperature in step S3 is 850–1000°C.

[0021] Preferably, the pressure in step S4 is 3.5 MPa;

[0022] Preferably, the reaction time in step S5 is 1 to 2 hours.

[0023] Preferably, in step S6, the cold trap is heated to -20 to 0°C, and the venting time is 5 to 20 minutes.

[0024] Preferably, it includes the following steps:

[0025] S1. Connect the cold trap to the gas outlet of the reactor's metal pipe, add metal chloride to the reactor in an amount that is two-thirds of the reactor's volume, and maintain pressure.

[0026] S2. The cold trap is cooled to -100 to -60°C;

[0027] S3. Heat the metal pipes of the reactor to 850-1000℃;

[0028] S4. Start introducing fluorine gas, and stop introducing gas when the pressure reaches 3.5 MPa;

[0029] S5. After the reaction has been going on for 1 to 2 hours, open the reactor outlet valve and collect the contents through the cold trap.

[0030] S6. After collection is complete, heat the cold trap to -20 to 0°C, open the vent, and close the vent after 5 to 20 minutes.

[0031] The method for synthesizing chlorine trifluoride according to the present invention has the following beneficial effects:

[0032] 1. This invention utilizes a metal pipe as a reactor. By controlling the temperature, the metal chloride is kept in a molten state, which enables the metal chloride and fluorine to generate chlorine gas. The chlorine gas then reacts with fluorine gas to generate chlorine trifluoride, which significantly improves the selectivity of the product and makes the purity of the collected product reach more than 90%.

[0033] 2. The reaction equipment uses metal pipes, which significantly improves the durability and safety of the equipment. Metal pipes have good chemical stability and mechanical strength, effectively preventing leakage and safety accidents during the reaction process.

[0034] 3. By selecting metal chlorides as raw materials, this invention can effectively reduce the risk compared to chlorine gas in traditional process raw materials. Detailed Implementation

[0035] To further illustrate the technical means and effects of the present invention in achieving the intended purpose, the following detailed description of the specific implementation methods, structures, features and effects of the present invention, in conjunction with preferred embodiments, is provided below.

[0036] In the rapidly developing field of electronic information materials, the application of specialty electronic gases is particularly important. Among them, fluorine-containing electronic gases, due to their unique chemical properties, occupy a pivotal position in the manufacturing process of electronic information materials. These gases are mainly used as cleaning agents and etchants, and can also be used as dopants and film-forming materials, playing a crucial role in improving the performance and stability of semiconductor devices.

[0037] Chlorine trifluoride (CIF3) is an important electronic specialty gas used for cleaning chemical vapor deposition (CVD) chambers and their piping. Unlike other fluorinated gases (such as NF3, C2F6, and CF4), CIF3 reacts with semiconductor materials at room temperature, making it suitable for cleaning cold-walled CVD chambers. Cleaning with CIF3 is a chemical etching process; the heat within the chamber is sufficient to decompose and react with the semiconductor material, avoiding the high-energy ion bombardment process of plasma, thus minimizing damage to the equipment. Compared to plasma pyrolysis for fluorination, CIF3 cleaning is simpler, more efficient, and provides superior cleaning results.

[0038] Currently, existing methods for synthesizing chlorine trifluoride suffer from problems such as harsh reaction conditions, low yields, or low product purity. The inventors prepared chlorine trifluoride using the reaction of chlorine and fluorine as described in existing technologies, but found that this method has low selectivity and yield. Furthermore, chlorine is a highly toxic gas, posing safety challenges and hindering industrial production.

[0039] Therefore, given the potential applications of chlorine trifluoride in semiconductor manufacturing and the limitations of existing synthesis methods, the inventors aim to explore an efficient and environmentally friendly method for synthesizing chlorine trifluoride. By optimizing reaction conditions and improving the synthesis process, it is expected that high-purity and high-yield chlorine trifluoride products can be obtained. Simultaneously, the inventors will also conduct a preliminary evaluation of the performance of chlorine trifluoride as an etching gas and cleaning gas; this part of the technical content is not described in detail in this application.

[0040] Example 1

[0041] A method for synthesizing chlorine trifluoride, the method comprising the following steps:

[0042] S1. Add magnesium chloride to the reactor. Connect the cold trap and fluorine storage tank to the gas inlet and outlet of the titanium alloy reactor, respectively, and maintain pressure on the connected reactor.

[0043] S2. Open the cold trap refrigerant line and lower the cold trap temperature to -100℃;

[0044] S3. Turn on the reactor electric heater to heat the reactor metal pipes to 850°C;

[0045] S4. Open the outlet valve of the fluorine storage tank and the inlet valve of the reactor to introduce fluorine gas into the metal pipeline of the reactor. When the reactor pressure reaches 3.5 MPa, stop the gas supply.

[0046] S5. After ventilating for 1 hour, close the outlet valve of the fluorine storage tank and the inlet valve of the reactor, and open the outlet valve of the reactor and the inlet valve of the cold trap to collect the fluorine.

[0047] S6. After collection is complete, heat the cold trap to -20°C, open the vent valve of the cold trap, and close the vent after 5 minutes.

[0048] impurities Chlorine trifluoride Chlorine Fluoride other Element 90.26％ 2.36％ 7.38％

[0049] Example 2

[0050] A method for synthesizing chlorine trifluoride, the method comprising the following steps:

[0051] S1. Add calcium chloride to the reactor. Connect the cold trap and fluorine storage tank to the gas inlet and outlet of the manganese-chromium alloy reactor, respectively, and maintain pressure on the connected reactor.

[0052] S2. Open the cold trap refrigerant line and lower the cold trap temperature to -60℃;

[0053] S3. Turn on the reactor electric heater to heat the reactor metal pipes to 1000℃;

[0054] S4. Open the outlet valve of the fluorine storage tank and the inlet valve of the reactor to introduce fluorine gas into the metal pipeline of the reactor. When the reactor pressure reaches 3.5 MPa, stop the gas supply.

[0055] S5. After ventilating for 2 hours, close the outlet valve of the fluorine storage tank and the inlet valve of the reactor, and open the outlet valve of the reactor and the inlet valve of the cold trap to collect the fluorine.

[0056] S6. After collection is complete, heat the cold trap to 0°C, open the vent valve of the cold trap, and close the vent after 20 minutes.

[0057] impurities Chlorine trifluoride Chlorine Fluoride other Element 90.67％ 3.38％ 5.95％

[0058] Example 3

[0059] A method for synthesizing chlorine trifluoride, the method comprising the following steps:

[0060] S1. Add sodium chloride to the reactor, connect the cold trap and fluorine storage tank to the gas inlet and outlet of the Monel reactor respectively, and maintain pressure on the connected reactor.

[0061] S2. Open the cold trap refrigerant line and lower the cold trap temperature to -80℃;

[0062] S3. Turn on the reactor electric heater to heat the reactor metal pipes to 900℃;

[0063] S4. Open the outlet valve of the fluorine storage tank and the inlet valve of the reactor to introduce fluorine gas into the metal pipeline of the reactor. When the reactor pressure reaches 3.5 MPa, stop the gas supply.

[0064] S5. After ventilating for 1.5 hours, close the outlet valve of the fluorine storage tank and the inlet valve of the reactor, and open the outlet valve of the reactor and the inlet valve of the cold trap to collect the fluorine.

[0065] S6. After collection is complete, heat the cold trap to -5°C, open the vent valve of the cold trap, and close the vent after 10 minutes.

[0066] impurities Chlorine trifluoride Chlorine Fluoride other Element 93.67％ 2.62％ 3.71％

[0067] Comparative Example 1

[0068] S1. Add magnesium chloride to the reactor, connect the cold trap and fluorine storage tank to the gas inlet and outlet of the Monel reactor respectively, and maintain pressure on the connected reactor.

[0069] S2. Open the cold trap refrigerant line and lower the cold trap temperature to -80℃;

[0070] S3. Turn on the reactor electric heater to heat the reactor metal pipes to 700℃;

[0071] S4. Open the outlet valve of the fluorine storage tank and the inlet valve of the reactor to introduce fluorine gas into the metal pipeline of the reactor. When the reactor pressure reaches 3.5 MPa, stop the gas supply.

[0072] S5. After ventilating for 1.5 hours, close the outlet valve of the fluorine storage tank and the inlet valve of the reactor, and open the outlet valve of the reactor and the inlet valve of the cold trap to collect the fluorine.

[0073] S6. After collection is complete, heat the cold trap to -5°C, open the vent valve of the cold trap, and close the vent after 10 minutes.

[0074] impurities Chlorine trifluoride Chlorine Fluoride other Element 22.92％ 66.92％ 10.16％

[0075] Comparative Example 2

[0076] S1. Add calcium chloride to the reactor, connect the cold trap and fluorine storage tank to the gas inlet and outlet of the Monel reactor respectively, and maintain pressure on the connected reactor.

[0077] S2. Open the cold trap refrigerant line and lower the cold trap temperature to -80℃;

[0078] S3. Turn on the reactor electric heater to heat the reactor metal pipes to 900℃;

[0079] S4. Open the outlet valve of the fluorine storage tank and the inlet valve of the reactor to introduce fluorine gas into the metal pipeline of the reactor. When the reactor pressure reaches 0.1 MPa, stop the gas supply.

[0080] S5. After ventilating for 1.5 hours, close the outlet valve of the fluorine storage tank and the inlet valve of the reactor, and open the outlet valve of the reactor and the inlet valve of the cold trap to collect the fluorine.

[0081] S6. After collection is complete, heat the cold trap to -5°C, open the vent valve of the cold trap, and close the vent after 10 minutes.

[0082] impurities Chlorine trifluoride Chlorine Fluoride other Element 49.92％ 46.61％ 3.47％

[0083] Comparative Example 3

[0084] S1. Add sodium chloride to the reactor, connect the cold trap and fluorine storage tank to the gas inlet and outlet of the Monel reactor respectively, and maintain pressure on the connected reactor.

[0085] S2. Open the cold trap refrigerant line and lower the cold trap temperature to -180℃;

[0086] S3. Turn on the reactor electric heater to heat the reactor metal pipes to 900℃;

[0087] S4. Open the outlet valve of the fluorine storage tank and the inlet valve of the reactor to introduce fluorine gas into the metal pipeline of the reactor. When the reactor pressure reaches 3.5 MPa, stop the gas supply.

[0088] S5. After ventilating for 1.5 hours, close the outlet valve of the fluorine storage tank and the inlet valve of the reactor, and open the outlet valve of the reactor and the inlet valve of the cold trap to collect the fluorine.

[0089] S6. After collection is complete, heat the cold trap to -5°C, open the vent valve of the cold trap, and close the vent after 10 minutes.

[0090] impurities Chlorine trifluoride Chlorine Fluoride other Element 62.92％ 29.41％ 7.67％

[0091] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. 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 method for synthesizing chlorine trifluoride, characterized in that, Metal chlorides are placed in a reactor with metal pipes, the reactor is heated, fluorine gas is introduced under high temperature conditions, and then collected through a cold trap to obtain chlorine trifluoride with a purity greater than 90%.

2. The method for synthesizing chlorine trifluoride according to claim 1, characterized in that, Includes the following steps: S1. Connect the cold trap to the gas outlet of the reactor's metal pipe, add the metal chloride into the reactor, and maintain the pressure. S2. Reduce the temperature of the cold trap; S3. Heat the metal pipes of the reactor to increase their temperature; S4. Introduce fluorine gas into the metal pipe of the reactor, and stop the gas flow after the pressure is reached; S5. After the reaction has proceeded for a period of time, begin collecting the product; S6. After collection is complete, heat the cold trap to a certain temperature, open the vent, and close the vent after a period of time.

3. The method for synthesizing chlorine trifluoride according to claim 1, characterized in that, Metal pipes are made of 316 stainless steel, Hastelloy, titanium alloy, Monel, or manganese-cadmium alloy.

4. The method for synthesizing chlorine trifluoride according to claim 1, characterized in that, The metal chlorides are sodium chloride, ferrous chloride, copper chloride, barium chloride, lithium chloride, magnesium chloride, calcium chloride, and potassium chloride, and the amount added is two-thirds of the reactor volume.

5. The method for synthesizing chlorine trifluoride according to claim 2, characterized in that, In step S2, the cold trap temperature is -100 to -60°C.

6. The method for synthesizing chlorine trifluoride according to claim 2, characterized in that, In step S3, the heating temperature is 850–1000°C.

7. The method for synthesizing chlorine trifluoride according to claim 2, characterized in that, The pressure in step S4 is 3.5 MPa.

8. The method for synthesizing chlorine trifluoride according to claim 2, characterized in that, The reaction time in step S5 is 1 to 2 hours.

9. The method for synthesizing chlorine trifluoride according to claim 2, characterized in that, In step S6, the cold trap is heated to -20 to 0°C, and the venting time is 5 to 20 minutes.

10. The method for synthesizing chlorine trifluoride according to claim 1, characterized in that, Includes the following steps: S1. Connect the cold trap to the gas outlet of the reactor's metal pipe, add metal chloride to the reactor at a volume of two-thirds, and maintain pressure. S2. The cold trap is cooled to -100 to -60°C; S3. Heat the metal pipes of the reactor to 850-1000℃; S4. Start introducing fluorine gas, and stop introducing gas when the pressure reaches 3.5 MPa; S5. After the reaction has been going on for 1 to 2 hours, open the reactor outlet valve and collect the contents through the cold trap. S6. After collection is complete, heat the cold trap to -20 to 0°C, open the vent, and close the vent after 5 to 20 minutes.