Tetrakis(hydroxymethyl)phosphonium chloride (THPC) is an organophosphorus compound with the chemical formula [P(CH2OH)4]Cl. It is a white water-soluble salt. THPC has applications as a precursor to fire-retardant materials,[1] as well as a microbiocide in commercial and industrial water systems.
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| Names | |
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| Preferred IUPAC name
Tetrakis(hydroxymethyl)phosphonium chloride | |
| Other names
Tetrahydroxymethylphosphonium chloride, THPC
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| Identifiers | |
| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.004.280 |
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PubChem CID
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| UNII | |
| UN number | 2810 |
CompTox Dashboard (EPA)
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| Properties | |
| C4H12ClO4P | |
| Molar mass | 190.56 g·mol−1 |
| Appearance | white solid |
| Density | 1.341 g/cm3 |
| Melting point | 150 °C (302 °F; 423 K) |
| Hazards | |
| GHS labelling: | |
    
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| Danger | |
| H301, H302, H311, H312, H314, H315, H330, H334, H411 | |
| P260, P261, P264, P270, P271, P273, P280, P284, P285, P301+P310, P301+P312, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P304+P341, P305+P351+P338, P310, P312, P320, P321, P322, P330, P332+P313, P342+P311, P361, P362, P363, P391, P403+P233, P405, P501 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Synthesis, structure, and reactions
editTHPC can be synthesized with high yield by treating phosphine with formaldehyde in the presence of hydrochloric acid.[1]
- PH3 + 4 H2C=O + HCl → [P(CH2OH)4]Cl
The cation P(CH2OH)4+ features four-coordinate phosphorus, as is typical for phosphonium salts.
THPC converts to tris(hydroxymethyl)phosphine upon treatment with aqueous sodium hydroxide:[2]
- [P(CH2OH)4]Cl + NaOH → P(CH2OH)3 + H2O + H2C=O + NaCl
Application in textiles
editTHPC has industrial importance in the production of crease-resistant and flame-retardant finishes on cotton textiles and other cellulosic fabrics.[3] [4] A flame-retardant finish can be prepared from THPC by the Proban Process,[5] in which THPC is treated with urea. The urea condenses with the hydroxymethyl groups on THPC. The phosphonium structure is converted to phosphine oxide as the result of this reaction.[6]
- [P(CH2OH)4]Cl + NH2CONH2 → (HOCH2)2P(O)CH2NHC(O)NH2 + HCl + HCHO + H2 + H2O
This reaction proceeds rapidly, forming insoluble high molecular weight polymers. The resulting product is applied to the fabrics in a "pad-dry process." This treated material is then treated with ammonia and ammonia hydroxide to produce fibers that are flame-retardant.
THPC can condense with many other types of monomers in addition to urea. These monomers include amines, phenols, and polybasic acids and anhydrides.
Tris(hydroxymethyl)phosphine and its uses
editTris(hydroxymethyl)phosphine, which is derived from tetrakis(hydroxymethyl)phosphonium chloride, is an intermediate in the preparation of the water-soluble ligand 1,3,5-triaza-7-phosphaadamantane (PTA). This conversion is achieved by treating hexamethylenetetramine with formaldehyde and tris(hydroxymethyl)phosphine.[7]
Tris(hydroxymethyl)phosphine can also be used to synthesize the heterocycle, N-boc-3-pyrroline by ring-closing metathesis using Grubbs' catalyst (bis(tricyclohexylphosphine)benzylidineruthenium dichloride). N-Boc-diallylamine is treated with Grubbs' catalyst, followed by tris(hydroxymethyl)phosphine. The carbon-carbon double bonds undergo ring closure, releasing ethene gas, resulting in N-boc-3-pyrroline.[8] The hydroxymethyl groups on THPC undergo replacement reactions when THPC is treated with α,β-unsaturated nitrile, acid, amide, and epoxides. For example, base induces condensation between THPC and acrylamide with displacement of the hydroxymethyl groups. (Z = CONH2)
- [P(CH2OH)4]Cl + NaOH + 3CH2=CHZ → P(CH2CH2Z)3 + 4CH2O + H2O + NaCl
Similar reactions occur when THPC is treated with acrylic acid; only one hydroxymethyl group is displaced, however.[9]
References
edit- ^ a b Svara, Jürgen; Weferling, Norbert; Hofmann, Thomas (2006). "Phosphorus Compounds, Organic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_545.pub2. ISBN 3527306730.
- ^ M. Caporali, L. Gonsalvi, F. Zanobini, M. Peruzzini "Synthesis of the Water-Soluble Bidentate (P,N) Ligand PTN(Me)" Inorg. Syntheses, 2011, Vol. 35, p. 92–108. doi:10.1002/9780470651568.ch5
- ^ Fischer, Klaus; Marquardt, Kurt; Schlüter, Kaspar; Gebert, Karlheinz; Borschel, Eva-Marie; Heimann, Sigismund; Kromm, Erich; Giesen, Volker; Schneider, Reinhard; Lee Wayland, Rosser (2000). "Textile Auxiliaries". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a26_227. ISBN 3-527-30673-0.
- ^ Weil, Edward D.; Levchik, Sergei V. (2008). "Flame Retardants in Commercial Use or Development for Textiles". J. Fire Sci. 26 (3): 243–281. doi:10.1177/0734904108089485. S2CID 98355305.
- ^ "Frequently asked questions: What is the PROBAN® process?". Rhodia Proban. Archived from the original on December 7, 2012. Retrieved February 25, 2013.
- ^ Reeves, Wilson A.; Guthrie, John D. (1956). "Intermediate for Flame-Resistant Polymers-Reactions of Tetrakis(hydroxymethyl)phosphonium Chloride". Industrial and Engineering Chemistry. 48 (1): 64–67. doi:10.1021/ie50553a021.
- ^ Daigel, Donald J.; Decuir, Tara J.; Robertson, Jeffrey B.; Darensbourg, Donald J. (2007). "1,3,5-Triaz-7-Phosphatricyclo[3.3.1.1 3,7 ]Decane and Derivatives". Inorganic Syntheses. Vol. 32. pp. 40–42. doi:10.1002/9780470132630.ch6. ISBN 978-0-470-13263-0.
{{cite book}}:|journal=ignored (help) - ^ Ferguson, Marcelle L.; O’Leary, Daniel J.; Grubbs, Robert H. (2003). "Ring-Closing Metathesis Synthesis Of N-Boc-3-Pyrroline". Organic Syntheses. 80: 85. doi:10.15227/orgsyn.080.0085
{{cite journal}}: CS1 maint: multiple names: authors list (link). - ^ Vullo, W. J. (1966). "Hydroxymethyl Replacement Reactions of Tetrakis(hydroxymethyl)phosphonium Chloride". Ind. Eng. Chem. Prod. Res. Dev. 58 (4): 346–349. doi:10.1021/i360020a011.