# Why is the boiling point of para hydroxybenzoic acid lower than that of ortho hydroxybenzoic acid?

As per the literature at 760mm of mercury, p-hydroxy benzoic acid has lower boiling point ($\pu{336^\circ C}$ - ChemSpider) than o-hydroxy benzoic acid ($\pu{372^\circ C}$ - ChemSpider). What is the reason behind this although for the former we can see intermolecular H-bonding?

• One consideration: the para compound can have a "bimolecular" hydrogen bond structure like acetic acid. – Oscar Lanzi May 15 '18 at 15:02