Nitrogen tetroxide

Howell and Van Wazer236 also studied N204 with a small basis set, which however, gave an energy of -407.650 Hartree and a barrier of 48.5 kJ mol-1. Griffiths et al. did not investigate the barrier.237 The authors do not attribute the weak bond to the occupation of the 6blu (a ) orbital. 

Ab initio Calculations on Molecules containing Five or Six Atoms Table 6 Computed energies and barriers to rotation for N204 

There have been more detailed studies on the Stfl reaction very recently. In 1975, Baybutt248 found that for CH4 + H- the addition of polarization functions to the basis has very little effect on the barrier for the reaction, but diffuse carbon s-functions have a more pronounced effect, increasing the barrier by 42—68 kJ mol-1 

Dedieu, A. Veillard, and B. Roos, Proceedings of the 6th Jerusalem Symposium on Quantum Chemistry , 1973, Israel Academy of Sciences, Jerusalem. 

Finally, Keil and Ahlrichs,249 reported PNO-CI and CEPA calculations on several Sn2 reactions, including that giving CH5-. The barrier height computed was 236 kJ mol-1, and the inclusion of correlation decreased the barrier by ca. 30 kJ mol-1. The larger drop found in ref. 245 was probably an artefact of the IEPA method. The errors in these very extensive calculations were believed to be only 10—30 kJ mol-1, which is indicative of the accuracy now attainable. 

Ahlrichs and Keil have made a more detailed study including correlation by the lEPA method, but essentially in a form including only a limited amount of correlation, in a manner similar to that used in the OVC method. Calculations were performed for various N—N distances and for the skew structure, in addition to the planar structure. The results show that the long N—N bond is due to (i) the de-localization of the bond pair over the whole molecule and (ii) to a rather strong repulsion between the doubly occupied orbitals of the NOj fragments. The coplanarity results from a delicate balance between the repulsive forces favouring the skew structure and the effects of bonding which favour the planar structure. In Table 6 some of these calculations are compared. 

Fukui and co-workers have discussed various factors involved in treating the reaction co-ordinate in surface calculations and applied the method to CHi-t-T.  

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Plutonium Purification. The aqueous feed for the second plutonium cycle is typically prepared by adding HNO and an excess of sodium nitrite, NaN02, to destroy the excess reductant and oxidize the Pu to the more extractable Pu . An alternative approach which reduces the amount of salt in the Hquid waste involves absorbing nitrogen tetroxide, N2O4, as a substitute for the NaN02 ... 

Fig. 1. Dimethyl sulfoxide manufacture with nitrogen tetroxide.

Titanium does not stress-crack in environments that cause stress-cracking in other metal alloys, eg, boiling 42% MgCl2, NaOH, sulfides, etc. Some of the aluminum-rich titanium alloys are susceptible to hot-salt stress-cracking. However, this is a laboratory observation and has not been confirmed in service. Titanium stress-cracks in methanol containing acid chlorides or sulfates, red Aiming nitric acid, nitrogen tetroxide, and trichloroethylene. 

Interest has continued with these materials because of their non-inflammable nature (they will not bum, even in pure oxygen), their excellent chemical resistance, including that of nitrogen tetroxide and chlorine trifluoride, a low Tg of -51°C and an extremely low solubility parameter of 10.6MPa. ... 

NITROGEN FERTILIZER SOLUTION NITROGEN MUSTARD NITROGEN TETROXIDE NITROGEN TRIFLUORIDE NITROGEN TRIOXIDE... 

Oxides of Nhrogen Nitric oxide Nitric oxide Nitrous oxide Nitorgen dioxide Nitrogen tetroxide... 

Fl Jmxyf,unini- 7803-49-8 2500 Nitrogen Tetroxide (also called Nitrogen Peroxide) IIIM4 7 - ... 

Nitrogen Tetroxide + UDMH 296 seconds (liquid storable)... 

Measurements in this held have been made by Berthelot and Ogier with nitrogen tetroxide Ann. de Chim. et Phys., [v.], 30, 382 (1883)), and with acetic acid ibid., 400), and some calculations with reference to steam have been made by Nernst Verhandl. Deutsch. Phys. Ges., 15, 313) and Levy ibid., 330), who utilised the vapour-pressure measurements of Holborn and Henning Ann. der Physik, (1906), 21 (1907), 22, 23). Wiedemann had previously observed that the specific heats of ethylbromide, ethyl-acetate, and benzene increase with temperature at about the same rate as that of nitrogen tetroxide at 200°. In the case of steam it was assumed that (i.) the polymerisation is to double molecules... 

Mg ribbon and fine Mg shavings can be ignited at air temps of about 950°F (Ref 26). Oxides of Be, Cd, Hg, Mo and Zn can react explosively with Mg when heated (Ref 8). Mg reacts with incandescence when heated with the cyanides of Cd, Co, Cu,Pb, Ni or Zn or with Ca carbide (Ref 9). It is spontaneously flam-mable when exposed to moist chlorine (Ref 10), and on contact with chloroform, methyl chloride (or mixts of both), an expl occurs (Ref 4). Mg also reacts violently with chlorinated hydrocarbons, nitrogen tetroxide and A1 chloride (Ref 14). The reduction of heated cupric oxide by admixed Mg is accompanied by incandescence and an expin (Ref 7).Mg exposed to moist fluorine is spontaneously flammable (Ref 11). When a mixt of Mg and Ca carbonate is heated in a current of hydrogen, a violent ex pin occurs (Ref 12). When Mo trioxide is heated with molten Mg, a violent detonation occurs (Ref 1). Liq oxygen (LOX) gives a detonable mixt when... 

Uses. Since 1947, 70 to 85% of the annual USA production of nitric acid has gone into the production of NH4 nitrate fertilizer, initially in the form of solid prills currently, increasing amounts have been supplied mixed with excess ammonia and/or urea as aqueous nitrogen solution for direct application to the soil. Some 15% is used in explsj (nitrates nitro compds), and about 10% is consumed by the chemical industry. As the red fuming acid or as nitrogen tetroxide, nitric acid is used extensively as the oxidizer in proplnts for rocketry. It is estimated that current USA capacity for nitric acid is in excess of 10 million tons (Refs 30, 34, 36 37)... 

Engineering Parameters Study of Nitrogen Tetroxide Flow Decay , AFRPL TR-72-38 (1972)... 

Scholl et al (Refs 3 4) prepared the same compds by treating ketoximes (such as pina-colone) with nitrogen tetroxide, but he assigned them the structure R2C=N-N02 and called them nitrimines. One of the compds described by him in Ref 4, p 27 is a weak expl. It is the Ag salt of pinacolone-nitraminic acid which puffs off on rapid heating (this compd described below under List of Nitrimines ). Further work on... 

Nitrogen Oxides as Rocket Fuel Oxidants Including The Theoretical Performances of Propellant Systems Employing Nitrogen Tetroxide , JPL PR No 9-23, Cal Inst Tech, Proj No TU2-1,... 

Nitrogen tetroxide is formed as an undesirable product in several instances, eg, during the storage of some energetic materials, particularly NC, NG and mixts contg them, such as propints and Dynamite. In these Ihe nitric esters decomp at elevated temps. In some cases, even such stable nitrocompds as TNT can begin to evolve N02 when stored at higher than ambient temps. 

Nitrogen tetroxide is one of the most insidious gases in terms of human toxicity. Inflammation of the lungs may cause only slight pain or pass unnoticed, but the resulting edema several days later may cause death. lOOppm is dangerous for even a short exposure, and 200 ppm may be fatal (Ref 25). Also see under Nitrous Fumes in this Vol... 

For additional information on Nitrogen tetroxide, see under Liquid Propellants in Vol... 

J.A. Herickes J. Ribovich, Study of Military Applications of Nitrogen Tetroxide Explosives , Summary Report No 3746, Bur-Mines, NSDl (1956) 15) P. Gray, The... 

The Results of Long-Term Storage Tests For Compatability of Nitrogen Tetroxide With Various Spacecraft Materials , SR No 2, JPL Contract No 951581 (NAS7-100) (1967)... 

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