Vapour pressure and vaporisation enthalpy for two key apple odorants, ethyl butyrate and ethyl hexanoate, at pressures from (15 to 105) kPa

Vapour pressure complementary data for two key apple aroma esters, ethyl butyrate and ethyl hexanoate, two compounds with high relevance to the food industry, were measure with a dynamic recirculation apparatus. For pressures from (15 to 105) kPa the temperatures experimentally assessed were from (340.1 to 395.2) K for ethyl butyrate, and from (378.4 to 440.9) K for ethyl hexanoate. Results of the vapour pressures were correlated using Antoine’s, extended Antoine’s and Wagner’s equations. Relative root mean square deviations were lower than 0.38% and 0.94% for ethyl butyrate and ethyl hexanoate, respectively. Experimental data of dibutoxymethane showed reasonable consistency with the information available in the literature. The vaporisation enthalpies were evaluated using the Clapeyron equation, together with the Virial equation of state to estimate the vapour compressibility factor, as well a correlation for saturated liquid molar volume. The results for both esters were comparable with data from the literature.