The enthalpies of dissolution in water at infinite dilution (i.d.) of propanal, butanal, 2-methylpropanal, pentanal, and 2,2-dimethylpropanal were measured by isothermal calorimetry at T = 298.15 K. The enthalpies of solution in water were derived by subtracting the enthalpies of the hydration reaction at 298.15 K from the measured enthalpies of dissolution. The values obtained were combined with the standard enthalpies of vaporisation to obtain the corresponding enthalpies of solvation at i.d. The CH2 group contribution to enthalpies of solvation at i.d. in water for linear aliphatic aldehydes was (-3.4 +- 0.5) kJ * mol-1 in good agreement with the average value obtained for a large number of organic compounds containing linear alkyl chains. The simple additive method adopted to estimate the molar enthalpy of solvation at i.d in water for the CHO functional group and its internal CO group gave (-28.1 +- 1.5) kJ * mol-1 and (-22.5 +- 1.5) kJ * mol-1, respectively. The enthalpies of solvation in heptane of linear and branched aldehydes with 3 to 11 C atoms were obtained using our earlier enthalpies of solution at i.d. and T = 298.15 K and recent experimental enthalpies of vaporisation from literature. Methylene group contribution to enthalpies of solvation at i.d.for linear aliphatic aldehydes in heptane was (-4.8 +- 0.1) kJ * mol-1. Enthalpy of transfer from heptane to water for CH2 group was (2.1 +- 0.4) kJ * mol-1.
Compounds
#
Formula
Name
1
C5H10O
pentanal
2
C4H8O
butanal
3
C5H10O
2,2-dimethylpropanal
4
C4H8O
2-methylpropanal
5
H2O
water
6
C3H6O
propanal
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.