DE1260449B - Process for the production of trifluoroamine oxide - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

Number:
File number:
Registration date:
Display day:

COIb

German class: 12 i - 21/52

1260 449
N 26348 IV a / 12 i
March 10, 1965
February 8, 1968

The invention relates to a process for the preparation of trifluoroamine oxide. For this new compound containing nitrogen, oxygen and fluorine, which has the formula ONF ₃ , there are numerous possible uses in chemical engineering, since this use is a particularly effective oxidizing agent. In the preparation of this new compound, according to the invention, difluoroamine is mixed with chlorine trifluoride and a halogen oxide, the mixture is caused to react to form trifluoroamine oxide and the trifluoroamine oxide obtained is separated off.

Trifluoraminoxyd is a colorless gas, and has a melting point of -161.5 ± 1.0 ⁰ C and a boiling point of about -89 ⁰ C, calculated from the vapor pressure values. The compound is thermally stable up to over 300 ^° C. and has a molecular weight of 87. It is relatively stable in acidic solution, does not hydrolyze easily in water and only slowly in concentrated alkalis.

Trifluoroamine oxide is reduced by an acidified potassium iodide solution.

Trifluoroamine oxide is used as a high-performance oxidizing agent in the field of liquid rocket propellants Use as it is a liquid under cryogenic conditions. The inventive Compound is a more effective oxidizing agent than chlorine trifluoride on certain fuels. It can also be used as an intermediate in the production of other compounds, the nitrogen-halogen bonds contain.

In most reactions, the trifluoroamine _{oxide reacts according to the formula ONF 3} , with each of the fluorine atoms and oxygen atoms being bonded to the nitrogen. In some reactions, however, the compound reacts like the ions NF ₂ O ⁺ and F ~.

In the process according to the invention, ClO ₂ , FClO ₂ or FClO ₃ can be used as halogen oxides, but preferably ClO ₂ .

The reaction between difluoroamine, chlorine trifluoride and the oxygen-containing halogen compound is carried out in the gas phase. The gaseous reactants are preferably used first cooled to a condensed phase in separate layers at temperatures below -126 ° C. Temperatures between -126 and -196 ° C can be used for condensation. After Condensation of the reactants are then heated to convert them to steam and made their vapors react. When warming up, the temperature becomes above Process for the production of trifluoroamine oxide

Applicant:

North American Aviation, Inc.,
Delaware, Calif. (V. St. A.)

Representative:

Dr.-Ing. E. Liebau and Dipl.-Ing. G. Liebau,

Patent attorneys,

8902 Göggingen, V.-Eichendorff-Str. 10

Named as inventor:

Emil A. Lawton, Woodland Hills, Calif .;

Donald Pilipovich, CanogaPark, Calif. (V. St. A.)

Increased -126 ⁰ C; the gas phase reaction is advantageously allowed to take place at temperatures between about -126 and 30 ° C. The preferred reaction temperatures are between about -85 and about 20 ° C. The reaction is essentially complete within 15 minutes, but reaction times from 1 minute to 24 hours can be used. After completion of the reaction, the gaseous reaction products are condensed in a vacuum system through a series of cold traps in the range -112 to -196 ⁰ C. It is preferable to use traps of -112, -142, -156 and -196 ° C to initially recover trifluoroamine oxide from the reaction mixture. Trifluoroamine oxide condenses in the -196 ⁰ C case together with some impurities. Various methods of removing contaminants from the trifluoroamine oxide can be used depending on the type of reaction vessel initially used in its manufacture. A preferred method, however, is that the material collected in the trap at -196 ° C is purified again by a trap at -183 ° C, thereby eliminating NF ₃ as an impurity.

This condensing, re-evaporation and re-condensation of gases is carried out in a vacuum system, and the temperatures mentioned above relate to a system in which a vacuum of 10 ^-3 is used to 10 ~ ⁴ mm Hg.

809 507/607

3 4

When the reaction in glass devices through- The compound trifluoroamine oxide is through

there is a tendency for the formation of potassium iodide according to the equation reduced Silicon tetrafluoride through the reaction of the fluorine- ίτ- ± ™ Βη ^ τ \ τη _ι_ λϊ? - _i_ it

containing compounds with the glass. SiF ₁ can be made from

are the Trifluoraminoxyd removed by from 5 A sample of the compound was a complex with an alkali metal fluoride, shot treated of potassium iodide and free iodine such as potassium fluoride, is formed with a above the SiF _4, wherein the NF ₃ O determined by titration with thiosulfate. By remains unaffected. Nitrosyl chloride, NO ₂ , chlorine - this process can be shown to give the compound difluoramine, NO, tetrafluorohydrazine, NF ₃ and the 3 equivalents of iodine per mole. Since NO is generated by these starting materials including chlorine trifluoride and io reaction, a complete difluoroamine can be present in the initial reaction chemical analysis by determining the amount mixture. It is preferable to carry out the reaction entReaction with an acid iodide ion under conditions achieved with standing NO.

which no difluoroamine in the reaction end product The molecular weight of the purified sample of the

is available. Nitrosyl chloride, NO ₂ and chlorine-15 compound was determined by the gas density method difluoramin can from the initial reaction. In such a determination beanspruchgemisch be removed in the -156 ⁰ C-FaIIe, 34.4 milligrams of the compound th a volume arising during NO at-196 ° C is not condensed from 8.84 cc under standard conditions for Temsierbar and by taking out from the system temperature and pressure. Separated in another determination. Any chlorine and oxygen containing 20 claimed 40.4 milligrams a volume of halogen compounds are usually in the 10.3 ecm. From these provisions, a medium--142 ⁰ C FaIIe was removed. Tetrafluorohydrazine can be determined Leres molecular weight of 87.5 for the compound by re-condensing the reaction product, which is very well cooled with the calculated MoIedurch to -156 and -183 ⁰ C traps corresponds weight of from 87 matches are removed. A large part of the tetrafluorohydrazine 25 The following examples, in which all parts and are condensed in the case of -156 ° C, and the percentages are parts by weight and percentages by weight of the material once purified, illustrate the preparation -183 ⁰ C case results in a trifluoroamine oxide which is free from trifluoroamine oxide and the use of this from tetrafluorohydrazine. The tetrafluorohydrazine compound, however, can be obtained from the trifluoroamine oxide by gas

Chromatography using a column,

those with a solid polychlorotrifluoroethylene and with a reaction vessel made of solid polychlorotrifluoro-

Polychlorotrifluoroethylene oil as the stationary liquid phase ethylene was with a cooling device and with is filled, be separated. Facilities for entry and exit of the

The compound according to the invention can also contain 35 gaseous reactants. The reaction of difluoroamine with chlorine tri-vessel was then cooled to -142 ° C. and connected to a fluoride and an oxygen-containing halogen compound vacuum system which contained a series of cold dung in the presence of an alkali metal fluoride, such as falling. The reaction vessel was separated from the LiF, NaF, KF, CsF and RbF, as a complexing agent vacuum system and made with 675 parts of difluorine for the difluoroamine. With this 40 amine and 607 parts of chlorine trifluoride charged, the modification of the reaction will advantageously contain an unknown amount of chlorine dioxide as an impurity first of all, the difluoroamine contained on the solid alkali metal solution. While the reaction vessel condenses from the fluoride. The Alkalimetallfiuorid-difluoro vacuum line was disconnected, the mixture for the amine mixture was then to about - heated 8O ⁰ C, allowed to stand heating to the room temperature, to form a complex of the materials. The 45 The original reactants had before the complex is then cooled again, and the rest of the reaction a total volume of 1280 parts reactants are condensed in the reaction vessel at under standard conditions, while after the reaction temperatures below the reaction temperature tion, the total volume is determined to be 1150 parts. The mixture is then reacted to. The mixture was then heated to the condensing temperature and the reaction was carried out in the manner described by means of cold traps in the vacuum system. -142 and -196 ° C under vacuum conditions

In this embodiment of the method, between 10 ^-3 and 10 * mm mercury column frakd the difluoroamine, ie in the form of an alkali metal. The -196 ⁰ C case contained 495 parts by volume of fluoride-difluoramine complex used. under standard conditions of the gas, and this

Trifluoroamine oxide, the novel compound, can be identified by its characteristic infrared spectrum, chlorodifluoramine and trace amounts of NO ₂ , nitrotified, which is shown in the drawing. The sylchloride and NO. Trifluoroamine oxide is shown in connection with strong absorptions at 530, 743, essentially pure form from this mixture through 885, 1690 and 1771 cm- ¹ . Fractionating the product using traps from -156

Samples of the compounds of Masen- were 60 and 196 ⁰ C subjected to eliminate all impurities spectral analysis, and the Massenspaltungs- except tetrafluorohydrazine NEN again won th image in a mass spectrometer using. The tetrafluorohydrazine is removed by successively applying an ionization current of 25 mA and Ma-refraction by means of drops from -156 and -183 ° C, currents of 0.005 and 0.008 showed m / e peaks.

at 68 (for NF ₂ O ⁺ ) and 87 (for NF ₃ O ⁺ ). In addition, 65 - ,,. . , ₉

, peaks for N ^+, O ^+, NFO ⁺ +, NO ^+, NF ^{+, lip 51 A}

NF ₂ ⁺ , F ⁺ and other minor impurities The procedure of Example 1 was observed, using 705 parts of chlorine trifluoride, the with

10

Chlorine dioxide was contaminated and 332 parts of difluoroamine were used. In this example, the reaction product was immediately fractionated by cold traps from -142 and -196 ⁰ C, and 135 parts Trifluoraminoxyd were obtained, which were contaminated with a small amount of silicon tetrafluoride. The SiF ₄ is expediently removed by forming a complex with potassium fluoride.

Example 3

The procedure of Example 1 was again used, with 359 parts of difluoroamine being added to a solid polychlorotrifluoroethylene reaction vessel previously charged with 2380 parts of sodium fluoride. The reaction vessel was then cooled to 5 * -196 ⁰ C, and 658 parts chlorine trifluoride, containing a small amount of chlorine dioxide was condensed into the vessel. The reaction vessel was then warmed to -65 ⁰ C and maintained for a period of about 90 minutes at this temperature. After the reaction time had elapsed, the gases formed during the reaction were condensed in cold traps of −95, −160 and −196 ° C. under a high vacuum. In the trap of -196 ° C, 131 parts of trifluoroamine oxide were recovered. Good results are also achieved if potassium fluoride, rubidium fluoride or cesium fluoride are used as the alkali metal fluoride, it being possible for the chlorine dioxide to be substituted _{by FClO 2} or FClO _3.

30th

Example 4

It was used the method of Example 3, the reaction vessel charged with 2380 parts of sodium fluoride and cooled to -142 ⁰ C and high vacuum conditions subjected. 314 parts of difluoroamine were condensed in the reaction vessel and the vessel was then cooled to -196 ° C. and charged with 770 parts of purified chlorine trifluoride. Chlorine dioxide (423 parts), obtained by the reaction of sulfuric acid, potassium chlorate and excess carbon dioxide, was introduced into the reaction vessel, the temperature being kept at -196 ° C. After all reactants in the reaction vessel were condensed, this was warmed to -65 ⁰ C and kept at this temperature for 3 hours, was fractionated and then the gas content of the reaction vessel by falling from -142, -160 and -196 ° C. 108 parts of trifluoroamine oxide and a trace of NO were recovered from the trap cooled to -196 ° C.

As mentioned, the compound according to the invention is an extremely high-energy oxidizing agent which, when used with fuels in rocket engine combustion, gives extremely strong impulses. With hydrazine in a ratio of 2 parts trifluoroamine oxide to 1 part hydrazine, a specific impulse of 293 seconds is achieved. With pentaborane in a ratio of 6 parts by weight of trifluoroamine oxide to 1 part of pentaborane, a specific pulse of 310 seconds is achieved. The figures given above are based on a heat of formation of -72 kilocalories per gram molecule of trifluoroamine oxide and on an assumed chamber pressure of 7 kg / cm ² , which relaxes to one atmosphere. The efficiency of the connection is expressed in seconds of the specific impulse, the latter being the parameter that describes the efficiency of a rocket fuel. The specific impulse is expressed as the thrust in kilograms that is generated per kilogram of fuel consumed per second. The performance of fuel compositions in which trifluoramine oxide is the oxidant can be compared to similar compositions containing hydrazine and N ₂ O ₄ and pentaborane and CIF ₃ . In these cases specific pulses of 292 and 290 are obtained from compositions that give optimal performance.

Claims (4)

Patent claims: 1. A process for the preparation of trifluoroamine oxide, characterized in that mix difluoramine with chlorine trifluoride and a halogen oxide to form the mixture of trifluoroamine oxide to react and the trifluoroamine oxide obtained is separated off. 2. The method according to claim 1, characterized in that condensed difluoroamine, chlorine trifluoride and a halogen oxide reactant for converting each of them to vapor are heated and the vapors of the three reactants are made to react. 3. The method according to claim 1 or 2, characterized in that the halogen oxide is chlorine dioxide is used. 4. Process according to claims 1 to 3, characterized in that difluoroamine in Form of an alkali metal fluoride-difluoroamine complex is used. 1 sheet of drawings 809 507/607 1.68 © Bundesdruckerei Berlin