Phosphine Explained

Phosphine (IUPAC name: phosphane) is a colorless, flammable, highly toxic compound with the chemical formula PH3, classed as a pnictogen hydride. Pure phosphine is odorless, but technical grade samples have a highly unpleasant odor like rotting fish, due to the presence of substituted phosphine and diphosphane . With traces of present, is spontaneously flammable in air (pyrophoric), burning with a luminous flame. Phosphine is a highly toxic respiratory poison, and is immediately dangerous to life or health at 50 ppm. Phosphine has a trigonal pyramidal structure.

Phosphines are compounds that include and the organophosphines, which are derived from by substituting one or more hydrogen atoms with organic groups. They have the general formula . Phosphanes are saturated phosphorus hydrides of the form, such as triphosphane. Phosphine, PH3, is the smallest of the phosphines and the smallest of the phosphanes.

History

Philippe Gengembre (1764–1838), a student of Lavoisier, first obtained phosphine in 1783 by heating white phosphorus in an aqueous solution of potash (potassium carbonate).[1] [2]

Perhaps because of its strong association with elemental phosphorus, phosphine was once regarded as a gaseous form of the element, but Lavoisier (1789) recognised it as a combination of phosphorus with hydrogen and described it as phosphure d'hydrogène (phosphide of hydrogen).[3]

In 1844, Paul Thénard, son of the French chemist Louis Jacques Thénard, used a cold trap to separate diphosphine from phosphine that had been generated from calcium phosphide, thereby demonstrating that is responsible for spontaneous flammability associated with, and also for the characteristic orange/brown color that can form on surfaces, which is a polymerisation product.[4] He considered diphosphine's formula to be, and thus an intermediate between elemental phosphorus, the higher polymers, and phosphine. Calcium phosphide (nominally) produces more than other phosphides because of the preponderance of P-P bonds in the starting material.

The name "phosphine" was first used for organophosphorus compounds in 1857, being analogous to organic amines .[5] [6] The gas was named "phosphine" by 1865 (or earlier).[7]

Structure and reactions

is a trigonal pyramidal molecule with C3v molecular symmetry. The length of the P−H bond is 1.42 Å, the H−P−H bond angles are 93.5°. The dipole moment is 0.58 D, which increases with substitution of methyl groups in the series:, 1.10 D;, 1.23 D;, 1.19 D. In contrast, the dipole moments of amines decrease with substitution, starting with ammonia, which has a dipole moment of 1.47 D. The low dipole moment and almost orthogonal bond angles lead to the conclusion that in the P−H bonds are almost entirely and phosphorus 3s orbital contributes little to the P-H bonding. For this reason, the lone pair on phosphorus is predominantly formed by the 3s orbital of phosphorus. The upfield chemical shift of it 31P NMR signal accords with the conclusion that the lone pair electrons occupy the 3s orbital (Fluck, 1973). This electronic structure leads to a lack of nucleophilicity in general and lack of basicity in particular (pKaH = –14),[8] as well as an ability to form only weak hydrogen bonds.[9]

The aqueous solubility of is slight: 0.22 cm3 of gas dissolves in 1 cm3 of water. Phosphine dissolves more readily in non-polar solvents than in water because of the non-polar P−H bonds. It is technically amphoteric in water, but acid and base activity is poor. Proton exchange proceeds via a phosphonium ion in acidic solutions and via phosphanide at high pH, with equilibrium constants Kb = and Ka = . Phosphine reacts with water only at high pressure and temperature, producing phosphoric acid and hydrogen:[10] [11]

Burning phosphine in the air produces phosphoric acid):[12]

Preparation and occurrence

Phosphine may be prepared in a variety of ways.[13] Industrially it can be made by the reaction of white phosphorus with sodium or potassium hydroxide, producing potassium or sodium hypophosphite as a by-product.

Alternatively, the acid-catalyzed disproportionation of white phosphorus yields phosphoric acid and phosphine. Both routes have industrial significance; the acid route is the preferred method if further reaction of the phosphine to substituted phosphines is needed. The acid route requires purification and pressurizing.

Laboratory routes

It is prepared in the laboratory by disproportionation of phosphorous acid:[14]

Alternative methods are the hydrolysis zinc phosphide:[15] Some other metal phosphides could be used including aluminium phosphide, or calcium phosphide. Pure samples of phosphine, free from, may be prepared using the action of potassium hydroxide on phosphonium iodide:

Occurrence

Phosphine is a worldwide constituent of the Earth's atmosphere at very low and highly variable concentrations.[16] It may contribute significantly to the global phosphorus biochemical cycle. The most likely source is reduction of phosphate in decaying organic matter, possibly via partial reductions and disproportionations, since environmental systems do not have known reducing agents of sufficient strength to directly convert phosphate to phosphine.[17]

It is also found in Jupiter's atmosphere.[18]

Possible extraterrestrial biosignature

See also: Life on Venus. In 2020 a spectroscopic analysis was reported to show signs of phosphine in the atmosphere of Venus in quantities that could not be explained by known abiotic processes.[19] [20] [21] Later re-analysis of this work showed interpolation errors had been made, and re-analysis of data with the fixed algorithm do not result in the detection of phosphine.[22] [23] The authors of the original study then claimed to detect it with a much lower concentration of 1 ppb.[24]

Applications

Organophosphorus chemistry

Phosphine is a precursor to many organophosphorus compounds. It reacts with formaldehyde in the presence of hydrogen chloride to give tetrakis(hydroxymethyl)phosphonium chloride, which is used in textiles. The hydrophosphination of alkenes is versatile route to a variety of phosphines. For example, in the presence of basic catalysts adds of Michael acceptors. Thus with acrylonitrile, it reacts to give tris(cyanoethyl)phosphine:[25]

Acid catalysis is applicable to hydrophosphination with isobutylene and related analogues:

where R is, alkyl, etc.

Microelectronics

Phosphine is used as a dopant in the semiconductor industry, and a precursor for the deposition of compound semiconductors. Commercially significant products include gallium phosphide and indium phosphide.

Fumigant (pest control)

See also: Fumigation. Phosphine is an attractive fumigant because it is lethal to insects and rodents, but degrades to phosphoric acid, which is non-toxic. As sources of phosphine, for farm use, pellets of aluminium phosphide (AlP), calcium phosphide, or zinc phosphide are used. These phosphides release phosphine upon contact with atmospheric water or rodents' stomach acid. These pellets also contain reagents to reduce the potential for ignition or explosion of the released phosphine.

An alternative is the use of phosphine gas itself which requires dilution with either or or even air to bring it below the flammability point. Use of the gas avoids the issues related with the solid residues left by metal phosphide and results in faster, more efficient control of the target pests.

One problem with phosphine fumigants is the increased resistance by insects.

Toxicity and safety

See also: White phosphorus munitions. Deaths have resulted from accidental exposure to fumigation materials containing aluminium phosphide or phosphine.[26] [27] [28] [29] It can be absorbed either by inhalation or transdermally.[26] As a respiratory poison, it affects the transport of oxygen or interferes with the utilization of oxygen by various cells in the body.[28] Exposure results in pulmonary edema (the lungs fill with fluid).[29] Phosphine gas is heavier than air so it stays near the floor.[30]

Phosphine appears to be mainly a redox toxin, causing cell damage by inducing oxidative stress and mitochondrial dysfunction.[31] Resistance in insects is caused by a mutation in a mitochondrial metabolic gene.

Phosphine can be absorbed into the body by inhalation. The main target organ of phosphine gas is the respiratory tract.[32] According to the 2009 U.S. National Institute for Occupational Safety and Health (NIOSH) pocket guide, and U.S. Occupational Safety and Health Administration (OSHA) regulation, the 8 hour average respiratory exposure should not exceed 0.3 ppm. NIOSH recommends that the short term respiratory exposure to phosphine gas should not exceed 1 ppm. The Immediately Dangerous to Life or Health level is 50 ppm. Overexposure to phosphine gas causes nausea, vomiting, abdominal pain, diarrhea, thirst, chest tightness, dyspnea (breathing difficulty), muscle pain, chills, stupor or syncope, and pulmonary edema.[33] [34] Phosphine has been reported to have the odor of decaying fish or garlic at concentrations below 0.3 ppm. The smell is normally restricted to laboratory areas or phosphine processing since the smell comes from the way the phosphine is extracted from the environment. However, it may occur elsewhere, such as in industrial waste landfills. Exposure to higher concentrations may cause olfactory fatigue.[35]

Fumigation hazards

Phosphine is used for pest control, but its usage is strictly regulated due to high toxicity.[36] [37] Gas from phosphine has high mortality rate[38] and has caused deaths in Sweden and other countries.[39] [40] [41]

Because the previously popular fumigant methyl bromide has been phased out in some countries under the Montreal Protocol, phosphine is the only widely used, cost-effective, rapidly acting fumigant that does not leave residues on the stored product. Pests with high levels of resistance toward phosphine have become common in Asia, Australia and Brazil. High level resistance is also likely to occur in other regions, but has not been as closely monitored. Genetic variants that contribute to high level resistance to phosphine have been identified in the dihydrolipoamide dehydrogenase gene.[42] Identification of this gene now allows rapid molecular identification of resistant insects.

Explosiveness

Phosphine gas is denser than air and hence may collect in low-lying areas. It can form explosive mixtures with air, and may also self-ignite.

In popular culture

In the 2008 pilot of the crime drama television series Breaking Bad, Walter White poisons two rival gangsters by adding red phosphorus to boiling water to produce phosphine gas. However, this reaction in reality would require white phosphorus instead, and for the water to contain sodium hydroxide.[43]

See also

Further reading

External links

Notes and References

  1. Gengembre (1783) "Mémoire sur un nouveau gas obtenu, par l'action des substances alkalines, sur le phosphore de Kunckel" (Memoir on a new gas obtained by the action of alkaline substances on Kunckel's phosphorus), Mémoires de mathématique et de physique, 10 : 651–658.
  2. For further information about the early history of phosphine, see:
    • The Encyclopædia Britannica (1911 edition), vol. 21, p. 480: Phosphorus: Phosphine.
    • Thomas Thomson, A System of Chemistry, 6th ed. (London, England: Baldwin, Cradock, and Joy, 1820), vol. 1, p. 272.
  3. Note:
    • On p. 222 of his Traité élémentaire de chimie, vol. 1, (Paris, France: Cuchet, 1789), Lavoisier calls the compound of phosphorus and hydrogen "phosphure d'hydrogène" (hydrogen phosphide). However, on p. 216, he calls the compound of hydrogen and phosphorus "Combinaison inconnue." (unknown combination), yet in a footnote, he says about the reactions of hydrogen with sulfur and with phosphorus: "Ces combinaisons ont lieu dans l'état de gaz & il en résulte du gaz hydrogène sulfurisé & phosphorisé." (These combinations occur in the gaseous state, and there results from them sulfurized and phosphorized hydrogen gas.)
    • In Robert Kerr's 1790 English translation of Lavoisier's Traité élémentaire de chimie ... — namely, Lavoisier with Robert Kerr, trans., Elements of Chemistry ... (Edinburgh, Scotland: William Creech, 1790) — Kerr translates Lavoisier's "phosphure d'hydrogène" as "phosphuret of hydrogen" (p. 204), and whereas Lavoisier — on p. 216 of his Traité élémentaire de chimie ... — gave no name to the combination of hydrogen and phosphorus, Kerr calls it "hydruret of phosphorus, or phosphuret of hydrogen" (p. 198). Lavoisier's note about this compound — "Combinaison inconnue." — is translated: "Hitherto unknown." Lavoisier's footnote is translated as: "These combinations take place in the state of gas, and form, respectively, sulphurated and phosphorated oxygen gas." The word "oxygen" in the translation is an error because the original text clearly reads "hydrogène" (hydrogen). (The error was corrected in subsequent editions.)
  4. Paul Thénard (1844) "Mémoire sur les combinaisons du phosphore avec l'hydrogène" (Memoir on the compounds of phosphorus with hydrogen), Comptes rendus, 18 : 652–655.
  5. In 1857, August Wilhelm von Hofmann announced the synthesis of organic compounds containing phosphorus, which he named "trimethylphosphine" and "triethylphosphine", in analogy with "amine" (organo-nitrogen compounds), "arsine" (organo-arsenic compounds), and "stibine" (organo-antimony compounds).
  6. A.W. Hofmann . Auguste Cahours . 1857 . Researches on the phosphorus bases . Proceedings of the Royal Society of London . 8 . 523–527 . (From page 524:) The bases Me3P and E3P, the products of this reaction, which we propose to call respectively trimethylphosphine and triethylphosphine, ... . 19 November 2020 . 10 February 2022 . https://web.archive.org/web/20220210111914/https://books.google.com/books?id=ZKkOAAAAIAAJ&q=phosphine&pg=PA523 . live .
  7. William Odling, A Course of Practical Chemistry Arranged for the Use of Medical Students, 2nd ed. (London, England: Longmans, Green, and Co., 1865), pp. 227, 230.
  8. Book: Introduction to Organic Chemistry. Streitwieser. Andrew. Heathcock. Clayton H. . Kosower. Edward M. . Medtech . revised 4th . 1st ed. 1998. 2017. 9789385998898. New Delhi. 828.
  9. Sennikov . P. G. . Weak H-Bonding by Second-Row (PH3, H2S) and Third-Row (AsH3, H2Se) Hydrides . Journal of Physical Chemistry . 1994 . 98 . 19 . 4973–4981 . 10.1021/j100070a006 .
  10. Material Safety Data Sheet: Phosphine/hydrogen Gas Mixture . September 8, 2008 . Matheson Tri-Gas . 4 July 2022 . 5 July 2022 . https://web.archive.org/web/20220705191148/https://uwaterloo.ca/giga-to-nanoelectronics-centre/sites/ca.giga-to-nanoelectronics-centre/files/uploads/files/phosphine-hydrogen.pdf . dead .
  11. Rabinowitz . Joseph . Woeller . Fritz . Flores . Jose . Krebsbach . Rita . November 1969 . Electric Discharge Reactions in Mixtures of Phosphine, Methane, Ammonia and Water . Nature . en . 224 . 5221 . 796–798 . 10.1038/224796a0 . 5361652 . 1969Natur.224..796R . 4195473 . 1476-4687.
  12. Web site: 2021-07-08 . Phosphine: Lung Damaging Agent . 2022-07-04 . United States . National Institute for Occupational Safety and Health (NIOSH) . en-us.
  13. Book: Toy, A. D. F. . The Chemistry of Phosphorus . Pergamon Press . Oxford, UK . 1973 .
  14. Book: Gokhale . S. D. . Jolly . W. L. . Inorganic Syntheses . Phosphine . 1967 . 9 . 56–58 . 10.1002/9780470132401.ch17. 978-0-470-13168-8 .
  15. 10.15227/orgsyn.098.0289 . Synthesis of tert-Alkyl Phosphines: Preparation of Di-(1-adamantyl)phosphonium Trifluoromethanesulfonate and Tri-(1-adamantyl)phosphine . 2021 . Barber . Thomas . Liam T.. Baljournal=Organic Syntheses . Organic Syntheses . 98 . 289–314 .
  16. Glindemann . D. . Bergmann . A. . Stottmeister . U. . Gassmann . G.. Phosphine in the lower terrestrial troposphere . Naturwissenschaften . 1996 . 83 . 3 . 131–133 . 10.1007/BF01142179 . 1996NW.....83..131G . 32611695 .
  17. Roels . J. . Verstraete . W. . Biological formation of volatile phosphorus compounds, a review paper . Bioresource Technology . 2001 . 79 . 3 . 243–250 . 10.1016/S0960-8524(01)00032-3 . 11499578 .
  18. News: Kaplan . Sarah . The first water clouds are found outside our solar system – around a failed star . September 14, 2020 . The Washington Post . July 11, 2016 . 15 September 2020 . https://web.archive.org/web/20200915162551/https://www.washingtonpost.com/news/speaking-of-science/wp/2016/07/11/the-first-water-clouds-are-found-outside-our-solar-system-around-a-failed-star/ . live .
  19. Phosphine as a Biosignature Gas in Exoplanet Atmospheres . Sousa-Silva . Clara . Seager . Sara . Ranjan . Sukrit . Petkowski . Janusz Jurand . Zhan . Zhuchang . Hu . Renyu . Bains . William . February 2020 . Astrobiology . 20 . 2 . 11 October 2019 . 10.1089/ast.2018.1954 . 2020AsBio..20..235S. 235–268 . 31755740 . 204401807 . 1910.05224 .
  20. News: A sign that aliens could stink . 18 December 2019 . MIT News . Jennifer . Chu . 14 September 2020 . 18 February 2021 . https://web.archive.org/web/20210218041422/https://news.mit.edu/2019/phosphine-aliens-stink-1218 . live .
  21. News: Phosphine Could Signal Existence of Alien Anaerobic Life on Rocky Planets . 26 December 2019 . Sci-News . 15 September 2020 . 14 September 2020 . https://web.archive.org/web/20200914100028/http://www.sci-news.com/astronomy/phosphine-biosignature-gas-07957.html . live .
  22. Snellen. I. A. G.. Re-analysis of the 267-GHz ALMA observations of Venus No statistically significant detection of phosphine. Astronomy and Astrophysics. 644. L2. 2020 . 2010.09761 . 2020A&A...644L...2S. 10.1051/0004-6361/202039717. Guzman-Ramirez. L.. Hogerheijde. M. R.. Hygate. A. P. S.. van der Tak. F. F. S.. 224803085.
  23. 2010.15188. The statistical reliability of 267 GHz JCMT observations of Venus: No significant evidence for phosphine absorption. 2021. Thompson. M. A.. Monthly Notices of the Royal Astronomical Society: Letters. 501. 1. L18–L22. 10.1093/mnrasl/slaa187. free . 2021MNRAS.501L..18T. 225103303.
  24. 2011.08176. Reply to: No evidence of phosphine in the atmosphere of Venus from independent analyses. 2021. Greaves. Jane S.. Richards. Anita M. S.. Bains. William. Rimmer. Paul B.. Clements. David L.. Seager. Sara. Petkowski. Janusz J.. Sousa-Silva. Clara. Ranjan. Sukrit. Fraser. Helen J.. Nature Astronomy. 5. 7. 636–639. 10.1038/s41550-021-01424-x. 2021NatAs...5..636G. 233296859.
  25. Phosphine in the Synthesis of Organophosphorus Compounds. Boris A. . Trofimov. Svetlana N. . Arbuzova. Nina K. . Gusarova. 1999. Russian Chemical Reviews. 68. 3 . 215–227 . 10.1070/RC1999v068n03ABEH000464. 1999RuCRv..68..215T . 250775640 .
  26. News: Two toddlers die after Jerusalem home sprayed for pests . Haaretz . Ido Efrati . Nir Hasson . 2014-01-22 . 2014-01-23 . 23 January 2014 . https://web.archive.org/web/20140123064603/http://www.haaretz.com/news/national/1.570036 . live .
  27. Web site: es . La familia de Alcalá de Guadaíra murió tras inhalar fosfina de unos tapones . 2014-02-03 . Radio y Televisión Española . EFE . RTVE.es . 23 July 2014 . 2 March 2014 . https://web.archive.org/web/20140302205408/http://www.rtve.es/noticias/20140203/familia-alcala-guadaira-murio-tras-inhalar-fosfina-unos-tapones/869841.shtml . live .
  28. News: Deaths of Quebec women in Thailand may have been caused by pesticide . 13 March 2014 . CBC News . Julia Sisler . 3 April 2017 . 4 April 2017 . https://web.archive.org/web/20170404131909/http://www.cbc.ca/news/deaths-of-quebec-women-in-thailand-may-have-been-caused-by-pesticide-1.2569434 . live .
  29. News: 4 children killed after pesticide released toxic gas underneath their home, police say. 6 January 2017. Washington Post. Amy B Wang. 3 January 2017. 25 June 2018. https://web.archive.org/web/20180625161014/https://www.washingtonpost.com/news/post-nation/wp/2017/01/03/4-children-killed-after-pesticide-released-toxic-gas-underneath-their-home-police-say/. live.
  30. Web site: Pesticide blamed in 8-month-old's death in Fort McMurray . CBC News . 2015-02-23 . 2015-02-23 . 24 February 2015 . https://web.archive.org/web/20150224051710/http://www.cbc.ca/news/canada/edmonton/pesticide-blamed-in-8-month-old-s-death-in-fort-mcmurray-1.2967286 . live .
  31. Nath . NS . Bhattacharya . I . Tuck . AG . Schlipalius . DI . Ebert . PR . Mechanisms of phosphine toxicity . Journal of Toxicology . 2011 . 2011 . 494168 . 10.1155/2011/494168 . 21776261. 3135219 . free .
  32. Web site: NIOSH Emergency Response Card . CDC . 2010-04-06 . 2 October 2017 . https://web.archive.org/web/20171002191640/https://www.cdc.gov/niosh/ershdb/emergencyresponsecard_29750035.html . live .
  33. Web site: NIOSH pocket guide . CDC . 2009-02-03 . 2010-04-06 . 11 May 2017 . https://web.archive.org/web/20170511081428/https://www.cdc.gov/niosh/npg/npgd0505.html . live .
  34. Web site: WHO – Data Sheets on Pesticides – No. 46: Phosphine . Inchem.org . 2010-04-06 . https://web.archive.org/web/20100218102324/http://www.inchem.org/documents/pds/pds/pest46_e.htm . 18 February 2010 . dead .
  35. NIOSH alert: preventing phosphine poisoning and explosions during fumigation. . 1999-09-01 . CDC . 10.26616/nioshpub99126 . en-US . 2010-04-06 . 19 June 2017 . https://web.archive.org/web/20170619104259/https://www.cdc.gov/niosh/docs/99-126/ . live . free .
  36. Web site: Wallstén . Beata . Åklagaren bekräftar: Familjen i Söderhamn förgiftades av fosfin . DN.se . 2024-02-13 . sv . 2024-02-13. https://archive.today/20240213090046/https://www.dn.se/sverige/aklagaren-bekraftar-familjen-i-soderhamn-forgiftades-av-fosfin/. 2024-02-13.
  37. Web site: . Hälsorisker och förebyggande rutiner vid hantering av fumigerade containrar . 2024-02-13. https://web.archive.org/web/20240213100055/https://osha.europa.eu/sites/default/files/845%20-%20SV.pdf. 2024-02-13.
  38. A Farrar . Ross . B Justus . Angelo . A Masurkar . Vikram . M Garrett . Peter . Unexpected survival after deliberate phosphine gas poisoning: An Australian experience of extracorporeal membrane oxygenation rescue in this setting . Anaesthesia and Intensive Care . 50 . 3 . 2022 . 0310-057X . 10.1177/0310057X211047603 . 250–254. 34871510 .
  39. News: Giftgåtan i Söderhamn: Gas tros ha dödat flickan . SVT Nyheter . 2024-02-13 . sv . 2024-02-13. https://web.archive.org/web/20240213083312/https://www.svt.se/nyheter/lokalt/gavleborg/giftgatan-i-soderhamn-gas-tros-ha-dodat-flickan. 2024-02-13. Berglin. Rikard.
  40. LJ . Willers-Russo . Three fatalities involving phosphine gas, produced as a result of methamphetamine manufacturing . Journal of Forensic Sciences . 1999 . J Forensic Sci . 44 . 3 . 647–652 . 10.1520/JFS14525J . 0022-1198 . 10408124 . 2024-02-13 .
  41. Moirangthem . Sangita . Vidua . Raghvendra . Jahan . Afsar . Patnaik . Mrinal . Chaurasia . Jai . Phosphine Gas Poisoning . American Journal of Forensic Medicine & Pathology . Ovid Technologies (Wolters Kluwer Health) . 44 . 4 . 2023-07-08 . 1533-404X . 10.1097/paf.0000000000000855 . 350–353. 37438888 .
  42. Schlipalius . D. I. . Valmas . N. . Tuck . A. G. . Jagadeesan . R. . Ma . L. . Kaur . R. . 2012 . A Core Metabolic Enzyme Mediates Resistance to Phosphine Gas . Science . 338 . 6108 . 807–810 . 10.1126/science.1224951 . etal . 23139334 . 2012Sci...338..807S . 10390339.
  43. Web site: Breaking Bad – poisoning gangsters with phosphine gas . Hare . Jonathan . 1 March 2011 . education in chemistry . Royal Society of Chemistry . https://web.archive.org/web/20230924072242/https://edu.rsc.org/analysis/breaking-bad-poisoning-gangsters-with-phosphine-gas/3007373.article . 24 September 2023.

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