Experimental results of and for binary mixtures (propylbenzene + an alkane or + an alkyl ethanoate)

Abstract

This article presents an experimental and theoretical contribution on binary mixtures alkylbenzene + alkanes or + alkylethanoates as a continuation of an investigation project on liquid mixtures containing aromatic compounds and a second component. So, excess molar enthalpies at T = 298.15 K and excess molar volumes at T = 298.15 and 318.15 K for a set of 11 binary mixtures formed by propylbenzene and alkanes (C₇ to C₁₆) and alkyl ethanoates (methyl to butyl) are presented. All systems studied showed endothermic effects increasing regularly the in mixtures with alkanes as the aliphatic hydrocarbon chain-length increases, however, in mixtures with ethanoates both excess properties decrease with the increase of the ester molecular weight. The s result positive in mixtures with all alkanes except with heptane and also with all alkylethanotes except with butyl ethanoate which present a sigmoidal representation. An increase in temperature produces in mixtures containing heptane and hexadecane and a almost null slope in the remain mixtures. However, the variation in mixtures with alkyl ethanoates is positive for methyl ethanaote changing to negative from ethyl. Experimental values for all systems are correlated with a suitable parametric equation which is function of the so-called active fraction. Finally, two known versions of the UNIFAC group contribution model are applied to our mixtures, giving acceptable results for all mixtures studied when one of the versions is used.

Keywords:

• Excess enthalpy
• Excess volumes
• Alkane
• Propylbenzene
• Ethanoates
• UNIFAC

Acknowledgment

The authors thank the Ministerio Educación y Ciencia of Spain for funding this work via project CTQ2006-12027.