The structure of diethyl ether and butan-1-ol are shown in the figure.
As shown in the figure the diethyl ether will be able to form hydrogen bond with water and so is butanol, due to presence of highly electro-negative element (oxygen)
However a molecule of diethyl ether is not able to form such hydrogen bond with another diethyl ether molecule. Due to this it has lower boiling point
Butanol is able to form hydrogen bond with another butanol molecule due to this it has high boiling point
