Nitric acid hydrogen bonding

In liquid nitric acid, hydrogen bonding gives a loose structure similar to that of hydrogencarbonate ions. However, although pure nitric acid does not attack metals readily and does not evolve carbon dioxide from a carbonate, it is a conducting liquid, and undergoes auto-ionisation thus ... 

More powerful oxidants are almost always needed. Those commonly used for cleavage of olefins — and for other degradations — include nitric acid, hydrogen peroxide, permanganate, chromic acid, very concentrated alkali hydroxides, and in particular ozone. The products to be expected from oxidative fission of an ethylenic carbon-carbon double bond are carbonyl compounds — an aldehyde or a ketone or both according as the doubly bonded carbon atoms do or do not carry a hydrogen atom — but it often happens that 1,2-glycols are obtained as intermediates. 

Another difficulty is that the extent to which hydrogen bonded association and ion-pairing influence the observed kinetics has yet to be determined. However the high order of the reaction in the stoichiometric concentration of nitric acid would seem to preclude a transition state composed only of a nitronium ion and an aromatic molecule. 

Table 1 Hsts some of the physical properties of duoroboric acid. It is a strong acid in water, equal to most mineral acids in strength and has a p p o of —4.9 as compared to —4.3 for nitric acid (9). The duoroborate ion contains a neady tetrahedral boron atom with almost equidistant B—F bonds in the sohd state. Although lattice effects and hydrogen bonding distort the ion, the average B—F distance is 0.138 nm the F—B—F angles are neady the theoretical 109° (10,11). Raman spectra on molten, ie, Hquid NaBF agree with the symmetrical tetrahedral stmcture (12).

Oxidation. Ketones are oxidized with powerful oxidizing agents such as chromic or nitric acid. During oxidation, carbon—carbon bond cleavage occurs to produce carboxyHc acids. Ketone oxidation with hydrogen peroxide, or prolonged exposure to air and heat, can produce peroxides. Concentrated solutions of ketone peroxides (>30%) may explode, but dilute solutions are useful in curing unsaturated polyester resin mixtures (see... 

In this reaction, called bromination, one of the hydrogen atoms has been replaced by a bromine atom. Notice that the double bond structure is not affected—this is not an addition reaction. Nitric acid causes a similar reaction, called nitration ... 

NH3. Ammonia is a colorless gas. It is a strong base, forms hydrogen bonds, is soluble in water, and is a fairly reactive molecule. Each year 12.4 million metric tons are manufactured by the Haber process (N2 + 3H2 2NH3 at 400°C and 250 atm), principally for nitric acid production, which is then used to make fertilizers and explosives. As a fertilizer, ammonia can be utilized in three ways first by direct injection... 

In nitric acid, three oxygen atoms are bonded directly to a nitrogen atom, and a hydrogen is bonded to one of the oxygens. Write the net ionic equation and draw a molecular picture that illustrates the reaction between nitric acid and water. 

Phosphoric acid, sulfuric acid, and the hydrogen sulfate ion are members of a group of acids known as oxoacids. An oxoacid has a central atom bonded to a variable number of oxygen atoms and OH groups. Except for the three oxoacids shown in Table (sulfuric acid, nitric acid, and perchloric acid), all of the oxoacids described in this textbook are weak acids. Chapter 17 describes in detail the chemistry of strong and weak acids, including carboxylic acids and oxoacids. 

Trialkyl phosphates form volatile 1 1 adducts with acids such as nitric and chloroacetic, from which the esters are recovered by base treatment. I.r. and n.m.r. spectral data suggest that these are hydrogen-bonded complexes. At low temperatures, in FSOaH-SbFj, trialkyl phosphates were shown (by n.m.r.) to give protonated species in which there appears to be considerable pir-d-rr back-donation from oxygen to phosphorus. These species are not stable the tri-n-butyl ester decomposing over the course of two days to MeaC+ and (HOiP. ... 

On modifying graphite nitrate, as follows from the material balance of the reaction, a major part of nitric acid is replaced by the organic intercalant. The latter, if it is protonated by the rest of nitric acid in the interlayer space, is capable of the strong hydrogen bonding with two... 

In this behavior, sulfur resembles iodine, which reacts in an analogous way to form polyiodides. Sulfur will also remove hydrogen from saturated hydrocarbons to produce H2S with the formation of carbon-carbon double bonds. Sulfur dissolves in hot concentrated nitric acid as a result of being oxidized as shown in this reaction ... 

Energy is needed to break the ionic bonds in the solid salt and energy is liberated forming hydration complexes like VI. We also break some of the natural hydrogen bonds in the water. The overall change in enthalpy is termed the enthalpy of solution, A// olutioni. Typical values are —207 kJmol-1 for nitric acid 34 kJmol-1 for potassium nitrate and —65.5 kJmol-1 for silver chloride. 

The choice of reagent determines whether a nitrosamine undergoes conversion to a nitramine by either nitrolysis or oxidation. An example is given for the conversion of 1,3,5-trinitroso-1,3,5-triazacyclohexane (109) to l,3,5-trinitro-l,3,5-triazacyclohexane (3) (RDX) - the use of 30 % hydrogen peroxide in 99 % nitric acid at subambient temperature goes via oxidation of the nitrosamine functionality, whereas dinitrogen pentoxide in pure nitric acid makes use of a nitrolysis pathway via C-N bond cleavage. 

Protons present in aqueous acid also act as reasonably efficient electron acceptors. If the reduced hydrogen atoms are formed on metallized suspensions, catalytic hydrogenation can result. For example, in contrast to the oxidative chemistry reported earlier for cyclohexene-4,5-bis-dicarboxylic acid (Eq. 28), if the reaction is conducted in the absence of oxygen in aqueous nitric acid, catalytic hydrogenation of the double bond becomes a major pathway, Eq. (34). ... 

The first examples of nitrofluorination of alkenes were demonstrated by the reaction in a solution of 10% nitric acid in hydrogen fluoride at — 10 C.204 Further investigation has shown that the rate of this conjugate addition is determined predominantly by the nature of the tr-bond (electron density, polarity).205 As a rule, the reaction is carried out at temperatures between - 60 C (i.e., 1,1-dichloro-or 1,1-difluoroethene) and + 20 C. However, nitrofluorination of hexafluoropropene is only successful at higher pressure and temperature, i.e. if the alkene rc-bond is less polar the regioselectivity of the addition is also unsatisfactory,205 e.g. reaction of 1 and 2.206... 

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