Chemistry Halogenation of an alcohol (iodation)

[duchuy]

Homework Statement

Turn R-OH to R-I

Relevant Equations

x

I don't understand why in order to make RI from ROH, you'd have to use FINSKELSTEIN condition:
ROH + PBR3 --> RBr
RBr + NaI --> RI + NaBr

and not directly
ROH + PI₃ --> RI

Thank you so much for your help!
Pardon me if my english is not correct.

<mentor edit>

 

[chemisttree]

Sure, you could use PI3. You could also use HI. Your choice. Look at costs...