Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

The vaporization enthalpies of a series of esters used commercially as flavor ingredients are reported as are their vapor pressures over the temperature range T/K = (298.15 to TB). Vaporization enthalpies and vapor pressures at T = 298.15 K (Dgl Hm(298.15)/kJ mol 1, p/Pa) for 3-methyl-2-butenyl acetate (47.8 +- 1.5, 468 +- 7.2), trans trans 2,4-hexadienyl acetate (54.7 +- 1.4,89 +- 1.5), ethyl 2-methylpentanoate (48.4 +- 1.5,410 +- 42), cis 3-hexenyl propionate (55.7 +- 1.0,66.2 +- 3), allyl hexanoate (55.2 +- 1.6,81.9 +- 10), pentyl butyrate (53.6 +- 0.6,109 +- 1.1), isoamyl isobutyrate (51.7 +- 1.6,180 +- 20), phenethyl acetate (61.3 +- 1.3,13.2 +- 0.2), cis-3-hexenyl butyrate (59.9 +- 1.7,25.7 +- 2.2), cis 3-hexenyl 2-methylbutyrate (61.5 +- 0.6,15.3 +- 1), ethyl cinnamate (70.4 +- 1.4, 1.5 +- 0.03), phenethyl propionate (65.6 +- 1.6, 4.8 +- 0.09), cis-5-octenyl propionate (65.3 +- 1.6, 7.0 +- 0.1), heptyl butyrate (65.1 +- 1.1, 7.8 +- 0.05), phenethyl butyrate (69.7 +- 1.4, 1.9 +- 0.4), linalyl acetate (62.5 +- 0.6,12.2 +- 0.2), citronellyl acetate (67.8 +- 1.8, 4.0 +- 0.4), and phenethyl hexanoate (78.8 +- 1.5,0.23 +- 0.005) have been evaluated by correlation gas chromatography experiments. The vaporization enthalpies of the esters studied are reproduced within +-2.0 kJ mol 1 using a simple additivity scheme. Constants for a third order polynomial are reported which reproduces vapor pressures and predicts normal boiling temperatures to within T = 3.0 K.