Methylphosphonic acid dichloride

Methylphosphonic acid dichloride
Names
IUPAC name
Methylphosphonic dichloride
Other names
Methanephosphonic dichloride, Methanephosphonic acid dichloride, methylphosphonyl dichloride
Identifiers
676-97-1
ChemSpider 12150
EC Number 211-634-4
Jmol interactive 3D Image
PubChem 12671
Properties
CH3Cl2OP
Molar mass 132.91 g·mol−1
Appearance White crystalline solid
Density 1.468 g/mL at 20 °C
Melting point 28 to 34 °C (82 to 93 °F; 301 to 307 K)
Boiling point 163 °C (325 °F; 436 K)
Hazards
Main hazards Very Toxic
R-phrases R14, R23/24/25, R26, R34
Flash point >110 °C
Lethal dose or concentration (LD, LC):
26 ppm/4h by inhalation (rat)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Methyl phosphonic dichloride is an organophosphorus compound. It has a number of potential uses but is most notable as being a precursor to several chemical weapons agents. It is a white crystalline solid, with a low melting point. It hydrolyzes readily and must be handled with care as it is exceedingly toxic.

Synthesis and reactions

Methyl phosphonic dichloride is produced by oxidation of methyldichlorophosphine, e.g. with sulfuryl chloride:[1]

MePCl2 + SO2Cl2 → MeP(O)Cl2 + SOCl2

It can also be produced from a range of methyl-phosphonates (e.g. dimethyl methylphosphonate) via chlorination with thionyl chloride. Various amines can be used to catalyse this process.[2] It reacts with hydrogen fluoride or sodium fluoride to produce methylphosphonyl difluoride, which is used in the production of sarin and soman nerve agents.

References

  1. Svara, J.; Weferling, N.; Hofmann, T. "Phosphorus Compounds, Organic," In 'Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2008. doi:10.1002/14356007.a19_545.pub2.
  2. Maier, Ludwig (1990). "ORGANIC PHOSPHORUS COMPOUNDS 90.l A CONVENIENT, ONE-STEP SYNTHESIS OF ALKYL- AND ARYLPHOSPHONYL DICHLORIDES". Phosphorus, Sulfur, and Silicon and the Related Elements 47 (3-4): 465–470. doi:10.1080/10426509008038002.
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