Sometimes, bromides can be used in place of chlorides (it's easier and safer to handle)

The most convenient route involves the reaction of white or red phosphorus with chlorine, in PCl3. The PCl3 solvent where the bulk process takes place is made by reacting dry chlorine with phosphorus directly, and then more dry phosphorus is added, followed by the addition of dry chlorine. The reaction takes place under reflux and the resulting phosphorus trichloride is fractionally distilled to prevent the formation of PCl5.

There is an equilibrium PCl5 <-> PCl3 + Cl2, so P + PCl5 -> PCl3 should work by adding excess red P