Densities at 30-150 degrees C and pressures to 3000 bar are reported for et
hane, n-pentane, n-pentane-d(12), n-pentane-d(12) + 25.5 wt % ethane, and m
ixtures of poly(ethylene co-butene) (PEB) in ethane, and FEB in n-pentane,
in n-pentane-d(12), and in an n-pentane-d(12) + 23.1 wt % ethane mixture. T
he density data are measured with a high-pressure variable volume cell adap
ted with a linear-variable differential transducer. A detailed comparison i
s performed for the experimentally measured densities obtained in this work
to experimental data available in the literature and to correlations repor
ted in the literature for n-pentane. The experimental densities reported in
this work have an estimated experimental uncertainty of 1.0-1.5%.