Why do phenols generally have higher boiling points than hydrocarbons of similar molecular weight?

Phenols possess higher boiling points than hydrocarbons of similar molecular weight primarily due to the presence of hydroxyl groups, which allow the molecules to participate in intermolecular hydrogen bonding.1

In fact, phenols are capable of forming even stronger hydrogen bonds than typical alcohols. These intermolecular forces create a stronger attraction between phenol molecules compared to the weaker forces present in hydrocarbons, requiring more energy to overcome during the transition from liquid to gas.12

For example, phenol has a molecular weight of 94 and a boiling point of 182 °C, whereas toluene—a hydrocarbon with a similar molecular weight of 92—boils at only 111 °C. This significant difference illustrates the substantial impact that hydrogen bonding has on the physical properties of these compounds.1