[HP]

Ah, yes now i grasp what you mean:
PCl3 + ROH --> P(OR)3 phosphite ester but and 3HCl
If you use some organic base for  HCl then reaction stops to thr phosphite esters which are generally used as plastilizers and retardant in plastics.
But what happens when do not use HCl acseptor under reflux  
Is possible:
P(OR)3 + 3HCl--> H3PO3 + 3 R-Cl