Alkali nitrates

Liquid/hquid reactions of industrial importance are fairly numerous. A hst of 26 classes of reactions with 61 references has been compiled by Doraiswamy and Sharma Heterogeneou.s Reactions, Wiley, 1984). They also indicate the kind of reactor normally used in each case. The reactions range from such prosaic examples as making soap with alkali, nitration of aromatics to make explosives, and alkylation of C4S with sulfuric acid to make improved gasoline, to some much less familiar operations. 

At higher concentrations the Raman spectra of aqueous solutions of alkali nitrates and of nitric acid have been investigated. Nitric acid was found to be incompletely dissociated, though for the alkali nitrates no evidence of incomplete dissociation was found. Since accurate measurements on solutions of nitric acid have not been made at concentrations below 4.0 molar, it is not certain how the extrapolation to infinite... 

There are a Tew compounds of alkalies, nitrate, and acetate thai have low solubilities, but most of them are quite complex in composition. For example, sodium uranyl acetate, NaUQifCHjCOOh has low solubility. Silver acetate is an exception but its solubility is moderate. 

Nitrites are the salts of nitrous acid, discovered by Scheele in 1774. The inorganic nitrites, with die general formula M.N02, where M is a metal, are well known. They are all insol in w with the exception of the alkali nitrites. Nitrites may be prepd either by thermal decompn of alkali nitrates 2KN03 2KNOJ + 02 or by reduction of nitrates by C or Pb 2KN03 + C 2KN02 + C02. The lone pair of electrons in the nitrite ion is sterically significant consequently, the nitrite ion is bent ... 

The spectral component of a Mg/alkali nitrate flare is a continuum with a broad max about 0.01 pm on either side of the resonance line (Ref 35)... 

Binary alkali nitrates have been systematically studied the isotherms are shown in Fig. 6. The Chemla effect occurs in all systems except for (Li, Na)N03. Figure 6 shows that with an increase in temperature the crossing point shifts toward higher concentrations of the smaller cation. 

Okada et al. found that the internal mobilities of LT in molten alkali nitrates are well expressed as a function of molar volume, independent of the kind of the second cation. This finding leads to a general empirical equation ... 

Figure 6. Isotherms of the internal mobilities in 10 binary alkali nitrates. C Chemla erossing point marked only for the unelear eases. (Reprinted from M. Chemla and I. Okada, lonie Mobilities of Monovalent Cations in Molten Salt Mixtures, Electrochim. Acta 35 1761-1776, Fig. 5. Copyright 1990 with permission from Elsevier Seienee.)...

The internal mobilities of alkali halides have not yet been investigated systematically as with the alkali nitrates. However, it seems that an equation similar to Eq. (12) holds. To indicate this explicitly, the reciprocal values of the internal mobilities at 973 K in (Li, CS)CP are shown in Fig. 8. Figure 8 indicates that m" is a linear function of Vm, as Eq. (12) suggests however, the parameters A, Vo, and E are different at two different Vm... 

The bulk viscosities of molten alkali nitrates measured by Ejima s group 140 are shown in Fig. 27, where the bulk viscosity decreases with increasing temperature. The ratios of /r are approximately constant over the temperature range investigated. This suggests that the activation energies of the bulk viscosity and the shear viscosity are much the same. 

Figure 27. Bulk viscosity of alkali nitrates. (Reprinted from Ref 140 with permission of the Japan Institute of Metals.)...

It is important from a practical viewpoint to predict the shear viscosity of mixtures from those of pure melts. For alkali nitrate melts, a linear dependence has been found between the reorientational line width obtained by Raman measurements and the ratio of temperature divided by shear viscosity.For NO3 ions, the depolarized Raman scattering from 1050cm" total stretching vibrational mode (Al) has a contribution to the line width L, which is caused by the reorientational relaxation time of the Csv axis of this ion. The Stokes-Einstein-Debye(SED) relation establishes a relation between the shear viscosity r of a melt and the relaxation time for the reorientation of a particle immersed in it ... 

It is unusual in being flammable with so high a chlorine content (70%), and mixtures with air may detonate if confined when ignited. One case of spontaneous ignition under ambient conditions was observed [1], It has an unusually low autoignition temperature (43 3°C). A survey of hazards and combustion is found in [2], There is a risk of combustion with fluorochloromethanes. Autoignition was observed on contact with traces of a mixture of alkali nitrates/nitrite. 

Fig. 2. Plot of 4AHj for the alkali nitrates versus the quantity (dt — rf,) /(< ,). The cation pair to which each point corresponds is listed next to each point.

Lithium nitrate is used in fireworks to impart carmine-red color to the flame. Its mixtures with other alkali nitrates produce very low melting eutectics, which are used as heat-transfer media. 

CA 42, 5230(1948) [Gasless delay fuze elements consisting of finely divided Ni (prepd by volatilizing Hg amalgam) and an oxidizing agent, such as Mn dioxide or alkali nitrate, chlorate or perchlorate]... 

The acid-base properties of fused alkali nitrates were first noted when dichromate was added to fused sodium-potassium nitrate eutectic (/)/. Gaseous nitrogen dioxide and oxygen were slowly given off with the conversion of the dichromate to chromate. It was postulated that N02+ was formed as intermediate ... 

The existence of the nitryl ion in the presence of acidic substances suggested that nitrate ion in fused alkali nitrates might dissociate into N02+ and 0 2 ions (5). To determine the extent of the dissociation, it was necessary to develop an electrode potentiometrically responsive to either N02+ or 0 2. The only possibility for a reversible N02+ electrode that came to mind was nitrogen dioxide gas bubbling over platinum. This electrode did respond to N02+ in acidic solutions, but as ex-... 

The potential of oxygen over platinum responded nicely to changes in oxygen pressure according to the Nernst expression (5). The reference electrode was silver immersed in 0 1M silver nitrate in the fused alkali nitrates, the mixture being contained in a thin glass envelope. To test the effect of changes in oxide ion concentration on the potential, a source of pure alkali oxide was needed. It is also ulti-... 

The basicities of Br03, C103 and I03 " (6) were studied next. It was first determined that Br03 and I03 " were considerably more basic than nitrate ion. Thus, these halates were studied in fused alkali nitrate solutions. The reactions studied were ... 

Figure C. Polarograms for a nitrate alkali nitrate melt containing traces of water...

The preparation of alkali carbonate from alkali nitrate.—The sodium nitrate required for the manufacture of nitric acid, and for the sulphuric acid chambers is converted into nitre-cake—sodium acid sulphate, and is utilized as salt-cake in making alkali. Many of the proposals for converting sodium nitrate into the carbonate, really aim at getting the alkali as a by-product in the manufacture of... 

According to W. C. Rontgen and J. Schneider,21 the mol. compressibility of soln. of the alkali nitrates with a molecule of the salt per 700 and 1500 mols. of water is ... 

---