Dimethylphosphite Explained

Dimethylphosphite is an organophosphorus compound with the formula (CH3O)2P(O)H, known as dimethyl hydrogen phosphite (DMHP). Dimethylphosphite, is a minor tautomer of the phosphorus(V) derivative. It is a reagent for generating other organophosphorus compounds, exploiting the high reactivity of the P-H bond. The molecule is tetrahedral. It is a colorless liquid. The compounds can be prepared by methanolysis of phosphorus trichloride or by heating diethylphosphite in methanol.[1]

Although studies have not been reported for this compound, the closely related diethylphosphite exists predominantly as the phosphorus(V) tautomer.[2]

This tautomeric nature of DMHP made it desirable as a precursor to the G-series compounds, and it was the most successful among all other phosphonate precursors.[3] The now obsolete process, which used it as a precursor, was called the DMHP process, investigated by Otto Ambros' team and implemented to scale sarin production.[4]

References

  1. Alcoholysis of Dialkyl Phosphites Under Microwave Conditions. Balint, Erika . Tajti, Adam . Drahos, Laszlo . Ilia, Gheorge . Keglevich, Gyorgy . Current Organic Chemistry. 17. 2013. 5. 555ā€“562. 10.2174/1385272811317050010.
  2. 10.1139/v79-039. Tautomerization Equilibria for Phosphorous Acid and its Ethyl Esters, Free Energies of Formation of Phosphorous and Phosphonic Acids and their Ethyl Esters, and p Ka Values for Ionization of the Pā€”H Bond in Phosphonic Acid and Phosphonic Esters . 1979 . Guthrie . J. Peter . Canadian Journal of Chemistry . 57 . 2 . 236ā€“239 . free .
  3. Sipri - Chemical Weapons: Destruction and Conversion. p 57-62
  4. Mark A. Prelas, Dabir S. Viswanath,. Science and Technology of Terrorism and Counterterrorism, Second lllllEdition. p 341-342.