Methylphosphonyl dichloride
{{Chembox
| ImageFile1 = Methylphosphonic dichloride-2D-by-AHRLS-2012.png
| ImageSize1 = 150px
| ImageFile2 = Methylphosphonic-dichloride-3D-balls-by-AHRLS-2012.png
| ImageSize2 = 150px
| PIN = Methylphosphonic dichloride
| OtherNames = Methanephosphonic dichloride
Methanephosphonic acid dichloride
Methylphosphonyl dichloride
Dichloro
|Section1={{Chembox Identifiers
| CASNo = 676-97-1
| PubChem = 12671
| ChemSpiderID = 12150
| EINECS = 211-634-4
| UNNumber = 9206
| SMILES = CP(=O)(Cl)Cl
| InChI = 1/CH3Cl2OP/c1-5(2,3)4/h1H3
| InChIKey = SCLFRABIDYGTAZ-UHFFFAOYAS
| StdInChI = 1S/CH3Cl2OP/c1-5(2,3)4/h1H3
| StdInChIKey = SCLFRABIDYGTAZ-UHFFFAOYSA-N
}}
|Section2={{Chembox Properties
| C=1 | H=3 | Cl=2 | O=1 | P=1
| Appearance = White crystalline solid
| Density = 1.468 g/mL at 20 °C
| MeltingPtC = 28 to 34
| MeltingPt_notes =
| BoilingPtC = 163
| Solubility = Reacts with water
| SolubleOther = Ether, THF
}}
|Section3={{Chembox Hazards
| MainHazards = Very toxic, reacts with water
| FlashPt = >110 °C
| LD50 = 26 ppm/4h by inhalation (rat)
| GHSPictograms = {{GHS05}}{{GHS06}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|314|330}}
| PPhrases = {{P-phrases|260|264|271|280|284|301+330+331|303+361+353|304+340|305+351+338|310|320|321|363|403+233|405|501}}
| AutoignitionPt =
}}
}}
Methylphosphonyl dichloride (DC) or dichloro is an organophosphorus compound. It has commercial application in oligonucleotide synthesis,{{list journal|work=Aldrich Handbook & Catalog of Fine Chemicals|location=Milwaukee, WI|publisher=Aldrich Chemical Company|date=1994}} p. 871. As [https://pubchem.ncbi.nlm.nih.gov/source/hsdb/6329#section=Manufacturing-Use-Information cited] in HSDB. 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.{{Cite web |date=June 26, 2020 |title=SAFETY DATA SHEET Methylphosphonic dichloride |url=https://www.sigmaaldrich.com/US/en/sds/aldrich/228052 |access-date=April 27, 2022 |website=SAFETY DATA SHEET Methylphosphonic dichloride |publisher=MilliporeSigma}}
Synthesis and reactions
Methylphosphonyl dichloride is produced by oxidation of methyldichlorophosphine, with sulfuryl chloride: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}}.
: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.{{cite journal|last=Maier|first=Ludwig|title=Organic Phosphorus Compounds 90.l A Convenient, One-Step Synthesis of Alkyl- and Arylphosphonyl Dichlorides|journal=Phosphorus, Sulfur, and Silicon and the Related Elements|year=1990|volume=47|issue=3–4|pages=465–470|doi=10.1080/10426509008038002}}
With hydrogen fluoride or sodium fluoride, it can be used to produce methylphosphonyl difluoride. With alcohols, it converts to the dialkoxide:{{cite journal |doi=10.15227/orgsyn.073.0152|title=Bis(Trifluoroethyl) (carboethoxymethyl)phosphonate|journal=Organic Syntheses|year=1996|volume=73|page=152|author=Carl Patois, Philippe Savignac, Elie About-Jaudet, Noël Collignon
}}
:CH3P(O)Cl2 + 2{{nbsp}}HOR → CH3P(O)(OR)2 + {{nbsp}}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
{{reflist}}
{{Chemical agents}}
Category:Nerve agent precursors