Changes in permittivity and density of molecular liquids under high pressure.

We collected and analyzed the density and permittivity of 57 nonpolar and dipolar molecular liquids at different temperatures (143 sets) and pressures (555 sets). No equation was found that could accurately predict the change to polar liquid permittivity by the change of its density in the range of the pressures and temperatures tested. Consequently, the influence of high hydrostatic pressure and temperature on liquid permittivity may be a more complicated process compared to density changes.

Compressibility of liquids. Rule of noncrossing V-P curvatures.

Weight analysis of the liquid introduced into the stainless steel bomb under pressures up to 1 kbar in the temperature range of 20-50 degrees C at the interval of 10 degrees C was performed for 1,4-dioxane, acetonitrile, toluene, ethyl acetate, chlorobenzene, and n-hexane. The coefficients of the Tait equation were determined for all of the solvents at each temperature. There was a clear linear relation between the tangent bulk modulus (1/beta T) at atmospheric pressure (1 bar) and the secant bulk modulus at 1 kbar; 1/betaT=0.