Investigation on enthalpies of combustion and heat capacities for 2-aminomethylpyridine derivatives

Abstract

The molar energies of combustion $$\left( {\Delta_{\text{c}} U_{\text{m}} } \right)$$ for 2-aminomethylpyridine (AMP), tert-butyl 2-[N-(tert-Y)-2-picolyamino]acetate (AMPY), N,N-dioctyl-2-(aminomethyl)pyridine (AMPO), and tert-butyl 2-(N-octyl-2-picolyamino)acetate (AMPA) were measured by an oxygen bomb calorimeter at 298.15 K, and the results are: − (3585.5 ± 2.4) kJ mol−1, − (10145.0 ± 7.2) kJ mol−1, − (14047.1 ± 18.8) kJ mol−1, − (12141.3 + 12.3) kJ mol−1, respectively. The standard molar enthalpies of combustion $$\left( {\Delta_{\text{c}} H_{\text{m}}^{\varTheta } } \right)$$ and standard molar enthalpies of formation $$\left( {\Delta_{\text{f}} H_{\text{m}}^{\varTheta } } \right)$$ for these compounds were derived from the experimental results and literature values. The values of $$\Delta_{\text{f}} H_{\text{m}}^{\varTheta }$$ for AMP, AMPY, AMPO and AMPA are 88.4 ± 2.5 kJ mol−1, − (930.4 ± 7.6)kJ mol−1, − (304.8 ± 19.0)kJ mol−1 and − (569.9 ± 12.6) kJ mol−1. The heat capacities at constant pressure for these compounds were measured with a DSC over the temperature range from 280 to 323 K, and the relationships between the heat capacity and temperature were obtained from measured results. The melting point and enthalpy of fusion for AMPY were also determined by DSC.