Dependence of solution thermodynamic functions on the character of the hetero-atom in sulfur- and oxygen-containing compounds
1. 
 
Substitution of an oxygen atom by a sulfur in aliphatic and cyclic ethers and aromatic heterocycles brings about a uniform increase in the energy of dispersive interaction, this being the thermodynamic basis for analogies in the GC behavior of S- and O-containing compounds. 
 
 
 
 
2. 
 
A simple method for calculating differences of differential molar free energies of solution δ(ΔG)ij from retention indices has been proposed and used to give a quantitative description of the differences in GC behavior of the compounds under discussion here.