Excess molr enthalpies H-m(E) of (2-butanol + benzene, or toluene, or o-, or m-, or p-xylene) over the entire composition range at the temperature 308.15 It have been measured in a flow microcalorimeter. The results are analysed in terms of a Mecke-Kempter type association model with a Flory contribution term and a quasi-lattice model by Barker.