|
Abstract
|
Excess molar enthalpies, DHm E , for the binary mixtures of butyl acetate ? 1- alkanols, namely (methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, and 1-hexanol), were measured over the whole range of composition at 298.15 K using a Parr 1455 solution calorimeter. The excess partial molar enthalpies, DHm,i E , were calculated from the experimental excess molar enthalpies using the Redlich–Kister polynomial equation. The sign of DHm E for all systems are positive because of the disruption of hydrogen bonding and dipole–dipole interactions in the alkanols and esters, respectively. The magnitude of the DHm E values increases with increasing alkyl chain length. The behavior of DHm E was analyzed in terms of the length of the alkanol chain, the nature and type of intermolecular interactions and the balance between positive and negative effects on deviations from ideality. The experimental excess molar enthalpy data have also been correlated using the Redlich–Kister and SSF equations and two local composition models (UNIQUAC and NRTL).
|