Sodium nitrate, reduction

Sodium nitrite has been synthesized by a number of chemical reactions involving the reduction of sodium nitrate [7631-99-4] NaNO. These include exposure to heat, light, and ionizing radiation (2), addition of lead metal to fused sodium nitrate at 400—450°C (2), reaction of the nitrate in the presence of sodium ferrate and nitric oxide at - 400° C (2), contacting molten sodium nitrate with hydrogen (7), and electrolytic reduction of sodium nitrate in a cell having a cation-exchange membrane, rhodium-plated titanium anode, and lead cathode (8). 

Palladium catalysts have been prepared by fusion of palladium chloride in sodium nitrate to give palladium oxide by reduction of palladium salts by alkaline formaldehyde or sodium formate, by hydrazine and by the reduction of palladium salts with hydrogen.The metal has been prepared in the form of palladium black, and in colloidal form in water containing a protective material, as well as upon supports. The supports commonly used are asbestos, barium carbonate, ... 

Because of Us high polarity and low nucleophilicity, a trifluoroacetic acid medium is usually used for the investigation of such carbocationic processes as solvolysis, protonation of alkenes, skeletal rearrangements, and hydride shifts [22-24] It also has been used for several synthetically useful reachons, such as electrophilic aromatic substitution [25], reductions [26, 27], and oxidations [28] Trifluoroacetic acid is a good medium for the nitration of aromatic compounds Nitration of benzene or toluene with sodium nitrate in trifluoroacetic acid is almost quantitative after 4 h at room temperature [25] Under these conditions, toluene gives the usual mixture of mononitrotoluenes in an o m p ratio of 61 6 2 6 35 8 A trifluoroacetic acid medium can be used for the reduction of acids, ketones, and alcohols with sodium borohydnde [26] or triethylsilane [27] Diary Iketones are smoothly reduced by sodium borohydnde in trifluoroacetic acid to diarylmethanes (equation 13)... 

Dining outgassing of scrap uranium-aluminium cermet reactor cores, powerful exotherms led to melting of 9 cores. It was found that the incident was initiated by reactions at 350°C between aluminium powder and sodium diuranate, which released enough heat to initiate subsequent exothermic reduction of ammonium uranyl hexafluoride, sodium nitrate, uranium oxide and vanadium trioxide by aluminium, leading to core melting. 

The solid is very reactive towards air, moisture or carbon dioxide, and tends to explode readily, also decomposing violently on heating. It is produced from sodium nitrate or sodium nitrite by electrolytic reduction, or action of sodium. 

Ke and Regier [71] have described a direct potentiometric determination of fluoride in seawater after extraction with 8-hydroxyquinoline. This procedure was applied to samples of seawater, fluoridated tap-water, well-water, and effluent from a phosphate reduction plant. Interfering metals, e.g., calcium, magnesium, iron, and aluminium were removed by extraction into a solution of 8-hydroxyquinoline in 2-butoxyethanol-chloroform after addition of glycine-sodium hydroxide buffer solution (pH 10.5 to 10.8). A buffer solution (sodium nitrate-l,2-diamino-cyclohexane-N,N,N. AT-tetra-acetic acid-acetic acid pH 5.5) was then added to adjust the total ionic strength and the fluoride ions were determined by means of a solid membrane fluoride-selective electrode (Orion, model 94-09). Results were in close agreement with and more reproducible than those obtained after distillation [72]. Omission of the extraction led to lower results. Four determinations can be made in one hour. 

Buchberger et al. [104] carried out a selective determination of iodide in brine. The performance of a potentiometric method using an ion-selective electrode and of liquid chromatography coupled with ultraviolet detection at 230 nm were compared as methods for the determination of iodide in the presence of other iodide species. Satisfactory results were obtained from the potentiometric method provided the solution was first diluted tenfold with 5 M sodium nitrate, and external standards were used. Better reproducibility was, however, achieved with HPLC, provided precautions were taken to prevent reduction of iodine to iodide in the mobile phase, for which extraction of iodine with carbon tetrachloride prior to analysis was recommended. This was the pre-... 

Palladium. Palladium catalysts are much like platinum, but a little more versatile. Palladium oxide is made by heating palladium chloride with sodium nitrate to fusion at 575-600°. Use palladium oxide (an equimolar amount) in the formulas already given for reducing with platinum oxide. Below is a reduction with palladium-carbon. 

Palladium catalysts resemble closely the platinum catalysts. Palladium oxide (PdO) is prepared from palladium chloride and sodium nitrate by fusion at 575-600° [29,30]. Elemental palladium is obtained by reduction of palladium chloride with sodium borohydride [27, 31], Supported palladium catalysts are prepared with the contents of 5% or 10% of palladium on charcoal, calcium carbonate and barium sulfate [32], Sometimes a special support can increase the selectivity of palladium. Palladium on strontium carbonate (2%) was successfully used for reduction of just y, (5-double bond in a system of oc, / , y, (5-unsaturated ketone [ii]. 

Elemental composition Na 27.08%, N 16.48%, 0 56.47%. An aqueous solution of the salt is analyzed for sodium by various instrumental techniques (See Sodium). Nitrate ion in solution can readily be measured by ion chromatography, nitrate-ion selective electrode, or various colorimetric methods, such as its reduction with cadmium to nitrite followed by diazotization. 

Support an hemispherical iron dish of 10 cm. diameter (or an iron crucible) on a ring stand and place in it about 75 g. of sodium nitrate. Heat the nitrate until it melts and just begins to evolve bubbles of oxygen. While maintaining a steady temperature, drop in pieces of granulated lead or chopped-up lead pipe, stirring well with an iron rod (old round file) after each addition. A little more than the equivalent of lead should be added, since some of it will be oxidized by the air. For this reason, a flat iron sand-bath dish is not suitable for the experiment. The reduction of the nitrate is rapid, and if much lead is added at a time, the mass may become incandescent. 

Silver nitrate in ammoniacal solution may be completely reduced to silver by aqueous arsenious oxide. The reduction is hindered by the presence of ammonium sulphate, owing to the decrease in concentration of the hydroxyl ions 5 neutral salts such as sodium sulphate or sodium nitrate have no effect. Similarly, auric chloride may be reduced to gold.6 At 20° C. an aqueous solution of vitreous arsenious oxide reacts 4 to 5 times as rapidly as an aqueous solution of the octahedral form 7 the greater rate of dissolution in water of the former variety has been mentioned (p. 137), but from supersaturated solutions of the two forms there is no appreciable difference in the rates of deposition. The explanation of the inferior reducing power of the crystalline variety may be that there exist anisotropic molecules which only slowly lose their anisotropic properties. An ammoniacal solution of arsenious oxide heated with cupric sulphate in a sealed tube at 100° C. causes reduction... 

Sodium hypnnitrite Na N 0 is formed (I) by reaction of sodium nitrate or nitrite solution with sodium amalgam (sodium dissolved in incrcuryl, alter which acetic acid is added to neutralize the alkali. Sodium stannite ferrous hydroxide, or electrolytic reduction w ith mercury cathode may also be utilized. (2) by reaclion of hydroxylamine sulfonic acid and sodium hydroxide. Silver hyponitrite is formed by reaclion of silver nitrate solution and sodium hyponitrite. 

Dienes can afford either mono- or di-mercurated products (equations 242 and 243).385-389-391 Mer-cury(II) trifluoroacetate or mercury(II) nitrate are the reagents of choice for this latter reaction. Alkaline sodium borohydride reduction is often accompanied here by formation of unsaturated alcohols. 

Experiments with sodium nitrate showed rapid reduction by Fe°, with nitrite as an intermediate and ammonia as final product. Iron acts as an electron donor and the reduction is coupled with metal corrosion (Equation 13.9). The reduction reaction in the model system was found to proceed in two sequential steps (Equation 13.30 and Equation 13.31), and the overall... 

The reduction of nitrate to nitrite can be accomplished satisfactorily, and the process is the subject of a recent patent.1 It has been shown (Mtlller and Weber)2 that in a divided cell, smooth platinum or copper cathodes reduce nitrate to nitrite and ammonia, but platinised platinum gives much ammonia and little nitrite. A spongy copper or silver cathode was found to give the best results. With a current density of 0 25 amps, per dm.2 and a concentration of 2 3 grams of sodium nitrate per litre, a current efficiency of 90 per cent, was obtained. The current efficiency with an amalgamated copper cathode was found to diminish when 50 per cent, of the nitrate had been changed. Considerable care is evidently needed to prevent the formation of ammonia, since it has been shown by W. H. Easton 3... 

C. i1. Burgess1 and C. Hambuechen, in 1903, investigated the various conditions requisite for the electrolytic production of a good white lead. They found that a two-compart-ment cell is necessary to obtain a pure product. When lead anodes and sodium nitrate solution are employed a certain quantity of basic lead salt is produced, and there is not therefore a 100 per cent, formation of pure lead nitrate. The reduction of sodium nitrate at copper cathodes cannot be prevented so that a certain amount of ammonia is formed, and the solution being alkaline after a time, plumbates are formed and a layer of spongy lead is deposited on the cathode. If, therefore, the cathode compartment be not separated from the anode, the loosely-deposited cathodic lead will fall into the white lead which is collecting at the bottom of the cell. 

---