Method for preparing phosphorus trifluoride

Abstract

The method for preparing phosphorous trifluoride according to the present invention comprises the steps of: controlling the particle size (D50) of NaF to 67 μm to 137 μm; and reacting the particle size-controlled NaF, PCl3, and a solvent to prepare phosphorus trifluoride. By maximizing reactivity through control of the NaF particle size, the conversion rate of NaF can be increased, thereby suppressing the generation of unreacted NaF. Further, the selectivity for phosphorus trifluoride is excellent, and the preparation cost can be reduced.

Description

Method for manufacturing phosphorus trifluoride

[0001] The present invention relates to a method for manufacturing phosphorus trifluoride.

[0002] As the demand for high-performance memory semiconductors continues to increase, there is a growing demand for processes that are more advanced than the current 7th generation process. Conventional etching gases exhibit a significant difference in the Bottom:Top ratio as the height increases, making it difficult to manufacture high-layer memory. However, the newly selected PF3 suppresses the chemical reaction of radicals at low temperatures, and P forms a protective film on the wafer surface, enabling narrower and deeper etching compared to existing etching gases. Consequently, efforts are being made to replace conventional gases with PF3, but research is ongoing due to the difficulty of achieving high purity and large-scale synthesis suitable for semiconductor processes.

[0003] Although there have been studies on PF3 as an intermediate in the synthesis step of LiPF6 used as an electrolyte in conventional lithium-ion batteries, research on the synthesis of PF3 has been very limited as it leads to a one-step process without separate purification or separation. Generally, PF3 and HCl can be obtained by reacting PCl3 with HF, but there is a disadvantage that purification is difficult due to the similar boiling points of PF3 and HCl.

[0004] To improve this, a method was developed to obtain PF3 and solid NaCl by reacting PCl3 with NaF, but this method has the disadvantage that the reaction is very slow and the conversion rate is low. Generally, NaF supplied undergoes a recrystallization process to achieve high purity, so it is supplied in the form of crystalline granules hundreds of micrometers in size. This granular form has the disadvantage that in heterogeneous reactions, the reaction rate is low and the conversion rate of NaF is also low due to the limited reaction surface area.

[0005] One aspect of the present invention for solving the aforementioned problem is to provide a method for producing phosphorus trifluoride that can suppress the generation of unreacted NaF by increasing the conversion rate of NaF through the control of NaF particle size to maximize reactivity, has excellent selectivity for phosphorus trifluoride, and can reduce manufacturing costs.

[0006] The technical problems intended to be solved in this document are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which this invention belongs from the description below.

[0007] To achieve the above objective, a method for producing phosphorus trifluoride according to one embodiment of the present invention may include: a step of controlling the particle size (D50) of NaF to 67 μm to 137 μm; and a step of producing phosphorus trifluoride by reacting the NaF with the controlled particle size, PCl3, and a solvent.

[0008] The step of controlling the NaF particle size according to one embodiment of the present invention may be performed by grinding for 20 to 120 minutes.

[0009] The step of controlling the NaF particle size according to one embodiment of the present invention may be performed by including a catalyst represented by the following chemical formula 1.

[0010] [Chemical Formula 1]

[0011] (M b ) x A y

[0012] (In the above chemical formula 1, M b is at least one selected from Sb, Fe, Sn, Ti, and Al, A is a halogen atom or an oxygen atom, and x and y are each independently real numbers from 1 to 3.)

[0013] The catalyst according to one embodiment of the present invention may be included in a ratio of 1:0.1 to 1:0.0001 relative to the total weight of NaF.

[0014] The catalyst according to one embodiment of the present invention may include one or more selected from diantimony trioxide (Sb2O3), antimony fluoride (SbF3), iron trioxide (Fe2O3), iron fluoride (FeF3), tin fluoride (SnF4), titanium fluoride (TiF4), and aluminum fluoride (AlF3).

[0015] In the step of producing phosphorus trifluoride according to one embodiment of the present invention, NaF and PCl3 with controlled particle sizes may be mixed in a weight ratio of 1.5:1 to 20:1.

[0016] In the step of preparing phosphorus trifluoride according to one embodiment of the present invention, PCl3 and a solvent may be mixed in a weight ratio of 3:1 to 10:1.

[0017] In the step of producing phosphorus trifluoride according to one embodiment of the present invention, one or more catalysts selected from diantimony trioxide (Sb2O3), antimony fluoride (SbF3), iron trioxide (Fe2O3), iron fluoride (FeF3), tin fluoride (SnF4), titanium fluoride (TiF4), and aluminum fluoride (AlF3) may be further included in a ratio of 1:0.1 to 1:0.0001 by weight with respect to the solvent.

[0018] After the step of producing phosphorus trifluoride according to one embodiment of the present invention, a step of regenerating NaF may be further included.

[0019] The step of regenerating the NaF according to one embodiment of the present invention may be performed by: mixing the NaF separated after the production of phosphorus trifluoride with a basic aqueous solution and reacting it at room temperature for 0.5 to 2 hours; and drying the solid salt produced by the reaction.

[0020] According to one embodiment of the present invention, the NaF and the aqueous base solution may be mixed in a ratio of 1:1 to 1:1.25.

[0021] The aqueous base solution according to one embodiment of the present invention may include one or more selected from NH4OH, NaOH, NaHCO3, and Na2CO3.

[0022] According to one embodiment of the present invention, the drying may be performed at 70 to 150°C for 1 to 12 hours.

[0023] According to the present invention, by maximizing reactivity through the control of NaF particle size, the conversion rate of NaF can be increased to suppress the generation of unreacted NaF, and a method for producing phosphorus trifluoride can be provided that has excellent selectivity and reduces manufacturing costs.

[0024] The effects obtainable from the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present invention belongs from the description below.

[0025] Figures 1 to 5 are SEM images observed after grinding NaF for 0 minutes, 20 minutes, 40 minutes, 60 minutes, and 120 minutes to control particle size according to one embodiment of the present invention.

[0026] Preferred embodiments of the present invention are described below. However, embodiments of the present invention may be modified in various other forms, and the technical concept of the present invention is not limited to the embodiments described below. Furthermore, the embodiments of the present invention are provided to more completely explain the present invention to those with average knowledge in the relevant technical field.

[0027] The terms used in this application are used merely to describe specific examples. For this reason, singular expressions include plural expressions unless the context clearly requires them to be singular. Additionally, it should be noted that terms such as “comprising” or “comprising” used in this application are used to clearly indicate the presence of features, steps, functions, components, or combinations thereof described in the specification, and are not used to preliminarily exclude the existence of other features, steps, functions, components, or combinations thereof.

[0028] Meanwhile, unless otherwise defined, all terms used in this specification shall be understood to have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Accordingly, unless explicitly defined in this specification, specific terms should not be interpreted in an overly ideal or formal sense. For instance, singular expressions in this specification include plural expressions unless the context clearly indicates an exception.

[0029] Additionally, terms such as "about," "substantially," etc., in this specification are used to mean at or near the stated value when inherent manufacturing and material tolerances are presented in the said sense, and are used to prevent unscrupulous infringers from unfairly exploiting the disclosed content in which precise or absolute values ​​are mentioned to aid in understanding the invention.

[0030] A method for manufacturing phosphorus trifluoride according to one embodiment of the present invention will be described in detail below.

[0031] A method for producing phosphorus trifluoride according to one embodiment of the present invention relates to a method for producing phosphorus trifluoride with excellent selectivity, wherein the particle size of NaF is controlled to a certain size prior to the reaction of PCl3 and NaF for the production of phosphorus trifluoride, and then the NaF with the controlled particle size is reacted with PCl3, thereby improving the conversion rate of NaF and significantly reducing the generation of unreacted NaF.

[0032] According to the phosphorus trifluoride manufacturing method of the present invention, the reactivity and conversion rate of NaF can be maximized by controlling the size of NaF particles to a certain size prior to the reaction with PCl3, thereby suppressing the generation of unreacted NaF and reducing manufacturing costs. Furthermore, process efficiency can be maximized by regenerating the separated NaF through an activation process after the reaction.

[0033] Specifically, a method for producing phosphorus trifluoride according to one embodiment of the present invention may include: a step of controlling the particle size (D50) of NaF to 67 μm to 137 μm; and a step of producing phosphorus trifluoride by reacting the NaF with the controlled particle size, PCl3, and a solvent.

[0034] The method for manufacturing phosphorus trifluoride is described below in each step.

[0035] First, a step to control the particle size of NaF is performed.

[0036] NaF used in the production of phosphorus trifluoride is provided in the form of crystalline granules hundreds of micrometers in size through a recrystallization process to produce high-purity phosphorus trifluoride. When the granular NaF reacts with PCl3, it reacts with PCl3 on the externally exposed surface of NaF. As a result of the reaction, NaF is converted into NaCl, forming NaCl crystals on the surface of NaF, and the reaction with PCl3 is inhibited due to the formed NaCl crystal layer. In this case, the conversion rate of NaF is very low, at the level of 10 to 20%, and there is a problem that the entire amount of deactivated NaF is discarded after the reaction.

[0037] Therefore, it is necessary to secure a sufficient reaction surface area of ​​NaF capable of reacting with PCl3 to improve the reactivity of NaF with PCl3, and thus reduce the generation of unreacted NaF.

[0038] Accordingly, the present invention aims to improve the reactivity of NaF and reduce the generation of unreacted NaF by performing a step of refining the particle size of NaF prior to the reaction with PCl3, thereby increasing the reaction surface area capable of reacting with PCl3.

[0039] In the present invention, a step of controlling the particle size (D50) of NaF to 67 μm to 137 μm can be performed prior to the production of phosphorus trifluoride. Preferably, the NaF particle size (D50) can be controlled to 70 μm to 130 μm, and more preferably to 80 μm to 120 μm.

[0040] If the above NaF particle size (D50) is less than 67㎛, the effect of improving the reactivity and conversion rate of NaF due to particle size reduction may be negligible, and if it exceeds 137㎛, a sufficient reaction area is not secured, so the reaction rate decreases, and consequently, the amount of unreacted NaF may increase.

[0041] The above NaF particle size control can be performed through a grinding process.

[0042] The grinding above may be performed for 20 to 120 minutes, preferably for 60 minutes. If the grinding time is less than 20 minutes, it may be difficult to secure the reaction area of ​​NaF targeted in the present invention, and if it exceeds 120 minutes, the reactivity and conversion rate effects of NaF relative to the secured reaction area may be negligible. The grinding above may be performed by milling together with zirconia balls.

[0043] In addition, a catalyst may be further included during the grinding process to efficiently control the NaF particle size.

[0044] The above catalyst may be a catalyst represented by the following chemical formula 1.

[0045] [Chemical Formula 1]

[0046] (M b ) x A y

[0047] (In the above chemical formula 1, M b is at least one selected from Sb, Fe, Sn, Ti, and Al, A is a halogen atom or an oxygen atom, and x and y are each independently real numbers from 1 to 3.)

[0048] Specifically, the catalyst may include one or more selected from antimony trioxide (Sb2O3), antimony fluoride (SbF3), iron trioxide (Fe2O3), iron fluoride (FeF3), tin fluoride (SnF4), titanium fluoride (TiF4), and aluminum fluoride (AlF3).

[0049] The catalyst may be included in a ratio of 1:0.1 to 1:0.0001 relative to the total weight of NaF. It is more desirable for the catalyst to be included in the above ratio, as this maximizes the refinement of NaF particle size according to the grinding time.

[0050] As described above, by controlling the particle size (D50) of NaF to 67㎛ to 137㎛, the PCl3 conversion rate can be increased to 78% or more, preferably 87% or 95% or more.

[0051] Next, the step of preparing phosphorus trifluoride is performed by reacting NaF with PCl3 and a solvent with particle size controlled as described above.

[0052] The step of manufacturing phosphorus trifluoride may include the step of introducing NaF into a reactor and the step of introducing PCl3 and a solvent into the reactor to manufacture phosphorus trifluoride. Additionally, after the step of introducing NaF, the step of vacuum purging the inside of the reactor with an inert gas may be further included.

[0053] The above solvent may be one or more selected from acetonitrile, toluene, and dimethylformamide (DMF).

[0054] At this time, PCl3 and the solvent may be mixed in a weight ratio of 3:1 to 10:1, and preferably in a weight ratio of 4:1 to 8:1. When PCl3 and the solvent are mixed within the above range, the solubility characteristics of PCl3 are improved, which can further improve the final yield of phosphorus trifluoride.

[0055] In addition, PCl3 and NaF can be mixed in a weight ratio of 1:1.5 to 1:20, and preferably in a weight ratio of 1:2.5 to 1:10. When PCl3 and NaF are mixed within the above range, the formation of by-products during the production of phosphorus trifluoride can be suppressed, thereby further improving the conversion rate and reaction yield.

[0056] In addition, when manufacturing the phosphorus trifluoride above, a catalyst may be further included in addition to NaF, PCl3, and a solvent with controlled particle size.

[0057] The catalyst may include one or more selected from antimony trioxide (Sb2O3), antimony fluoride (SbF3), iron trioxide (Fe2O3), iron fluoride (FeF3), tin fluoride (SnF4), titanium fluoride (TiF4), and aluminum fluoride (AlF3). The catalyst may be mixed with the solvent in a weight ratio of 1:0.1 to 1:0.0001. If the weight ratio of the catalyst to the solvent exceeds 1:0.1, economic efficiency may be reduced and catalytic activity may be lowered, while if it is less than 1:0.0001, the role of the catalyst may be negligible.

[0058] Phosphorus trifluoride prepared by reacting NaF, PCl3, and a solvent with controlled particle sizes as described above may contain by-products such as HCl, unreacted NaF, unreacted PCl3, and solvent in addition to phosphorus trifluoride.

[0059] Accordingly, the method for producing phosphorus trifluoride according to the present invention may further include a step of regenerating NaF after the step of producing phosphorus trifluoride.

[0060] After the reaction for the production of phosphorus trifluoride, the reactants used in the reaction are present in the NaF. After the reaction is completed, the NaF and the reactants react very slowly; if the unreacted reactants are exposed to the outside, they may react violently with moisture in the air, generating corrosive fumes. Therefore, the regeneration of NaF must be carried out while the outside air is blocked. In addition, a large amount of acid is present on the surface of the NaF separated after the reaction.

[0061] Accordingly, the present invention utilizes the difference in solubility between NaF and NaCl to selectively remove NaCl and acid formed on the surface of NaF, thereby enabling a process to activate the deactivated NaF.

[0062] Specifically, the NaF separated after the above reaction is mixed with a basic aqueous solution and reacted.

[0063] As a result of the above reaction, the NaCl and acid on the surface dissolved in the basic aqueous solution are washed away, and at the same time, highly reactive hydroxyl groups are increased on the surface of NaF, thereby enabling the acquisition of activated NaF. That is, if the NaCl crystals formed on the surface of NaF after the reaction are removed by reaction with the basic solution, the surface exposure of NaF increases, and thus the reactivity can be increased.

[0064] The above basic solution may include one or more selected from NH4OH, NaOH, NaHCO3, and Na2CO3, which can selectively dissolve NaCl and acid on the surface of NaF.

[0065] The above NaF and basic aqueous solution can be mixed in a ratio of 1:1 to 1:1.25. If the basic aqueous solution is included in an amount that is too high relative to NaF, it may damage not only the acid on the surface of NaF but also NaF, and if it is included in an amount that is too low, the acid on the surface of NaF may not be completely removed.

[0066] The above NaF and basic aqueous solution can be reacted at room temperature for 0.5 to 2 hours. If the reaction time is less than 0.5 hours, NaCl may not be sufficiently removed, and if it exceeds 2 hours, NaF may dissolve together, reducing the recovery rate.

[0067] As described above, the solid salt, which is a precipitate formed after reacting NaF with a basic aqueous solution, can be separated by drying at 70 to 150°C. At this time, grinding may also be performed along with the drying.

[0068] When using NaF regenerated through the above process, the conversion rate of PCl3 can be improved to 67% or more, preferably 70% or more.

[0069] The recycled NaF separated in this way can be reused by being input into the phosphorus trifluoride manufacturing stage. Due to its superior reactivity compared to pure NaF, it can not only increase the efficiency of phosphorus trifluoride production but also reduce process costs by lowering raw material costs.

[0070] The present invention will be explained in more detail below through the following examples. However, the following examples are merely illustrative of the present invention, and the scope of the present invention is not limited thereto.

[0071] Examples

[0072] As shown in Table 1 below, NaF was ground for 0 to 120 minutes to control the particle size (D50) of NaF. Subsequently, NaF with the controlled particle size (D50), PCl3, acetonitrile (AN), and a catalyst (Sb2O3) were mixed in a closed reactor and reacted to produce phosphorus trifluoride.

[0073] Experimental Example 1. Evaluation of reactivity according to NaF particle size (D50)

[0074] The NaF particle size (D50) according to grinding time was observed by SEM and is shown in Figures 1 to 5. In addition, the reaction time, reaction conversion rate, and selectivity according to the NaF particle size (D50) were measured, and the results are shown in Table 1 below.

[0075] The reaction time was expressed as the time to reach 80% of the maximum conversion to PF3.

[0076] The reaction conversion rate was calculated by checking the amount of phosphorus trifluoride (PF3) produced by checking the pressure gauge installed in the reactor, and the unreacted acetonitrile and PCl3 were removed by flowing a dry trap at -20℃ at a rate of 0.2 L / min and collecting the gas in a collection cylinder.

[0077] Selectivity was analyzed using the mass spectrum.

[0078] Classification Reaction Ratio Grinding Time (min) Particle Size (D50, μm) Reaction Time (min / @80%) Reaction Conversion Rate (%) Selectivity (%) NaFPCl3AnSb2O3 Example 1 2.75 10.10.00 120 137 187 7879 Example 2 2.75 10.10.00 140 1186 58783 Example 3 2.75 10.10.00 160 835 59 589 Example 4 2.75 10.10.00 1120 67 47 9387 Comparative Example 1 2.75 10.10.00 102 272 40 4385

[0079] As shown in Table 1 above, in Examples 1 to 4, where the particle size (D50) of NaF before reaction with PCl3 was controlled to 67–137 μm, the reaction time was significantly reduced compared to Comparative Example 1, where the particle size was not controlled. It was confirmed that the reaction conversion rate was 78% or higher and the phosphorus trifluoride (PF3) selectivity was also excellent at 79% or higher. From these results, it was found that the reaction conversion rate and selectivity during the production of phosphorus trifluoride can be improved by increasing the reactivity of NaF through the control of the particle size of NaF.

[0080] Experimental Example 2. Evaluation of Reactivity Following NaF Regeneration

[0081] After preparing phosphorus trifluoride in Example 1 above, unreacted NaF was separated, and a process to regenerate NaF was performed as follows.

[0082] The unreacted NaF was mixed with a 0.5 M NHOH aqueous solution in a ratio of 1:1.25 and reacted at room temperature for 0.5 to 2 hours. Subsequently, the reaction solution was removed, and the solid salt precipitate was separated. Then, the regenerated NaF was obtained by drying and grinding at 70 to 150°C. The above NaF regeneration process was repeated four times.

[0083] Phosphorus trifluoride was prepared using the above-mentioned regenerated NaF, and the reaction time and reaction conversion rate were evaluated, and the results are shown in Table 2 below.

[0084] In Table 2 below, the recovery rate represents the amount of NaF recovered by regenerating unreacted NaF after phosphorus trifluoride production in the corresponding cycle, and the additional input NaF represents the amount of NaF added to the NaF recovered in the previous cycle to adjust the initial mass of NaF to 100%. Additionally, the reaction time is expressed as the time to reach the maximum conversion rate to PF3.

[0085] Classification Reaction Ratio Recovery Rate Additional Input NaF Reaction Time (min) Reaction Conversion Rate (%) NaFPCl3AnSb2O3 Cycle 12.75 10.10.00 185% -240 43.2 Cycle 22.75 10.10.00 181% 15% 746 7.8 Cycle 32.75 10.10.00 182% 19% 776 8.4 Cycle 42.75 10.10.00 181% 18% 787 1.5

[0086] As shown in Table 2 above, in Cycle 2, where NaF separated after phosphorus trifluoride production in Cycle 1 was regenerated and phosphorus trifluoride was produced using the regenerated NaF as a raw material, it was confirmed that the reaction time and conversion rate were improved compared to Cycle 1, which used pure NaF. In addition, it was confirmed that the same results were observed in Cycles 3 and 4, which used NaF regenerated from the previous cycle. From these results, it was found that when phosphorus trifluoride is produced using regenerated NaF, which is prepared by mixing unreacted NaF after phosphorus trifluoride production with a basic aqueous solution, the reactivity and conversion rate can be increased compared to when phosphorus trifluoride is produced using pure NaF.

[0087] Although embodiments of the invention disclosed above have been illustrated and described, the disclosed invention is not limited to the specific embodiments described above, and various modifications may be made by those skilled in the art to which the disclosed invention belongs without departing from the essence claimed in the claims.

Claims

1. A step of controlling the particle size (D50) of NaF to 67㎛ to 137㎛; and A method for producing phosphorus trifluoride comprising the step of producing phosphorus trifluoride by reacting NaF, PCl3, and a solvent with controlled particle sizes.

2. In Paragraph 1, The step of controlling the NaF particle size above is a method for producing phosphorus trifluoride, performed by grinding for 20 to 120 minutes.

3. In Paragraph 2, A method for producing phosphorus trifluoride, wherein the step of controlling the NaF particle size is performed by including a catalyst represented by the following chemical formula 1. [Chemical Formula 1] (M b ) x A y (In the above chemical formula 1, M b is at least one selected from Sb, Fe, Sn, Ti, and Al, A is a halogen atom or an oxygen atom, and x and y are each independently real numbers from 1 to 3.) 4. In Paragraph 3, A method for producing phosphorus trifluoride in which the above catalyst is included in a ratio of 1:0.1 to 1:0.0001 relative to the total weight of NaF.

5. In Paragraph 3, A method for producing phosphorus trifluoride, wherein the catalyst comprises one or more selected from diantimony trioxide (Sb2O3), antimony fluoride (SbF3), iron trioxide (Fe2O3), iron fluoride (FeF3), tin fluoride (SnF4), titanium fluoride (TiF4), and aluminum fluoride (AlF3).

6. In Paragraph 1, A method for producing phosphorus trifluoride in which, in the step of producing phosphorus trifluoride above, particle-sized NaF and PCl3 are mixed in a weight ratio of 1.5:1 to 20:

1.

7. In Paragraph 1, A method for producing phosphorus trifluoride in which, in the step of producing phosphorus trifluoride above, PCl3 and a solvent are mixed in a weight ratio of 3:1 to 10:

1.

8. In Paragraph 1, A method for producing phosphorus trifluoride, wherein, in the step of producing phosphorus trifluoride, one or more catalysts selected from diantimony trioxide (Sb2O3), antimony fluoride (SbF3), ferric trioxide (Fe2O3), iron fluoride (FeF3), tin fluoride (SnF4), titanium fluoride (TiF4), and aluminum fluoride (AlF3) are further included in a ratio of 1:0.1 to 1:0.0001 by weight with respect to the solvent.

9. In Paragraph 1, A method for producing phosphorus trifluoride, comprising an additional step of regenerating NaF after the step of producing phosphorus trifluoride.

10. In Paragraph 9, A method for producing phosphorus trifluoride, wherein the step of regenerating the NaF is performed by mixing the NaF separated after the production of phosphorus trifluoride with a basic aqueous solution and reacting it at room temperature for 0.5 to 2 hours; and drying the solid salt produced by the reaction.

11. In Paragraph 10, A method for preparing phosphorus trifluoride in which the above NaF and basic aqueous solution are mixed in a ratio of 1:1 to 1:1.

25.

12. In Paragraph 10, A method for producing phosphorus trifluoride, wherein the above basic aqueous solution comprises one or more selected from NH4OH, NaOH, NaHCO3, and Na2CO3.

13. In Paragraph 10, A method for producing phosphorus trifluoride in which the above drying is performed at 70 to 150°C for 1 to 12 hours.

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