METHOD FOR PRODUCING TRIFLUOROAMINE OXIDE

Abstract

There is provided a method for producing trifluoroamine oxide. The method includes a step of preparing an intermediate product by simultaneously providing and reacting nitrogen trifluoride and nitrous oxide under the presence of a SbF.sub.5 reaction catalyst; and a step of producing trifluoroamine oxide by reacting the intermediate product with potassium fluoride. The step of reacting the intermediate product with potassium fluoride is performed under atmospheric pressure and room temperature.

Claims

1. A method for producing trifluoroamine oxide comprising steps of: preparing an intermediate product by simultaneously feeding and reacting nitrogen trifluoride and nitrous oxide under the presence of a reaction catalyst of SbF.sub.5; and producing trifluoroamine oxide by reacting the intermediate product with potassium fluoride.

2. The method of claim 1, wherein reacting the intermediate product with potassium fluoride is performed under atmospheric pressure and room temperature conditions.

3. The method of claim 1, further comprising a step of pyrolyzing KSbF.sub.6 obtained as a by-product in the step of producing trifluoroamine oxide to recover SbF.sub.5, wherein the recovered SbF5 is reused as the reaction catalyst in the subsequent step of preparing the intermediate product.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 is a flowchart illustrating the method for producing trifluoroamine oxide according to the embodiment of the present invention.

DETAILED DESCRIPTION

[0020] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. However, the following embodiments and examples are merely illustrative of preferred configurations of the present invention, and the scope of the present invention is not limited to these configurations. In the following description, the hardware configuration and software configuration, process flow, manufacturing condition, size, material, shape, etc. of the apparatus are not intended to limit the scope of the present invention, particularly unless specifically stated.

[0021] The method for producing trifluoroamine oxide according to an embodiment of the present invention described below, when synthesizing trifluoroamine oxide by decomposing NF.sub.2OSbF.sub.6, which is an intermediate product, in the SbF.sub.5/NF.sub.3/N.sub.2O reaction system described in Patent Literature 2 or Patent Literature 3, employs potassium fluoride (KF) which enables a spontaneous reaction at atmospheric pressure and room temperature, rather than sodium fluoride requiring heating at about 150° C. to 200° C. under vacuum. Accordingly, since vacuum equipment is not required as a reactor and additional heating is not required for the reaction, manufacturing costs can be reduced. In addition, it is possible to improve productivity due to a fast reaction speed.

[0022] FIG. 1 is a flowchart illustrating the method for producing trifluoroamine oxide according to the embodiment of the present invention.

[0023] Referring to FIG. 1, the method for producing trifluoroamine oxide according to the embodiment of the present invention includes the steps of: preparing an intermediate product by simultaneously providing and reacting nitrogen trifluoride and nitrous oxide under the presence of a reaction catalyst of SbF.sub.5 (S10); and producing trifluoroamine oxide by reacting the intermediate product with potassium fluoride (S20). In this method, the reaction of the intermediate product with potassium fluoride can be performed under atmospheric pressure and room temperature conditions.

[0024] Hereinafter, the method for producing trifluoroamine oxide according to the present embodiment will be described in detail for each step.

[0025] First, the producing method of trifluoroamine oxide according to the embodiment of the present invention includes the step S10 of preparing the intermediate product by reacting nitrogen trifluoride and nitrous oxide under the presence of a reaction catalyst.

[0026] In the step of preparing the intermediate product, the reaction of either Reaction Formula 1 or Reaction Formula 2 is performed, or the reactions of Reaction Formulas 1 and 2 are simultaneously performed. In Reaction Formulas 1 and 2, the reaction catalyst is SbF.sub.5. Examples of the reactions using the reaction catalyst are shown in the following Reaction Formulas 1 and 2.

NF.sub.3+N.sub.2O+SbF.sub.5.fwdarw.NF.sub.2OSbF.sub.6+N.sub.2  <Reaction Formula 1>

NF.sub.3+N.sub.2O+2SbF.sub.5.fwdarw.NF.sub.2OSb.sub.2F.sub.11+N.sub.2  <Reaction Formula 2>

[0027] In the step S10 of preparing the intermediate product, the reaction time may be reduced by removing the generated nitrogen (N.sub.2) and the reactant gases mixed therewith and additionally providing a fresh feed of nitrogen trifluoride and nitrous oxide.

[0028] In the step S10 of preparing the intermediate product, as the reactions of Reaction Formula 1 and Reaction Formula 2 proceeds, the reaction rate becomes slow, and the reaction time becomes very long for 80 hours or more. To solve this problem, nitrogen (N.sub.2) and the reactant gases mixed therewith are removed and a fresh feed of nitrogen trifluoride and nitrous oxide are additionally provided during the reactions of the step S10 for preparing the intermediate product, thereby the reaction time may be reduced by 80% or more, more preferably 85% or more, compared to the prior art, to 8 to 10 hours.

[0029] In addition, in the step S10 of preparing the intermediate product, nitrogen trifluoride and nitrous oxide may be separated from the mixture of nitrogen and the reactant gases and may be reused. For example, nitrogen is removed from the mixture of the nitrogen and the reactant gases through a distillation process, and nitrogen trifluoride and nitrous oxide are separated and recycled to be reused in the reactions of the step S10 of preparing the intermediate product. The recycle may be made every time when the ratio of a remaining amount of SbF.sub.5 relative to an initial amount, the conversion ratio, becomes about 40% to about 95%, preferably about 50% to about 90%, and more preferably about 60% to about 85%. The time to reach the conversion ratio described above in the reaction is only 2 to 3 hours, thus the reaction time to achieve the total conversion ratio of 100% can be reduced to less than 10 hours.

[0030] As described above, during the reactions of the step S10 of preparing the intermediate product, nitrogen and the reactant gases may be removed, and a fresh feed of nitrogen trifluoride and nitrous oxide or nitrogen trifluoride and nitrous oxide recovered from the mixture of nitrogen and the reactant gases may be additionally provided, thereby significantly reducing the reaction time. In addition, the size of the reactor for producing the same amount of trifluoroamine oxide, can be reduced to about ⅛ to 1/20, whereby productivity can be improved.

[0031] The reaction ratio of the reaction catalyst, nitrogen trifluoride, and nitrous oxide is preferably 2: 1-10:1-10 in the step S10 of preparing the intermediate product, more preferably 2: 1-5:1-5, even more preferably 2:2-5:2-5, and most preferably 2:3-5:3-5. The reaction ratio of the reaction catalyst, nitrogen trifluoride, and nitrous oxide is basically 2:1:1 in a mole number, and the molar ratio of nitrogen trifluoride and nitrous oxide may be 1 to 10, respectively. If the reaction ratio of the reaction catalyst, nitrogen trifluoride, and nitrous oxide is less than 2:1:1 (the molar ratio of nitrogen trifluoride and nitrous oxide is less than 1, respectively), the unreacted reaction catalyst such as SbF.sub.5, which is highly hygroscopic and smokable, might remain and act as impurities in the reaction process of producing trifluoroamine oxide, and at the same time, it is very difficult to perform a pulverization process due to generation of heat and fume. If the reaction ratio is more than 2:10:10 (the molar ratio of nitrogen trifluoride and nitrous oxide is more than 10, respectively), the reaction pressure goes too high, resulting in the increase of reactor manufacturing costs and the risk of explosion during the reaction. So, the molar ratio is preferably 2:2:2 (reaction catalyst:nitrogen trifluoride:nitrous oxide), and more preferably 2:1.2:2. This is because when the intermediate product NF.sub.2O-salt is prepared, the reaction catalyst and nitrogen trifluoride (NF.sub.3) form a primary salt by chlorination and then react with nitrous oxide (N.sub.2O). So, it is preferred to add a little excessive amount of nitrous oxide (N.sub.2O) which displays a relatively lower reactivity.

[0032] In the step S10 of preparing the intermediate product, the reaction is performed preferably in a temperature range of 110° C. to 150° C., more preferably in a temperature range of 120° C. to 150° C., and most preferably in a temperature range of 130° C. to 150° C. If the reaction temperature is lower than 110° C., which is close to the melting point of the intermediate product NF.sub.2O-salt, the solid NF.sub.2O-salt is precipitated, so that stirring becomes difficult and absorption of gaseous NF.sub.3 and N.sub.2O becomes slow, which results in that the reaction does not go smoothly. If the reaction temperature is higher than 150° C., the decomposition reaction is partially induced so that the raw materials, NF.sub.3 and N.sub.2O, might be regenerated or the byproducts such as NO and NO.sub.2 might be generated, resulting in the decrease of yield. If the reaction temperature is too high, high pressure is applied to the reactor, and vapor pressure of the raw materials. NF.sub.3 and N.sub.2O also increases. Then, absorbency of the reaction catalyst existing in the liquid phase is reduced as well, and thereby the production cost of the reactor goes high, and the reaction rate is lowered.

[0033] The reactions of Reaction Formula 1 and Reaction Formula 2, which comprise the step S10 of preparing the intermediate product, are gas-liquid phase reactions. Accordingly, unlike in a gas-gas reaction, the intermediate catalyst SbF.sub.5 which is in the liquid phase absorbs gaseous raw materials. NF.sub.3 and N.sub.2O, leading to neutralization reaction. Therefore, the reaction temperature is preferably maintained at a temperature lower than the boiling point of SbF.sub.5, 149.5° C., and it is important to maintain a minimum temperature at which stirring can be smoothly performed.

[0034] Further, in the step S10 of preparing the intermediate product, the reactions are performed in a suitable high-pressure reactor, preferably in a reactor comprising an anchor type stirring device in the size of half the inner diameter of the reactor. The absorption of NF.sub.3 and N.sub.2O is promoted through the reactor and the stirring is maintained preferably at a rotation speed of 50 rpm to 800 rpm for progressing smooth reaction, more preferably at a rotation speed of 100 rpm to 500 rpm, and most preferably at a rotation speed of 200 rpm to 400 rpm. If the rotation speed is less than 50 rpm, the absorption of the gaseous raw materials, NF.sub.3 and N.sub.2O, becomes too slow in the course of the gas-liquid phase reaction, and thereby the reaction progress goes slow, suggesting that the reactor size needs to be increased and the productivity is decreased. If the rotation speed exceeds 800 rpm, mechanical abrasion due to high-speed stirring may occur, resulting in the increase of maintenance costs.

[0035] The type of the stirrer can be exemplified by a grand seal, a mechanical seal and a magnetic drive. However, considering the reactions at a high temperature and a high pressure, a magnetic drive is more preferred. The material of the reactor used in the reaction can be stainless steel, hastelloy or alloy. When stainless steel is used for the reactor, it is preferred to perform passivation using fluorine (F.sub.2) gas before use.

[0036] In the step S10 of preparing the intermediate product, nitrogen trifluoride and nitrous oxide can be fed preferably simultaneously under the presence of a reaction catalyst, or nitrogen trifluoride may be fed to the reactor first and then nitrous oxide may be subsequently fed thereto. On the other hand, if nitrous oxide is fed first under the presence of the reaction catalyst and then nitrogen trifluoride is subsequently fed, the reaction takes too long, and the yield becomes very low.

[0037] In the step S10 of preparing the intermediate product, the progress of the reaction can be calculated by tracing the consumed gaseous raw materials of nitrogen trifluoride (NF.sub.3) and nitrous oxide (N.sub.2O), and the resulting gaseous nitrogen (N.sub.2) by gas chromatography. In general, calibration is performed with a standard gas before calculation.

[0038] Particularly, the reactions of the step of preparing the intermediate product may include a process of tracking and analyzing the proportion of nitrogen trifluoride and nitrous oxide consumed and the ratio of nitrogen generated by using at least one system selected from the group consisting of gas chromatography TCD, 5% fluorocol/carbopack B column and molecular sieve capillary column, during the reactions.

[0039] The producing method of trifluoroamine oxide according to an aspect of the present invention comprises a step S20 of producing trifluoroamine oxide by reacting the intermediate product with potassium fluoride. The reaction between the intermediate product and potassium fluoride may be performed spontaneously under atmospheric pressure and room temperature conditions.

[0040] In the step S20 of producing trifluoroamine oxide (F.sub.3NO), Reaction Formula 3 or Reaction Formula 4 may be performed, or Reaction Formula 3 and Reaction Formula 4 may be performed together.

NF.sub.2OSbF.sub.6+KF.fwdarw.F.sub.3NO+KSbF.sub.6  <Reaction Formula 3>

NF.sub.2OSb.sub.2F.sub.11+KF.fwdarw.F.sub.3NO+2KSbF.sub.6  <Reaction Formula 4>

[0041] In the step S20 of producing trifluoroamine oxide, the reaction ratio of the intermediate product and potassium fluoride is preferably 1:1-4. The reaction of the step of producing trifluoroamine oxide is a solid-solid reaction. Thus, solid-solid surface contact is very important. In the reaction proposed in the present invention, the reaction molar ratio of NF.sub.2O-salt and potassium fluoride (KF), which are reactants, is preferably 1.0 to 4.0. When the fed amount of potassium fluoride is less than 1.0 mol, it is difficult to complete the reaction, and when the amount of potassium fluoride exceeds 4.0 mol, the amount of fed solid increases, and thus problems may occur in stirring. Uniform mixing of the NF.sub.2O-salt and KF is important to activate the reaction in the solid-solid reaction. When sufficient contact is not made due to a problem in stirring, an extremely low yield of trifluoroamine oxide (F.sub.3NO) may be obtained. In order to increase contacts between the reactants, the NF.sub.2O-salt and the KF should be sufficiently pulverized and mixed to initiate a reaction, whereby resulting in an increase of yield, and more preferably, the reactants may be mixed and formed in pellets, whereby a smooth reaction may be carried out.

[0042] In addition, in the step S20 of producing the trifluoroamine oxide, the reaction can be spontaneously performed at atmospheric pressure and room temperature. Therefore, in order for the reaction to be performed, it is not necessary to make the inside of the reactor vacuum or reduced pressure conditions or to further heat the reactor.

[0043] Further, in the step S20 of producing trifluoroamine oxide, the degree to which the reaction is progressed may be calculated by tracking gaseous materials by gas chromatography. Typically, calibration is performed with a standard gas prior to tracking.

[0044] Specifically, in the step S20 of producing trifluoroamine oxide, the method may further include a process of tracking and analyzing a ratio of F.sub.3NO, which is a product, and by-products (NF.sub.3. N.sub.2O and NO) using at least one of gas chromatography TCD, 5% fluorocol/carbopack B column and molecular sieve capillary column during the reactions.

[0045] Although not shown in FIG. 1. KSbF.sub.6 obtained as a by-product in the step S20 of producing trifluoroamine oxide may be heated and decomposed to recover SbF.sub.5, which may be reused as the reaction catalyst in the step S10 of preparing the intermediate product. Accordingly, it is possible to further reduce manufacturing costs by reducing the amount of SbF.sub.5 used.

[0046] As described above, the above description is merely exemplary and should not be construed as limiting. The technical idea of the present invention should be defined only by the invention as set forth in the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention. Therefore, it will be obvious to a person skilled in the art that the above-described embodiments may be implemented by being modified in various forms.