Excess molar enthalpies of the ternary systems (acetonitrile plus methyl isobutyrate plus toluene) and (propionitrile plus methyl isobutyrate plus ethylbenzene) at 298.15 K

Excess molar enthalpies were measured at 298.15 K with a flow calorimeter built in our laboratory for the two ternary systems (acetonitrile+methyl isobutyrate+toluene) and (propionitrile+methyl isobutyrate+ethylbenzene). Experimental data were nicely predicted by some empirical and semiempirical procedures, exception made for UNIFAC group contribution method. The latter equation proved unsatisfactory for all mixtures containing methyl isobutyrate. The first ternary set proved a good model system to simulate mixing enthalpies reported in the literature for mixtures of poly(styrene-co-acrylonitrile) with polymethylmethacrylate.