Triphenylphosphine dichloride is usually prepared fresh by the addition of chlorine to triphenylphosphine.
:PhP + Cl → PhPCl
Both reagents are typically used in solution to ensure the correct stoichiometry.
PhPCl can also be obtained by the reaction of iodobenzene dichloride (PhICl) and triphenylphosphine.
Alternatively, PhPCl can be obtained by chlorination of triphenylphosphine oxide with, for example, phosphorus trichloride, as in Grignard's original 1931 synthesis.