| Revision as of 12:21, 15 February 2012 editBeetstra (talk | contribs)Edit filter managers, Administrators172,031 edits Saving copy of the {{chembox}} taken from revid 474113321 of page Hypophosphorous_acid for the Chem/Drugbox validation project (updated: ''). |
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{{short description|Chemical compound}} |
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{{ambox | text = This page contains a copy of the infobox ({{tl|chembox}}) taken from revid of page ] with values updated to verified values.}} |
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{{Distinguish|Hypophosphoric acid}} |
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{{Chembox |
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{{Chembox |
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| Verifiedfields = changed |
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| verifiedrevid = 448784732 |
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| Watchedfields = changed |
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| Reference = <ref>Ralph H. Petrucci, ''General Chemistry'', Ninth Edition, 2007, p. 946</ref> |
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| verifiedrevid = 476993494 |
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| ImageFileL1 = Hypophosphorous-acid-2D.png |
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| Reference = <ref>{{cite book|first=Ralph H.|last= Petrucci |title=General Chemistry |edition=9th |date=2007 |page= 946}}</ref> |
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| ImageSizeL1 = 120px |
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| ImageFileL1 = Hypophosphorous-acid-2D.png |
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| ImageNameL1 = Wireframe model of hypophosphorous acid |
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| ImageNameL1 = Wireframe model of hypophosphorous acid |
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| ImageFileR1 = Hypophosphorous-acid-3D-balls.png |
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| ImageFileR1 = Hypophosphorous-acid-3D-balls.png |
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| ImageSizeR1 = 120px |
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| ImageName1 = Ball and stick model of hypophosphorous acid |
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| ImageName1 = Ball and stick model of hypophosphorous acid |
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| IUPACName = Phosphinic acid |
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| IUPACName = Phosphinic acid |
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| OtherNames = Hydroxy(oxo)-λ<sup>5</sup>-phosphane<br /> |
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| OtherNames = Hydroxy(oxo)-''λ''<sup>5</sup>-phosphane<br /> |
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Hydroxy-λ<sup>5</sup>-phosphanone<br /> |
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Hydroxy-''λ''<sup>5</sup>-phosphanone<br /> |
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Oxo-λ<sup>5</sup>-phosphanol<br /> |
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Oxo-''λ''<sup>5</sup>-phosphanol<br /> |
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Oxo-λ<sup>5</sup>-phosphinous acid |
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Oxo-''λ''<sup>5</sup>-phosphinous acid<br /> |
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Phosphonous acid (for minor tautomer) |
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| Section1 = {{Chembox Identifiers |
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|Section1={{Chembox Identifiers |
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| StdInChI_Ref = {{stdinchicite|correct|chemspider}} |
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| StdInChI_Ref = {{stdinchicite|correct|chemspider}} |
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| StdInChI = 1S/H3O2P/c1-3-2/h3H2,(H,1,2) |
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| StdInChI = 1S/H3O2P/c1-3-2/h3H2,(H,1,2) |
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| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} |
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| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} |
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| StdInChIKey = ACVYVLVWPXVTIT-UHFFFAOYSA-N |
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| StdInChIKey = ACVYVLVWPXVTIT-UHFFFAOYSA-N |
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| CASNo = 6303-21-5 |
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| CASNo = 6303-21-5 |
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| CASNo_Ref = {{cascite|correct|CAS}} |
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| CASNo_Ref = {{cascite|correct|CAS}} |
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| UNII_Ref = {{fdacite|correct|FDA}} |
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| CASNo1 = 57583-56-9 |
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| UNII = 8B1RL9B4ZJ |
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| CASNo1_Comment = (<sup>2</sup>''H''<sub>3</sub>) |
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| PubChem = 3085127 |
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| PubChem = 3085127 |
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| PubChem_Comment = (<sup>2</sup>''H''<sub>3</sub>) |
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| PubChem_Comment = (<sup>2</sup>''H''<sub>3</sub>) |
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| ChemSpiderID = 10449263 |
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| PubChem_Ref = {{PubChem}} |
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| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
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| ChemSpiderID = 10449263 |
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| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
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| ChemSpiderID1_Ref = {{chemspidercite|correct|chemspider}} |
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| ChemSpiderID1 = 10459437 |
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| ChemSpiderID1 = 10459437 |
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| ChemSpiderID1_Comment = (<sup>17</sup>''O''<sub>2</sub>) |
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| ChemSpiderID1_Comment = (<sup>17</sup>''O''<sub>2</sub>) |
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| ChemSpiderID2_Ref = {{chemspidercite|correct|chemspider}} |
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| ChemSpiderID1_Ref = {{Chemspidercite}} |
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| ChemSpiderID2 = 2342086 |
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| ChemSpiderID2 = 2342086 |
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| ChemSpiderID2_Comment = (<sup>2</sup>''H''<sub>3</sub>) |
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| ChemSpiderID2_Comment = (<sup>2</sup>''H''<sub>3</sub>) |
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| UNNumber = UN 3264 |
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| ChemSpiderID2_Ref = {{Chemspidercite}} |
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| ChEBI_Ref = {{ebicite|correct|EBI}} |
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| UNNumber = UN 3264 |
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| ChEBI_Ref = {{ebicite|correct|EBI}} |
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| ChEBI = 29031 |
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| ChEBI = 29031 |
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| SMILES = O=PO |
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| SMILES = O=O |
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| KEGG_Ref = {{keggcite|correct|kegg}} |
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| ChEMBL_Ref = {{ebicite|changed|EBI}} |
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| ChEMBL = 2105054 |
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| KEGG_Ref = {{keggcite|correct|kegg}} |
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| KEGG = D02334 |
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| KEGG = D02334 |
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| InChI = 1/H3O2P/c1-3-2/h3H2,(H,1,2) |
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| InChI = 1/H3O2P/c1-3-2/h3H2,(H,1,2) |
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| InChIKey = ACVYVLVWPXVTIT-UHFFFAOYAQ |
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| InChIKey = ACVYVLVWPXVTIT-UHFFFAOYAQ |
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}} |
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}} |
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| Section2 = {{Chembox Properties |
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|Section2={{Chembox Properties |
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| Formula = H<sub>3</sub>PO<sub>2</sub> |
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| Formula = H<sub>3</sub>PO<sub>2</sub> |
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| Appearance = colorless, ] crystals or oily liquid |
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| Appearance = colorless, ] crystals or oily liquid |
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| MolarMass = 66.00 g/mol |
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| MolarMass = 66.00 g/mol |
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| Density = 1.493 g/cm<sup>3</sup> <ref>Pradyot Patnaik. ''Handbook of Inorganic Chemicals''. McGraw-Hill, 2002, ISBN 0070494398</ref> |
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| Density = 1.493 g/cm<sup>3</sup><ref>Pradyot Patnaik. ''Handbook of Inorganic Chemicals''. McGraw-Hill, 2002, {{ISBN|0-07-049439-8}}</ref> |
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1.22 g/cm<sup>3</sup> (50 wt% aq. solution) |
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| Solubility = miscible |
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| Solubility = miscible |
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| SolubleOther = very soluble in ], ] |
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| SolubleOther = very soluble in ], ] |
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| MeltingPtC = 26.5 |
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| MeltingPtC = 26.5 |
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| BoilingPt = 130 °C decomp. |
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| pKa = 1.2 |
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| BoilingPtC = 130 |
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| BoilingPt_notes = decomposes |
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| Viscosity = |
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| ConjugateBase = ] |
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| pKa = 1.2 |
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| Viscosity = |
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}} |
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}} |
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| Section3 = {{Chembox Structure |
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|Section3={{Chembox Structure |
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| MolShape = pseudo-tetrahedral |
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| MolShape = pseudo-tetrahedral |
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| Dipole = |
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| Dipole = |
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}} |
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}} |
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| Section7 = {{Chembox Hazards |
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|Section7={{Chembox Hazards |
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| ExternalMSDS = |
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| ExternalSDS = |
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| FlashPt = Non-flammable |
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| EUIndex = Not listed |
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| FlashPt = Non-flammable |
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}} |
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}} |
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| Section8 = {{Chembox Related |
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|Section8={{Chembox Related |
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| Function = ] ]s |
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| OtherFunction_label = ] ]s |
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| OtherFunctn = ]<br/>] |
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| OtherFunction = ]<br/>] |
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| OtherCpds = ]<br/>] |
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| OtherCompounds = ]<br/>] |
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}} |
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}} |
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}} |
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'''Hypophosphorous acid''' ('''HPA'''), or '''phosphinic acid''', is a ] ] and a powerful ] with ] H<sub>3</sub>PO<sub>2</sub>. It is a colorless low-melting compound, which is soluble in water, ] |
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and alcohols. The formula for this acid is generally written H<sub>3</sub>PO<sub>2</sub>, but a more descriptive presentation is HOP(O)H<sub>2</sub>, which highlights its ] character. Salts derived from this acid are called ]s.<ref>{{Greenwood&Earnshaw2nd}}</ref> |
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HOP(O)H<sub>2</sub> exists in ] with the minor ] HP(OH)<sub>2</sub>. Sometimes the minor tautomer is called hypophosphorous acid and the major tautomer is called phosphinic acid. |
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==Preparation and availability== |
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Hypophosphorous acid was first prepared in 1816 by the French chemist ] (1785–1838).<ref>Dulong prepared ''acide hypo-phosphoreux'' by adding barium phosphide (Ba<sub>3</sub>P<sub>2</sub>) to water, which yielded ] gas (PH<sub>3</sub>), barium phosphate, and barium hypophosphite. Since the phosphine gas left the solution and the barium phosphate precipitated, only the barium hypophosphite remained in solution. Hypophosphorous acid could then be obtained from the filtrate by adding sulfuric acid, which precipitated barium sulfate, leaving hypophosphorous acid in solution. See: |
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* Dulong (1816) (Extract from a memoir on the compounds of phosphorus with oxygen), ''Annales de Chimie et de Physique'', '''2''' : 141–150. |
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* Graham, Thomas, ''Elements of Inorganic Chemistry'', 2nd ed. (Philadelphia, Pennsylvania: Blanchard and Lea, 1858), </ref> |
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The acid is prepared industrially via a two step process: Firstly, elemental ] reacts with ] and ] ]s to give an aqueous solution of hypophosphites: |
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:P<sub>4</sub> + 4 OH<sup>−</sup> + 4 H<sub>2</sub>O → 4 {{chem|H|2|PO|2|−}} + 2 H<sub>2</sub> |
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Any ]s produced in this step can be selectively precipitated out by treatment with ] salts. The purified material is then treated with a strong, non-oxidizing acid (often ]) to give the free hypophosphorous acid: |
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:{{chem|H|2|PO|2|−}} + H<sup>+</sup> → H<sub>3</sub>PO<sub>2</sub> |
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HPA is usually supplied as a 50% aqueous solution. Anhydrous acid cannot be obtained by simple evaporation of the water, as the acid readily oxidises to ] and ] and also ] to phosphorous acid and ]. Pure anhydrous hypophosphorous acid can be formed by the continuous extraction of aqueous solutions with ].<ref>{{Greenwood&Earnshaw2nd|page=513}}</ref> |
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==Properties== |
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:] |
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The molecule displays P(═O)H to P–OH ] similar to that of ]; the P(═O) form is strongly favoured.<ref>{{cite journal | last1=Janesko | first1=Benjamin G. | last2=Fisher | first2=Henry C. | last3=Bridle | first3=Mark J. | last4=Montchamp | first4=Jean-Luc | title=P(═O)H to P–OH Tautomerism: A Theoretical and Experimental Study | journal=The Journal of Organic Chemistry | publisher=American Chemical Society (ACS) | volume=80 | issue=20 | date=2015-09-29 | issn=0022-3263 | doi=10.1021/acs.joc.5b01618 | pages=10025–10032| pmid=26372089 }}</ref> |
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HPA is usually supplied as a 50% aqueous solution and heating at low temperatures (up to about 90 °C) prompts it to react with water to form ] and hydrogen gas. |
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: H<sub>3</sub>PO<sub>2</sub> + H<sub>2</sub>O → H<sub>3</sub>PO<sub>3</sub> + H<sub>2</sub> |
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Heating above 110 °C causes hypophosphorous acid to undergo ] to give phosphorous acid and ].<ref>{{cite journal |last1=Shechkov |first1=G. T. |last2=Pevneva |first2=I. A. |last3=Meshkova |first3=O. A. |title=Thermal Disproportionation of Hypophosphorous Acid |journal=Russian Journal of Applied Chemistry |date=August 2003 |volume=76 |issue=8 |pages=1354–1355 |doi=10.1023/B:RJAC.0000008318.22178.07|s2cid=96861842 }}</ref> |
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: 3 H<sub>3</sub>PO<sub>2</sub> → 2 H<sub>3</sub>PO<sub>3</sub> + PH<sub>3</sub> |
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==Reactions== |
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===Inorganic=== |
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Hypophosphorous acid can reduce chromium(III) oxide to chromium(II) oxide: |
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:H<sub>3</sub>PO<sub>2</sub> + 2 Cr<sub>2</sub>O<sub>3</sub> → 4 CrO + H<sub>3</sub>PO<sub>4</sub> |
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===Inorganic derivatives=== |
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Most metal-hypophosphite complexes are unstable, owing to the tendency of hypophosphites to reduce metal cations back into the bulk metal. Some examples have been characterised,<ref>{{cite journal |last1=Kuratieva |first1=Natalia V. |last2=Naumova |first2=Marina I. |last3=Podberezskaya |first3=Nina V. |last4=Naumov |first4=Dmitry Yu. |title=The bivalent metal hypophosphites Sr(H 2 PO 2 ) 2, Pb(H 2 PO 2 ) 2 and Ba(H 2 PO 2 ) 2 |journal=Acta Crystallographica Section C Crystal Structure Communications |date=2005-02-15 |volume=61 |issue=2 |pages=i14–i16 |doi=10.1107/S010827010403166X|pmid=15695880 |bibcode=2005AcCrC..61I..14K }}</ref><ref>{{cite journal |last1=Naumova |first1=Marina I. |last2=Kuratieva |first2=Natalia V. |last3=Podberezskaya |first3=Nina V. |last4=Naumov |first4=Dmitry Yu. |title=The alkali hypophosphites KH 2 PO 2, RbH 2 PO 2 and CsH 2 PO 2 |journal=Acta Crystallographica Section C Crystal Structure Communications |date=2004-05-15 |volume=60 |issue=5 |pages=i53–i55 |doi=10.1107/S0108270104002409|pmid=15131359 |bibcode=2004AcCrC..60I..53N }}</ref> including the important nickel salt (H<sub>2</sub>PO<sub>2</sub>)<sub>2</sub>.<ref>{{cite journal |last1=Kuratieva |first1=Natalia V. |last2=Naumova |first2=Marina I. |last3=Naumov |first3=Dmitry Yu. |last4=Podberezskaya |first4=Nina V. |title=Hexaaquanickel(II) bis(hypophosphite) |journal=Acta Crystallographica Section C Crystal Structure Communications |date=2003-01-15 |volume=59 |issue=1 |pages=i1–i3 |doi=10.1107/S0108270102018541|pmid=12506208 |bibcode=2003AcCrC..59I...1K }}</ref> |
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====DEA List I chemical status==== |
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Because hypophosphorous acid can reduce elemental ] to form ], which is a reagent effective for reducing ] or ] to ],<ref name="ARKIVOC">{{cite journal|last1=Gordon |first1=P. E. |last2=Fry |first2=A. J. |last3=Hicks |first3=L. D. |title=Further studies on the reduction of benzylic alcohols by hypophosphorous acid/iodine|date= 23 August 2005 |url=http://content.arkat-usa.org/ARKIVOC/JOURNAL_CONTENT/manuscripts/2005/EJ-1559CP%20as%20published%20mainmanuscript.pdf|journal= Arkivoc |volume=2005 |issue=vi |pages=393–400|issn=1424-6376}}</ref> the ] designated hypophosphorous acid (and its salts) as a ] effective November 16, 2001.<ref name="66 CFR 52670"> 17 October 2001.</ref> Accordingly, handlers of hypophosphorous acid or its salts in the ] are subject to stringent regulatory controls including registration, recordkeeping, reporting, and import/export requirements pursuant to the ] and 21 ] §§ 1309 and 1310.<ref name="66 CFR 52670"/><ref name="21 CFR 1309">{{Cite web |url=http://www.access.gpo.gov/nara/cfr/waisidx_06/21cfr1309_06.html |title=21 CFR 1309 |access-date=2007-05-02 |archive-url=https://web.archive.org/web/20090503063012/http://www.access.gpo.gov/nara/cfr/waisidx_06/21cfr1309_06.html |archive-date=2009-05-03 }}</ref><ref name="CSA"></ref> |
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===Organic=== |
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In organic chemistry, H<sub>3</sub>PO<sub>2</sub> can be used for the reduction of ], converting {{chem|ArN|2|+}} to Ar–H.<ref>{{Cite book|title=Organic Chemistry|author1=William H. Brown |author2=Brent L. Iverson |author3=Eric Anslyn |author4=Christopher S. Foote |publisher=Cengage Learning|year=2013|isbn=978-1-133-95284-8|page=1003}}</ref><ref name="robison">{{OrgSynth|last1=Robison |first1=M. M. |last2=Robison |first2=B. L. |date1956 |prep=cv4p0947 |title=2,4,6-Tribromobenzoic acid |volume=36|page=94 |collvol=4|collvolpage=947}}</ref><ref name="kornblum">{{OrgSynth|last=Kornblum |first=N. |year=1941 |title=3,3′-Dimethoxybiphenyl and 3,3′-Dimethylbiphenyl|volume=21|page=30 |doi=10.15227/orgsyn.021.0030}}</ref> When ] in a concentrated solution of hypophosphorous acid, an ] substituent can be removed from arenes. |
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Owing to its ability to function as a mild reducing agent and oxygen scavenger it is sometimes used as an additive in ] reactions, where it prevents the formation of colored impurities. |
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It is used to prepare phosphinic acid derivatives.<ref>{{cite journal|title=Palladium-Catalyzed Dehydrative Allylation of Hypophosphorous Acid with Allylic Alcohols|author=Karla Bravo-Altamirano |author2=Jean-Luc Montchamp |journal=Org. Synth.|year=2008|volume=85|page=96|doi=10.15227/orgsyn.085.0096|doi-access=free}}</ref> |
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==Applications== |
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Hypophosphorous acid (and its salts) are used to reduce metal salts back into bulk metals. It is effective for various ] ions (i.e. those of: Co, Cu, Ag, Mn, Pt) but is most commonly used to reduce ].<ref>{{cite journal |last1=Guyon |first1=Carole |last2=Métay |first2=Estelle |last3=Popowycz |first3=Florence |last4=Lemaire |first4=Marc |title=Synthetic applications of hypophosphite derivatives in reduction |journal=Organic & Biomolecular Chemistry |date=2015 |volume=13 |issue=29 |pages=7879–7906 |doi=10.1039/C5OB01032B|pmid=26083977 }}</ref> This forms the basis of ] (Ni–P), which is the single largest industrial application of hypophosphites. For this application it is principally used as a salt (]).<ref>{{cite journal|last1=Abrantes|first1=L. M.|title=On the Mechanism of Electroless Ni–P Plating|journal=Journal of the Electrochemical Society|date=1994|volume=141|issue=9|pages=2356–2360|doi=10.1149/1.2055125|bibcode=1994JElS..141.2356A}}</ref> |
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==Sources== |
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*{{Cotton&Wilkinson6th}} |
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* |
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*{{cite book|first=D. E. C. |last=Corbridge |title=Phosphorus: An Outline of its Chemistry, Biochemistry, and Technology |year=1995 |edition=5th |publisher=Elsevier |location=Amsterdam |isbn=0-444-89307-5}} |
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*{{cite book|first1=V. V. |last1=Popik |first2=A. G. |last2=Wright |first3=T. A. |last3=Khan |first4=J. A. |last4=Murphy |chapter=Hypophosphorous Acid|title= Encyclopedia of Reagents for Organic Synthesis |editor-first=L. |editor-last=Paquette |date=2004 |publisher=J. Wiley & Sons |location=New York |doi=10.1002/047084289X|hdl=10261/236866 |isbn=978-0-471-93623-7 }} |
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*{{cite book|first1=D. W. |last1=Rich |first2=M. C. |last2=Smith |title=Electroless Deposition of Nickel, Cobalt & Iron |publisher=IBM Corporation |location=Poughkeepsie, NY |date=1971}} |
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==References== |
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{{reflist}} |
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{{Hydrogen compounds}} |
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] |
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] |
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] |
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] |
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] |