Molar excess volumes of binary liquid mixtures: 2-pyrrolidinone with C-6-C-10 n-alkanols

The excess volumes V-E Of the binary mixtures 2-pyrrolidinone - (C-6-C-10) n-alkanols have been calculated from density measurements over the whole composition range and the 298.15-318.15 K temperature range. The excess volumes were independent of temperature, but changed noticeably with the chain length of the alkanol. The V-E values were only positive starting from heptanol, with the maximum value, 0.239 cm(3) mol(-1), for equimolar decanol. The observed changeover V-E <0 to V-E >0 suggests that the steric effect is primarily responsible for the positive contributions to V-E. The thermal expansion coefficients alpha were evaluated from the variation af densities with temperature.