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Organic Phosphorus Compounds 59. A new method for the synthesis of phosphonic dichlorides
Author(s) -
Maier Ludwig
Publication year - 1973
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19730560143
Subject(s) - chemistry , yield (engineering) , sulfur , phosphorus trichloride , phosphorus , medicinal chemistry , molar ratio , organic chemistry , inorganic chemistry , catalysis , materials science , metallurgy
Heating of thiophosphonic dichlorides, RP(S)Cl 2 , R CH 3 , C 2 H 3 , C 2 H 5 , with a molar equivalent of SOCl 2 under pressure at 150° for 5 to 8 h yields phosphonic dichlorides in quantitative yield. In addition sulfur and sulfur dichloride is formed according to the equation:\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm RP}\left({\rm S} \right){\rm Cl}_{\rm 2} + {\rm SOCl}_{\rm 2} \to {\rm RP}\left({\rm O} \right){\rm Cl}_{\rm 2} + {\rm SCl}_{\rm 2} + {\rm S} $$\end{document}This method is particularly useful for the preparation of CH 3 P(O)Cl 2 since it was observed that chlorination of CH 3 P(O)(OCH 3 ) 2 with PCl 5 yields CH 3 OP(O)Cl 2 as a by‐product which is difficult to separate from CH 3 P(O)Cl 2 . On the other hand chlorination of methylphosphonic acid with PCl 5 also gives pure CH 3 P(O)Cl 2\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm CH}_{\rm 3} {\rm P}\left({\rm O} \right)\left({{\rm OH}} \right)_2 + 2{\rm PCl}_{\rm 5} \to {\rm CH}_{\rm 3} {\rm P}\left({\rm O} \right){\rm Cl}_{\rm 2} + 2{\rm HCl} + {\rm 2POCl}_{\rm 3} $$\end{document} .