The vaporization enthalpies and vapor pressures of acetoin, ethyl 3-hydroxybutyrate and ethyl 3-hydroxyhexanoate, found in a variety of foods and flavors, are evaluated at T = 298.15K using correlation-gas chromatography; values of (48.7+-0.4), (55.9+-0.6) and (61.9+-0.6) kJ mol-1, respectively, were obtained. These values are in good agreement with estimated values.Vapor pressures of the standards as a function of temperature were also used to calculate vapor pressures of the target compounds and all resulting data were fit to second order polynomials. These polynomials were then used to predict boiling temperatures of both standards and target substances. Agreement with experimental boiling temperatures was generally within 10K suggesting that vapor pressures are accurate to within a factor of two. Acetoin exists as an equilibrium mixture of monomer and dimer. This report provides an example of the utility of using correlation-gas chromatography to obtain thermochemical data on an impure material.
Compounds
#
Formula
Name
1
C4H8O2
2,3-butanolone
2
C6H12O3
ethyl 3-hydroxybutanoate
3
C8H16O3
ethyl 3-hydroxyhexanoate
Datasets
The table above is generated from the ThermoML associated json file (link above).
POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied;
the numbers refer to the table of compounds on the left.
Type
Compound-#
Property
Variable
Constraint
Phase
Method
#Points
POMD
1
Molar enthalpy of vaporization or sublimation, kJ/mol ; Liquid
Temperature, K; Liquid
Liquid
Gas
GC correlation
1
POMD
1
Vapor or sublimation pressure, kPa ; Liquid
Temperature, K; Liquid
Liquid
Gas
GC correlation
7
POMD
2
Molar enthalpy of vaporization or sublimation, kJ/mol ; Liquid
Temperature, K; Liquid
Liquid
Gas
GC correlation
1
POMD
2
Vapor or sublimation pressure, kPa ; Liquid
Temperature, K; Liquid
Liquid
Gas
GC correlation
7
POMD
3
Molar enthalpy of vaporization or sublimation, kJ/mol ; Liquid