Hydrogen bond lifetimes and equilibria in hydroxyl functionalized ionic liquids This work investigates the hydrogen bond (HB) lifetimes and equilibrium in hydroxyl functionalized pyridinium based ionic liquids. Two types of intermolecular HBs are observed: typical cation anion HBs are competing with atypical cation cation HBs . By employing molecular dynamics simulations the equilibrium between those HBs was examined as a function of temperature and alkyl chain length. In addition the influence of the different HBs on the structure and dynamics of the ionic liquid are discussed. Also HB lifetimes where examined.<eng>