Dimethylphosphine oxide


Dimethylphosphine oxide is an organophosphorus compound with the formula 2PH. It is a colorless liquid that soluble in polar organic solvents. It exists as the phosphine oxide, not the hydroxy tautomer. A related compound is diphenylphosphine oxide. Both are sometimes called secondary phosphine oxides.

Preparation

The compound arises by the hydrolysis of chlorodimethylphosphine:
Methanol, but not ethanol, can also be used in place of water, the co-product being methyl chloride.
Since chlorodimethylphosphine is dangerous to handle, alternative routes to dimethylphosphine oxide have been developed. A popular method starts with diethylphosphite, according to the following idealized equations:

Reactions

Chlorination gives dimethylphosphoryl chloride. It undergoes hydroxymethylation with formaldehyde.
Many aldehydes effect a similar reaction.