Question

How can we convert ethanol to propanenitrile?

Answer 1

Conversion of Ethanol to Propanenitrile:

Step 1: Formation of Bromoethane

At first, the Ethanol is treated with Red phosphorus and Bromine to form Bromoethane:

$\underset{\mathrm{Ethanol}}{{\mathrm{CH}}_3-{\mathrm{CH}}_2-\mathrm{OH}}\stackrel{\mathrm{red}\mathrm{P}/{\mathrm{Br}}_2}{\to }\underset{\mathrm{Bromoethane}}{{\mathrm{CH}}_3-{\mathrm{CH}}_2-\mathrm{Br}}$

Step 2: Formation of Propanenitrile

This Bromoethane formed is then reacted with Potassium cyanide in aqueous ethanol to form our required product Propanenitrile:

$\underset{\mathrm{Bromoethane}}{{\mathrm{CH}}_3-{\mathrm{CH}}_2-\mathrm{Br}}\underset{\mathrm{Ethanol}\left(\mathrm{aq}\right)}{\overset{\mathrm{KCN}}{\to }}\underset{\mathrm{Propanenitrile}}{{\mathrm{CH}}_3-{\mathrm{CH}}_2-\mathrm{CN}}+\underset{\mathrm{Potassium}\mathrm{bromide}}{\mathrm{KBr}}$

This formation of Propanenitrile from Ethanol is a 2 step reaction.

Therefore, Ethanol reacted with $\mathrm{red}\mathrm{P}/{\mathrm{Br}}_2$followed by reaction with $\mathrm{KCN}$ in aqueous ethanol forms Propanenitrile.