Methylphosphonic acid can be prepared from
triethylphosphite by first using a
Michaelis-Arbuzov reaction to generate the phosphorus(V) centre: :CH3Cl + P(OC2H5)3 → CH3PO(OC2H5)2 + C2H5Cl The resulting dialkylphosphonate is then treated with
chlorotrimethylsilane before
hydrolysis of the siloxyphosphonate to generate the desired product. :CH3PO(OC2H5)2 + 2 Me3SiCl → CH3PO(OSiMe3)2 + 2 C2H5Cl :CH3PO(OSiMe3)2 + 2H2O → CH3PO(OH)2 + 2 HOSiMe3 The reaction pathway proceeds via the siloxyphosphonate intermediate due to the difficulty in directly hydrolysing dialkylphosphonates.
Katritzky and co-workers published a
one-pot synthesis of methylphosphonic acid in 1989. ==References==