Methylphosphonyl dichloride

Last updated
Methylphosphonyl dichloride
Methylphosphonic dichloride-2D-by-AHRLS-2012.png
Methylphosphonic-dichloride-3D-balls-by-AHRLS-2012.png
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 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 211-634-4
PubChem CID
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
AppearanceWhite 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:
GHS-pictogram-acid.svg GHS-pictogram-skull.svg
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]

Contents

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.

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Sarin is an extremely toxic organophosphorus compound. A colourless, odourless liquid, it is used as a chemical weapon due to its extreme potency as a nerve agent. Exposure can be lethal even at very low concentrations, where death can occur within one to ten minutes after direct inhalation of a lethal dose, due to suffocation from respiratory paralysis, unless antidotes are quickly administered. People who absorb a non-lethal dose and do not receive immediate medical treatment may suffer permanent neurological damage.

<span class="mw-page-title-main">Soman</span> Chemical compound (nerve agent)

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<span class="mw-page-title-main">Acyl halide</span> Oxoacid compound with an –OH group replaced by a halogen

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<span class="mw-page-title-main">Copper(II) chloride</span> Chemical compound

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<span class="mw-page-title-main">Thionyl chloride</span> Inorganic compound (SOCl2)

Thionyl chloride is an inorganic compound with the chemical formula SOCl2. It is a moderately volatile, colourless liquid with an unpleasant acrid odour. Thionyl chloride is primarily used as a chlorinating reagent, with approximately 45,000 tonnes per year being produced during the early 1990s, but is occasionally also used as a solvent. It is toxic, reacts with water, and is also listed under the Chemical Weapons Convention as it may be used for the production of chemical weapons.

<span class="mw-page-title-main">Phosphorus pentachloride</span> Chemical compound

Phosphorus pentachloride is the chemical compound with the formula PCl5. It is one of the most important phosphorus chlorides/oxychlorides, others being PCl3 and POCl3. PCl5 finds use as a chlorinating reagent. It is a colourless, water-sensitive solid, although commercial samples can be yellowish and contaminated with hydrogen chloride.

<span class="mw-page-title-main">Phosphorus trichloride</span> Chemical compound

Phosphorus trichloride is an inorganic compound with the chemical formula PCl3. A colorless liquid when pure, it is an important industrial chemical, being used for the manufacture of phosphites and other organophosphorus compounds. It is toxic and reacts readily with water to release hydrogen chloride.

<span class="mw-page-title-main">Dimethyl methylphosphonate</span> Chemical compound

Dimethyl methylphosphonate is an organophosphorus compound with the chemical formula CH3PO(OCH3)2. It is a colourless liquid, which is primarily used as a flame retardant.

Organophosphorus chemistry is the scientific study of the synthesis and properties of organophosphorus compounds, which are organic compounds containing phosphorus. They are used primarily in pest control as an alternative to chlorinated hydrocarbons that persist in the environment. Some organophosphorus compounds are highly effective insecticides, although some are extremely toxic to humans, including sarin and VX nerve agents.

<span class="mw-page-title-main">Thiophosgene</span> Chemical compound

Thiophosgene is a red liquid with the formula CSCl2. It is a molecule with trigonal planar geometry. There are two reactive C–Cl bonds that allow it to be used in diverse organic syntheses.

Methylphosphonyl difluoride (DF), also known as EA-1251 or difluoro, is a chemical weapon precursor. Its chemical formula is CH3POF2. It is a Schedule 1 substance under the Chemical Weapons Convention. It is used for production of sarin and soman as a component of binary chemical weapons; an example is the M687 artillery shell, where it is used together with a mixture of isopropyl alcohol and isopropyl amine, producing sarin.

<span class="mw-page-title-main">Tributylphosphine</span> Chemical compound

Tributylphosphine is the organophosphorus compound with the chemical formula P(CH2CH2CH2CH3)3, often abbreviated as PBu3. It is a tertiary phosphine. It is an oily liquid at room temperature, with a nauseating odor. It reacts slowly with atmospheric oxygen, and rapidly with other oxidizing agents, to give the corresponding phosphine oxide. It is usually handled using air-free techniques.

<span class="mw-page-title-main">Trimethyl phosphite</span> Chemical compound

Trimethyl phosphite is an organophosphorus compound with the formula P(OCH3)3, often abbreviated P(OMe)3. It is a colorless liquid with a highly pungent odor. It is the simplest phosphite ester and finds used as a ligand in organometallic chemistry and as a reagent in organic synthesis. The molecule features a pyramidal phosphorus(III) center bound to three methoxy groups.

<span class="mw-page-title-main">Methylphosphonic acid</span> Chemical compound

Methylphosphonic acid is an organophosphorus compound with the chemical formula CH3P(O)(OH)2. The phosphorus center is tetrahedral and is bonded to a methyl group, two OH groups and an oxygen. Methylphosphonic acid is a white, non-volatile solid that is poorly soluble in organic solvent but soluble in water and common alcohols.

<span class="mw-page-title-main">Methyldichlorophosphine</span> Chemical compound

Methyldichlorophosphine (alternatively known as dichloro(methyl)phosphane, SW and methylphosphonous dichloride) is an organophosphorus compound with the chemical formula CH3PCl2. It is a colorless, corrosive, flammable, and highly reactive liquid with a pungent odor.

Methylphosphinic acid is a monobasic acid, the simplest of the phosphinic acids. A central phosphorus atom is connected to a hydroxy group, a hydrogen atom, a methyl group and an oxygen. Derivatives of methylphosphinic acid can have the phosphorus connected hydrogen atom replaced by other organic groups. In early days what is now called methylphosphonic acid was also called methylphosphinic acid.

In organophosphorus chemistry, the Kinnear–Perren reaction (sometimes the Clay-Kinnear-Perren reaction) is used to prepare alkylphosphonyl dichlorides (RP(O)Cl2) and alkylphosphonate esters (RP(O)(OR')2). The reactants are alkyl chloride, phosphorus trichloride, and aluminium trichloride as catalyst. The reaction proceeds via the alkyltrichlorophosphonium salt:

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)