Nitrate sodium

Sodium nitrate nitrate [7631-99-4] NaNO, is found in naturally occurring deposits associated with sodium chloride, sodium sulfate, potassium chloride, potassium nitrate, magnesium chloride, and other salts. Accumulations of sodium nitrate have been reported in several countries, but the only ones being commercially exploited are the unique nitrate-rich deposits in Chile, South America. Natural sodium nitrate is also referred to as Chilean saltpeter or Chilean nitrate. 

The armual world production of sodium nitrate was steady throughout the early 1990s. About 85% is suppHed by the natural product. The maximum world production of sodium nitrate occurred around 1930, at 3,000,000 t/yr, but the highest production levels attained by the Chilean nitrate industry (ca 2,900,000 t/yr) occurred in the late 1920s. Synthetic sodium nitrate production peaked in the mid-1930s at 730,000 t/yr. During that period, the Chilean industry production decreased to 1,360,000 t/yr. 

Sodium nitrate is used as a fertiliser and in a number of industrial processes. In the period from 1880—1910 it accounted for 60% of the world fertiliser nitrogen production. In the 1990s sodium nitrate accounts for 0.1% of the world fertiliser nitrogen production, and is used for some specific crops and soil conditions. This decline has resulted from an enormous growth in fertiliser manufacture and an increased use of less expensive nitrogen fertilisers (qv) produced from synthetic ammonia (qv), such as urea (qv), ammonium nitrate, ammonium phosphates, ammonium sulfate, and ammonia itself (see Ammonium compounds). The commercial production of synthetic ammonia began in 1921, soon after the end of World War I. The main industrial market for sodium nitrate was at first the manufacture of nitric acid (qv) and explosives (see Explosives and propellants). As of the mid-1990s sodium nitrate was used in the production of some explosives and in a number of industrial areas. 

The Chilean nitrate deposits are located in the north of Chile, in a plateau between the coastal range and the Andes mountains, in the Atacama desert. These deposits are scattered across an area extending some 700 km in length, and ranging in width from a few kilometers to about 50 km. Most deposits are in areas of low rehef, about 1200 m above sea level. The nitrate ore, caUche, is a conglomerate of insoluble and barren material such as breccia, sands, and clays (qv), firmly cemented by soluble oxidized salts that are predominandy sulfates, nitrates, and chlorides of sodium, potassium, and magnesium. Cahche also contains significant quantities of borates, chromates, chlorates, perchlorates, and iodates. 

The nitrate deposits are made up of several layers (Fig. 1). The ore bodies are very heterogeneous and variable in size, thickness, composition, and hardness. The overburden may include chuca a layer of unconsoHdated sand, silt, and clay, andpanqueque a layer of semiconsoHdated and porous material poody cemented by salts over poody cemented gravel. The ore composition has degraded considerably since the eady days of the industry, when it was reported that ores of up to 50% sodium nitrate were mined. There are stiU reserves that can be commercially mined well into the twenty-first century (1). 

Numerous theories exist as to how the Chilean deposits formed and survived. It has been postulated that the unique nitrate-rich caliche deposits of northern Chile owe diein existence to an environment favorable to accumulation and preservation of the deposits, rather than to any unusual source of the saline materials (2). The essential conditions are an extremely arid climate similar to that of the Atacama desert in the 1990s, slow accumulation during the late Tertiary and Quaternary periods, and a paucity of nitrate-utilizing plants and soil microorganisms. 

Huge deposits of sodium nitrate (NaNOs) were discovered in 1821 by Mariano Eduardo de Rivero, a Spanish (Peruvian) naturalist and chemist, in the coastal province of Tarapaca. Subsequent exploration showed that these deposits exist in widely dispersed nitrate beds (salitreras) extending for more than 700 km from about 18°30 S in Pampa de Tarapaca to 27° S in Pampa de Tactal (fig. 3.2). This whole territory is an extremely arid plateau (rain once in 3-4, or even 8-10, years) situated between the western slopes of the high Cordillera de Los Andes and the Pacific Coastal Range at altitudes of between 1 and 4 km above the sea level, and at distances of about 

Major areas of nitrate deposits (marked in black) in northern Chile. 

25 to 150 km from the Pacific. The crude mineral, caliche, is a conglomerate of insoluble material cemented by soluble oxidized salts, including nitrates, sulfates, and chlorides of sodium, calcium, potassium, and magnesinm as well as borates and iodates. 

Earlier explanations of these huge nitrate accumulations ranged from decay of aquatic plants in inland arms of the Pacific to nitrification and leaching of seabird gnano at the margins of saline lakes. In reality, the deposits were laid down not becanse of any exceptional source of mineral compounds bnt becanse the extraordi- 

These ancient evaporites are typically made up of several distinct layers thin, powdery chuca (10-30 cm of silt, sand, and small rocks) on the surface, moderately to firmly cemented costra (0.5-2 m of either hard or brittle material), and then the caliche, 1-3 m of firmly cemented nitrate underlaid by coba, an uncemented regolith (fig. 3.3). Veins and layers of very pure nitrate are common in some areas, rare in others. Nitrogen content of these deposits varied widely nitrate accounted for as little as 6.5% of the extracted mass in the poorest caliche, and as much as 70% in some salitreras of Tarapaca. Typical share of NaNOs in the exploited deposits was initially 40-50%, but by the beginning of the twentieth century it fell to below 

Data reported for the protolysis constant of water in sodium nitrate media are listed in Table 5.28. There are only a few data reported for the protolysis constant of water in sodium nitrate media. The ion interaction coefficient data determined 

Robinson and Stokes (1959) listed osmotic coefficient data for sodium nitrate solutions. Water activity data were derived from these data using Eq. (5.18). The dependence of the water activity data on the ionic strength in sodium nitrate solutions can be described using Eq. (5.19), and the values derived for and 2 are 0.03034 0.00016 X 10 and -0.75 0.03 X 10 kgmol , respectively. 

The oxygen evolved acts as an oxidizer when fuel components are present, producing high-temperature combustion products. 

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Adams catalyst, platinum oxide, Pt02 H20. Produced by fusion of H2PtCl6 with sodium nitrate at 500-550 C and leaching of the cooled melt with water. Stable in air, activated by hydrogen. Used as a hydrogenation catalyst for converting alkenes to alkanes at low pressure and temperature. Often used on Si02... 

Steam is by far the most widely used medium, useful up to about 475 K. Up to about 700 K organic liquids such as the dowtherms and mineral oil may be used. Mercury and molten salts, such as the eutectic mixture of sodium nitrite, sodium nitrate and potassium nitrate may be used up to 875 K, while above this temperature air and flue gases must be used. 

Most iodine produced commercially comes from the sodium iodate(V) remaining after sodium nitrate has been crystallised from Chile saltpetre. The iodatefV) is first reduced to iodide by blowing sulphur dioxide into the solution (or by addition of sodium sulphite) ... 

Method 1. From ammonium chloroplatinate. Place 3 0 g. of ammonium chloroplatinate and 30 g. of A.R. sodium nitrate (1) in Pyrex beaker or porcelain casserole and heat gently at first until the rapid evolution of gas slackens, and then more strongly until a temperature of about 300° is reached. This operation occupies about 15 minutes, and there is no spattering. Maintain the fluid mass at 500-530° for 30 minutes, and allow the mixture to cool. Treat the sohd mass with 50 ml. of water. The brown precipitate of platinum oxide (PtOj.HjO) settles to the bottom. Wash it once or twice by decantation, filter througha hardened filter paper on a Gooch crucible, and wash on the filter until practically free from nitrates. Stop the washing process immediately the precipitate tends to become colloidal (2) traces of sodium nitrate do not affect the efficiency of the catalyst. Dry the oxide in a desiccator, and weigh out portions of the dried material as required. 

Method 2. From chloroplatinic acid. Dissolve 3 - 5 g. of the purest commercial chloroplatinic acid (3) in 10 ml. of water contained in a 250 ml. P3rrex beaker or porcelain casserole, and add 35 g. of A.R. sodium nitrate (1), Evaporate the mixture to dryness by heating gently over a Bunsen flame whilst stirring with a glass rod. Then raise the temperature... 

Cautiously add 250 g. (136 ml.) of concentrated sulphuric acid in a thin stream and with stirring to 400 ml. of water contained in a 1 litre bolt-head or three-necked flask, and then dissolve 150 g. of sodium nitrate in the diluted acid. Cool in a bath of ice or iced water. Melt 94 g. of phenol with 20 ml. of water, and add this from a separatory funnel to the stirred mixture in the flask at such a rate that the temperature does not rise above 20°. Continue the stirring for a further 2 hours after all the phenol has been added. Pour oflF the mother liquid from the resinous mixture of nitro compounds. Melt the residue with 500 ml. of water, shake and allow the contents of the flask to settle. Pour oflF the wash liquor and repeat the washing at least two or three times to ensure the complete removal of any residual acid. Steam distil the mixture (Fig. II, 40, 1 or Fig. II, 41, 1) until no more o-nitrophenol passes over if the latter tends to solidify in the condenser, turn oflF the cooling water temporarily. Collect the distillate in cold water, filter at the pump, and drain thoroughly. Dry upon filter paper in the air. The yield of o-nitrophenol, m.p. 46° (1), is 50 g. 

In a 500 ml. three-necked flask, equipped with a thermometer, mechanical stirrer and efficient reflux condenser, dissolve 16 g. of sodium hydroxide pellets in 95 ml. of hot methyl alcohol. Add 49 g. of guanidine nitrate, stir the mixture at 50-65° for 15 minutes, and then cool to about 20°. Filter oflF the separated sodium nitrate and wash with two 12 ml. portions of methyl alcohol. Return the combined filtrates to the clean reaction flask, add 69 g. of sulphanilamide (Section IX,9) and stir at 50-55° for 15 minutes. Detach the reflux condenser and, with the aid of a still-head ( knee-tube ), arrange the apparatus for distillation from an oil bath with stirring about 100 ml. of methyl alcohol are recovered. Add 12 g. of pure cycZohexanol. Raise the temperature of the oil bath to 180-190° and continue the distillation. Reaction commences with the evolution of ammonia when the uiternal temperature reaches 145°. Maintain the... 

Sodium nitrate (NaN03) and potassium nitrate (KNO3) are formed by the... 

Certain features of the addition of acetyl nitrate to olefins in acetic anhydride may be relevant to the mechanism of aromatic nitration by this reagent. The rapid reaction results in predominantly cw-addition to yield a mixture of the y -nitro-acetate and y5-nitro-nitrate. The reaction was facilitated by the addition of sulphuric acid, in which case the 3rield of / -nitro-nitrate was reduced, whereas the addition of sodium nitrate favoured the formation of this compound over that of the acetate. As already mentioned ( 5.3. i), a solution of nitric acid (c. i 6 mol 1 ) in acetic anhydride prepared at — 10 °C would yield 95-97 % of the nitric acid by precipitation with urea, whereas from a similar solution prepared at 20-25 °C and cooled rapidly to —10 °C only 30% of the acid could be recovered. The difference between these values was attributed to the formation of acetyl nitrate. A solution prepared at room... 

The effects of added species. The rate of nitration of benzene, according to a rate law kinetically of the first order in the concentration of aromatic, was reduced by sodium nitrate, a concentration of io mol 1 of the latter retarding nitration by a factor of about Lithium nitrate... 

Expts. 16, //. Pure nitric acid was used. In expt. 16 the reaction was of the first order in the concentration of the aromatic, and of half-life 1-1-5 minutes (similar to that of toluene under the same conditions). In expt. 17 the sodium nitrate slowed the reaction (half-life c. 60 min). About 2 % of an acetoxylated product was formed (table 5-4). 

Potassium (or sodium) nitrate (saturated 376.5 For neutral and basic aqueous solutions ... 

Sodium hypobromite dissolve 100 g of NaOH in 250 mL of water and add 25 mL of bromine. Sodium nitrate, NaN03—Q.5N 43 g per liter. 

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