Sodium nitrate - Wikipedia
Sodium nitrate - Wikipedia
Soda niter
cubic niter Identifiers
- -99-4 Y
- ChEMBL N
- Y
- 231-554-3
- WC
- 8M4L3H2ZVZ Y
- InChI=1S/NO3.Na/c2-1(3)4;/q-1;+1 YKey: VWDWKYIASSYTQR-UHFFFAOYSA-N Y
- InChI=1/NO3.Na/c2-1(3)4;/q-1;+1Key: VWDWKYIASSYTQR-UHFFFAOYAL
- [Na+].[O-][N+]([O-])=O
91.2 g/100 g water (25 °C)[1][2]
180 g/100 g water (100 °C) Solubility very soluble in ammonia, hydrazine
soluble in alcohol
slightly soluble in pyridine
insoluble in acetone Magnetic susceptibility (χ) −25.6·10−6 cm3/mol Refractive index (nD) 1.587 (trigonal)
1.336 (rhombohedral) Viscosity 2.85 cP (317 °C) Structure trigonal and rhombohedral Thermochemistry Heat capacity (C) 93.05 J/(mol K) Std molar
entropy (S⦵298) 116 J/(mol K)[3] Std enthalpy of
formation (ΔfH⦵298) −467 kJ/mol[3] Gibbs free energy (ΔfG⦵) −365.9 kJ/mol Hazards Occupational safety and health (OHS/OSH): Main hazards Harmful (Xn)
Oxidant (O) GHS labelling: NFPA 704 (fire diamond) Flash point Non-flammable Lethal dose or concentration (LD, LC): LD50 (median dose) mg/kg Safety data sheet (SDS) ICSC Related compounds Other anions Sodium nitrite Other cations Lithium nitrate
Potassium nitrate
Rubidium nitrate
Caesium nitrate Related compounds Sodium sulfate
Sodium chloride Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N (what is YN ?) Chemical compound
Sodium nitrate is the chemical compound with the formula NaNO3. This alkali metal nitrate salt is also known as Chile saltpeter (large deposits of which were historically mined in Chile)[4][5] to distinguish it from ordinary saltpeter, potassium nitrate. The mineral form is also known as nitratine, nitratite or soda niter.
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Sodium nitrate is a white deliquescent solid very soluble in water. It is a readily available source of the nitrate anion (NO3−), which is useful in several reactions carried out on industrial scales for the production of fertilizers, pyrotechnics, smoke bombs and other explosives, glass and pottery enamels, food preservatives (esp. meats), and solid rocket propellant. It has been mined extensively for these purposes.
History
[edit]The first shipment of saltpeter to Europe arrived in England from Peru in or , right after that country's independence from Spain, but did not find any buyers and was dumped at sea in order to avoid customs toll.[6][7] With time, however, the mining of South American saltpeter became a profitable business (in , England alone consumed 47,000 metric tons).[7] Chile fought the War of the Pacific (–) against the allies Peru and Bolivia and took over their richest deposits of saltpeter. In , Ralph Walter Graystone Wyckoff determined its crystal structure using X-ray crystallography.
Occurrence
[edit]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.[8] Nitrates accumulate on land through marine-fog precipitation and sea-spray oxidation/desiccation followed by gravitational settling of airborne NaNO3, KNO3, NaCl, Na2SO4, and I, in the hot-dry desert atmosphere.[9] El Niño/La Niña extreme aridity/torrential rain cycles favor nitrates accumulation through both aridity and water solution/remobilization/transportation onto slopes and into basins; capillary solution movement forms layers of nitrates; pure nitrate forms rare veins. 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 s, 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 Valdivia, María Elena and Pampa Blanca, and there it used to be called white gold.[4][5] 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 .
Synthesis
[edit]Sodium nitrate is also synthesized industrially by neutralizing nitric acid with sodium carbonate or sodium bicarbonate:
- 2 HNO3 + Na2CO3 → 2 NaNO3 + H2O + CO2
- HNO3 + NaHCO3 → NaNO3 + H2O + CO2
or also by neutralizing it with sodium hydroxide (however, this reaction is very exothermic):
- HNO3 + NaOH → NaNO3 + H2O
or by mixing stoichiometric amounts of ammonium nitrate and sodium hydroxide, sodium bicarbonate or sodium carbonate:
- NH4NO3 + NaOH → NaNO3 + NH4OH
- NH4NO3 + NaHCO3 → NaNO3 + NH4HCO3
- 2NH4NO3 + Na2CO3 → 2NaNO3 + (NH4)2CO3
Uses
[edit]Most sodium nitrate is used in fertilizers, where it supplies a water-soluble form of nitrogen. Its use, which is mainly outside of high-income countries, is attractive since it does not alter the pH of the soil. Another major use is as a complement to ammonium nitrate in explosives. Molten sodium nitrate and its solutions with potassium nitrate have good thermal stability (up to 600 °C) and high heat capacities. These properties are suitable for thermally annealing metals and for storing thermal energy in solar applications.[10]
Food
[edit]Sodium nitrate is also a food additive used as a preservative and color 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,[11] US[12] and Australia and New Zealand.[13] Sodium nitrate should not be confused with sodium nitrite, which is also a common food additive and preservative used, for example, in deli meats.
Thermal storage
[edit]Sodium nitrate has also been investigated as a phase-change material for thermal energy recovery, owing to its relatively high melting enthalpy of 178 J/g.[14][15] Examples of the applications of sodium nitrate used for thermal energy storage include solar thermal power technologies and direct steam generating parabolic troughs.[14]
Steel coating
[edit] Main article: Black oxideSodium nitrate is used in a steel coating process in which it forms a surface of magnetite layer.[16]
Health concerns
[edit]Studies have shown a link between increased levels of nitrates and increased deaths from certain diseases including Alzheimer's disease, diabetes mellitus, stomach cancer, and Parkinson's disease: possibly through the damaging effect of nitrosamines on DNA; however, little has been done to control for other possible causes in the epidemiological results.[17] Nitrosamines, formed in cured meats containing sodium nitrate and nitrite, have been linked to gastric cancer and esophageal cancer.[18] Sodium nitrate and nitrite are associated with a higher risk of colorectal cancer.[19]
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Substantial evidence in recent decades, facilitated by an increased understanding of pathological processes and science, exists in support of the theory that processed meat increases the risk of colon cancer and that this is due to the nitrate content. 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 carcinogenic NOCs (nitroso compounds). NOCs can be formed either when meat is cured or in the body as meat is digested.[20]
However, several things complicate the otherwise straightforward understanding that "nitrates in food raise the risk of cancer". Processed meats have no fiber, vitamins, or phytochemical antioxidants[citation needed], are high in sodium, may contain high fat, and are often fried or cooked at a temperature sufficient to degrade protein into nitrosamines. Nitrates are key intermediates and effectors in the primary vasculature signaling which is necessary for all mammals to survive.[21]
See also
[edit]- Sodium nitrite
References
[edit]Further reading
[edit]- Archer, Donald G. (). "Thermodynamic properties of the NaNO3 + H2O system". Journal of Physical and Chemical Reference Data. 29 (5): –. Bibcode:JPCRD..29.A. doi:10./1.. ISSN -.
- Barnum, Dennis (). "Some history of nitrates". Journal of Chemical Education. 80 (12): –. Bibcode:JChEd..80.B. doi:10./ed080p.
- Jones, Grinnell (). "Nitrogen: Its Fixation, Its Uses in Peace and War". The Quarterly Journal of Economics. 34 (3): 391–431.
- Mullin, J. W. (). Crystallization. Butterworth-Heinemann. ISBN 978-0---6.
What's the deal with Nitrates and Nitrites used in meat products?
What are Nitrates and Nitrites?
Nitrates and nitrites are short names for “sodium nitrate” and “sodium nitrite” which are forms of salt. Salt (sodium chloride) has been used for thousands of years to preserve meat well before the discovery of refrigeration. Several centuries ago, nitrate and nitrite salts were found in salt by accident and it was soon realized these closely related ingredients helped extend the shelf life (aka. preserve) of meat by preventing rancidity and by also controlling the growth of bacteria. Today, purified nitrate and nitrite are commercially manufactured for many uses from fertilizer to a variety of foods such as cured meats and toothpaste. With a vast amount of research focused to learn more about these two unique salts, several discoveries were made:
- Nitrite salt is responsible for very effectively improving meat quality and safety;
- Nitrate salt is inert and must be first converted by bacteria to the form nitrite before it can be helpful for meat quality and safety;
- When added to meat at the allowed levels set forth by USDA, nitrite completely inhibits Clostridium botulinum growth, almost completely inhibits Clostridium perfringens, and slows the growth of many other pathogenic bacteria such as Listeria monocytogenes;
- Because biological reactions happen when added to meat products, nitrates and nitrites are classified as curing ingredients by USDA;
- Because nitrate and nitrite slow almost all bacteria that cause food spoilage and sickness, they are classified as preservatives by USDA.
Dietary Sources of Nitrates and Nitrites?
Much confusion has existed about where our oral intake of nitrate and nitrite actually comes from. There are three main sources of dietary nitrate and nitrite:
- Most of the nitrate and nitrite we consume is from the nitrate present in leafy vegetables. Nearly all vegetables contain nitrates (ranging from 0.001 to 1.0%) which accumulates in the plant from the uptake of nitrogen in the soil during the growing period. When consumed, a portion of the nitrate from vegetables is converted to nitrite by the bacteria found in our mouth. Other nitrate is swallowed and stored in our body until it is needed. Nearly 80% of the nitrate we consume is from vegetables.
- Most water contains a very small amount of nitrate and nitrite and depending on the amount you drink, it can be a major source (much more than from processed meats).
- Cured meat products also serve as a small source (~5% of our total intake) of nitrate and nitrite. Nearly all (~90%) of nitrate and nitrite added to cured meats is broken down and converted to other safe compounds. Levels of nitrate and nitrite present in cured meats at the time of store purchase are usually between 0. and 0.004%.
Is it Safe to Consume Nitrate and Nitrite?
What we know about nitrate and nitrite:
- Both nitrate and nitrite are substances approved by FDA and USDA for use in foods.
- Levels of nitrate and nitrite used in meat products are carefully controlled by Federal laws and monitored by the USDA or state government officials.
- Pure nitrite, if consumed at levels of ~3-5 grams (equivalent to 6,000-10,000 servings of cured meat eaten at one sitting), can be very dangerous and even cause death because it binds to oxygen in your body stronger than the hemoglobinoxygen binding in your blood thus not allowing oxygen to reach several important organs.
- Decades of research have shown when nitrate and nitrite are carefully used following prescribed levels regulated by the USDA, these ingredients are completely safe and pose no human health risks whatsoever.
- Extensive and universally accepted academic research has shown, if careful control of use is not followed, a slight human health risk could exist. For example, if high levels of nitrite exist in foods that are high in protein and are exposed to high temperature (>300°F) cooking, such as bacon frying, very small amounts (parts per billion) of nitrosamines (compounds classified as a carcinogen) could be formed. As a result, bacon curing is carefully controlled (a lower level of nitrite is required, an ingredient (Vitamin C) is added to further reduce any remaining nitrite after product manufacture, and nitrate addition is prohibited so a potential source of additional nitrite isn’t available for nitrosamine reactions).
- Recent medical research has shown nitrite is critical for maintaining human health by controlling blood pressure, preventing memory loss, and accelerating wound healing. Medical research has also shown that both nitrite and nitrate are continuously being synthesized in our bodies from the amino acid arginine to meet the physiological demands are body needs to maintain homeostasis (good health). This means our bodies actually make our own nitrate and nitrite!
What about Meat Products without Nitrates or Nitrites?
An overabundance of retail meat product options exist in supermarkets today. “Traditional”, “Natural”, and “Organic” are three labeling categories of meat products commonly found yet can provide quite a bit of confusion.
Traditional meat products are those that follow normal labeling standards for any given product classification and description outlined by prescribed labeling requirements published by USDA. Many traditional meat products are required to contain curing ingredients (nitrate and/or nitrite) with strict usage requirements (eg. bacon) or to meet consumer expectations (eg. hams, hot dogs, etc.). Some products are not required in include curing ingredients at all but instead are added by the manufacture by choice (eg. turkey breast). USDA regulations explain when nitrate/nitrite is required, allowed, or prohibited.
Uncured meat products are those that do not contain nitrate or nitrite. Within this category, you can find meat products in stores with the word “uncured” printed on the product label. This describes products traditionally required or expected to contain curing ingredients but allowed to be made without nitrate and nitrite as long as the word “uncured” is added to the package label.
Natural meat products are those manufactured under stricter rules than traditional products which require minimal processing and also do not allow any added artificial coloring, flavoring, or preservatives. Because nitrate and nitrite used for traditional products are made by purification, they are not allowed.
Organic meat products must follow standards established by the National Organic Program and governed by the USDA Organic Foods Production Act regarding practices and substances that may be used for production, processing, and handling of organic foods. Both purified nitrate and nitrite are listed as prohibited ingredients and as such may not be used.
What are “Natural” Nitrates and Nitrites?
Because nitrates and nitrites are considered so important for safety, quality, and health by so many people (the government, scientists, manufactures, and many others), natural sources of these ingredients have been explored, identified, and successfully used to replace purified nitrate and nitrite. Vegetables high in naturally accumulating nitrate and nitrite (such as celery) are now commonly used to cure meat products with a natural, plant-based source for curing. Interesting, there is no difference between purified or plant based nitrate or nitrite. They are the exact same molecules…just from a different source.
Unfortunately, because USDA labeling rules do not yet exist for products cured using plant-based nitrate and nitrite, they are required to be labeled “uncured”. As one would expect, it can be quite confusing to find some products that are labeled “uncured” yet having cured properties such as a pink color. Updated labeling is being planned by USDA to clarify this unfortunate confusion. How can you tell if a meat product is cured using a purified or a natural source? If cured with a purified source, you will seed the words “sodium nitrite” on the label. If cured with a natural source, you will see the words “celery powder” or other similar vegetable ingredients on the label instead.
Contact us to discuss your requirements of Sodium Nitrate Powder(fr,ko,rm). Our experienced sales team can help you identify the options that best suit your needs.
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