Standard molar enthalpies of formation of 1-methyl-2-piperidinemethanol, 1-piperidineethanol, and 2-piperidineethanol

The standard (p∘ = 0.1 MPa) molar enthalpies of combustion, ΔcHm∘, for the liquid compounds 1-methyl-2-piperidinemethanol, 1-piperidineethanol, and 2-piperidineethanol, were measured by static bomb calorimetry, in oxygen, at T = 298.15 K. The standard molar enthalpies of vaporization, at T = 298.15 K, of these three liquid compounds were determined by Calvet microcalorimetry. -ΔcHm∘(l)/(kJ·mol-1)ΔlgHm∘/(kJ·mol-1)1-Methyl-2-piperidinemethanol4598.3 ± 1.868.22 ± 0.711-Piperidineethanol4595.2 ± 1.764.18 ± 0.812-Piperidineethanol4566.2 ± 1.375.24 ± 0.52Full-size tableTable optionsView in workspaceDownload as CSVThese values, were used to derive the standard molar enthalpies of formation of the compounds, at T = 298.15 K, in their liquid and gaseous phase, respectively. The derived standard molar enthalpies of formation, in the gaseous state, are analyzed in terms of enthalpic increments and interpreted in terms of molecular structure.