A THERMODYNAMIC STUDY OF MOLECULAR ASSOCIATION BY GAS-LIQUID-CHROMATOGRAPHY

Of two gas-liquid chromatographic methods, the one developed by Martir e and Riedl has been used to study thermodynamic parameters of associa ted systems and the results with four donors and seven acceptors are p resented. The donors pre cetyldimethylamine (CDA), tri-n-octylamine (T OA) dilauryl ether (DLE) and dilauryl thioether (DLTE) and accepters a re ethanol, two propanols and four butanols. It has been found that gl c method is as competent as any other standard method for measuring in teraction of molecular association and the data obtained are systemati c. The magnitude of the equilibrium constants for any particular syste m determined by glc method is somewhat larger and with different metho ds (such as calorimetry), magnitudes Pre different but tile enthalpies of formation of molecular association are obtained close to each othe r indicating that the latter is less affected by side-effects. It has been concluded, therefore, that the enthalpies measured are more relia ble and have been subjected to Drago's double-scale equations to compu te the average electrostatic and covalent contributions.