Methylphosphonic acid dichloride
|Methylphosphonic acid dichloride|
|Jmol-3D images||Image 1|
|Molar mass||132.91 g mol−1|
|Appearance||White crystalline solid|
|Density||1.468 g/mL at 20 °C|
|R-phrases||R14, R23/24/25, R26, R34|
|Main hazards||Very Toxic|
|LD50||26 ppm/4h by inhalation (rat)|
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
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
- 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. It reacts with hydrogen fluoride or sodium fluoride to produce methylphosphonyl difluoride, which is used in the production of sarin and soman nerve agents.
- 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.