Chemistry:Dimethylphosphine oxide
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| Names | |
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| Preferred IUPAC name
Dimethyl-λ5-phosphanone | |
| Other names
dimethylphosphinous acid tautomer
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| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
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PubChem CID
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| Properties | |
| C2H7OP | |
| Molar mass | 78.051 g·mol−1 |
| Appearance | colorless liquid |
| Boiling point | 65–67 °C |
| Hazards | |
| GHS pictograms | 
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| GHS Signal word | Warning |
| H302, H315, H319, H335 | |
| P261, P264, P270, P271, P280, P301+312, P302+352, P304+340, P305+351+338, P312, P321, P330, P332+313, P337+313, P362, P403+233, P405, P501 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Dimethylphosphine oxide is an organophosphorus compound with the formula (CH3)2P(O)H. It is a colorless liquid that soluble in polar organic solvents. It exists as the phosphine oxide, not the hydroxy tautomer. A related compound is diphenylphosphine oxide. Both are sometimes called secondary phosphine oxides.
Preparation
The compound arises by the hydrolysis of chlorodimethylphosphine:[1]
- Me2PCl + H2O → Me2P(O)H + HCl
Methanol, but not ethanol, can also be used in place of water, the co-product being methyl chloride.
Since chlorodimethylphosphine is dangerous to handle, alternative routes to dimethylphosphine oxide have been developed. A popular method starts with diethylphosphite, according to the following idealized equations:[2]
- (C2H5O)2P(O)H + 3 CH3MgBr → (CH3)2P(O)MgBr + 2 MgBr(OC2H5) + CH4
- (CH3)2P(O)MgBr + H2O → (CH3)2P(O)H + 2 MgBr(OH)
Reactions
Chlorination gives dimethylphosphoryl chloride. It undergoes hydroxymethylation with formaldehyde.
- Me2P(O)H + CH2O → Me2P(O)CH2OH
Many aldehydes effect a similar reaction.
References
- ↑ Kleiner, H. J. (1974). "Herstellung und Umsetzungen von Dimethylphosphinoxid (Preparation and Reactions of Dimethylphosphine Oxide)". Justus Liebigs Ann. Chem.: 751-764. doi:10.1002/jlac.197419740507.
- ↑ Hays, H. R. (1968). "Reaction of diethyl phosphonate with methyl and ethyl Grignard reagents". J. Org. Chem. 33: 3690-3694. doi:10.1021/jo01274a003.
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