US3256169A - Process of producing nitrosamine additives - Google Patents

Description

June 1966 I B. BERGHAUS ETAL 3,

PROCESS OF PRODUCING NITROSAMINE ADDITIVES Filed Aug. 24, 1964 9 INVENTOR Bernhard fiery/mas Maria Slaesc/ze ATTORNEYS United States Patent 3,256,169 PROCESS OF PRODUCING NITROSAMINE ADDITIVES Bernhard Berghaus, Zurich, and Maria Staesche, Wettingen, Aargau, Switzerland, assignors to Elektrophysikalische Anstalt Bernhard Berghaus, Vaduz, Liechtenstein, a corporation of Liechtenstein Filed Aug. 24, 1964, Ser. No. 391,388 13 Claims. (Cl. 204-177) This application is a continuation-in-part of application Ser. No. 27,212 filed May 5, 1960 now Patent No. 3,152,056 dated October 6, 1964. p

The present invention relates to the synthesis of addition compounds of nitrogen-hydrogen and nitrosamine and more particularly to such a synthesis by means of an electric jet discharge.

So far, addition complexes of nitrogen-hydrogen compounds with nitrosamine, such as nitrosamine-hydrazineammonia additives and nitrosamine-ammonia additives, have not had any previous commercial application. It has now been found that such nitrosamine additives are particularly well suited as initial or basic materials for the production of hydrazine. Thus the problem which the present inventors faced was to find a convenient and advantageous process for preparing such nitrosamine addition compounds.

In the process according to the present invention for the preparation of nitrosamine addition compounds, a gas comprising nitrogen and hydrogen and consisting of one or more gases of the group ammonia, nitrogen and hydrogen, preferably ammonia alone, and a further reactant comprising oxygen or nitric oxide, is conducted through a jetlike glow discharge, and the reaction products subsequently are separated, preferably with the aid of a coolant trap in which the nitrosamine additives accumulate.

Suitably the reactants are fed through a nozzle into a reaction vessel, and the jetlike glow discharge is produced in the gas jet issuing from the nozzle. The latter preferably is connected as an electrode of the glow discharge, suitably as the cathode. Further, the process suitably is carried out in a reaction vessel with one or more annular electrodes of which preferably at least one is operated as an anode of the glow discharge. Moreover, it is of advantage in most cases to use for the generation of the jetlike glow discharge a reaction vessel in protected by protective gaps or slits from the destructive effect of the discharge.

The glow discharge suitably is effected at a gas pressure from one millimeter Hg to 30 millimeters Hg, preferably from 2 to 6 millimeters Hg. Further, the glow discharge preferably is carried out at voltages from 150 to 400 v. Liquid air or liquid nitrogen preferably is used for cooling the coolant trap.

The invention will be described in greater detail with the aid of the apparatus for carrying out the present process as shown in the accompanying figure which is a schematic representation of a suitable jet discharge reaction chamber andaccompanying apparatus.

In the apparatus shown, the reaction chamber 1 is enclosed on all sides by metallic walls 2 that are formed as double walls adapted to receive and conduct a cooling current in direction of the arrow 3 through the intermediate space 4. The chamber v1 is hermetically closed at its top by a cover 5 composed of electrically insulating material. The cover carries a metallic annular feeding means 6 of which the interior duct 7 opens into the chamber 1 through a terminating nozzle 8. The

3,256,169 Patented June 14, 1966 wall enclosing the duct 7 and the nozzle 8 is provided with cooling ducts 9 and 10 through which flows a coolant such as water or liquid air in the direction from inlet 11 to outlet 12. The points of transition from metal to insulating material on the cover 5 are protected, in

' a manner known per se, by gaps or slits 13 and 14.

Before that portion of the metallic feeding means 6 and nozzle 8 which protrudes into the discharge chamber 1, is produced an electric field, for which purpose a ring 1511- is perpendicularly disposed as counterelectrode immediately in front of the mouth of nozzle 8, which ring is adjustable along the nozzle axis and is held by the interior conductor of the insulated bushing 17a. The clear diameter of ring 15a, which is coaxial to the nozzle axis, suffices not to foul the gas jet issuing from the nozzle. The ring 15a is connected via a switch 16a to one pole of a voltage source 18 of which the other pole is connected to said means 6 via switch 16. A direct voltage source 18 is preferably utilized of which the negative pole supplies said means 6 via switch 16. O the other hand, one pole of a voltage source 19, for example for direct voltage, is connected to switch 16a, and the center tap of said source is connected via a switch 16b and a bushing 17b to ring 15b, while the other pole thereof is connected to ring via a switch 16c and a bushing 17c. It has proven of advantage to have electrode 15b positive with respect to electrode 15a.

To said means 6 are fed, perhaps together with a carrier gas and the initial reactants through the pipe 21 which maybe cut off by a valve 20. If required, the initial reactants may be mixed in advance in the mixer 22. The pressure P may be read from a manometer 26. To the lower end of chamber 1 is connected an outlet line 27 that extends via a shut-off valve 28 to an absorption assembly 29a and a pump unit 29. The latter is so dimensioned that in chamber 1 at the mouth of line 27 'may be maintained a predetermined. pressure P that is readable from a pressure gage 34. The pressure ratio P :P shall be increasable to high values.

The nitrosamine addition compound accumulates in the absorption assembly 29:: which is a cooling trap cooled by liquid air or other suitable means not shown.

I An essential feature of the present process is the maintenance of a jetlike' glow discharge 36 in reaction chamber 1. For such purpose suitably a'pressure of 1 to 30 millimeters mercury, preferably from 2 to 6 Hg, is produced in chamber 1 and maintained at least in the immediate vicinity of the mouth of line 27, and at the same time a gas stream under the pressure P is supplied to chamber 1 through the nozzlelike opening 8 in said means 6. By properly adjusting the pressure P at the mouth of nozzle 8, the clear width thereof and the pump throughput on line 27, a steady state is attained in which there is a pressure difierence (P P in the reaction chamber between the mouth of nozzle 8 and the outlet line 27. The entering gas stream adjacent to the mouth of nozzle 8 assumes the shape of a gas jet, suchv shape being different depending on the nozzle form; In FIG. 1 the jet, which is spheroidal with respect to the nozzle axis, is schematically indicated by the dotted lines 36, the radial extent of the spindle-shaped boundary surfaces being, however, exaggerated for a better understanding. .For the same reason, the jet deformations arising directly at the month are not shown.

When the gas stream in chamber 1 spreads unhindered, the individual gas particles will pass at high velocity over the greatest portion of the distance between nozzle mouth 8 and the counterelectrodes 15. By suit-able selection of the total pressure drop (P -P the velocity and thus the flow time of the reactants is adjustable to the desired value in wide limits.

. Within the jet there develops fromthe usual glow phenomenon on the cathode, a sort of luminescence, mostly in the form of a luminous ray, which with respect to its structure is different from all the phenomena of gas and glow discharges known so far. The appearance and shape of the luminscent zone apparently is defined by the gas jet, .but occasionally a Stratification is noticeable within the luminescence. The spectral range of the light emission is set, within a certain range, by the reactions taking place in the jet. The light-emitting regions inside the jet are not, of course, the only portions that enter into question for the present purpose of carrying out reactions, rather the reaction zone proper may comprise also nonluminous jet portions as well as the immediate vicinity thereof and may extend into the nozzle opening 8.

The shape of the reaction zone is determined to a large extent by the flow velocity of the jet, although the reaction zone does not have to extend entirely across the jet. An essential feature of the present form of discharge is the sharp demarcation thereof with respect to its vicinity, which would seem to depend on the steep pressure drop from the jet interior to the rim thereof. As, in accordance with a known conformity, the energy exchange of gas discharge rises according to an approximately cubic function with the gas pressure, and since, there is already a pressure P at the rim of the vessel, the reaction appears to be most intense inside the jet where at the same time prevails a maximum ion density at a relatively low temperature. The reactants, according to all experience, are already dissociated by the electric action shortly after leaving nozzle 8. When passing through the high ion density of jet 36, the reaction of the individual ions occurs.

The length of time during which the reactants remain in the jet, is normally in the order of fractions of milliseconds to fractions of seconds. Such short and adjustable duration of action and the above mentioned fact that the reactants leaving the jet arrive at once in a space portion of different pressure, another concentration and 'another temperature, is considered the cause of the surprising chemical effect of the present process.

When supplying ammonia and oxygen in excess through nozzle 8 into the apparatus, products of light to deep blue are obtained when freezing the reaction products with the aid of liquid air. When thawing these products at temperatures from -110 to 100 C., they melt to a deep-red liquid under vigorous gas discharge.

When further heating said liquid, it emits only slight gas quantities, and the color of the liquid gradually brightens and is a light yellow at about l C. The heating curve of the liquid extends from thawing (from 110 to 100 C.) to room temperature quite uniformly, without stops or discontinuities. It follows, therefrom, that the liquid comprises a uniform compound and not a mixture of different substances, and neither are there any rearrangements of this liquid-forming compound within the temperature range from 100 to +20 C., for on presence of a mixture there would be stops or constant levels at the temperatures of distillation of the various mixture components, while in the case of rearrangements there would be discontinuities in the heating curve.

The liquid, therefore, has the same composition at any temperature Within this temperature range, and a sample for analyzing the liquid may be taken at any temperature within said range.

In the present case, a sample for analysis was taken at 10 C., and no free ammonia was found therein. The sample had an alkaline reaction with a high iodine consumption, the reaction to hydrazine with p-dirnethylaminobenzaldehyde was positive in fresh solution, but regressed quickly. However, the iodine consumption does not similarly decrease. The liquid evaporates in a few weeks when allowing it to stand, a high gas pressure arising in closed vessels. The liquid comprises a nitrosamine-ammonia additive of the type where a, b and c integers.

The invention is illustrated, but not limited, by the following specific examples:

EXAMPLE 1 10 liters NH were mixed with 13 liters O and introduced through nozzle 8 into the reaction chamber. At 185 volts and 104 watts, the pressure P was between 15 and 5 mm. Hg. A linden greenish jet was formed which below the anode changed to green with blue and, on the bottom of the vessel, to green with yellow.

8.76 grams of a deep-blue substance were frozen, which on thawing at 110 C. suddenly ran together to a red liquid containing nitrosamine NH NO While a gas escaped. Upon further heating to more than 10 C., said red liquid yielded 6.16 grams of a slightly yellow liquid while emitting a small volume of gas. This latter liquid did not comprise any free ammonia, had a strong alkaline reaction and a high consumption of iodine. It showed a reaction to indicate hydrazine in the fresh state only. On letting the liquid stand at room temperature, it developed relatively large quantities of gas and evaporated entirely after a few weeks.

EXAMPLE 2 By introducing 4 parts by volume of ammonia and one part by volume of nitric oxide through nozzle 8 into the apparatus described with a gas throughput of 3 liters per minute, a pressure of to mm., a voltage from 200 to 340 v. and at 300 to 400 w. power, 18 gms. of a deep-blue product is obtained when freezing the reaction products with liquid air, which product on thawing at about C. also will melt to a deep-red liquid that upon further heating will emit small quantities of gas and of which the color will gradually brighten. At approximately -l0 C. the color of the liquid is a yellowish red. The heating curve of the liquid is also continuous and without stops. Free ammonia was not present in a sample taken at 10 C. The liquid comprises a nitrosamine-ammonia additive of the formula in which b is very small in respect to a and c and at the limit mayapproach zero. The sample with p-dimethylaminobenzaldehyde does not react to indicate hydrazine, but on determining the ammonia content, the nitrosamine content and the nitrogen content of the sample, there will be found yet very small quantities of hydrazine, in addition to nitrosamine and amomnia. From this it follows that the actual nitrogen content in most cases is somewhat higher than the nitrogen content calculated from the nitrosamine content and the ammonia content.

EXAMPLE 3 26 liters of a mixture of ammonia gas NH and nitric oxide N0 in a volumetric ratio 1:1 were conducted through nozzle 8 into the reaction chamber within 230 seconds. At v. and 19.2 w. the gas pressure in the reaction chamber was between 8 and 2 mm. Hg. There was formed a reddish yellow jet issuing from the nozzle, of which the color merged to blue below the anode ring.

7.86 grams of a deep-blue substance was frozen, which ran together at --110 C. to a deep-red liquid while emitting a relatively large quantity of gas. On further heating, the liquid only emitted small quantities of gas yet and gradually changed its'color to a bright red and orange and, finally at -10 C., to a yellowish red. A sample taken at 10 C. contained 41% by weight of ammonia and 59% of nitrosamine NH NO, the ammonia being added to the nitrosamine. The sample did not contain any free ammonia and neither showed any reaction to hydrazine with p-dimethylaminobenzaldehyde.

But said liquid which is red at very low temperatures and which turns yellow upon heating, also is obtained with mixtures of at least two of the substances ammonia, nitrogen, and hydrogen, with oxygen or nitric oxide, or a mixture of the two latter substances. This liquid reacts similarly as in the cited examples and comprises an additive of the type a(NH -NO)'b(N H -NH )-c(NH a, b and c being integers, whereby at the limit b may approach zero.

The liquid forming the reaction product, which is red and turns yellow upon heating, by means of finely dispersed metal such as Rainey-nickel may in all cases be reduced to a substance that contains relatively large parts of hydrazine. Particularly good results were obtained by the reduction of a liquid jet discharge reaction product of ammonia and nitric oxide to which at approxi- 'rnately 100 C. were added finely divided Raincy-nickel.

The reduced liquid showed a preponderant part of hydrazine.

With reference to the three examples described may be remarked that in industrial production that portion of the gases introduced into the reaction vessel which is not consumed in the formation of the reaction product, may again be added, of course, to the process cycle while correspondingly adding the used-up gas quantities. In a continual process in accordance with the present invention therefore, only so much substance has to be introduced into the process as has been withdrawn from the cycle in the form of reaction product.

It is to be understood, of course, that the foregoing disclosure relates only to preferred embodiments of the invention and that numerous modifications, additions and alterations may be made therein without departing from the spirit and scope of the invention as set forth in the appended claims.

What we claim is:

1. A process for the production of an addition com pound of nitrosamine and nitrogen hydrogen compounds comprising subjecting a member selected from the group consisting of (l) ammonia gas and (2) at least two gases of the group consisting of ammonia gas, nitrogen and hydrogen and a reactant selected from the group consisting of oxygen and nitrogen oxide to the action of an electric glow discharge in the form of a jet discharge to form said additions compounds and separating the reaction mixture.

2. A process according to claim 1 in which the reaction is conducted under a pressure from about-1 to mm. Hg.

3. A process according to claim 2 in which the pressure is about 2 to 6 mm. Hg.

4. A process according to claim 1 in which the potential difference at the power source for the discharge is from to 400 volts.

5. A process according to claim 4 in which the potential dilference is from to volts.

. mixture is recovered by freezing.

7. A process according to claim 6 in which the freezing of the reaction mixture is effected by liquid air.

8. A process according to claim 1 in which the nitrogenhydrogen compounds are selected from the group consisting of hydrazine and ammonia.

9. A process according to claim 1 in which the reactants are ammonia gas and nitric oxide in a volumetric amount from 4 parts of ammonia to 1 part of ammonia per volume of nitric oxide.

10. A process according to claim 1 in which a slight volumetric excess of oxygen is reacted with ammonia.

11. A process for the production of an addition compound of nitrosamine and at least one member of the group consisting of ammonia and hydrazine comprising introducing at high velocity under pressure through a metallic nozzle shaped restricted inlet into a reaction zone at reduced pressure a member selected from the group consisting of (1) ammonia gas and (2) at least two gases containing said addition compound; removing the formedreaction mixture rapidly from said zone and separating said addition compound from the withdrawn reaction mixture.

12. A process according to claim 11 in which the restricted-inlet has a clear width of about 1 mm.

13. A process according to claim 11 wherein the metallic nozzle electrode is cathodic.

References Cited by the Examiner UNITED STATES PATENTS 3,003,061 10/1961 I Berghaus et al 204-1312 3,020,223 2/1962 Manion 204-177 OTHER REFERENCES Journal of Physical Chemistry, Vol. XXXVH, No. 7,

JOHN H. MACK, Primary Examiner.

HOWARD S. WILLIAMS, Examiner.

Claims (1)

1. A PROCESS FOR THE PRODUCTION OF AN ADDITION COMPOUND OF NITROSAMINE AND NITROGEN-HYDROGEN COMPOUNDS COMPRISING SUBJECTING A MEMBER SELECTED FROM THE GROUP CONSISTING OF (1) AMMONIA GAS AND (2) AT LEAST TWO GASES OF THE GROUP CONSISTING OF AMMONIA GAS, NITROGEN AND HYDROGEN AND A REACTANT SELECTED FROM THE GROUP CONSISTING OF OXYGEN AND NITROGEN OXIDE TO THE ACTION OF AN ELECTRIC GLOW DISCHARGE IN THE FORM OF A JET DISCHARGE TO FORM SAID ADDITIONS COMPOUNDS AND SEPARATING THE REACTION MIXTURE.

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