Sodium nitrate


Sodium nitrate
Sodium nitrate
Identifiers
CAS number 7631-99-4 YesY
PubChem 24268
ChemSpider 22688 YesY
UNII 8M4L3H2ZVZ YesY
UN number 1498
ChEMBL CHEMBL1644698 N
RTECS number WC5600000
Jmol-3D images Image 1
Properties
Molecular formula NaNO3
Molar mass 84.9947 g/mol
Appearance White powder or colorless crystals with sweet smell
Density 2.257 g/cm3, solid
Melting point

308 °C

Boiling point

380 °C decomp.

Solubility in water 730 g/L (0°C)
921 g/L (25 °C)
1800 g/L (100 °C)
Solubility very soluble in ammonia; soluble in alcohol
Refractive index (nD) 1.587 (trigonal)
1.336 (rhomobohedral)
Structure
Crystal structure trigonal and rhombohedral
Thermochemistry
Std enthalpy of
formation
ΔfHo298
−468 kJ/mol
Standard molar
entropy
So298
117 J·mol−1 K−1
Hazards
MSDS ICSC 0185
EU Index Not listed
Main hazards Oxidant, irritant
NFPA 704
NFPA 704.svg
0
1
0
OX
Flash point Non-flammable
LD50 3236 mg/kg
Related compounds
Other anions Sodium nitrite
Other cations Lithium nitrate
Potassium nitrate
Rubidium nitrate
Caesium nitrate
Related compounds Sodium sulfate
Sodium chloride
 N nitrate (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Sodium nitrate is the chemical compound with the formula NaNO3. This salt, also known as Chile saltpeter or Peru saltpeter (due to the large deposits found in each country) to distinguish it from ordinary saltpeter, potassium nitrate, is a white solid which is very soluble in water. The mineral form is also known as nitratine, nitratite or soda niter.

Sodium nitrate may be used as a constituent of fertilizers, pyrotechnics and smoke bombs, glass and pottery enamels, as a food preservative and a solid rocket propellant. It has been mined extensively for these purposes.

Contents

History

The first shipment of Chile saltpeter to Europe arrived in England in 1820 or 1825, but did not find any buyers and was dumped at sea in order to avoid customs toll.[1][2] With time, however, the mining of South American saltpeter became a profitable business (in 1859, England alone consumed 47,000 metric tons[2]). Chile fought against the allies Peru and Bolivia in the War of the Pacific 1879-1884 and took over the richest deposits. In 1919, Ralph Walter Graystone Wyckoff determined its crystal structure using X-ray crystallography.

Sources

The largest accumulations of naturally occurring sodium nitrate are found in Chile and Peru, where nitrate salts are bound within mineral deposits called caliche ore.[3] For more than a century, the world supply of the compound was mined almost exclusively from the Atacama desert in northern Chile until, at the turn of the 20th century, German chemists Fritz Haber and Carl Bosch developed a process for producing ammonia from the atmosphere on an industrial scale (see Haber process). With the onset of World War I, Germany began converting ammonia from this process into a synthetic Chilean saltpeter which was as practical as the natural compound in production of gunpowder and other munitions. By the 1940s, this conversion process resulted in a dramatic decline in demand for sodium nitrate procured from natural sources.

Chile still has the largest reserves of caliche, with active mines in such locations as Pedro de Valdivia, María Elena and Pampa Blanca, and there it used to be called white gold. Sodium nitrate, potassium nitrate, sodium sulfate and iodine are all obtained by the processing of caliche. The former Chilean saltpeter mining communities of Humberstone and Santa Laura were declared Unesco World Heritage sites in 2005.

Sodium nitrate is also synthesized industrially by neutralizing nitric acid with soda ash

2 HNO3 + Na2CO3 → 2 NaNO3 + H2O + CO2

or by mixing stoichiometric amounts of ammonium nitrate and sodium hydroxide or sodium bicarbonate.

NH4NO3 + NaOH → NaNO3 + NH4OH
NH4NO3 + NaHCO3 → NaNO3 + NH4HCO3

Applications

Sodium nitrate was used extensively as a fertilizer and a raw material for the manufacture of gunpowder in the late 19th century. It can be combined with iron hydroxide to make a resin.

Sodium nitrate should not be confused with the related compound, sodium nitrite. Sodium nitrate in the brine gives cooked corned beef its classic reddish color (without it corned beef comes out gray), and it kills botulism spores. Nitrate is actually changed to nitrite by bacterial action during processing and storage and nitrate itself has no effect on meat color.[citation needed]

It can be used in the production of nitric acid by combining it with sulfuric acid and subsequent separation through fractional distillation of the nitric acid, leaving behind a residue of sodium bisulfate. Hobbyist gold refiners use sodium nitrate to make a hybrid aqua regia that dissolves gold and other metals.

Less common applications include as an oxidizer in fireworks replacing potassium nitrate commonly found in black powder and as a component in instant cold packs.[4]

Sodium nitrate is used together with potassium nitrate and Calcium nitrate for heat storage and, more recently, for heat transfer in solar power plants.

It is also used in the wastewater industry for facultative microorganism respiration. Nitrosomonas, a genus of microorganisms, consumes nitrate in preference to oxygen, enabling it to grow more rapidly in the wastewater to be treated.

Sodium nitrate is also a food additive used as a preservative and colour fixative in cured meats and poultry; it is listed under its INS number 251 or E number E251. It is approved for use in the EU,[5] USA[6] and Australia and New Zealand.[7]

A mixture of sodium nitrate and potassium nitrate is used as energy storage material in prototype plants, such as Andasol Solar Power Station and the [Archimede project].

Health concerns

Like sodium nitrite, sodium nitrate forms nitrosamines – human carcinogens known to cause DNA damage and increased cellular degeneration. Studies have shown a link between increased levels of nitrates and increased deaths from certain diseases including Alzheimer's, diabetes mellitus and Parkinson's, possibly through the damaging effect of nitrosamines on DNA.[8] Nitrosamines, formed in cured meats containing sodium nitrate and nitrite, have been linked to gastric cancer and oesophageal cancer.[9] Sodium nitrate and nitrite are associated with a higher risk of colorectal cancer.[10] World Cancer Research Fund UK,[11] states that one of the reasons that processed meat increases the risk of colon cancer is its content of nitrate. A small amount of the nitrate added to meat as a preservative breaks down into nitrite, in addition to any nitrite that may also be added. The nitrite then reacts with protein-rich foods (such as meat) to produce N-nitroso compounds (NOCs). Some types of NOCs are known to cause cancer. NOCs can be formed either when meat is cured or in the body as meat is digested.

See also

Notes and references

  1. ^ S. H. Baekeland "Några sidor af den kemiska industrien" (1914) Svensk Kemisk Tidskrift, p. 140.
  2. ^ a b Friedrich Georg Wieck, Uppfinningarnas bok (1873, Swedish translation of Buch der Erfindungen), vol. 4, p. 473.
  3. ^ Stephen R. Bown, A Most Damnable Invention: Dynamite, Nitrates, and the Making of the Modern World, Macmillan, 2005, ISBN 0-312-32913-X, p. 157
  4. ^ Albert A. Robbins "Chemical freezing package" U.S. Patent 2,898,744, Issue date: August 1959
  5. ^ UK Food Standards Agency: "Current EU approved additives and their E Numbers". http://www.food.gov.uk/safereating/chemsafe/additivesbranch/enumberlist. Retrieved 2011-10-27. 
  6. ^ US Food and Drug Administration: "Listing of Food Additives Status Part II". http://www.fda.gov/Food/FoodIngredientsPackaging/FoodAdditives/ucm191033.htm#ftnT. Retrieved 2011-10-27. 
  7. ^ Australia New Zealand Food Standards Code"Standard 1.2.4 - Labelling of ingredients". http://www.comlaw.gov.au/Details/F2011C00827. Retrieved 2011-10-27. 
  8. ^ De La Monte, SM; Neusner, A; Chu, J; Lawton, M (2009). "Epidemilogical trends strongly suggest exposures as etiologic agents in the pathogenesis of sporadic Alzheimer's disease, diabetes mellitus, and non-alcoholic steatohepatitis". Journal of Alzheimer's disease : JAD 17 (3): 519–29. doi:10.3233/JAD-2009-1070. PMID 19363256. 
  9. ^ http://ecnis.openrepository.com/ecnis/handle/10146/25215
  10. ^ Cross, AJ; Ferrucci, LM; Risch, A; Graubard, BI; Ward, MH; Park, Y; Hollenbeck, AR; Schatzkin, A et al. (2010). "A large prospective study of meat consumption and colorectal cancer risk: An investigation of potential mechanisms underlying this association". Cancer research 70 (6): 2406–14. doi:10.1158/0008-5472.CAN-09-3929. PMC 2840051. PMID 20215514. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2840051. 
  11. ^ "Why does processed meat increase bowel cancer risk?", World Cancer Research Fund (2010) accessdate 2010-03-06

Further reading

External links


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Look at other dictionaries:

  • sodium nitrate — n. a clear, odorless, crystalline salt, NaNO3, used in manufacturing nitric acid, sodium nitrite, explosives, fertilizers, etc., and as an oxidizing agent …   English World dictionary

  • sodium nitrate — n a deliquescent crystalline salt NaNO3 used as a fertilizer and an oxidizing agent and in curing meat called also saltpeter see CHILE SALTPETER * * * a compound, NaNO3, used as a reagent, in fertilizers, and in certain industrial processes; it… …   Medical dictionary

  • sodium nitrate — natrio nitratas statusas T sritis chemija formulė NaNO₃ atitikmenys: angl. Chile niter; Chile nitrate; Chile nitre; Chile saltpeter, US; Chile saltpetre, GB; natric saltpeter, US; natric saltpetre, GB; soda nitre; sodium nitrate rus. натрий… …   Chemijos terminų aiškinamasis žodynas

  • sodium nitrate — noun (NaNO3) used especially as a fertilizer and explosive (Freq. 3) • Syn: ↑soda niter • Hypernyms: ↑nitrate • Substance Holonyms: ↑fertilizer, ↑fertiliser, ↑plant food …   Useful english dictionary

  • sodium nitrate — noun the sodium salt of nitric acid, NaNO; used as a food preservative, and as an oxidizing agent in explosives etc. Syn: caliche, E251, soda niter …   Wiktionary

  • sodium nitrate — noun Date: 1869 a deliquescent crystalline salt NaNO3 used as a fertilizer and an oxidizing agent and in curing meat …   New Collegiate Dictionary

  • sodium nitrate — Chem. a crystalline, water soluble compound, NaNO3, that occurs naturally as soda niter: used in fertilizers, explosives, and glass, and as a color fixative in processed meats. * * * …   Universalium

  • sodium nitrate — niter, white crystalline salt (used in the manufacture of gunpowder, explosives, fertilizers and for curing meats) …   English contemporary dictionary

  • sodium nitrate — noun a white powder compound used mainly in the manufacture of fertilizers. [NaNO3.] …   English new terms dictionary

  • sodium nitrate — UK / US noun [uncountable] chemistry a chemical compound used in making fertilizers and for keeping meat fresh …   English dictionary


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