# How would you expect phosphorus pentachloride to react with ethanol? How does this reaction resemble the reaction of phosphorus pentachloride with ethanoic acid?

Nov 29, 2016

With alcohol:
$P C {l}_{5} + R O H \rightarrow O = P C {l}_{3} + R C l + H C l$

#### Explanation:

With acid:

$P C {l}_{5} + R C \left(= O\right) O H \rightarrow O = P C {l}_{3} + R C \left(= O\right) C l + H C l$

$\text{Phosphorus pentachloride}$ is a halogenating agent. It is rarely used these days, as you have to remove the $\text{pockle3}$ after the reaction. $P C {l}_{5}$ is very water sensitive, and a bit hard to handle. A better alternative might be $\text{thionyl chloride}$, which you can pour out of a bottle and distill off:

$R C {O}_{2} H + S O C {l}_{2} + \Delta \rightarrow R C \left(= O\right) C l + S {O}_{2} \uparrow + H C l \uparrow$