Nitric acid as a function

Clegg, S. L, and P. Brinibleconibe, Equilibrium Partial Pressures and Mean Activity and Osmotic Coefficients of 0-100% Nitric Acid as a Function of Temperature, J. Phys. Chem., 94, 5369-5380 (1990), and references therein. 

Cuillerdier compared the radiolytic stability of several malonamides [(C4H9(CH3) NCO)2CHRy ] in t-butylbenzene in contact with nitric acid as a function of the central alkyl chain R" (3.3 kGy h1, 40°C) (215). The order of stability, established on the total concentration of amide functions measured by potentiometry in nonaque-ous medium, was H < C2H5 < C2H4OC6H13 = C2H4OC2H4OC6H13. The authors then proposed the following tendencies ... 

Clegg SL, Brimblecombe P (1990a) Equilibrium partial pressures and mean activity and osmotic coefficients of 0-100% nitric acid as a function of temperature. J Phys Chem 94 5369-5380 Clegg SL, Brimblecombe P (1990b) The solubility and activity coefficient of oxygen in salt solutions and brines. Geochim Cosmochim Acta 54 3315-3328... 

Table 30 Physical properties of aqueous nitric acid as a function of composition...

In the absence of a standard source of NO, nitric acid vapor appears useful as a secondary standard since data on the HN03 content of saturated nitric acid as a function of concentration and temperature are available (3). However, in order to avoid high values, the acid should be boiled to remove the dissolved N02 or NO usually present (as indicated by brown coloration). 

The unreacted nitric acid partitioned itself between the acid and hydrocarbon phases. Figure 8 indicates the fates of the feed nitric acid as a function of composition of the hydrocarbon phase for the runs described above. The fractions of nitric acid that were retained (unreacted) in the product acid and that reacted both decreased as the nitrobenzene content increased toward 100 percent. At the conditions investigated, pure nitrobenzene was essentially unreactive. In these runs, the fraction of feed nitric acid that was extracted by the hydrocarbon phase increased almost linearly from about 2 to 30 percent as the nitrobenzene content increased from 0 to 100 percent. Clearly nitric acid extraction is important at higher benzene conversions (to nitrobenzene). ... 

Figure 3. Molecular ratio of(a)HNOj to TBP(left) and (b)HNOs to H2O (right) in the TBP complex with nitric acid as a function of molecular ratio of nitric acid to water in equilibrated aqueous nitric acid.

The crevice gap h (Fig. 2) controls the volume/surface ratio of the crevice the smaller this ratio, the faster the environment changes due to surfece reactions. However, the crevice gap must be wide enough for the environment to enter but it becomes inefficient if it is too wide. Figure 4 [1] shows the extent of crevice corrosion of unalloyed steel in nitric acid as a function of the gap. For stainless steels in chloride environments, short incubation times are obtained for crevice gaps of the order of a micrometer or less [2,3] and the incubation time increases rapidly with the crevice width. As a consequence, surface roughness is of major importance, and, for example, crevice corrosion can be avoided by polishing the surfaces in contact with seals to a smooth finish. 

Swinarski and Piotrowski also examined the conductivity of pure nitric and sulphuric acids as a function of temperature (Fig. 5). The curve for nitric acid has a maximum at 20°C. At 40°C the conductivity falls. 

TABLE III Distribution coefficients of Am [III] and Eu [III] between nitrobenzenic mixtures of 0.25 N 1-10 phe-nanthroline and 0.25 N nonanoic acid as a function of aqueous nitric acid concentration (y = 0.1]... 

Calculate the chemical potential of sulfuric acid as a function of the chemical potentials of nitric acid and the two solids. 

That s right—it might seem weird because nitric acid is essentially functioning as a base to remove a proton from sulfuric acid. And it might make us uncomfortable to use nitric acid as a base, but that is exactly what is happening. Why Because relative to sulfuric acid, nitric acid is a base. It s all relative. 

These variations permit the separation of other components, if desired. Additional data on uranium, plutonium, and nitric acid distribution coefficients as a function of TBP concentration, solvent saturation, and salting strength are available (24,25). Algorithms have also been developed for the prediction of fission product distributions in the PUREX process (23). 

An important aspect of nitrating toluene to nitrotoluene is the very low solubility of toluene and nitroioluenes in nitrating mix Is. Therefore the nitration proceeds in a two-phase system and the rate of nitration depends greatly on dispersion, which in turn depends on keeping the two phases efficiently stirred. This is emphasized in Fig 4, which gives the yield of MNT for a 11/64/25% nitric acid/sulfuric acid/water MA and a nitration time of 30 minutes as a function of stirring speed... 

Fig 5 shows the yield of MNT as a function of acid/toluene ratio for a MA of 27/55/18% nitric acid/sulfuric acid/water and a nitration time of 50 minutes at 30°... 

Fig. 11-14. (a) Corrosion rate of metallic iron in nitric acid solution as a function of concentration of nitric add and (b) schematic polarization curves for mixed electrode reaction of a corroding iron in nitric add W p, = iron corrosion rate CHNO3 = concentration of nitric add t" (t ) = current of anodic iron dissolution (cathodic nitric add reduction) dashed curve 1= cathodic current of reduction of nitric add in dilute solution dashed ciuve 2 s cathodic current of reduction of nitric add in concentrated solution. [From Tomashov, 1966 for (a).]... 

In concentrated solutions, direct action of nitrate ion is also taken into consideration. In addition, in concentrated nitric acid, nitric acid molecule (HNO3) coexists. Although it is known that NOs plays an important role in concentrated nitric acid, precise formation process was not known. Recently, it was clarified that the formation of the NO3 radical is formed by two different processes reaction of OH with molecular HNO3 and direct action of radiation to HNO3 and NO3 [121]. Experimentally obtained temporal behavior of N03 and its yield as a function of nitrate ions are shown in Figs. 7 and 8, respectively. 

Figure 12.22 shows the composition in terms of the weight percent HNO, and H2S04 as a function of temperature as solid SAT is cooled from 194 K under conditions corresponding to a pressure of 50 rnbar in an atmosphere containing 5 ppm HzO and an HNO, concentration of 10 ppb (Koop and Carslaw, 1996). Under these particular conditions, as the temperature falls below 192 K, the SAT is in equilibrium with a liquid film on the particle containing both HN03 and H20. The particular temperature at which SAT deliquesces is a function of the water vapor and gaseous nitric acid concentrations as shown in Fig. 12.23. As the temperature falls further and more HNO, and HzO are taken up into the liquid, the solid SAT dissolves completely, forming a ternary solution of the two acids and water. This solution can then act again to nucleate PSCs.

Note Rinkenbach Aaronsen (Ref A) measured die yield of Diethylene Glycoldinitrote as a function of the ratio of sulfuric acid to the amount of water present when nitration was complete, holding the nitric acid in a constant excess. They found that a value of 3-15 gave the maximum yield, about 83%, and reasoned that more ooncd sulfuric acid dehydrated the DEGc to form poly EGc s which, gave lesser yields of dinitrates Properties and Uses of EGDN (Refs 1, 2, 5,... 

The reduction potential for the nitrate(V)/nitrate(III) couple in acid solution of +0.94 V indicates from the limited data in Table 6.12 that nitrate(V) ion in acidic solution is a reasonably good oxidizing agent. However, nitric acid as an oxidant usually functions in a different manner, with the production of brown fumes with a metal (e.g. copper) or a metal sulfide (e.g. FeS2). The brown fumes consist of N204 (brown gas) and its monomer N02 (colourless gas). Concentrated nitric acid consists of about 70% of the acid in an aqueous solution. In such a solution there is some dissociation of the nitric acid molecules to give the nitronium ion, N02, which represents the primary oxidizing species ... 

The consumption of nitric and acetic acids is plotted as a function of percent water in the system in Figure 4. The minimum in the nitric acid curve at the 5% level coincides with the maximum in yield (Figure 3). This is not surprising it merely indicates that the yield depends on the activity of the cocatalyst. 

One method of determining the values of the exponents in a rate law is to carry out a series of experiments in which the initial rate of a reaction is measured as a function of different sets of initial concentrations. Consider, for example, the air oxidation of nitric oxide, one of the reactions that contributes to the formation of acid rain ... 

Carbamoyl methyl Phosphine Oxide Derivatives The physicochemical properties of various aryl derivatives of CMPO have been investigated at the Vernadsky Institute of Geochemistry and Analytical Chemistry. Extraction of americium and lanthanides from nitric acid with solutions of diphenyl- and dibutyl-(diethylcarbamoylmethyl) phosphine oxides (Ph2Et2-CMPO and Bu2Et2-CMPO) in dichloroethane have been investigated as a function of the concentrations of the extractants and nitric acid (110, 111). The observed dependences are characterized... 

FIGURE 4.5 Strontium distribution ratios of DC18C6 (1) (10 1 M in NPHE) and CA16 (2) (ICE2 M in NPHE) as a function of the nitric acid concentration. 

---