Thermochemistry of fusion, solution and hydrogen bonding in benzamide, N-methylbenzamide, and acetanilide

•Enthalpies of fusion at tm and solution at 298.15K of three amides were measured.•Heat capacities of two amides in the crystalline and liquid phases were determined.•Relationship between the enthalpies of fusion and solution of three amides was analyzed.•Solution enthalpies of supercooled liquids at 298.15K were derived.•Hydrogen bond enthalpies in liquid benzamide and N-methylbenzamide were evaluated. Aromatic amides are important precursors for biologically active compounds and are often considered model objects containing a NHCO group, which is ubiquitous in living organisms. In this work we experimentally studied the fusion and solution thermochemistry, and the crystal and liquid heat capacities of three amides: acetanilide, benzamide, and N-methylbenzamide. From the experimental and literature data obtained, the fusion enthalpies at 298.15 K were derived and their relationship with the solution enthalpies of the crystals in N,N-dimethylformamide was analyzed. From the analysis, the solution enthalpies of quasi-equilibrium liquid amides at 298.15 K and hydrogen bonding enthalpies in the neat liquid were derived. The solution enthalpies of quasi-equilibrium liquid amides at 298.15 K are useful for the further evaluation of the fusion enthalpies of benzamide and acetanilide derivatives at 298.15 K by solution calorimetry.