DETERMINATION OF THERMODYNAMIC FUNCTIONS OF SORPTION FOR CYCLOHEXYL-N-ALKANES, PIPERIDYL-N-ALKANES, MORPHOLYL-N-ALKANES, AND THIOMORPHOLYL-N-ALKANES BY CAPILLARY GAS-LIQUID-CHROMATOGRAPHY

The values of partial molar free energy (Delta G), enthalpy (Delta H), and entropy (Delta S) of sorption in the homologous series of N-alkyl piperidines, N-alkylmorpholines, N-alkylthiomorpholines, and alkylcycl ohexanes were determined. It was found that the free energy of sorptio n is determined to a greater extent by the enthalpy term than by the e ntropy one. The free energy of sorption of the first homolog decreases when the n-alkyl chain is attached directly to the carbon atom of the cycle and increases in the case of N-alkylsubstituted heterocycles. T he influence of the heteroatom nature on intermolecular interactions o f homologs with the nonpolar stationary phase was quantitatively estim ated on the basis of thermodynamic data.