Vapor pressure and enthalpy of vaporization of 2-amino-3-methylpyridine

Article abstract of DOI:10.1021/je700371w

The vapor pressure of 2-amino-3-methylpyridine was measured in the temperature range of (328.70 to 499.88) K using the boiling point method. The Antoine equation was used to describe the vapor pressure data, and the parameters in the equation were determined by means of the least-square regression method. The deviation of experimental data from the corresponding calculated values was within 0.30 %. On the basis of the equation, the enthalpy of vaporization of 2-amino-3-methylpyridine at normal boiling point (T _b) was obtained from the slope of the plot of In p vs 1/T. The standard enthalpy of vaporization Δ_vapH(298.15 K) was estimated by Othmer's method. Using 3-methylpyridine as the standard substance, the value of Δ_vap#(298.15 K) was found to be 62.58 kJ·mol ^-1. A parallel value of Δ_vapH(298.15 K) was also obtained using benzene as the standard substance. Additionally the Watson relation was employed to verify the value of Δ_vapH(298.15 K), from which it was shown that the value of the standard enthalpy of vaporization was acceptable.