Propanol has a higher boiling point than butane because propanol contains an –OH group which is involved in intermolecular hydrogen bonding. This hydrogen bonding creates strong attractive forces between propanol molecules, requiring more energy to overcome during boiling.

In contrast, butane is a hydrocarbon that lacks the ability to form hydrogen bonds. The absence of hydrogen bonding in butane means its molecules are held together only by weaker intermolecular forces, resulting in a lower boiling point.

The high boiling points of alcohols compared to hydrocarbons of comparable molecular masses is a characteristic property due to the presence of hydrogen bonding in alcohols, which is lacking in hydrocarbons.