Phosphoric acid (orthophosphoric acid, monophosphoric acid or phosphoric(V) acid) is a colorless, odorless phosphorus-containing solid, and inorganic compound with the chemical formulaH3PO4. It is commonly encountered as an 85% aqueous solution, which is a colourless, odourless, and non-volatile syrupy liquid. It is a major industrial chemical, being a component of many fertilizers.
The name "orthophosphoric acid" can be used to distinguish this specific acid from other "phosphoric acids", such as pyrophosphoric acid. Nevertheless, the term "phosphoric acid" often means this specific compound; and that is the current IUPAC nomenclature.
Calcium sulfate (gypsum, CaSO4) is a by-product, which is removed as phosphogypsum. The hydrogen fluoride (HF) gas is streamed into a wet (water) scrubber producing hydrofluoric acid. In both cases the phosphoric acid solution usually contains 23–33% P2O5 (32–46% H3PO4). It may be concentrated to produce commercial- or merchant-grade phosphoric acid, which contains about 54–62% P2O5 (75–85% H3PO4). Further removal of water yields superphosphoric acid with a P2O5 concentration above 70% (corresponding to nearly 100% H3PO4). The phosphoric acid from both processes may be further purified by removing compounds of arsenic and other potentially toxic impurities.
Dry process
To produce food-grade phosphoric acid, phosphate ore is first reduced with coke in an electric arc furnace, to give elemental phosphorus. Silica is also added, resulting in the production of calcium silicate slag. Elemental phosphorus is distilled out of the furnace and burned with air to produce high-purity phosphorus pentoxide, which is dissolved in water to make phosphoric acid.[18]
Acidic properties
In aqueous solution phosphoric acid behaves as a triprotic acid.
H3PO4 ⇌ H2PO−4 + H+, pKa1 = 2.14
H2PO−4 ⇌ HPO2−4 + H+, pKa2 = 7.20
HPO2−4 ⇌ PO3−4 + H+, pKa3 = 12.37
The difference between successive pKa values is sufficiently large so that salts of either monohydrogen phosphate, HPO2−4 or dihydrogen phosphate, H2PO−4, can be prepared from a solution of phosphoric acid by adjusting the pH to be mid-way between the respective pK values.
Food-grade phosphoric acid (additive E338[20]) is used to acidify foods and beverages such as various colas and jams, providing a tangy or sour taste. The phosphoric acid also serves as a preservative.[21] Soft drinks containing phosphoric acid, which would include Coca-Cola, are sometimes called phosphate sodas or phosphates. Phosphoric acid in soft drinks has the potential to cause dental erosion.[22] Phosphoric acid also has the potential to contribute to the formation of kidney stones, especially in those who have had kidney stones previously.[23]
as a pH adjuster in cosmetics and skin-care products[27]
as a sanitizing agent in the dairy, food, and brewing industries[28]
Safety
Phosphoric acid is not a strong acid. However, at moderate concentrations phosphoric acid solutions are irritating to the skin. Contact with concentrated solutions can cause severe skin burns and permanent eye damage.[29]
A link has been shown between long-term regular cola intake and osteoporosis in later middle age in women (but not men).[30]
^Christensen, J. H.; Reed, R. B. (1955). "Design and Analysis Data—Density of Aqueous Solutions of Phosphoric Acid Measurements at 25 °C". Ind. Eng. Chem. 47 (6): 1277–1280. doi:10.1021/ie50546a061.
^"CAMEO Chemicals Datasheet – Phosphoric Acid". from the original on 15 August 2019. Retrieved 15 August 2019.
^"Phosphoric acid". www.chemspider.com. from the original on 12 March 2020. Retrieved 3 March 2020.
^Brown, Earl H.; Whitt, Carlton D. (1952). "Vapor Pressure of Phosphoric Acids". Industrial & Engineering Chemistry. 44 (3): 615–618. doi:10.1021/ie50507a050.
^Seidell, Atherton; Linke, William F. (1952). Solubilities of Inorganic and Organic Compounds. Van Nostrand. from the original on 11 March 2020. Retrieved 2 June 2014.
^Edwards, O. W.; Dunn, R. L.; Hatfield, J. D. (1964). "Refractive Index of Phosphoric Acid Solutions at 25 C.". J. Chem. Eng. Data. 9 (4): 508–509. doi:10.1021/je60023a010.
^Geeson, Michael B.; Cummins, Christopher C. (2020). "Let's Make White Phosphorus Obsolete". ACS Central Science. 6 (6): 848–860. doi:10.1021/acscentsci.0c00332. PMC7318074. PMID 32607432.
^Schrödter, Klaus; Bettermann, Gerhard; Staffel, Thomas; Wahl, Friedrich; Klein, Thomas; Hofmann, Thomas (2008). "Phosphoric Acid and Phosphates". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_465.pub3.
^"Current EU approved additives and their E Numbers". Foods Standards Agency. 14 March 2012. from the original on 21 August 2013. Retrieved 22 July 2012.
^"Why is phosphoric acid used in some Coca‑Cola drinks?| Frequently Asked Questions | Coca-Cola GB". www.coca-cola.co.uk. from the original on 2 August 2021. Retrieved 31 August 2021.
^Moynihan, P. J. (23 November 2002). "Dietary advice in dental practice". British Dental Journal. 193 (10): 563–568. doi:10.1038/sj.bdj.4801628. PMID 12481178.
^Qaseem, A; Dallas, P; Forciea, MA; Starkey, M; et al. (4 November 2014). "Dietary and pharmacologic management to prevent recurrent nephrolithiasis in adults: A clinical practice guideline from the American College of Physicians". Annals of Internal Medicine. 161 (9): 659–67. doi:10.7326/M13-2908. PMID 25364887.
^Toles, C.; Rimmer, S.; Hower, J. C. (1996). "Production of activated carbons from a washington lignite using phosphoric acid activation". Carbon. 34 (11): 1419. doi:10.1016/S0008-6223(96)00093-0.
^Wet chemical etching. 25 September 2012 at the Wayback Machine umd.edu.
^Wolf, S.; R. N. Tauber (1986). Silicon processing for the VLSI era: Volume 1 – Process technology. p. 534. ISBN978-0-9616721-6-4.
^. Cosmetic ingredient dictionary. Paula's Choice. Archived from the original on 18 January 2008. Retrieved 16 November 2007.
^"STAR SAN" (PDF). Five Star Chemicals. (PDF) from the original on 8 February 2016. Retrieved 17 August 2015.
^"Phosphoric Acid, 85 wt.% SDS". Sigma-Aldrich. 5 May 2016. from the original on 18 January 2017. Retrieved 16 January 2017.
^Tucker KL, Morita K, Qiao N, Hannan MT, Cupples LA, Kiel DP (1 October 2006). "Colas, but not other carbonated beverages, are associated with low bone mineral density in older women: The Framingham Osteoporosis Study". American Journal of Clinical Nutrition. 84 (4): 936–942. doi:10.1093/ajcn/84.4.936. PMID 17023723.
Wikimedia Commons has media related to phosphoric acid.
National pollutant inventory – Phosphoric acid fact sheet
NIOSH Pocket guide to chemical hazards
January 22, 2023
phosphoric, acid, this, article, about, orthophosphoric, acid, other, acids, commonly, called, phosphoric, acid, phosphates, confused, with, phosphorous, acid, orthophosphoric, acid, monophosphoric, acid, phosphoric, acid, colorless, odorless, phosphorus, cont. This article is about orthophosphoric acid For other acids commonly called phosphoric acid see Phosphoric acids and phosphates Not to be confused with Phosphorous acid Phosphoric acid orthophosphoric acid monophosphoric acid or phosphoric V acid is a colorless odorless phosphorus containing solid and inorganic compound with the chemical formula H3PO4 It is commonly encountered as an 85 aqueous solution which is a colourless odourless and non volatile syrupy liquid It is a major industrial chemical being a component of many fertilizers Phosphoric acid NamesIUPAC name Phosphoric acidOther names Orthophosphoric acidIdentifiersCAS Number 7664 38 2 Y3D model JSmol Interactive imageChEBI CHEBI 26078 YChEMBL ChEMBL1187 YChemSpider 979 YECHA InfoCard 100 028 758EC Number 231 633 2E number E338 antioxidants KEGG D05467 YPubChem CID 1004RTECS number TB6300000UNII E4GA8884NN YUN number 1805CompTox Dashboard EPA DTXSID5024263InChI InChI 1S H3O4P c1 5 2 3 4 h H3 1 2 3 4 YKey NBIIXXVUZAFLBC UHFFFAOYSA N YInChI 1 H3O4P c1 5 2 3 4 h H3 1 2 3 4 Key NBIIXXVUZAFLBC UHFFFAOYAISMILES OP O O OPropertiesChemical formula H3PO4Molar mass 97 994 g mol 1Appearance Colorless solidOdor OdorlessDensity 1 6845 g cm3 25 C 85 1 1 834 g cm3 solid 2 Melting point 40 42 4 C 104 0 108 3 F 313 1 315 5 K 6 Boiling point 212 C 414 F 3 only water evaporates 4 Solubility in water 392 2 g 100 g 16 3 C 369 4 g 100 mL 0 5 C 446 g 100 mL 15 C 5 548 g 100 mL 20 C 6 Solubility Soluble in ethanollog P 2 15 7 Vapor pressure 0 03 mmHg 20 C 8 Conjugate base Dihydrogen phosphateMagnetic susceptibility x 43 8 10 6 cm3 mol 10 Refractive index nD 1 3420 8 8 w w aq soln 11 1 4320 85 aq soln 25 CViscosity 2 4 9 4 cP 85 aq soln 147 cP 100 StructureCrystal structure MonoclinicMolecular shape TetrahedralThermochemistry 12 Heat capacity C 145 0 J mol K Std molarentropy S 298 150 8 J mol K Std enthalpy offormation DfH 298 1271 7 kJ molGibbs free energy DfG 1123 6 kJ molHazardsGHS labelling Pictograms 13 Signal word DangerHazard statements H290 H314 13 Precautionary statements P280 P305 P351 P338 P310 13 NFPA 704 fire diamond 300Flash point Non flammableLethal dose or concentration LD LC LD50 median dose 1530 mg kg rat oral 14 NIOSH US health exposure limits PEL Permissible TWA 1 mg m3 8 REL Recommended TWA 1 mg m3 ST 3 mg m3 8 IDLH Immediate danger 1000 mg m3 8 Safety data sheet SDS ICSC 1008Related compoundsRelated phosphorus oxoacids Hypophosphorous acidPhosphorous acidPyrophosphoric acidTriphosphoric acidPeroxomonophosphoric acidPeroxodiphosphoric acidExcept where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa N verify what is Y N Infobox references The compound is an acid Removal of all three H ions gives the phosphate ion PO3 4 Removal of one or two protons gives dihydrogen phosphate ion H2PO 4 and the hydrogen phosphate ion HPO2 4 respectively Phosphoric acid forms esters called organophosphates 15 The name orthophosphoric acid can be used to distinguish this specific acid from other phosphoric acids such as pyrophosphoric acid Nevertheless the term phosphoric acid often means this specific compound and that is the current IUPAC nomenclature Contents 1 Production 1 1 Wet process 1 2 Dry process 2 Acidic properties 3 Uses 4 Safety 5 See also 6 References 7 Cited sources 8 External linksProduction EditPhosphoric acid is produced industrially by one of two routes wet processes and dry 16 Wet process Edit In the wet process a phosphate containing mineral such as calcium hydroxyapatite and fluorapatite are treated with sulfuric acid 17 Ca5 PO4 3OH 5 H2SO4 3 H3PO4 5 CaSO4 H2O Ca5 PO4 3F 5 H2SO4 3 H3PO4 5 CaSO4 HFCalcium sulfate gypsum CaSO4 is a by product which is removed as phosphogypsum The hydrogen fluoride HF gas is streamed into a wet water scrubber producing hydrofluoric acid In both cases the phosphoric acid solution usually contains 23 33 P2O5 32 46 H3PO4 It may be concentrated to produce commercial or merchant grade phosphoric acid which contains about 54 62 P2O5 75 85 H3PO4 Further removal of water yields superphosphoric acid with a P2O5 concentration above 70 corresponding to nearly 100 H3PO4 The phosphoric acid from both processes may be further purified by removing compounds of arsenic and other potentially toxic impurities Dry process Edit To produce food grade phosphoric acid phosphate ore is first reduced with coke in an electric arc furnace to give elemental phosphorus Silica is also added resulting in the production of calcium silicate slag Elemental phosphorus is distilled out of the furnace and burned with air to produce high purity phosphorus pentoxide which is dissolved in water to make phosphoric acid 18 Acidic properties EditIn aqueous solution phosphoric acid behaves as a triprotic acid H3PO4 H2PO 4 H pKa1 2 14 H2PO 4 HPO2 4 H pKa2 7 20 HPO2 4 PO3 4 H pKa3 12 37The difference between successive pKa values is sufficiently large so that salts of either monohydrogen phosphate HPO2 4 or dihydrogen phosphate H2PO 4 can be prepared from a solution of phosphoric acid by adjusting the pH to be mid way between the respective pK values Uses EditSee also Phosphorus Food additive The dominant use of phosphoric acid is for fertilizers consuming approximately 90 of production 19 Application Demand 2006 in thousands of tons Main phosphate derivativesSoaps and detergents 1836 STPPFood industry 309 STPP Na5P3O10 SHMP TSP SAPP SAlP MCP DSP Na2HPO4 H3PO4Water treatment 164 SHMP STPP TSPP MSP NaH2PO4 DSPToothpastes 68 DCP CaHPO4 IMP SMFPOther applications 287 STPP Na3P3O9 TCP APP DAP zinc phosphate Zn3 PO4 2 aluminium phosphate AlPO4 H3PO4Food grade phosphoric acid additive E338 20 is used to acidify foods and beverages such as various colas and jams providing a tangy or sour taste The phosphoric acid also serves as a preservative 21 Soft drinks containing phosphoric acid which would include Coca Cola are sometimes called phosphate sodas or phosphates Phosphoric acid in soft drinks has the potential to cause dental erosion 22 Phosphoric acid also has the potential to contribute to the formation of kidney stones especially in those who have had kidney stones previously 23 Specific applications of phosphoric acid include in anti rust treatment by phosphate conversion coating or passivation to prevent iron oxidation by means of the Parkerization process as an external standard for phosphorus 31 nuclear magnetic resonance in phosphoric acid fuel cells in activated carbon production 24 in compound semiconductor processing to etch Indium gallium arsenide selectively with respect to indium phosphide 25 in microfabrication to etch silicon nitride selectively with respect to silicon dioxide 26 in microfabrication to etch aluminum as a pH adjuster in cosmetics and skin care products 27 as a sanitizing agent in the dairy food and brewing industries 28 Safety EditPhosphoric acid is not a strong acid However at moderate concentrations phosphoric acid solutions are irritating to the skin Contact with concentrated solutions can cause severe skin burns and permanent eye damage 29 A link has been shown between long term regular cola intake and osteoporosis in later middle age in women but not men 30 See also EditPhosphate fertilizers such as ammonium phosphate fertilizersReferences Edit Christensen J H Reed R B 1955 Design and Analysis Data Density of Aqueous Solutions of Phosphoric Acid Measurements at 25 C Ind Eng Chem 47 6 1277 1280 doi 10 1021 ie50546a061 CAMEO Chemicals Datasheet Phosphoric Acid Archived from the original on 15 August 2019 Retrieved 15 August 2019 Phosphoric acid www chemspider com Archived from the original on 12 March 2020 Retrieved 3 March 2020 Brown Earl H Whitt Carlton D 1952 Vapor Pressure of Phosphoric Acids Industrial amp Engineering Chemistry 44 3 615 618 doi 10 1021 ie50507a050 Seidell Atherton Linke William F 1952 Solubilities of Inorganic and Organic Compounds Van Nostrand Archived from the original on 11 March 2020 Retrieved 2 June 2014 a b Haynes p 4 80 phosphoric acid msds Archived from the original on 4 July 2017 Retrieved 2 May 2018 a b c d NIOSH Pocket Guide to Chemical Hazards 0506 National Institute for Occupational Safety and Health NIOSH Haynes p 5 92 Haynes p 4 134 Edwards O W Dunn R L Hatfield J D 1964 Refractive Index of Phosphoric Acid Solutions at 25 C J Chem Eng Data 9 4 508 509 doi 10 1021 je60023a010 Haynes p 5 13 a b c Sigma Aldrich Co Phosphoric acid Phosphoric acid Immediately Dangerous to Life or Health Concentrations IDLH National Institute for Occupational Safety and Health NIOSH Westheimer F H 6 June 1987 Why nature chose phosphates Science 235 4793 1173 1178 see pp 1175 1176 Bibcode 1987Sci 235 1173W CiteSeerX 10 1 1 462 3441 doi 10 1126 science 2434996 PMID 2434996 Becker Pierre 1988 Phosphates and phosphoric acid New York Marcel Dekker ISBN 978 0824717124 Greenwood Norman N Earnshaw Alan 1997 Chemistry of the Elements 2nd ed Butterworth Heinemann pp 520 522 ISBN 978 0 08 037941 8 Geeson Michael B Cummins Christopher C 2020 Let s Make White Phosphorus Obsolete ACS Central Science 6 6 848 860 doi 10 1021 acscentsci 0c00332 PMC 7318074 PMID 32607432 Schrodter Klaus Bettermann Gerhard Staffel Thomas Wahl Friedrich Klein Thomas Hofmann Thomas 2008 Phosphoric Acid and Phosphates Ullmann s Encyclopedia of Industrial Chemistry Weinheim Wiley VCH doi 10 1002 14356007 a19 465 pub3 Current EU approved additives and their E Numbers Foods Standards Agency 14 March 2012 Archived from the original on 21 August 2013 Retrieved 22 July 2012 Why is phosphoric acid used in some Coca Cola drinks Frequently Asked Questions Coca Cola GB www coca cola co uk Archived from the original on 2 August 2021 Retrieved 31 August 2021 Moynihan P J 23 November 2002 Dietary advice in dental practice British Dental Journal 193 10 563 568 doi 10 1038 sj bdj 4801628 PMID 12481178 Qaseem A Dallas P Forciea MA Starkey M et al 4 November 2014 Dietary and pharmacologic management to prevent recurrent nephrolithiasis in adults A clinical practice guideline from the American College of Physicians Annals of Internal Medicine 161 9 659 67 doi 10 7326 M13 2908 PMID 25364887 Toles C Rimmer S Hower J C 1996 Production of activated carbons from a washington lignite using phosphoric acid activation Carbon 34 11 1419 doi 10 1016 S0008 6223 96 00093 0 Wet chemical etching Archived 25 September 2012 at the Wayback Machine umd edu Wolf S R N Tauber 1986 Silicon processing for the VLSI era Volume 1 Process technology p 534 ISBN 978 0 9616721 6 4 Ingredient dictionary P Cosmetic ingredient dictionary Paula s Choice Archived from the original on 18 January 2008 Retrieved 16 November 2007 STAR SAN PDF Five Star Chemicals Archived PDF from the original on 8 February 2016 Retrieved 17 August 2015 Phosphoric Acid 85 wt SDS Sigma Aldrich 5 May 2016 Archived from the original on 18 January 2017 Retrieved 16 January 2017 Tucker KL Morita K Qiao N Hannan MT Cupples LA Kiel DP 1 October 2006 Colas but not other carbonated beverages are associated with low bone mineral density in older women The Framingham Osteoporosis Study American Journal of Clinical Nutrition 84 4 936 942 doi 10 1093 ajcn 84 4 936 PMID 17023723 Cited sources EditHaynes William M ed 2011 CRC Handbook of Chemistry and Physics 92nd ed CRC Press ISBN 978 1439855119 External links Edit Wikimedia Commons has media related to phosphoric acid National pollutant inventory Phosphoric acid fact sheet NIOSH Pocket guide to chemical hazards Retrieved from https en wikipedia org w index php title Phosphoric acid amp oldid 1130242735, wikipedia, wiki, book, books, library,
