Ammonium sulfate (American English and international scientific usage; ammonium sulphate in British English); (NH4)2SO4, is an inorganic salt with a number of commercial uses. The most common use is as a soil fertilizer. It contains 21% nitrogen and 24% sulfur.

Uses

Agriculture

The primary use of ammonium sulfate is as a fertilizer for alkaline soils. In the soil, the ammonium ion is released and forms a small amount of acid, lowering the pH balance of the soil, while contributing essential nitrogen for plant growth. One disadvantage to the use of ammonium sulfate is its low nitrogen content relative to ammonium nitrate, which elevates transportation costs.[2]

It is also used as an agricultural spray adjuvant for water-soluble insecticides, herbicides, and fungicides. There, it functions to bind iron and calcium cations that are present in both well water and plant cells. It is particularly effective as an adjuvant for 2,4-D (amine), glyphosate, and glufosinate herbicides.

Laboratory use

Ammonium sulfate precipitation is a common method for protein purification by precipitation. As the ionic strength of a solution increases, the solubility of proteins in that solution decreases. Being extremely soluble in water, ammonium sulfate can "salt out" (precipitate) proteins from aqueous solutions.[3][4] Precipitation by ammonium sulfate is a result of a reduction in solubility rather than protein denaturation, thus the precipitated protein can be resolubilized through the use of standard buffers.[5] Ammonium sulfate precipitation provides a convenient and simple means to fractionate complex protein mixtures.[6]

In the analysis of rubber lattices, volatile fatty acids are analyzed by precipitating rubber with a 35% ammonium sulfate solution, which leaves a clear liquid from which volatile fatty acids are regenerated with sulfuric acid and then distilled with steam. Selective precipitation with ammonium sulfate, opposite to the usual precipitation technique which uses acetic acid, does not interfere with the determination of volatile fatty acids.[7]

Food additive

As a food additive, ammonium sulfate is considered generally recognized as safe (GRAS) by the U.S. Food and Drug Administration,[8] and in the European Union it is designated by the E number E517. It is used as an acidity regulator in flours and breads.[9][10][11]

Other uses

Ammonium sulfate is a precursor to other ammonium salts, especially ammonium persulfate.

Ammonium sulfate is listed as an ingredient for many United States vaccines per the Centers for Disease Control.[12]

Ammonium sulfate has also been used in flame retardant compositions acting much like diammonium phosphate. As a flame retardant, it increases the combustion temperature of the material, decreases maximum weight loss rates, and causes an increase in the production of residue or char.[13]

Preparation

Ammonium sulfate is made by treating ammonia with sulfuric acid:

2 NH3 + H2SO4 → (NH4)2SO4

A mixture of ammonia gas and water vapor is introduced into a reactor that contains a saturated solution of ammonium sulfate and about 2% to 4% of free sulfuric acid at 60 °C. Concentrated sulfuric acid is added to keep the solution acidic, and to retain its level of free acid. The heat of reaction keeps reactor temperature at 60 °C. Dry, powdered ammonium sulfate may be formed by spraying sulfuric acid into a reaction chamber filled with ammonia gas. The heat of reaction evaporates all water present in the system, forming a powdery salt. Approximately 6,000 million tons were produced in 1981.[2]

Ammonium sulfate also is manufactured from gypsum (CaSO4·2H2O). Finely divided gypsum is added to an ammonium carbonate solution. Calcium carbonate precipitates as a solid, leaving ammonium sulfate in the solution.

(NH4)2CO3 + CaSO4 → (NH4)2SO4 + CaCO3

Ammonium sulfate occurs naturally as the rare mineral mascagnite in volcanic fumaroles and due to coal fires on some dumps.[14]

Ammonium sulfate is a byproduct in the production of methyl methacrylate.[15]

Properties

Ammonium sulfate becomes ferroelectric at temperatures below –49.5 °C. At room temperature it crystallises in the orthorhombic system, with cell sizes of a = 7.729 Å, b = 10.560 Å, c = 5.951 Å. When chilled into the ferrorelectric state, the symmetry of the crystal changes to space group Pna21.[16]

Reactions

Ammonium sulfate decomposes upon heating above 250 °C (482 °F), first forming ammonium bisulfate. Heating at higher temperatures results in decomposition into ammonia, nitrogen, sulfur dioxide, and water.[17]

As a salt of a strong acid (H2SO4) and weak base (NH3), its solution is acidic; the pH of 0.1 M solution is 5.5. In aqueous solution the reactions are those of NH+
4 and SO2−
4 ions. For example, addition of barium chloride, precipitates out barium sulfate. The filtrate on evaporation yields ammonium chloride.

Ammonium sulfate forms many double salts (ammonium metal sulfates) when its solution is mixed with equimolar solutions of metal sulfates and the solution is slowly evaporated. With trivalent metal ions, alums such as ferric ammonium sulfate are formed. Double metal sulfates include ammonium cobaltous sulfate, ferrous diammonium sulfate, ammonium nickel sulfate which are known as Tutton's salts and ammonium ceric sulfate.[2] Anhydrous double sulfates of ammonium also occur in the Langbeinites family. The ammonia produced has a pungent smell and is toxic.

Airborne particles of evaporated ammonium sulfate comprise approximately 30% of fine particulate pollution worldwide.[18]

It reacts with additional sulfuric acid to give triammonium hydrogen disulphate,, (NH4)3H(SO4)2.[19]

Legislation and control

In November 2009, a ban on ammonium sulfate, ammonium nitrate and calcium ammonium nitrate fertilizers was imposed in the former Malakand Division—comprising the Upper Dir, Lower Dir, Swat, Chitral and Malakand districts of the North West Frontier Province (NWFP) of Pakistan, by the NWFP government, following reports that they were used by militants to make explosives. In January 2010, these substances were also banned in Afghanistan for the same reason.[20]

See also

References

  1. ^ Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, Florida: CRC Press. ISBN 0-8493-0487-3.
  2. ^ a b c Zapp, Karl-Heinz (2012). "Ammonium Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a02_243. ISBN 9783527303854.
  3. ^ Duong-Ly, Krisna C.; Gabelli, Sandra B. (2014-01-01). "Salting out of Proteins Using Ammonium Sulfate Precipitation". In Lorsch, Jon (ed.). Methods in Enzymology. Laboratory Methods in Enzymology: Protein Part C. Vol. 541. Academic Press. pp. 85–94. doi:10.1016/B978-0-12-420119-4.00007-0. ISBN 9780124201194. PMID 24674064.
  4. ^ Duong-Ly, Krisna C.; Gabelli, Sandra B. (2014-01-01). "Salting out of Proteins Using Ammonium Sulfate Precipitation". Laboratory Methods in Enzymology: Protein Part C. Vol. 541. pp. 85–94. doi:10.1016/B978-0-12-420119-4.00007-0. ISBN 9780124201194. ISSN 1557-7988. PMID 24674064.
  5. ^ Wingfield, Paul T. (2017-05-05). "Protein Precipitation Using Ammonium Sulfate". Current Protocols in Protein Science. 13 (1): A.3F.1–8. doi:10.1002/0471140864.psa03fs13. ISBN 978-0471140863. ISSN 1934-3655. PMC 4817497. PMID 18429073.
  6. ^ "Ammonium Sulfate Calculator". EnCor Biotechnology Inc. 2013. Archived from the original on January 26, 2016. Retrieved March 2, 2013.
  7. ^ ASTM Standard Specification for Rubber Concentrates D 1076-06
  8. ^ "Select Committee on GRAS Substances (SCOGS) Opinion: Ammonium sulfate". U.S. Food and Drug Administration. August 16, 2011. Archived from the original on February 11, 2012. Retrieved March 2, 2013.
  9. ^ "Panera Bread: Menu & Nutrition: Nutrition Information Profile". Archived from the original on August 19, 2009. Retrieved March 2, 2013.
  10. ^ "Official Subway Restaurants U.S. Products Ingredients Guide". Archived from the original on August 14, 2011. Retrieved March 2, 2013.
  11. ^ Sarah Klein (May 14, 2012). "Gross Ingredients In Processed Foods". The Huffington Post. Archived from the original on May 18, 2012. Retrieved March 2, 2013.
  12. ^ "Vaccine Excipient & Media Summary" (PDF). Centers for Disease Control and Prevention (CDC). February 2012. Archived (PDF) from the original on February 5, 2011. Retrieved March 2, 2013.
  13. ^ George, C. W.; Susott, R. A. (April 1971). "Effects of Ammonium Phosphate and Sulfate on the Pyrolysis and Combustion of Cellulose". Research Paper INT-90. Intermountain Forest and Range Experiment Station: USDA Forest Service. OL 16022833M.
  14. ^ "Mascagnite". Mindat. Archived from the original on January 19, 2013. Retrieved March 2, 2013.
  15. ^ Bauer, Jr., William (2002). "Methacrylic Acid and Derivatives". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a16_441. ISBN 978-3-527-30673-2..
  16. ^ Okaya, Y.; K. Vedam; R. Pepinsky (1958). "Non-isomorphism of ferroelectric phases of ammonium sulfate and ammonium fluoberyllate". Acta Crystallographica. 11 (4): 307. Bibcode:1958AcCry..11..307O. doi:10.1107/s0365110x58000803. ISSN 0365-110X.
  17. ^ Liu Ke-wei, Chen Tian-lang (2002). "Studies on the thermal decomposition of ammonium sulfate". Chemical Research and Application (in Chinese). 14 (6). doi:10.3969/j.issn.1004-1656.2002.06.038.
  18. ^ "Where Does Air Pollution Come From?". www.purakamasks.com. 2019-02-15. Archived from the original on 2019-02-20. Retrieved 2019-02-20.
  19. ^ Suzuki, S.; Makita, Y. (1978). "The crystal structure of Triammonium hydrogen Disulphate, (NH4)3H(SO4)2". Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry. 34 (3): 732–735. Bibcode:1978AcCrB..34..732S. doi:10.1107/S0567740878003969.
  20. ^ "PAKISTAN: 'Anti-terrorist' fertilizer ban hinders farmers". IRIN Humanitarian News and Analysis. 2010. Archived from the original on May 13, 2013. Retrieved April 24, 2013.

Further reading

Allikas: https://en.wikipedia.org/wiki/E517
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