Methylphosphonyl dichloride

Methylphosphonyl dichloride
Names
	Preferred IUPAC name Methylphosphonic dichloride
	Other names Methanephosphonic dichloride; Methanephosphonic acid dichloride; Methylphosphonyl dichloride
Identifiers
CAS Number	676-97-1;
3D model (JSmol)	Interactive image;
ChemSpider	12150;
ECHA InfoCard	100.010.578
EC Number	211-634-4;
PubChem CID	12671;
CompTox Dashboard (EPA)	DTXSID6060979 ;
	InChI InChI=1S/CH3Cl2OP/c1-5(2,3)4/h1H3 Key: SCLFRABIDYGTAZ-UHFFFAOYSA-N; InChI=1/CH3Cl2OP/c1-5(2,3)4/h1H3 Key: SCLFRABIDYGTAZ-UHFFFAOYAS;
	SMILES CP(=O)(Cl)Cl;
Properties
Chemical formula	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
	Occupational safety and health (OHS/OSH):
Main hazards	Very Toxic
Flash point	>110 °C
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	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.^{[citation needed]}

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

^ 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.
^ 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.

[Svara-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.

[1]

[2]