Estimation of molar heat capacities in solution from gas chromatographic data.
The temperature dependence of retention data (retention or capacity factors) is measured for 35 aliphatic ketones and aldehydes as model compounds on a dimethylpolysiloxane stationary phase. A novel model is derived to determine the heat of solution and the solution molar heat capacities from the fits of the log natural of the difference of the retention factor and the column temperature (T) versus 1/T and the temperature arrangement. The convex curvature present in the residual plots of a former defined equation of ours disappears when applying a newly defined model. A detailed statistical analysis clearly shows the superiority of the refined model to the earlier one in a broader temperature range. The validation of this model is made through a comparison of heat capacity values taken from literature determined by different methods. The molar heat capacity of a pure liquid oxo compound is similar to that of when the same compound is solvated in a stationary phase.
Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences, Budapest. heberger@chemres.hu
K
K
Héberger
M
M
Görgényi