Nitric acid behaviour

It is the nitronium ion which is responsible for nitrating actions in organic chemistry which are carried out in a mixture of nitric and sulphuric acids. When nitric acid is dissolved in water, its behaviour is that of a strong acid, i.e. ... 

These elements are generally unaffected by non-oxidising acids (behaviour expected for non-metallic elements) but they do react when heated with concentrated sulphuric and nitric acids, both powerful oxidising agents. Sulphur is oxidised to sulphur dioxide by hot concentrated sulphuric acid,... 

Thus nitric acid behaves as a base in hydrogen fluoride. Hence increases of conductivity when substances dissolve in hydrogen fluoride may be due to acidic or basic behaviour. 

The state of aqueous solutions of nitric acid In strongly acidic solutions water is a weaker base than its behaviour in dilute solutions would predict, for it is almost unprotonated in concentrated nitric acid, and only partially protonated in concentrated sulphuric acid. The addition of water to nitric acid affects the equilibrium leading to the formation of the nitronium and nitrate ions ( 2.2.1). The intensity of the peak in the Raman spectrum associated with the nitronium ion decreases with the progressive addition of water, and the peak is absent from the spectrum of solutions containing more than about 5% of water a similar effect has been observed in the infra-red spectrum. ... 

Olah and his co-workers compared the behaviour of nitronium salts in competitive nitrations with the behaviour of other nitrating systems. The results are given in table 4.1, columns (a)-(j), and also in table 4.2. The results obtained from competitive nitrations using solutions of nitric acid in organic solvents (table 4.1, columns (6)-(e)) are in line with those obtained by earlier workers. The evidence that in nitromethane,... 

Beryllium is readily attacked by most acids and, being amphoteric, is slowly attacked by caustic alkalis with the evolution of hydrogen. As might be anticipated, in view of the controlling influence of the surface film of beryllia on corrosion behaviour, concentrated nitric acid has little effect on beryllium , while the dilute acid results in slow attack. Hot acid is much more reactive. Nitric acid is in fact often used to pickle-off residual mild steel from hot-extruded clad beryllium. 

The US Bureau of Mines found the chemical and galvanic corrosion behaviour of both the TZM and Mo-30W alloy to be generally equal or superior to that of unalloyed molybdenum in many aqueous solutions of acids, bases and salts. Notable exceptions occurred in 6-1 % nitric acid where both alloys corroded appreciably faster than molybdenum. In mercuric chloride solutions the TZM alloy was susceptible to a type of crevice corrosion which was not due to differential aeration. The alloys were usually not adversely affected by contact with dissimilar metals in galvanic couple experiments, but the dissimilar metals sometimes corroded galvanically. Both alloys were resistant to synthetic sea water spray at 60°C. 

For some chemical plant applications the iron content of the titanium employed can influence its behaviour, e.g. in some strengths of nitric acid, and in chlorine dioxide, preferential weld attack may occur if the iron... 

This section is mainly concerned with reactions that involve nitric acid, of which behaviour is even more difficult to interpret. Indeed, nitric acid is not only a strong oxidant but also a nitrating agent,especially when it is combined with sulphuric acid. With nitrated derivatives it can also be destabilising due to its acidic property, which faciiitates the compounds decomposition. Since most reactions give rise to a detonation it is even more difficult to interpret the accidents. 

A mixture of nitric acid/acetic anhydride is very sensitive and detonates very easily. This behaviour was explained by the following reaction ... 

It is not only the esters of organic acids which combine, in the manner of the ethyl acetoacetate synthesis , with the enolates of ketones and of esters an analogous behaviour is shown by the esters of nitrous and nitric, acids. The process which leads to the formation of isonitroso-and atinitro-compounds yields products fundamentally similar to those already described just as with ethyl acetate the group CO.CHs enters, so here, the NO- and N02-groups are involved, and enolise " exactly as does >O=0 ... 

Strongly oxidizing or solvating chemicals such as concentrated solutions of nitric acid, chromic acid, hydrochloric and hydrochlorous acids, ammonia, organic amines can chemically attack CPE resins Good behaviour, little or no effect... 

Strong acids Good behaviour with certain dilute acids, attacked by concentrated acids, dilute sulfuric and nitric acids Bases Good behaviour only with low concentration solutions, attacked by certain bases... 

Agrawal and co-workers" " also conducted extensive studies into the synthesis, characterization and thermal and explosive behaviour of (113) (K-56, TNABN). 2,5,7,9-Tetraazabi-cyclo[4.3.0]nonane-8-one (112) was synthesized from the direct reaction of ethylenediamine with glyoxal, followed by reaction of the resulting cyclic imine with urea in concentrated hydrochloric acid nitration of (112) was achieved in 51 % yield with a mixture of nitric acid-acetic anhydride. Agrawal showed that K-56/TNABN is significantly more resistant to hydrolytic destruction than TNGU. 

As suggested by its behaviour towards sulphuric and nitric acids, thionyl chloride is of value as a reagent for the replacement of hydroxyl groups by chlorine, and amongst the organic compounds it finds frequent application instead of the commoner chlorides or oxychloride of phosphorus.2... 

Wilson and Miles [12] have measured the absorption of nitric acid by treating with it nitrocotton of 13.8% N. Under a pressure of 4 mm Hg as much as 15% of HN03, was absorbed by this nitrocotton. Nitric acid is absorbed better by a lowernitrated substance, just as the absorption of water vapour is easier in the case of lower-nitrated nitrocellulose. The maximum absorption has been established with nitrocellulose of 7% N. The amount of nitric acid absorbed by cellulose depends on its type. For native cellulose it amounts to about 25% by weight of the cellulose, and approaches 50% for mercerized cellulose. Such differences in the behaviour of different kinds of nitrocellulose indicates that swelling has an appreciable influence on absorption. Mercerized cotton which is more liable to swell simultaneously shows stronger absorption. 

The data collected below illustrate the behaviour of nitrostarch obtained by treatment with nitric acid alone, without any admixture of sulphuric acid (Table 104). 

A fundamental difference between starch and cellulose is shown by their behaviour in the presence of nitric acid. Starch brought into contact with nitric acid of over 76% concentration swells and eventually dissolves, whereas cellulose swells only insignificantly and generally does not dissolve (as described already it can only be dissolved in nitric acid of ca. 80% HN03). 

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