DENSITY AND SPEED OF SOUND VARIATION WITH TEMPERATURE FOR THE TERNARY MIXTURE METHYL TERT-BUTYL ETHER + 1-BUTANOL + N-DECANE

MASCATO E.; MARIANO A.; POSTIGO M.; PIÑEIRO M. M.; VIJANDE J.; LEGIDO J. L.

Morelia, Mexico

Conferencia; VII Iberoamerican Conference on Phase Equilibria and Fluid Properties for Process Design; 2006

Multicomponent mixtures including ethers, alkanes and alkanols have been studied for several authors, because the use of alkanol and branched ethers as oxygenating agents for fuels has lead to an increasing interest in the thermodynamic properties of this type of systems. These mixtures may be used as gasoline additives for octane enhancing and pollution reducing effects. Despite previous studies that stated that methyl tert-butyl ether might produce underground water pollution, recent results show that bioremediation processes for this substance are not completely understood yet, which might lead again to their practical use. In addition, thermodynamic properties of these mixtures are of interest in order to characterise the hydroxyl and ether functional groups specific interactions. This work reports densities (r) and speeds of sound (u) at temperatures from 288.15 to 308.15 K, and excess molar enthalpies (hE) at 298.15 K, for the system methyl tert-butyl ether (MTBE) + 1-butanol + n-decane. From experimental data, excess molar volumes (VE) and excess isentropic compressibility (ksE) were calculated. Information about chemical and intramolecular effects can be obtained from excess molar volumes, and excess enthalpies, while the derived excess isentropic compressibilities reflect lower energy effects (intermolecular and packing phenomena). The results were analyzed in terms of the molecular interaction between the components of the mixtures. Finally, experimental excess enthalpies results are compared with the estimations obtained by applying the group-contribution models of UNIFAC and DISQUAC.