Methylphosphonyl dichloride (DC) or dichloro is an organophosphorus compound. It has a number of commercial uses[vague] 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.[1]
Synthesis and reactions
Methylphosphonyl dichloride is produced by oxidation of methyldichlorophosphine, with sulfuryl chloride:[2]
- 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.[3] With hydrogen fluoride or sodium fluoride, it can be used to produce methylphosphonyl difluoride. With alcohols, it converts to the dialkoxide:[4]
- 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
- ^ "SAFETY DATA SHEET Methylphosphonic dichloride". SAFETY DATA SHEET Methylphosphonic dichloride. MilliporeSigma. June 26, 2020. Retrieved April 27, 2022.
- ^ 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.
- ^ Carl Patois, Philippe Savignac, Elie About-Jaudet, Noël Collignon (1996). "Bis(Trifluoroethyl) (carboethoxymethyl)phosphonate". Organic Syntheses. 73: 152. doi:10.15227/orgsyn.073.0152.
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