Microcalorimetry and high-performance liquid chromatography have been used to conduct a thermodynamic investigation of the following reactions: 1,4--D-xylobiose(aq) + H2O(l) = 2 D-xylose(aq), (1) 1,4--D-xylotriose + 2 H2O(l) = 3 D-xylose(aq), (2) D-maltose(aq) + H2O(l) = 2 -D-glucose(aq), (3) D-cellobiose(aq) + H2O(l) = 2 -D-glucose(aq). (4) The results of the equilibrium measurements were K = (1.46 ± 0.15)∙103 for reaction (1) and K = 551 ± 34 for reaction (3). Although it was not possible to measure a value for the equilibrium constant for reaction (4), it was possible to obtain the value K = 657 for this reaction via a thermochemical cycle calculation. Selected property values from this reaction catalog were then used to calculate best values of the standard molar Gibbs free energy of formation fGm, the standard molar enthalpy of formation fHm, the standard molar entropy Sm, and the standard molar heat capacity Cp,m for the substances of interest to this investigation.
Citation: Journal of Chemical Thermodynamics
Pub Type: Journals