Methylphosphonyl dichloride

Methylphosphonyl dichloride
Names
Preferred IUPAC name
Methylphosphonic dichloride
Other names
Methanephosphonic dichloride
Methanephosphonic acid dichloride
Methylphosphonyl dichloride
Dichloro
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.010.578 Edit this at Wikidata
EC Number
  • 211-634-4
UN number 9206
  • 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
  • CP(=O)(Cl)Cl
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)
Reacts with water
Solubility Ether, THF
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Very toxic, reacts with water
GHS labelling:
GHS05: CorrosiveGHS06: Toxic
Danger
H314, H330
P260, P264, P271, P280, P284, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P320, P321, P363, P403+P233, P405, P501
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).

Methylphosphonyl dichloride (DC) or dichloro is an organophosphorus compound. It has commercial application in oligonucleotide synthesis,[1] but is most notable as being a precursor to several chemical weapons agents. It is a white crystalline solid that melts slightly above room temperature.[2]

Synthesis and reactions

Methylphosphonyl dichloride is produced by oxidation of methyldichlorophosphine, with sulfuryl chloride:[3]

CH3PCl2 + SO2Cl2 → CH3P(O)Cl2 + SOCl2

It can also be produced from a range of methylphosphonates (e.g. dimethyl methylphosphonate) via chlorination with thionyl chloride. Various amines catalyse this process.[4] With hydrogen fluoride or sodium fluoride, it can be used to produce methylphosphonyl difluoride. With alcohols, it converts to the dialkoxide:[5]

CH3P(O)Cl2 + 2 HOR → CH3P(O)(OR)2 +  HCl

Safety

Methylphosphonyl dichloride is very toxic and reacts vigorously with water to release hydrochloric acid. It is also listed under Schedule 2 of the Chemical Weapons Convention as it is used in the production of organophosphorus nerve agents such as sarin and soman.

References

  1. ^ Aldrich Handbook & Catalog of Fine Chemicals. Milwaukee, WI: Aldrich Chemical Company.   1994. p. 871. As cited in HSDB.
  2. ^ "SAFETY DATA SHEET Methylphosphonic dichloride". SAFETY DATA SHEET Methylphosphonic dichloride. MilliporeSigma. June 26, 2020. Retrieved April 27, 2022.
  3. ^ 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.
  4. ^ 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.
  5. ^ Carl Patois, Philippe Savignac, Elie About-Jaudet, Noël Collignon (1996). "Bis(Trifluoroethyl) (carboethoxymethyl)phosphonate". Organic Syntheses. 73: 152. doi:10.15227/orgsyn.073.0152.{{cite journal}}: CS1 maint: multiple names: authors list (link)