Nitrous anhydride

Salpetrigsaure, /. nitrous acid, -anhydrid, n. nitrous anhydride, dinitrogen trioxide, -atlier, m. nitrous ether (ethyl nitrite), salpetrisch, a. nitrous. 

It is decompd even by weak acids with evolution of brown fumes of nitrous anhydride (Ref 1) KN02 detonates violently when heated in the presence of thiosulfates or cyanides. Ref 1 states that when mixed with K cyanide, the mixt burns, and at 450°, it explds violently. Ref 6 details instances of molten KN02 being violently decompd by boron, and of a wgorous reaction attended by flame caused by the addition of a 0 little amm sulfate to fused KNOa... 

Secondary amines. The reaction of secondary amine type compounds with nitrous acid (HO NO) has been reviewed extensively by Turney and Wright (17), Ridd (18), Scanlan (19) and Mirvish (20). In a system containing (HO NO) as the nitrosating agent, the possible nitrosyl carriers are (H2O NO), (NO2 NO) and (NO+). The reactivity of (NO+) is very low and it is not considered an effective nitrosating form. Nitrous acidium ion (H2O NO+) plays a significant role only at concentrated acidic condi tions. Therefore, it seems likely that at the dilute acidic conditions that are encountered in the environment, it is nitrous anhydride (N2O3 = NO2 NO) which nitrosates secondary amines. 

JPreparatim.— By mixing liquefied nitrous anhydride with a small quantify of water —... 

By the ootiou of nitrous anhydride, propylamine is trans formed into propylio oloohol —... 

By the action of nitrous anhydride, alanin ie conveFted into Inctio acid —... 

In tho manu cture of sulphuiio aoid on the large scale, the nitrous anhydride is again acted on by water and transformed into nitric acid and nitric oxide ... 

The crude sulphuric aoid may be eed finm traces of nitrous anhydride (which it always contains) by the addition of some smmonio sulphate —... 

Nitrous Anhydride. Assemble an apparatus as shown in Fig. 79, replacing test tube 1 with a small Wurtz flask provided with a dropping funnel, and immerse U-tube 3 into a cooling mixture (ice and salt). Put 1-2 g of starch on the bottom of the flask, and pour 5-6 ml of a 50% nitric acid solution into the dropping funnel. 

Adding the nitric acid dropwise to the starch, observe the liquefaction of the nitrous anhydride in U-tube 3. If no reaction occurs, carefully heat the flask with the reaction mixture. What is the colour of the liquid in U-tube 5 ... 

Formation.—When sulphur dioxide is passed into ice-cold fuming nitric acid, crystals of nitrosulphonic. acid separate.1 The acid is also obtained when sulphuric acid is treated with excess of nitrogen peroxide.2 It is also formed by the interaction of sulphur dioxide and nitrogen peroxide both in the absence or presence of water,8 and by the addition in equimolecular proportion of liquid nitrogen tetroxide to chloro-sulphonic acid in the absence of moisture.4 Sulphuric acid acts on either nitrous anhydride or nitrosyl chloride with formation of nitrosulphonic acid, according to the equations ... 

However, the physiological mechanisms of formation of these S-nitroso compounds is not clear.520-521 One mechanism may involve conversion by 02 to nitrous anhydride.511 522... 

The yield of ethyl oxomalonate is decreased if the nitrous anhydride is not dried. 

Nitrous oxide, or a gas with an analogous composition, is the anhydride of hyponitrous acid, H2N202, and could be called hyponitrous anhydride. Owing to our defective notation, it cannot be called nitrous anhydride by analogy with the nomenclature employed in many other cases. Nitrous anhydride, N203, is the anhydride of nitrous acid, HN02. To adjust the nomenclature, nitrous oxide would have to be called hyponitrous oxide. While the action of water on nitrous or hyponitrous anhydride does not form hyponitrous acid, yet the dehydration of hyponitrous acid by cone, sulphuric acid forms nitrous or hyponitrous oxide ... 

G. Canneri found that the treatment of a suspension of thallium sesquioxide in water with liquid nitrous anhydride, and subsequent evaporation of the soln., even in the cold under reduced press., yields, not thallic nitrite, but thallous nitrate. The latter is also obtained when soln. of thallic sulphate and barium nitrite are mixed in the cold, and the resulting liquid evaporated at low temp. That thallic nitrite is capable of existence in soln., although it cannot be obtained in the solid condition, is shown by the analyses and properties of the soln. The treatment of an aq. soln. of thallic nitrite with alcohol yields a precipitate of the sequioxide. In ethereal soln., thallic nitrite is far more stable, and the salt separates in the solid state on evaporation of the solvent it could not, however, be analyzed directly. Decomposition of thallic nitrite, with formation of thallous nitrate, takes place solely in accordance with the equation T1 (N02)3->TlN03+N2Os, neither intermediate reduction products nor thallous-thallic complex compounds being formed. 

Nitroso-d-naphthol, II, 61-62 Nitroso- 3-phenylhydroxylamine, IV, 21 w-Nitrotoluene, III, 91-93 -Nitrotoluene, II, 53 iw-Nitro- -toluidine, III, 91 Nitrous anhydride, IV, 27... 

A recent review of the reactivity of aliphatic amines towards nitrous anhydride (Mirvish, 1975), provides evidence that these reaction rates are curiously insensitive to the basicity of the substrate even though the overall reaction rate is much less than the encounter rate. The reason for this is not clear. 

---