Methanol → Diphenyl methylphosphonate

Participants

Reaction Steps

A reactor fitted with an efficient condenser, thermometer, mechanical stirrer and side-arm addition funnel was charged with 1552 g (5.0 mol) of triphenyl phosphite. The reactant was placed under a nitrogen blanket and heated to reflux. A solution of 5.0 g of methyl iodide in 160 g (5.1 mol) of methanol was then slowly added over a two hour period. Throughout the addition, the temperature of the reactor contents was maintained within the 200°-250° C. range. One further hour at 215° C. proved sufficient for the reaction to reach completion. Subsequently, an aspirator vacuum distillation removed 468 g (5.0 mol) of phenol containing a small amount of anisole. Thereafter, a high vacuum distillation recovered 1150 g (4.6 mol, 92% yield) of diphenyl methylphosphonate. Glc analysis using a 6 foot column packed with 10% OV-101 on chromosorb W, was employed to monitor the progress of both the reaction and distillation. The 31P signal for the product appeared at -24.0 ppm. Proton nmr signals were seen at τ8.36 (3 H, doublet, J=18 HZ, CH3P) and τ2.9-2.5 (10 H, multiplet, phenyl).

Provenance & Evidence