Amines generally have lower boiling points than alcohols of comparable molar mass because amines have weaker hydrogen bonds than alcohols.
Consider the compounds methanol and methylamine.
Methanol, ##”CH”_3″OH”##: molar mass = 32 g/mol; boiling point = 65 °C
Methylamine, ##”CH”_3″NH”_2##: molar mass = 31 g/mol; boiling point = -6 °C
Methanol has strong hydrogen bonds.
The strong intermolecular forces give methanol a high boiling point.
It is a liquid at room temperature.
Methylamine also has hydrogen bonds.
But the H-bonds in methylamine are weaker, because N is less electronegative than O.
It requires less energy to break the weaker intermolecular forces, so methylamine has a lower boiling point than methanol.
Methylamine is a gas at room temperature.